Seat Elevation Systems as an Accessory to Power Wheelchairs (Group 3)

The Centers for Medicare & Medicaid Services (CMS) finds that power seat elevation equipment on Medicare-covered power wheelchairs (PWCs) falls within the benefit category for durable medical equipment (DME). This Benefit Category Determination (BCD) expands the scope of the proposed benefit category decision based on consideration of public comments on the proposed decision memorandum. Section 1861(n) of the Social Security Act (the Act) defines what items are considered to be DME and 42 CFR 414.202 provides additional details on the definition of DME.

After considering the public comments on the proposed decision memorandum, CMS is also expanding coverage beyond the proposed decision. CMS finds in this national coverage analysis that the evidence is sufficient to determine that power seat elevation equipment is reasonable and necessary for individuals using complex rehabilitative power-driven wheelchairs[1] when the following conditions are met:

1. The individual has undergone a specialty evaluation that confirms the individual’s ability to safely operate the seat elevation equipment in the home. This evaluation must be performed by a licensed/certified medical professional such as a physical therapist (PT), occupational therapist (OT), or other practitioner, who has specific training and experience in rehabilitation wheelchair evaluations; and,

2. At least one of the following apply:

In addition, the Durable Medical Equipment Medicare Administrative Contractor (DME MAC) has discretion to determine reasonable and necessary coverage of power seat elevation equipment for individuals who use Medicare covered PWCs other than complex rehabilitative power-driven wheelchairs.

See Appendices B and C for the NCD manual language. Revisions to Appendix C also include technical updates to the narrative background to reflect the current regulations at 42 CFR §§414.202, 414.114, and 414.240.

We are including responses to public comments in this final decision memorandum, consistent with §1862(l)(3) of the Act, in two sections of this decision memorandum. Section IV.B includes comment summary and responses for the Benefit Category Determination. Section VIII.B.7 includes comment summary and responses with respect to section 1862(a)(1)(A) of the Act.

TO: 	Administrative File:  CAG-00461N

SUBJECT: 	National Coverage Determination for Power Seat Elevation Equipment on Power Wheelchairs

DATE: 		May 16, 2023

I. Decision

The Centers for Medicare & Medicaid Services (CMS) finds that power seat elevation equipment on Medicare-covered power wheelchairs (PWCs) falls within the benefit category for durable medical equipment (DME). This Benefit Category Determination (BCD) expands the scope of the proposed benefit category decision based on consideration of public comments on the proposed decision memorandum. Section 1861(n) of the Social Security Act (the Act) defines what items are considered to be DME and 42 CFR 414.202 provides additional details on the definition of DME.

After considering the public comments on the proposed decision memorandum, CMS is also expanding coverage beyond the proposed decision. CMS finds in this national coverage analysis that the evidence is sufficient to determine that power seat elevation equipment is reasonable and necessary for individuals using complex rehabilitative power-driven wheelchairs[1] when the following conditions are met:

1. The individual has undergone a specialty evaluation that confirms the individual’s ability to safely operate the seat elevation equipment in the home. This evaluation must be performed by a licensed/certified medical professional such as a physical therapist (PT), occupational therapist (OT), or other practitioner, who has specific training and experience in rehabilitation wheelchair evaluations; and,

2. At least one of the following apply:

In addition, the Durable Medical Equipment Medicare Administrative Contractor (DME MAC) has discretion to determine reasonable and necessary coverage of power seat elevation equipment for individuals who use Medicare covered PWCs other than complex rehabilitative power-driven wheelchairs.

See Appendices B and C for the NCD manual language. Revisions to Appendix C also include technical updates to the narrative background to reflect the current regulations at 42 CFR §§414.202, 414.114, and 414.240.

We are including responses to public comments in this final decision memorandum, consistent with §1862(l)(3) of the Act, in two sections of this decision memorandum. Section IV.B includes comment summary and responses for the Benefit Category Determination. Section VIII.B.7 includes comment summary and responses with respect to section 1862(a)(1)(A) of the Act.

II. Background

Throughout this document we use numerous acronyms, some of which are not defined as they are presented in direct quotations. Please find below a list of these acronyms and corresponding full terminology:

ALS - Amyotrophic Lateral Sclerosis
ANSI - American National Standards Institute
ATP - Assistive Technology Professional
BCD - Benefit Category Determination
CDC - Centers for Disease Control and Prevention
CIPD - Chronic Inflammatory Demyelinating Polyneuropathy
CMS - Centers for Medicare & Medicaid Services
CVA - cerebrovascular accident
DME - durable medical equipment
EMG - electromyography
FDA - Food and Drug Administration
IBM - Inclusion Body Myositis
ICF - International Classification of Functioning, Disability and Health
ITEM - Independence Through Enhancement of Medicare and Medicaid Coalition
MAE - mobility assistive equipment
MRADL - mobility related activity of daily living
NCA - National Coverage Analysis
NCD - National Coverage Determination
OT - Occupational Therapist
PT - Physical Therapist
PWC - Power Wheelchair
RESNA - Rehabilitation Engineering & Assistive Technology Society of North America
SCI - spinal cord injury
SPT - sitting pivot transfer
UE - upper extremity
US - United States

According to the Centers for Disease Control and Prevention (CDC), 61 million adults in the United States live with a disability. A mobility device may be required to enhance the ability of persons to move about their homes, increasing participation and activity levels in daily tasks (Salminen, Brandt, Samuelsson, Töytäri and Malmivaara, 2009). In 2005, CMS established an algorithmic process to aid in the determination of the appropriate type and complexity of mobility assistive equipment that may restore a beneficiary’s ability to participate in mobility related activities of daily living (MRADLs) such as toileting, feeding, dressing, grooming, and bathing in customary locations in the home. The resulting National Coverage Determination noted that various mobility limitations impair the ability of beneficiaries to participate in one or more MRADLs in the home. These mobility limitations include ones that:  

Prevent the beneficiary from accomplishing the MRADLs entirely, or,

Place the beneficiary at reasonably determined heightened risk of morbidity or mortality secondary to the attempts to participate in MRADLs, or,

Prevent the beneficiary from completing the MRADLs within a reasonable time frame (NCD 280.3, 2005).

In the United States, 5.5 million adults use wheelchairs (Taylor, 2018). Even as wheelchairs may improve mobility, they may also produce harms to their users. For example, musculoskeletal pain as a result of the use of a wheelchair is very common. In one study, pain affected 50% of wheelchair users. The most common site of pain found was that of the upper extremity, and specifically the shoulder, with a prevalence of approximately 44% (Liampas et al., 2021). Some authors have attributed shoulder pain to the use of manual wheelchairs alone. However, in those who experience spinal cord injuries, it has also been documented that a similar prevalence of shoulder pain exists in power wheelchair users. The mechanism of injury to cause shoulder pain in the power wheelchair user may include previous propulsion of a manual chair, excessive use of the upper extremities in order to perform activities of daily living, ischial pressure relief, etc. However, it is also possible that repetitive transfers are among the causes of this discomfort in those who use power chairs (Jain, Higgins, Katz & Garshick, 2010). It has been reported that in long-term wheelchair users, transferring to nonlevel surfaces are among the activities that produce the highest level of shoulder pain (Rice et al., 2013).

Transfers are the act of maneuvering oneself into and out of the wheelchair to and from a variety of surfaces (e.g., bed, commodes, bathtubs) (Toro, Koontz & Cooper, 2013). By necessity, transfers must be accomplished in order to achieve mobility. It has been documented that transfers are performed on average 11-20 times per day by many active wheelchair users (Koontz, Bass, Cooper, 2015). In general, most transfers can be performed using seated or standing maneuvers, with the choice depending in part, on the individual’s functional capabilities (Mix & Specht, 2000).

Examples of seated transfers include an anterior/posterior transfer and a sitting pivot transfer (SPT) (Ellwood, 1982). The SPT is the most common transfer employed by users of wheelchairs for activities of daily living. It is utilized in transfers onto level and non-level surfaces. Other names for the SPT are depression, side-approach, or lateral transfers (Koontz, Toro, Kankipati, Naber, & Cooper, 2012).

During an SPT, the individual brings his/her/their buttocks forward towards the edge of the initial surface, places the feet in a stable position, leaves one hand on the initial surface (trailing) while placing the other hand on the target surface (leading). Then muscles in the arms are used to push up off of the surfaces and pivot the body about the feet, swinging the trunk over to land the buttocks onto the adjacent surface (Koontz et al., 2012). In individuals with spinal cord injuries, it has been documented that there is commonly a preferred direction of the transfer. However, individuals are likely to be proficient in transfers performed in both directions, as a preferred direction may not always be able to be accommodated within the environment (^bGagnon et al., 2009).

The SPT causes the individual to entirely or partially support themselves on their upper extremities (UEs) (Koontz, Bass & Kulich, 2021). However, the glenohumeral joint (shoulder) is not structurally designed for weight bearing as are the joints of the lower extremity. The glenoid, the socket for the humeral head, is shallow. The cartilage that surrounds it, the fibrous labrum, is the only structure available for the shoulder’s peripheral stability. The plane of the joint is vertical. During SPTs, the arms are in low angles of elevation, with the joint capsule loose and the reinforcing ligaments slack. Therefore, it is left to the shoulder muscles to provide joint stability. In doing so however, the forces generated can be the source of painful limitations to daily activities (Requejo et al., 2008). It has been reported that the intra-articular pressure in the shoulder during a wheelchair-to-bed transfer exceeds the mean arterial pressure by more than two and a half times, and that this pressure may be a factor that contributes to the high rate of musculoskeletal problems about the shoulder in individuals who are paraplegic (Bayley, Cochran & Sledge, 1987). As these forces may be applied in a repetitive manner throughout the day, any resultant impairment or injury may significantly and negatively impact the ability to perform activities of daily living, triggering a loss of independence and a decrease in quality of life (Rice et al., 2013).

Not all wheelchair transfers are performed from the seated position. Some users of wheelchairs are able to come to a standing position from a chair in order to perform a transfer. For those with disabilities, the sit to stand movement may be performed with numerous compensatory mechanisms and transfer techniques (Butler, Nene & Major, 1991; van der Kruk, Silverman, Reilly, & Bull, 2021). For example, a stand-pivot transfer may be used by individuals who can achieve and maintain standing for a short period of time. During this transfer, the individual arises from a seated to a standing position and pivots to an adjacent surface to sit down (Mix & Specht, 2000). Being so common, the effort to rise from a chair seat is often taken for granted. However, research has shown that standing from a seated position requires more leg strength and greater joint ranges of motion than walking or stair climbing (Klein, Talaty, Esquenazi, Whyte & Keenan, 2001).

Depending on circumstances, the difficulty of the act of sit to stand may be related to the development of shoulder pain and other symptoms of upper extremity overuse in people with lower extremity impairments and neuromuscular disorders as they use their upper extremities to compensate for leg weakness (Klein, Whyte, Keenan, Esquenazi & Polansky, 2000). For example, pushing on the chair arms has the effect of reducing joint moments[2] at the hip and knee, thereby reducing the muscular force necessary to accomplish the standing movement, and aiding in the accomplishment of the sit to stand task (Butler, et al., 1991). Given this information, it is interesting to note that in survivors of polio, the literature has described an association between lower extremity weakness and shoulder symptoms which could be detrimental to quality of life (Klein et al., 2000). This association in those who tend to increase their reliance on their upper extremities for mobility may not be surprising. In a more recent study of younger versus older adults, it was found that the older participants demonstrated significantly lower knee extensor and joint forces than the young when not using arm rests during a sit to stand activity. The older group were also found to have higher shoulder joint contact forces while using arm rests, suggesting a change in movement strategies as lower extremities naturally weaken with age (Smith, Reilly & Bull, 2020). This tendency to compensate for weakness by using other parts of the body could over time make everyday activities more susceptible to age-related (and disease-related) functional decline and may leave the individual vulnerable to injury without the ability to transfer into and out of a mobility device.

Some individuals believe that power seat elevation equipment may mitigate these transfer related challenges for those who use a power wheelchair. A power seat elevation device is equipment that raises and lowers users of wheelchairs while they remain in the seated position. The device uses an electromechanical lift system to provide varying amounts of vertical seat to floor height. It does not change the seated angles or the seat’s angle relative to the ground. Other terms used to describe this device include a power elevating seat (PES) and power adjustable seat height (PASH) (Schiappa et al., 2019). Various devices of this nature can raise the seat 10 - 12 inches from a standard height with user operated controls in order to either accommodate the variable heights of surfaces in the home (e.g. wheelchair, bed, toilet, etc.) and allow level transfers or provide a higher surface from which to initiate standing (Sonenblum, Maurer, Hanes, Piriano & Sprigle, 2021).

Besides transfers, it is possible that additional factors cause upper extremity injury in those who use wheelchairs. The most prevalent finding on magnetic resonance images in individuals with shoulder pain are abnormalities of the rotator cuff. While the etiology of rotator cuff disease is likely multi-factorial, mechanical compression of the rotator cuff tendons during shoulder motion is one mechanism that is thought to be a source of pain. Subacromial compression of the rotator cuff tendons is generally believed to occur during shoulder elevation motion and is defined as compression and abrasion of the bursal side of the rotator cuff against the underside of the corocoacromial arch (Lawrence, Schlangen, Schneider, et al., 2017).

There are many authors who believe that excessive use of the upper extremities in the performance of activities of daily living and other overhead upper extremity activities might be likely sources of shoulder pain for individuals who use wheelchairs (Paralyzed Veterans of America Consortium for Spinal Cord Medicine, 2005; Jain, Higgins, Katz & Garshick, 2010; Requejo et al., 2008). As with transfers, a power seat elevation system may alleviate some of the difficulties that arise due to the need to perform repetitive overhead reaching from standard wheelchair height seating.

III. History of Medicare Coverage

The Medicare National Coverage Determinations Manual (CMS Pub. 100-03), Chapter 1, Part 4, addresses coverage of items and medical equipment within the benefit category of DME. Section 280.1 of this manual, “Durable Medical Equipment Reference List,” provides a quick reference tool for determining the coverage status of certain items. Even if an item falls within the benefit category definition of DME, it cannot be covered under Part B if it is subject to a statutory exclusion or is not reasonable and necessary for diagnosis or treatment of an illness or injury, or to improve the functioning of a malformed body member.

CMS has issued several NCDs regarding DME and mobility assistive equipment. The Durable Medical Equipment Reference List (NCD 280.1) includes several specific items of mobility assistance equipment that may be covered and especially for those items commonly referred to by both brand and generic names. Also, NCD 280.3 (effective 2005) established reasonable and necessary requirements for “mobility assistive equipment” (MAE), including some items that have been classified as DME since the Medicare program began.

The most recent BCD NCD related to MAE was issued on July 26, 2006 for a product called the Independence iBOT 4000 Mobility System (iBOT). NCD 280.15 (effective 2006) addresses coverage of specific power wheelchair functions for the iBOT, including stair climbing, the ability to operate on uneven terrain, and the ability to operate with the user in a seated position at an elevated height (described as a balance function). The NCA for this BCD NCD discusses the definition of DME, and states that equipment that is primarily and customarily used for nonmedical purposes may not be considered “medical” equipment for which payment can be made under the Medicare program, even if the item has some remote medically related use. The NCA concluded the iBOT seat elevation equipment/balance function was not primarily medical in nature because seat elevation serves the same purpose as other equipment that assist all persons in reaching items out of reach or having an “eye-level” conversation with a standing person.

CMS has not undertaken a significant review of these technologies in rulemaking or by an NCD since 2006.

A. Current Request

CMS received a formal request from the Independence Through Enhancement of Medicare and Medicaid (“ITEM’) Coalition and other supporting organizations, to reconsider National Coverage Determination (NCD) 280.3, Mobility Assistive Equipment in order to establish a benefit category for power seat elevation equipment in Group 3 PWCs and to include coverage of same for certain beneficiaries. Upon accepting this request, we believed it appropriate to consider both the benefit category and coverage of power seat elevation equipment on PWCs in a unique BCD NCD. The formal request letter can be viewed via the tracking sheet for this NCA on the CMS website at https://www.cms.gov/medicare-coverage-database/view/ncacal-tracking-sheet.aspx?ncaid=309&ncacaldoctype=all&status=all&sortBy=status&bc=17

The formal request from the ITEM coalition also asked to reconsider benefit category and coverage for standing equipment associated with Group 3 PWCs. While CMS has accepted that request, because the evidence base for power seat elevation wheelchair equipment is distinct from that of power wheelchair standing equipment, it is outside the scope of this analysis. CMS will consider these items in a separate future National Coverage Analysis.

IV. Benefit Category Determination

Medicare is a defined benefit program. An item or service must fall within a benefit category as a prerequisite to Medicare coverage. Title XVIII of the Act governs the Medicare program. Under the Medicare program, the scope of benefits available to eligible beneficiaries is prescribed by law and divided into several main parts. Part A is the hospital insurance program and Part B is the voluntary supplementary medical insurance program. The scope of benefits under Part B is described in section 1832 of the Act. Section 1861(n) of the Act defines DME and lists durable medical equipment (DME) items. Section 1861(s) of the Act defines the term “medical and other health services.” Section 1861(n) of the Act specifically identifies wheelchairs as DME.

In addition to the statutory definition of DME, 42 CFR 414.202 of our regulations defines DME as equipment furnished by a supplier or a home health agency that meets the following conditions:

1. Can withstand repeated use.
2. Effective with respect to items classified as DME after January 1, 2012, has an expected life of at least 3 years.
3. Is primarily and customarily used to serve a medical purpose.
4. Generally is not useful to an individual in the absence of an illness or injury.
5. Is appropriate for use in the home.

For items to be considered DME, all five criteria of the definition must be met. The CMS policies for determining whether an item meets the definition of DME are further outlined in the Medicare Benefit Policy Manual (CMS Pub. 100-02), Chapter 15, Section 110.1.

• In evaluating whether the first two criteria are satisfied, we will consider an item to be durable if it can withstand repeated use (i.e., the equipment can be rented and used by successive patients) and has an expected life of at least 3 years.
• Under the third and fourth criterion, equipment is considered to be medical equipment if it is primarily and customarily used to serve a medical purpose and generally is not useful to a person in the absence of an illness or injury. Equipment that is primarily and customarily used for a nonmedical purpose may not be considered “medical” equipment for which payment can be made under the Medicare program, even if the item has some remote medically-related use.
• Finally, under the fifth criteria, the equipment must be appropriate for use in the home.

Additionally, the Medicare Benefit Policy Manual (CMS Pub. 100-02), Chapter 16, Section 20, describes the general exclusions from Medicare coverage.

CMS uses the definitions in the Act and our regulations, as well as other established policies, to determine if an item or service falls within one or more Medicare benefit categories. Medicare payment is contingent upon a determination that an item or service falls under a benefit category, is not specifically excluded from coverage, and is “reasonable and necessary,” as required by section 1862(a)(1)(A) of the Act. In conducting our analysis of whether an item or service falls within the DME benefit category, CMS reviews the functions and features of the item or service, as well as applicable research and clinical studies that demonstrate how it meets the definition of DME, and serves a medical purpose.

Historically, Medicare has covered power-operated wheelchairs as DME, but if the wheelchair includes other enhancing features, such as 4-wheel drive, Medicare has limited its coverage only to the wheelchair, since the enhancing features do not serve a medical purpose or are generally inappropriate for use in the patient’s home (and, thus, are not DME).

A. Benefit Category Evidence

Our analysis of diagnosis codes reported on Medicare claims for Group 3 PWCs in 2019-2022 shows that the majority of users of Group 3 PWCs are diagnosed with conditions that include but are not limited to Parkinson’s Disease, Multiple Sclerosis, Cerebral Palsy, Paraplegia (unspecified), Quadriplegia, Post-Polio Syndrome, and Amyotrophic Lateral Sclerosis (ALS). For those individuals who qualify for coverage of a Group 3 PWC, coverage of the additional seat elevation equipment can only be made if the equipment falls within a Medicare benefit category (i.e., DME), and is determined to be reasonable and necessary.

Similar to individuals with Medicare who use Group 3 PWCs, some individuals who use Group 2 PWCs face the same obstacles with non-level transfers. The top diagnoses for those using Group 2 PWCs in 2019-2022 were acquired absence of limb (amputation), pressure ulcer, chronic obstructive pulmonary disease (COPD), and congestive heart failure (CHF) respectively. While the majority of non-Group 3 wheelchair users have medical conditions that still permit full weight bearing activity, some users may have conditions such as myositis, lupus and rheumatoid arthritis or have amputations with comorbid conditions that may require them to use their devices as the primary means of mobility in their homes. As these aforementioned patients (e.g., myositis, lupus, rheumatoid arthritis, amputations) become reliant on their wheelchairs as the sole means of mobility, it is expected that they will use their upper extremities to bear weight and face the same obstacles as those patients in Group 3 PWCs.

As noted in Section II (Background), transfers are the act of maneuvering oneself into and out of the wheelchair to and from a variety of surfaces (e.g., bed, commodes, bathtubs) (Toro, Koontz & Cooper, 2013). For individuals requiring routine use of mobility assist devices, it is the primary means by which all other mobility activities of daily living is achieved and can range on average of 11-20 times per day (Koontz, Bass, Cooper, 2015). Without the ability to transfer effectively, users would be unable to access their mobility devices to initiate certain MRADLs or partake in those activities that can affect improvement in their conditions (Selph et al., 2021, Haas et al, 1998, Majmudar et al, 2014). The inability to transfer effectively could lead to deterioration of a patient’s underlying condition and expose them to the well documented risks of prolonged immobility.

While often described by users as gateways to independence, transfers are also described as one of the activities that produce the most pain in individuals who use wheelchairs long term (Daylan, Cardenas-1999). In addition, the transfer process can be risky with transfers accounting for 51% of falls in patients with spinal cord injuries and multiple sclerosis in one study (Sunga et al., 2019). Transfers have also been found to be the most frequent cause of falls in patients with MS (Rice et al., 2017) and are the second most common cause of falls in users of wheelchairs presenting to an emergency department (Xiang et al, 2006). In addition to producing traumatic injury, these falls can lead to additional immobility as the result of a voluntary decrease in activity due to a fear of falling (Sunga et al., 2019, Rice et al., 2017, Barbareschi, Cheng 2018).

Numerous intrinsic and environmental factors contribute to the difficulties faced when users of wheelchairs attempt transfers. Intrinsic factors include the user’s underlying medical condition such as preexisting neuromuscular disorders, comorbidities, muscular strength, spasticity, level of fatigue, body habitus, training skills, and cognitive abilities that can impact their ability to transfer effectively (Desroches et al., 2013). With regards to environmental factors, the International Classification of Functioning, Disability and Health (ICF) provides a framework for discussing health and disability for persons who use wheeled mobility devices (WHO-2002). The ICF defines environmental factors as all external factors that influence participation either as barriers or facilitators and includes features within the natural and built environment (WHO-2002). The built environment would include those in a user’s home including the height of the surfaces required to move to/from on a daily basis.

One of the most significant tasks and impediments that users must confront daily is the non-level transfer where there is a vertical height differential between the user’s wheeled mobility device and the surface they are transitioning to. One example is the differential between average bed height (24 inches), and the average static height of a wheelchair (19 inches). Depending on a user’s circumstances, this would imply several uphill transfers during the course of a day. While this differential may seem surmountable to some and falls within the current Americans with Disabilities Act guidelines of 8 inches, it may also present a significant impediment for those who lack the physical capacity or the additional assistance to perform the task. Large gaps in height and width are reported as one of the most common difficulties users of wheelchairs face in the built environment (Barabarsechi et al., 2020). A height differential of only 1-2 inches (2.54cm-5.08cm) may be challenging or impossible for some users to perform (Gagnon et al., 2009).

A recent study (Koontz et al., 2021) of 112 users demonstrated that the majority of daily transfers occurred in a non-level manner and that 90.5% of participants viewed transferring from their wheeled mobility device to a higher surface as a limiting factor. A smaller observational study by Barbareschi et al. in 2022 of 13 users with above level transfer ability found their self-described ability to transfer was significantly lower for non-level transfers performed between surfaces featuring gaps of 5-15cm when compared to level transfers.

The largest study was performed by Toro, Koontz, et al. in 2013 and involved 120 users of wheeled mobility devices with underlying conditions such as stroke, spinal cord injury, cerebral palsy, multiple sclerosis, ALS, and lower extremity amputation. Study participants were asked to transfer from their personal wheeled mobility devices to a custom-built station that had featured adjustable differentials in height, gap width, and obstacles such as arm rests to resemble commonly encountered environmental transfer situations. Results showed that the easiest transfer height (95% percentile) achieved occurred when the target height was close to the level of the participants’ wheeled mobility device, 55.9cm and 56cm respectively. This illustrates that transfers are best achieved when the height of the user’s wheeled mobility device is similar to the target height; in other words, level. With an average seat height of 56cm, the study found that the target should range from 54.4cm to 55.9cm in order to meet the 95th percentile needs of users when there are no gaps or obstacles present. Conversely, users had a more difficult time when trying to access larger gaps in height differential when obstacles were present. When grab bars were installed, some participants were able to overcome the height differential. Unfortunately, many users of wheeled mobility devices may lack the financial means or ability to add these aids to their personal living environment. These findings are in line with the findings in prior studies (Barbareschi et al, 2022, Koontz et al., 2012 and Gagnon 2005).

In order to perform non-level transfers, users must use a variety of techniques such as the side pivot transfer. The side pivot transfer requires the user to push off with their arms and pivot the body about the feet, swinging the trunk onto the target surface. This requires significant use of the upper extremities making the integrity of the arms and shoulders paramount to a successful transfer.

Users of wheelchairs long term reported that the greatest degree of shoulder pain occurred when performing non-level transfers (Curtis and Roach 1995) while one recent study (Barabareshci and Holland 2019) found that 66% of subjects felt that transfer activity exacerbated their underlying shoulder pain. Patients with spinal cord injury frequently suffer from chronic pain resulting from long term use of the upper extremities for weight bearing and the daily demands of mobility propulsion (Brose et al., 2008, Liampas et al., 2021). Users with neuromuscular disorders such as multiple sclerosis, ALS and inclusion body myositis (IBM) often experience upper extremity dysfunction. While lower extremity instability is a hallmark of multiple sclerosis, upper extremity dysfunction may also be present in the form of spasticity, ataxia, tremor, sensory loss, weakness and pain (Bertoni et al., 2015). Patients with inflammatory myopathies such as IBM experience progressive arm weakness while the presence of isolated shoulder weakness has been proposed as a new diagnostic feature of ALS (Hamada et al., 2022).

In addition to those with Group 3 PWCs, beneficiaries who use non-Group 3 PWCs may also need to use their shoulders in performing non-level transfers to/from their devices as their underlying conditions progress. Studies have shown that some patients with rheumatoid arthritis, inclusion body myositis, and amputations who use non-Group 3 wheelchairs can decline to the point where they may require wheelchairs for full time mobility. A 5 year follow up study of 732 patients (Young, et al.,2000) with rheumatoid arthritis found that 10% of participants had progressed to requiring wheelchair use and/or home adaptations. Inclusion body myositis classically presents as proximal lower extremity weakness and/or distal arm weakness. In a long-term European study (Benveniste, et al., 2011) of 136 patients found that after a median duration of 14 years from the onset of symptoms, 37% were using wheelchairs. A study of military veterans from the Vietnam-era and recent conflicts with traumatic limb loss (Laferrier, et al. 2010) found that more than half of individuals with lower limb loss used their wheelchairs for mobility despite prosthetic training and years of prosthetic use. The highest rate of prosthetic abandonment occurred in those with transfemoral amputations. A smaller long-term study of Vietnam era veterans (Dougherty 1999) with bilateral transfemoral amputations found that only 22% utilized their prosthetic devices for walking. Elderly persons who have amputations may experience frailty in addition to having comorbid conditions such as cardiovascular disease, and end stage renal disease that make functional ambulation difficult due to its physical demands. A single center retrospective cohort study (Chopra, et al.,2018) found that only 46% of patients who received major lower extremity amputations for vascular disease were ambulatory one year following their procedures. A literature review (Fortington, et al., 2012) found that only 20% of elderly persons with lower extremity amputations were able to maintain household ambulation with their prosthetics long term.

Shoulder pain is a common occurrence for persons with lower extremity amputations (Morgan, et al., 2017). In a survey of 255 persons with lower extremity amputations (Ehde, et al., 2000) that included a significant amount of transfemoral amputations, 31% of respondents described persistent shoulder pain. In a study of female users of wheelchairs who played basketball (Curtis, et al., 1999), those with lower extremity amputations averaged a higher shoulder index pain score (WUSPI) twice that of other groups with conditions such as spine bifida and spinal cord injury.

A significant factor in the development of the shoulder pain and dysfunction described below is the degree of loading force experienced by the upper extremities during the transfer process. One study (Forslund et al., 2007), investigated the body and arm forces generated by SCI patients, during a non-level transfer of 7cm (2 inches) from a study platform to their personal wheelchair. Of note, the participants had no prior restrictions in their range of motion. The study found that the amount of weight experienced by the upper extremities constituted a significant percentage of their body weight. An early study (Wang et al., 1994) that measured upper extremity reaction forces in healthy volunteers who simulated non-level transfers found that the non-level transfer produced the greatest reaction forces while transfers to level or lower heights produced less force.

While non-level transfers serve as obstacles to users of wheelchairs, level transfers make the process easier by minimizing the strain on the upper extremity joints (Wang 1994, Toro 2013). One type of equipment that helps users perform a level transfer is a seat elevation device. A study (Sonenblum et al., 2021) of users of PWCs with seat elevation devices found that the majority of participants used their seat elevation devices to facilitate transfers in a level or downhill fashion.

B. Public Comment on Benefit Category

Public comments sometimes cite the published clinical evidence and give CMS useful information. Public comments that give information on unpublished evidence such as the results of individual practitioners or patients are less rigorous and therefore less statistically reliable for making a coverage determination.

CMS uses the initial public comments to inform its proposed decision. CMS responds in detail to the public comments on a proposed decision when issuing the final decision memorandum. All comments that were able to have personal health information redacted may be viewed in their entirety by using the following link https://www.cms.gov/medicare-coverage-database/view/ncacal-public-comments.aspx?ncaid=309&ncacaldoctype=all&status=all&sortBy=status&bc=17

Initial Comment Period:  August 15, 2022 - September 14, 2022

During the initial 30-day public comment period following the release of the tracking sheet, CMS received 3,601 timely comments. Of these 3,601 comments, 57 were not published on the CMS website due to extensive personal health information content; however, all comments that were in scope and timely were considered for this proposed decision. Seventy-eight comments only discussed topics that are outside the scope of this national coverage analysis. Of the 3,523 in-scope comments, 3,468 supported a benefit category determination of DME for seat elevation equipment for Group 3 PWCs. No commenters indicated an objection to a benefit category determination of DME and 55 commenters did not state a clear position regarding a benefit category determination of DME for seat elevation equipment.

Users of Group 3 wheelchairs and their caregivers support benefit category determination of DME for the seat elevation feature for wheelchair transfer purposes to move to and from the bed, toilet, shower, and vehicle. Users of wheelchairs and caregivers found the seat elevation feature useful and beneficial in preventing injuries, reaching items in the home to perform activities of daily living, and communicating with others using eye-to-eye contact. Patient advocacy organizations also support a benefit category determination of DME for seat elevation systems with Group 3 wheelchairs for transfer, reaching, communication purposes in order to foster a greater sense of independence for users of Group 3 wheelchairs.

The majority of comments were provided by users of wheelchairs, caregivers and other individuals. Comments were also provided by many advocacy organizations and individual advocates, professional societies and member organizations, state agencies, assistive technology and DME manufacturers and their employees, DME suppliers and their employees, health systems, hospitals, rehabilitation and other healthcare providers, as well as individual healthcare professionals, providers of home and community-based services, and other school and community professionals.

Many commenters provided references for our deliberation of this NCA. We very much appreciate this information. All such references were assessed for inclusion in our evidence review.

Second Comment Period:  February 15, 2023 - March 17, 2023

During the second 30-day public comment period, after the posting of the proposed decision memorandum, CMS received 2,133 timely comments, including one comment from an advocacy organization related to a neurological disease that included an attachment of comments from more than 500 of the association’s members representing individuals and caregivers/family of individuals. Of the 2,133 timely comments, 3 were not published on the CMS website due to extensive personal health information content; however, all comments that were in scope and timely were considered for this decision. Thirty comments only discussed topics that are outside the scope of this national coverage analysis. Of the 2,103 in-scope comments, the vast majority generally supported a benefit category determination of DME for power seat elevation equipment on PWCs. No commenters indicated an objection to a benefit category determination of DME for power seat elevation equipment; and 30 commenters did not state a clear position.

Most commenters also discussed other reasons that individuals use seat elevation equipment in addition to transfers. Many also submitted specific recommendations for CMS to make a benefit category determination of DME for power seat elevation equipment based on (1) performing reaching activities, and (2) improving line of sight for safety purposes.

Many commenters also discussed seat elevation with respect to reducing cervical spine strain and injury, reductions in strain, injury, time, cost, and/or burden to caregivers (paid and unpaid). The majority of commenters also discussed the physical and mental health or psycho-social benefits of conducting eye-level conversations and having vertical visual access to the world. Many described seat elevation equipment on PWCs as “vital”, “necessary”, “essential”, and not a “convenience item” or “luxury item.” Many spoke in both broad and specific terms about how PWCs and seat elevation equipment provide independence, safety for transfers and daily activities, meaning their use reduces falls and injuries or increases safe functioning in the home and community. Many commenters also discussed PWCs and seat elevation equipment in terms of access and participation in home activities, school, community and employment. Also, many of the commenters shared personal experiences using wheelchairs or shared their experiences as caregivers, family members, friends, neighbors, work and school colleagues and others in their communities. Finally, many commenters discussed the financial costs of PWCs, seat elevation equipment, other required equipment and/or home modifications.

The majority of comments were provided by users of wheelchairs, caregivers and other individuals. Comments were also provided by many advocacy organizations and individual advocates. In addition, many comments were provided by health care professional societies and member organizations, state agencies including state Medicaid agencies, assistive technology and wheelchair manufacturers and their employees, DME suppliers and their employees, health systems, hospitals, rehabilitation and other healthcare providers as well as individual healthcare professionals, providers of home and community-based services and other school and community professionals.

Many commenters provided references for our deliberation of this NCA. All such references were assessed for inclusion in our evidence review.

Comments and Responses:

General

Comment: We received many comments from individuals who use PWCs as well as their family members, friends, caregivers and advocates.

Response: We sincerely thank these commenters for openly sharing with us the challenges of their medical conditions. We have learned a great deal from these comments and are appreciative of the time and effort expended in providing comments. Many of the comments support the clinical literature reviewed by CMS.

Powered Wheelchair Groups

Comment: Many commenters requested that power seat elevation equipment on Group 2 PWCs be given a benefit category of DME. Some commenters requested that power seat elevation equipment on Group 4 and Group 5 PWCs be given a benefit category of DME.

Response: After careful consideration of comments, we have expanded the scope of the proposed benefit category decision to include power seat elevation as DME on all Medicare-covered PWCs, i.e., Groups 2, 3, and 5 (Group 1 PWCs are not able to accommodate seat elevation systems). Our final determination is that power seat elevation equipment used primarily by people with Medicare for assistance in transfers and reaching while in a Medicare-covered power wheelchair meets the Medicare definition of DME. We consider the power seat elevation equipment in these cases to be equipment necessary for the effective use of a power wheelchair classified as DME by section 1861(n) of the Social Security Act, and as such, the equipment necessary for the effective use of the DME would also fall within the benefit category for DME.

Note that HCPCS codes for Group 5 power wheelchairs were established to describe pediatric size PWCs for use for patients with a weight of up to 125 pounds which may be covered if it is determined that the PWC is reasonable and necessary for use in the home by the individual with Medicare. Therefore, seat elevation equipment could also be covered if it is considered reasonable and necessary for use with a Medicare-covered Group 5 power wheelchair.

HCPCS codes for Group 4 PWCs were established to describe PWCs which are not covered by Medicare because they have performance capabilities not needed for use in the home; therefore, seat elevation equipment, while classified as DME per this NCD, would not be eligible for coverage for use on a PWC base that is non-covered by Medicare.

BCD NCD Criteria

Comment:  Many commenters support the coverage of power seat elevation systems for Group 3 PWCs to carry out various activities outside of the home. Specifically, commenters provided numerous examples of how seat elevation equipment could be beneficial while shopping, crossing the street, accessing elevator buttons, traveling, dining in restaurants, providing child care, providing volunteer services, using public restrooms, and attending church services, concerts, and sporting events, etc. Also, commenters explained how seat elevation could be helpful while receiving medical care in clinical and diagnostic settings.

Response: While power seat elevation equipment may be useful in settings outside of the home, it is important to note that section 1861(n) of the Social Security Act defines DME as equipment used in the patient’s home. Whether or not the equipment serves a medical purpose outside the home is not a factor when determining if the equipment is DME for Medicare purposes. As explained in Section IV (Benefit Category Determination), 42 CFR §414.202 of our regulations outlines five criteria that must be met for equipment to be categorized as DME for Medicare purposes, one of which is that the equipment must be appropriate for use in the home. We have determined that power seat elevation equipment on PWCs meets all five criteria and thus is DME. If power seat elevation equipment on a power wheelchair is determined to be medically necessary for use by an individual with Medicare in their home, the individual may also use the equipment outside their home and for nonmedical uses within the home.

Comment: One commenter requested clarification for the definition of home with respect to DME.

Response: The definition of home refers to a Medicare beneficiary’s dwelling, apartment, relative’s home, home for the aged, or some other type of institution used as the patient’s home other than a hospital or a skilled nursing facility. This definition is provided in detail in Section 110.1 of Chapter 15 of the Medicare Benefit Policy Manual (CMS 100-02).

Comment:  Several commenters questioned the requirement that an item (i.e., power seat elevation on PWCs) must be for use in the home to be categorized as DME.

Response:  The statute defines the term “durable medical equipment” to include wheelchairs used in the patient’s home and prohibits payment for items which are not reasonable and necessary for the treatment of illness or injury or to improve the functioning of a malformed body member. Payment cannot be made for equipment which is not used for the treatment of illness or injury or to improve the functioning of a malformed body member in the home. Equipment which meets the Medicare definition of DME in regulations at 42 CFR §414.202 and is medically necessary for use by the individual with Medicare in the home may be covered as DME and used by the individual both inside and outside their home.

Comment: Many commenters requested that power seat elevation equipment on PWCs serves a medical purpose to aid individuals in performing reaching activities and thus the equipment should be given a benefit category of DME.

Response: After careful consideration of comments, our final determination is that power seat elevation equipment used primarily by people with Medicare for assistance in transfers and also for assistance in reaching while in a power wheelchair covered as DME meets the Medicare definition of DME. We consider the power seat elevation equipment in these cases to be equipment necessary for the effective use of a power wheelchair classified as DME by section 1861(n) of the Social Security Act, and as such, the equipment necessary for the effective use of the DME would also fall within the benefit category for DME.

Comment: Many commenters requested that power seat elevation equipment on PWCs serves a medical purpose to improve line of sight and thus the equipment should be given a benefit category of DME.

Response: We recognize that power seat elevation equipment on PWCs provides many benefits to the user, including that of improving line of sight. However, we believe that this is a common need among many persons and that if the primary purpose of the seat elevation function is to assist a patient in improving line of sight, then the function of that seat elevation would not be presumptively medical in nature. However, if power seat elevation equipment is also capable of assisting a user in making surfaces level for transfers in and out of the power wheelchair or in reaching from an elevated level, which evidence indicates may help eliminate or reduce shoulder pain and injury, such equipment can be considered DME when used on Medicare-covered PWCs.

Comment: Many commenters support designation of power seat elevation equipment for Group 3 wheelchairs as DME to provide safe and effective lateral wheelchair transfers to and from the bed, toilet and seating furniture in the patient’s home.

Response: We appreciate and agree with the supportive comments.

Comment: Many commenters discussed the role that power seat elevation equipment may play in mitigating neck pain.

Response: We reviewed two studies (Kovacs 2018, Llampas 2021) that illustrated that neck strain is common in users of wheelchairs, but both stated that it was multifactorial with other conditions such as seat cushion, seat angle, vibration and propulsion as other possible factors. A study (Kirby 2003) found that the most comfortable neck position was achieved when gazing forward with the neck slightly flexed. The researchers acknowledged that the results were limited by the small size (20), its heterogeneity and the variability of the data. The results of another study (Sabari 2016) used ambulatory participants and the researchers acknowledged it was difficult to generalize their findings to long term wheelchair use.

Other Comments

Comment: One commenter suggested that Medicare cover the seat elevation feature for manual wheelchairs (specifically, HCPCS code K0005 manual wheelchairs).

Response: This comment is out of scope of the NCA, which addresses power seat elevation on PWCs.

Comment: A few commenters have requested CMS to consider power seat elevation equipment as a power seat function similar to power tilt and power recline functions that require Medicare beneficiary protection. Additionally, commenters suggested that CMS consider a power seat function as a single power option and when other functions such as power tilt and power recline functions are combined, the whole unit will be considered as a multiple power option base. They explained that the single power wheelchair option or multiple options may change the power wheelchair’s center of gravity and affect the wheelchair’s performance and stability.

Response: These comments are out of scope because the NCA addresses the benefit category determination and reasonable and necessary criteria for power seat elevation on PWCs. We plan to address and seek public feedback on the HCPCS coding of powered seat elevation systems in an upcoming HCPCS Level II Public Meeting using the process outlined at 42 CFR §414.240. This process involves the posting of preliminary coding determinations for DMEPOS items and services on CMS.gov as part of the agenda for the HCPCS Public Meeting and Consultation Process. The agenda and timing for the public meetings are posted in advance of the meetings and are available at the following CMS website: https://www.cms.gov/Medicare/Coding/MedHCPCSGenInfo/HCPCSPublicMeetings.

Comment: Several commenters have stated that power seat elevation equipment may help to prevent family members, caregivers, physical therapists, and occupational therapist from injuring and straining themselves while transporting patients from the wheelchair to a bed, toilet, and seating furniture.

Response: These comments are out of scope. We recognize that power seat elevation on PWCs may also benefit an individual with Medicare’s support network. However, to determine whether an item or service can be classified as DME for Medicare, we determine whether it meets all five conditions stated in section IV (Benefit Category Determination) specifically as it relates to individuals with Medicare.

Comment: Several commenters questioned why the proposed NCD referred to the 2006 Benefit Category Determination NCD for the Independence iBOT 4000 Mobility System (iBOT) given that the NCD was established over 15 years ago. Commenters felt the iBOT determination was based on a different device that served a different purpose and older evidence that did not contemplate power seat elevation systems.

Response: We appreciate and have considered the comments, but continue to believe that the iBOT BCD NCD (NCD 280.15) is relevant and appropriate to cite in the history of Medicare coverage section of the proposed power seat elevation equipment NCA. CMS has reviewed current evidence for power seat elevation equipment, including that submitted as part of the formal request from the Independence Through Enhancement of Medicare and Medicaid (“ITEM”) Coalition and other supporting organizations, to reconsider NCD 280.3, in developing the proposed and final decision memos.

Comment: Several commenters provided recommendations around the HCPCS coding of power seat elevation equipment in terms of both new and existing coding so that the technology and the needs of the users would be recognized.

Response:  We thank the commenters for their input and suggestions; however, these comments are out of scope. We plan to address and seek public feedback on the HCPCS coding of powered seat elevation systems in an upcoming HCPCS Level II Public Meeting using the process outlined at 42 CFR §414.240. This process involves the posting of preliminary coding determinations for DMEPOS items and services on CMS.gov as part of the agenda for the HCPCS Public Meeting and Consultation Process. The agenda and timing for the public meetings are posted in advance of the meetings and are available at the following CMS website: https://www.cms.gov/Medicare/Coding/MedHCPCSGenInfo/HCPCSPublicMeetings.

Comment: Several commenters requested that we consider the establishment of appropriate payment amounts or perform a cost impact analysis on the utilization as part of the NCD for the power seat elevation equipment. Other commenters asked that we work with interested parties in considering changes to the payment and coverage requirements for PWCs to accommodate power seat elevation systems for beneficiaries with new and existing wheelchairs.

Response:  While we appreciate the comments, Medicare payment, payment methodology and implementation concerns are outside the scope of Medicare coverage under this NCA. We note that we intend to consider the coding and payment needed to implement this benefit at a future HCPCS Level II Public Meeting using the process outlined at 42 CFR §414.240. This process involves the posting of preliminary payment determinations for DMEPOS items and services on CMS.gov as part of the agenda for the HCPCS Public Meeting and Consultation Process. The agenda and timing for the public meetings are posted in advance of the meetings and are available at the following CMS website: https://www.cms.gov/Medicare/Coding/MedHCPCSGenInfo/HCPCSPublicMeetings.

C. CMS Benefit Category Analysis

Our analysis is based on whether power seat elevation equipment used on power-operated wheelchairs meets all criteria required under the definition of DME: (a) ability to withstand repeated use, (b) expected life of at least 3 years, (c) primarily and customarily used to serve a medical purpose, (d)generally not useful to a person in the absence of an illness or injury, and (e) appropriate for use in the home.

(a) Ability To Withstand Repeated Use
This criterion under 42 CFR 414.202 addresses the issue of whether an item of medical equipment can withstand repeated use, which means it is an item that can be rented and used by successive patients. Equipment must be able to withstand repeated use to fall within the scope of the Medicare Part B benefit for DME. Power seated elevation systems are durable equipment that are a component of a power wheelchair that is rented and used by successive patients to raise and lower the user while they remain in a seated position. Therefore, we believe this equipment meets the requirement to withstand repeated use; that is, equipment that could normally be rented and used by successive patients.

(b) Expected Life of at Least 3 Years
Power seat elevation equipment is a durable wheelchair component that CMS believes will typically be able to withstand repeated use for at least 3 years.

(c) Primarily and Customarily Used To Serve a Medical Purpose

Power seat elevation equipment is a wheelchair accessory that is added to a power wheelchair. The equipment assists an individual in transferring into and out of the Medicare-covered power wheelchair, thus reducing or eliminating shoulder pain and injury associated with repetitive transfers. It also elevates an individual to assist in performing reaching activities, thus reducing or eliminating shoulder pain and injury associated with repetitive reaching. Therefore, CMS considers power seat elevation equipment to be primarily medical in nature.

 For PWC users who must rely on their upper extremities to perform a transfer, the act of the transfer can place considerable strain on the upper extremities (Smith, Reilly & Bull, 2020). This results in musculoskeletal pain, most commonly in the upper extremities and more specifically in the shoulder area (Liampas et al., 2021; Klein, Talaty, Esquenazi, Whyte & Keenan, 2001; Klein, 2001). Those with long-term wheelchair use experience the highest level of shoulder pain when transferring to non-level surfaces (Rice et al., 2013). Furthermore, it appears that repetitive transfers are among the causes of shoulder discomfort in those who use power chairs (Jain, Higgins, Katz & Garshick, 2010).

CMS reviewed and considered the evidence detailed in both in Section VIII (Evidence to Evaluate a Reasonable and Necessary Determination) and Section IV.A (Benefit Category Evidence). Based on our review of the evidence, we believe that transferring from a higher/elevated height (i.e., performing a level or nearer-to level transfer) results in less stress and strain on upper extremities as compared to making a non-level transfer (Janssen, Bussmann & Stam, 2002; Munro & Steele, 1998; Burdett, Habasevich, Pisciotta & Simon, 1985; Finlay, Bayle, Rosen & Milling, 1983; Gagnon, Nadeau, Noreau, Dehail & Gravel, 2008; Gagnon, Nadeau, Noreau, Eng & Gravel, 2008; Gagnon, Nadeau, Noreau, Eng & Gravel, 2009). These results might further indicate that using power seat elevation equipment to perform a level transfer could decrease the potential of shoulder injury and pain for those who repetitively are faced with these obstacles.

As explained in Section IV.A (Benefit Category Evidence), individuals with Medicare who use Group 3 PWCs may have mobility limitations due to a neurological condition, myopathy, or congenital skeletal deformity. These medical conditions are such that, by necessity, the individual must perform repetitive wheelchair transfers for independence and/or mobility in the home over the long-term. Furthermore, these individuals have medical conditions such that they must rely on their upper extremities to perform the transfer. In addition, some individuals with Medicare who use PWCs other than Group 3 PWCs have or will become reliant on their wheelchairs as the sole means of mobility and thus must rely on their upper extremities to perform the transfers.

Regarding the role of power seat elevation in helping users of PWCs eliminate or reduce shoulder pain associated with reaching, as discussed in Section VIII (Evidence to Evaluate a Reasonable and Necessary Determination), individuals who use wheelchairs spend a considerable amount of time using their upper extremities to reach (Ding et al., 2008; Mesoros et al., 2022). They also spend a significantly higher percentage of time in humeral elevations (30˚-60˚) associated with compression of the rotator cuff than do those individuals who are not users of wheelchairs. Individuals who use wheelchairs also spend a larger part of their day using their upper extremity dynamically in the potentially painful humeral ranges of 60˚-90˚ and 90˚-120˚ as compared to those who do not use wheelchairs. These movement arcs match those required when reaching near or above shoulder height (Goodwin et al., 2021; Hastings & Goldstein, 2004). CMS reviewed this evidence and, based on our review, we believe that being able to elevate prior to reaching can help to avoid repetitively using upper extremities in potentially painful humeral ranges and thus can help to decrease the potential of shoulder injury and pain for users of PWCs repetitively faced with needing to reach.

Our analysis and review of the evidence support our conclusion that some individuals with Medicare who qualify for a power wheelchair can experience shoulder pain and injury associated with repetitive transfers and also with repetitive reach.

(d) Generally Not Useful to a Person in the Absence of an Illness or Injury
CMS has determined that power seat elevation equipment used in combination with a power wheelchair is generally not useful to a person in the absence of an illness or injury because people who do not use wheelchairs (which are classified as DME and are generally not useful to a person in the absence of an illness or injury) would not use the seat elevation equipment to transfer in and out of a wheelchair or to perform reaching activities.

(e) Appropriate for Use in the Home
Power seated elevation systems are used to assist the user with transfers from the wheelchair to a variety of areas in the home such as the bed or toilet and to transfer from those areas of the home back into the wheelchair. They are also a component of PWCs, and a wheelchair is DME that is appropriate for use in the home. Thus, the power seated elevation system on the wheelchair is appropriate for use in the home.

D. Benefit Category Determination

There is sufficient evidence to conclude that power seat elevation equipment on Medicare-covered PWCs falls within the benefit category for DME.

This conclusion is based on the evidence that powered seat elevation equipment serves a medical purpose in assisting with transfers in and out of a power wheelchair and with performing reaching activities to eliminate or reduce shoulder injuries, making the power seat elevation equipment necessary for the effective use of a power wheelchair classified as DME per section 1861(n) of the Act. Also relevant is the precedent established by classification of seat lift mechanisms as DME per section 1861(n) of the Act for individuals to transfer in and out of chairs to facilitate mobility within the home.

Note: The addition of power seat elevation equipment on a PWC does not change the type of PWC being billed to Medicare. In particular, when an individual with Medicare qualifies for a complex rehabilitative power-driven wheelchair, then if they also qualify for power seat elevation equipment on that PWC, the PWC remains classified as a complex rehabilitative power-driven wheelchair when the power seat elevation equipment is added to it. Conversely, when an individual with Medicare qualifies for a PWC that is not a complex rehabilitative power-driven wheelchair, then if they also qualify for power seat elevation equipment on that PWC, the PWC is still not classified as a complex rehabilitative power-driven wheelchair when the power seat elevation equipment is added to it.

V. Timeline of Recent Activities 

VI. Food and Drug Administration (FDA) Status

The FDA identifies a powered wheelchair as a Class II battery-operated device with wheels that is intended for medical purposes to provide mobility to persons restricted to a sitting position (21 CFR 890.3860). It is required to meet performance standards, such as ANSI/RESNA testing standards, as verified by an independent testing facility.

A seating system with power adjustable seat height may be identified by FDA as a component to a power wheelchair. A wheelchair component is a device intended for medical purposes that is generally sold as an integral part of a wheelchair, but may also be sold separately as a replacement part (21 CFR 890.3920).

VII. General Methodological Principles

When making national coverage determinations, CMS generally evaluates relevant clinical evidence to determine whether or not the evidence is of sufficient quality to support a finding that an item or service falling within a benefit category is reasonable and necessary for the diagnosis or treatment of illness or injury or to improve the functioning of a malformed body member. The critical appraisal of the evidence enables us to determine to what degree we are confident that: 1) the specific assessment questions can be answered conclusively; and 2) the intervention will improve health outcomes for beneficiaries. An improved health outcome is one of several considerations in determining whether an item or service is reasonable and necessary.

A detailed account of the methodological principles of study design that the Agency utilizes to assess the relevant literature on a therapeutic or diagnostic item or service for specific conditions can be found in Appendix A.

Public comments sometimes cite published clinical evidence and give CMS useful information. Public comments that give information on unpublished evidence such as the results of individual practitioners or patients are less rigorous and therefore less useful for making a coverage determination. Public comments that contain personal health information will be redacted (if feasible) or not be made available to the public. CMS responds in detail to the public comments on a proposed national coverage determination when issuing the final national coverage determination.

VIII. Evidence to Evaluate a Reasonable and Necessary Determination

A. Introduction

This section provides a summary of the evidence we considered during our review. The evidence reviewed to date includes the published medical literature related to the characteristics that allow a power seat elevation system to compensate for the mobility limitations that are experienced by power wheelchair users during seated or standing transfers performed in the home or during reaching to accomplish MRADLs.

B. Discussion of Evidence

1. Evidence Question(s)

The following questions guided our review and analysis of the evidence below:

1. Is the evidence sufficient to demonstrate that power seat elevation equipment associated with a power wheelchair can improve the mobility limitation(s) related to wheelchair transfers that may constrain certain beneficiaries as they attempt to accomplish their MRADLs in customary locations in the home? These limitations may prevent the individual from accomplishing the MRADLs entirely, place the individual at reasonably determined heightened risk of morbidity or mortality secondary to the attempts to participate in MRADLs, and/or, prevent the individual from completing the MRADLs within a reasonable time frame.


2. Is the evidence sufficient to demonstrate that power seat elevation equipment associated with a power wheelchair can improve and/or reduce the pain and /or pathology associated with reach that may constrain certain beneficiaries as they attempt to accomplish their MRADLs in customary locations in the home? These limitations may prevent the individual from accomplishing the MRADLs entirely, place the individual at reasonably determined heightened risk of morbidity or mortality secondary to the attempts to participate in MRADLs, and/or, prevent the individual from completing the MRADLs within a reasonable time frame.

2. External Technology Assessments

CMS did not request an external technology assessment (TA) on this issue.

3. Internal Technology Assessment

Literature Search Methods

Although we recognize there may be many uses for power seat elevation equipment (e.g. increased reach, promotion of social integration, improvement of pedestrian safety, etc.), for the reasonable and necessary determination, we limited our literature search to what falls within the benefit category determination; that being the use of this device to improve shoulder injury and pathology that may be created by transfers and reaching activities.

The ITEM Coalition NCD request asked CMS to establish coverage for power seat elevation systems specifically associated with Group 3 PWCs. We expanded the literature search beyond the ITEM Coalition request to include any wheeled mobility device to address our evidence question in VIII.B.1 above. The consideration of the expanded literature search on this subject is relevant to this decision because the motion and forces generated during the performance of sitting and standing transfers used in conjunction with diverse types of wheeled mobility devices, provides us with the physiologic and functional information that describes how power seat elevation equipment associated with PWCs may affect a transfer from one surface to another in the home environment.

Based on the scope of the expanded literature search scope, we sought out prospective clinical studies that demonstrated the biomechanical, electromyographic and/or functional abilities of wheelchair users who execute SPTs to perform incremental uneven transfers compared to their ability to perform level transfers. We also searched for prospective clinical studies that demonstrated these abilities of wheelchair users who execute standing transfers from wheelchair seats of incremental heights. We did not find any such studies. Therefore, we considered studies that examined the functional ability of individuals to achieve a standing position from various specified seat heights of traditional and otherwise stationary chair furniture.

Similarly, we sought out prospective clinical studies that were meant to explore differences in the ability to reach during the performance of MRADLs from the seated wheelchair position as compared to the standing position. Again, we expanded our literature search to include the use of any wheeled mobility device to address our evidence question, doing so because we expected that the upper extremity consequences of performing MRADLs from a seated position would be the same or similar for the individual who used any type of this equipment.

We searched both Medline and EMBASE using key words that included and/or combined subject topics such as: wheelchair transfers (level/non-level, even/uneven), sitting pivot transfers, sit-to-stand transfers, (seated) activities of daily living, shoulder injuries, rotator cuff injuries, shoulder impingement syndrome, biomechanics and the like. We also reviewed the references submitted to us by the requester and commenters, searched for pertinent systematic reviews and guidelines and performed a hand search of bibliographies to identify other pertinent articles. We excluded references that discussed floor to chair transfers as such transfers are not typically used for MRADLs. Study participants must have demonstrated an illness or injury that impaired their mobility; studies of subjects without physical impairments were excluded. We also excluded single case studies. Where we assumed the sample population represented the frail elderly because of their living situation, we noted same in our discussion.

No constraints were placed on dates of studies or types of outcomes in our literature review. Only English language articles were evaluated. If information outside the scope of this NCA was found in an assessed article, it was not included in the NCA.

The clinical evidence relevant to our review included 13 individual studies reported in scientific journals, one Final Report for the U.S. Access Board, one professional guideline, and one professional society position paper. They are summarized below:

Burdett RG, Habasevich R, Pisciotta J, Simon SR. Biomechanical comparison of rising from two types of chairs. Phys Ther. 1985 Aug;65(8):1177-83. doi: 10.1093/ptj/65.8.1177. PMID: 4023063

The purpose of this study was to compare the joint moments exerted at the hip, knee, and ankle joints for adults during rising from a standard chair and the E-Z Up Artherapedic Chair. In this study, the seat of a standard chair is approximately 0.43 m from the floor; the seat of the E-Z chair is 0.64 m from the floor.

Of the subjects investigated, four experienced disabilities. Each subject rose from a chair under four conditions in random sequence: standard chair without using arm assistance, standard chair with arm assistance, E-Z chair without using arm assistance, and E-Z chair with arm assistance.

Subject 1, who had received bilateral total knee replacements because of osteoarthritis two years previously, and had no pain during movement, demonstrated decreased moments when he used the E-Z chair as compared to the standard chair. Subject 2, who experienced a high below knee amputation on the left, was not able to rise from the standard chair without use of his arms. The residual leg had to exert a much higher than normal joint moment at the knee during rising from the standard chair. The use of the E-Z chair helped decrease the moment of his right knee by approximately 50% during the chair rise activity. Subject 3, who experienced some spasticity and general weakness in his lower extremities in addition to a right patellectomy, could not rise from either chair without use of his arms. His left knee appeared to bear the brunt of the forces due to chair rise. The use of the E-Z chair allowed a large decrease in the moment at this joint. However, an increase in the moment at the left hip to a value close to that normally experienced in rising from a standard chair was noted during this activity in the E-Z chair. Subject 4, who was nine days post op left total hip replacement, was also unable to rise from the standard chair without using his arms. The subject favored his left hip and compensated with higher than normal moments in his right knee. Using the E-Z chair and assistance from his arms, the moment at the right knee decreased substantially while the moments at other joints remained essentially unchanged.

The authors concluded the use of the higher chair decreased the stress on the muscles and joints of the hip and knee during chair rise activities compared to that of a standard, lower chair. They believe that without the option of rising from a higher rather than a standard chair height, this activity might otherwise be impossible for some individuals to accomplish independently and in particular, for those individuals with a combination of upper and lower extremity impairments.

Finlay OE, Bayles TB, Rosen C, Milling J. Effects of Chair Design, Age and Cognitive Status on Mobility. Age and Ageing. 1983: 12(4): 329-335.https://doi.org/10.1093/ageing/12.4.329

The aim of this study was to evaluate the ease in rising from chairs in a target population of elderly, ambulant individuals with mixed disabilities who resided in Elderly Persons Homes.

Thirty residents with mixed disabilities (average age 81.90 years, SD = 6.75 years; median length of residence 21 months with range of 1 month to 8 years 11 months) took part in a comparison of ease of arising from a standard easy chair (armchair) supplied to the Elderly Person Homes (unloaded seat height 14.0 inches; effective seat height 11.5 inches) as compared to a Haypark chair used for rehabilitation (unloaded seat height 18.0 inches; effective seat height 16.0 inches). Each resident was afforded two trials for each chair; the first to gain familiarity with the task and the second for recording of results. A 30-minute interval was provided between the trials. One physiotherapist asked each resident to rise. Two other physiotherapists evaluated the difficulty of the resident movement. Resident effort was categorized as unable to rise without help, able to rise with difficulty and able to rise without difficulty.

Overall, 15 residents (50%) could rise more easily from the chair with the effective seat height of 16.0 inches than from the lower armchair (P<0.002, sign test, two tailed) with an effective seat height of 11.5 inches. Furthermore, though seven residents were unable to rise at all without help from the lower armchair, five of those seven residents could rise, albeit with difficulty from the higher Haypark chair and one could rise from it without difficulty.

From a sister study concurrently performed, the authors also stated that residents did not benefit from optimal chair arm height if the seat height was low. They also noted that the total sample of the two studies was 92 and that 39 of these residents were chairfast without help to rise. However, 77% of these chairfast residents could get up by themselves from the higher Haypark chair (which also included arm height at recommended levels). The authors concluded that the population tested could more easily rise from a seat height of 16-17 inches than from that of a lower seat.

Gagnon D, Duclos C, Desjardins P, Nadeau S, Danakas M. Measuring dynamic stability requirements during sitting pivot transfers using stabilizing and destabilizing forces in individuals with complete motor paraplegia. J Biomech. 2012;45(8):1554-1558. doi:10.1016/j.jbiomech.2012.02.018

The objective of study was to use an equilibrium model to quantify the dynamic stability of individuals with SCI while they perform sitting pivot transfers toward a target seat of the same height (even SPT) and one 10 cm higher than the initial seat (uneven SPT).

Ten male participants with complete motor impairments sustained at least one year earlier resulting from a traumatic SCI volunteered for this study (range of injury T4-T11). Mean age was 41.2 years (SD = 8.8), mean time since injury was 9.9 years (SD = 12.0). All subjects used a manual wheelchair as their primary source of mobility and both routinely and independently performed SPTs to similar height surfaces during their daily activities (mean number of transfers per day = 21.4 (SD = 6.2)). Potential participants were excluded if they presented any clinical evidence of secondary impairments or conditions that may have limited their ability to perform the SPTs.

Participants initially transferred from one instrumented chair set at a height of 50 cm to another of the same height using their habitual initial hand/feet position and movement strategies. While doing so, their hands were positioned flat on two hand force plates separately attach to each chair and their feet were resting on two force plates embedded into the floor. The hand force plates were adjusted to assure that the width of the seats corresponded to that of their own wheelchair. The height of the target seat was then raised by 10 cm (uneven SPT) so that similar transfers could be performed. After a familiarization period, three transfer trials were recorded for each experimental task. Kinematic parameters were continuously recorded. A model measuring destabilizing and stabilizing forces was used to quantify dynamic postural stability during the SPTs. All data was time normalized.

Based on their results, the authors stated that individuals with complete motor thoracic SCI encounter greater dynamic postural instability during the transition phases when performing SPTs, i.e., around the time the buttocks lose contact with the initial seat and around the time the buttocks land on the target seat. However, the height of the target seat had no significant effect on the dynamic postural stability requirements during the SPTs.

Gagnon D, Nadeau S, Gravel D, Noreau L, Larivière C, McFadyen B. Movement patterns and muscular demands during posterior transfers toward an elevated surface in individuals with spinal cord injury. Spinal Cord. 2005 Feb;43(2):74-84. doi: 10.1038/sj.sc.3101660. PMID: 15356677

The objective of this study was to compare the movement strategies and muscular demand of six muscles during the accomplishment of level versus non-level posterior wheelchair transfers. Ten male volunteers participated in this laboratory study. All experienced spinal cord injuries (C7-L2). Mean age was 39.2 ± 9.3 years and their mean time post injury was 15.1 ± 11.7 years. The inclusion criteria consisted of a muscle strength score of the triceps brachii greater than 3/5 on manual muscle testing and either A or B classification of the spinal cord injury. Participants did not demonstrate any musculoskeletal evidence of injury to the upper extremities nor did they have any conditions to limit their abilities to perform a posterior transfer.

The muscles tested in this study included the long head of the biceps brachii, the long head of the triceps brachii, the anterior deltoid, the clavicular portion of the pectoralis major, the latissimus dorsi and the lower portion of the trapezius. The muscle actions examined were elbow flexion and extension, shoulder flexion, extension, adduction and depression.

All participants were asked to perform two different posterior transfers. The first transfer was a backward movement from a long sitting position on an even surface with hands placed symmetrically alongside the body (even task). In the second transfer, subjects had to raise themselves sufficiently from a long sitting position on a low surface to land on an elevated surface 10 cm higher (elevated task). For the elevated tasks, subjects were instructed to perform the transfer using three different hand placement strategies: both hands on the lower surface, both hands on the elevated surface and one hand on each of the lower and higher surfaces (during which measurements were made from the dominant side which was placed on the upper surface). The posterior transfer on the even surface was performed using only hands symmetrically placed on each side of the body on the mat platform. After a familiarization period, subjects performed a minimum of three trials for each task using their normal movement strategies. Rest periods between transfers were used to prevent fatigue. The demands made by the transfer upon each muscle was estimated using the electromyographic muscular utilization ratio (EMUR). This parameter was obtained by dividing the EMG value recorded during the transfer maneuver by the maximal EMG values obtained from a maximal effort performed on a dynamometer and converting this number to a percentage. This ratio allows the determination of the level of effort generated by each muscle during the posterior transfers. Mean EMUR values were calculated for the lift phase of the transfers.

All ten subjects completed the posterior transfer on an even surface. Seven subjects successfully completed the elevated transfer using both hands on the lower surface, five subjects were able to execute it with one hand on each surface and only three subjects performed the transfer with both hands on the elevated surface. One subject was not able to transfer to the elevated surface using any of the three hand placements.

The authors noted that a forward-flexion pattern at the head and trunk was observed when either one or two hands remained on the lower surface, whereas a lift strategy was seen when both hands were placed on the elevated surface. Mean EMURs for the transfer strategies demonstrated that the level transfers were not the ones that necessarily generated the lowest EMURs; all the tested muscles produced lower mean EMURs during an elevated transfer in at least one of the hand positions than did those same muscles during a level transfer. Moreover, transferring to the elevated surface with hands on the lower surface required lower mean EMURs than the transfer to the even surface in all muscles except the biceps. However, when both hands were placed on the elevated surface to accomplish the transfer, the triceps, anterior deltoid, trapezius and latissimus dorsi muscles presented their highest EMUR.

The authors believed that the posterior transfer with hands on the elevated surface was the most challenging approach in terms of the muscular effort required during the higher transfer, explaining why only three subjects could successfully complete the task.

The goal of this study was to quantify the three-dimensional reaction forces exerted under the hands, feet and buttocks during the SPT of individuals with spinal cord injury to a target seat height of both the same and higher level. The trial also allowed a study of the effect of target seat height on the magnitude of the reaction forces under the hands of the leading and trailing upper extremities during the lift phase of a SPT.

A convenience sample of 12 right handed men (mean age 41.5 years, age range 21-54 years; mean time since injury 9.1 ± 11.1 years; mean transfers per day 20 ± 7) with complete traumatic sensory-motor thoracic SCI (ASIA A or B) volunteered for the study. Levels of injury ranged from T4-T11. The participants all routinely performed sitting transfers in daily life and possessed the ability to independently perform sitting transfers between seats of various heights without aids. Furthermore, these participants demonstrated no condition and/or subjective/objective signs or symptoms of musculoskeletal impairment that would interfere with SPTs.

A force-sensing system was developed to continuously record reaction forces underneath the feet, buttocks and leading and trailing hands during transfers. Ground reaction forces (GRFs), representative of the external loading sustained by the body segment being recorded, were continuously monitored as participants performed SPTs from the instrumented chair to the target chair, initially set at a height of 0.5 m. This height mimicked the combined wheelchair and cushion heights calculated among all participants that matched the height from which the subjects routinely initiated a SPT in everyday life (0.53 m, SD 0.02: same). The width of the instrumented chairs was adjusted to that of the width of the participants own wheelchair. After a familiarization period, three transfer trials were recorded for each participant. Subsequently, the height of the target seat was positioned 0.1 m higher than the initial one to reach 0.6 meters (high) and three additional transfers were recorded for each subject.

For all transfers, the right UE acted as the leading UE and the left as the trailing UE. Initial hand, feet and buttock positions were marked to ensure similar starting points across trials for each subject. The participants were encouraged to use their regular transfer strategies during the study. Each data point was normalized as a percentage of body weight (%BW). The GRFs were also time normalized. Group means were generated to report out data.

All participants had the ability to transfer to a seat of the same height. Only ten participants were able to transfer to the target seat that was 0.1 m higher than the initial one.

The authors found that there was no significant association between the level of SCI and the mean or peak force components. They however did find that although the mean (same height = 22.9%; high height = 19.6%) and peak (same height = 29.1%; high height = 27.6%) vertical forces recorded under the feet were considerable, the mean (p < 0.0001) and peak (p< 0.0001) forces were much greater under the hands (mean: same height = 61.3%; high height = 64.4%; peak; same height= 84.1%; high height = 84.5%) during the lift phase of the transfers.

Furthermore, for the mean vertical reaction forces, target seat height (same vs high) had a statistically significant effect when looking at each hand separately. For the trailing hand, a higher (p= 0.001) mean vertical reaction force was recorded when transferring toward the high target seat (34.1%) compared with the one of the same height (29.4%). This relationship was reversed under the leading hand (p=0.021) where a greater mean vertical reaction force was reached transferring to the target seat of the same height (same=31.9% vs high=30.3%). Similar mean vertical reaction forces were found between the leading and trailing hands (same = 31.9% vs 29.4%; high = 30.3% vs 34.1%) when transferring toward a target seat of same (p = 0.115) or higher height (p = 0.088) than the initial seat.

For the peak vertical reaction forces, both hand roles (leading vs trailing) and target seat heights (same vs high) were found to have had a significant effect. The trailing hand supported a greater peak vertical reaction force (same = 44.5%; high = 48.6%) than the leading hand (same = 39.6%; high = 36%) during the 2 transfer tasks tested (p= 0.020, same height and p<0.0001 high height). The trailing hand supported additional (p = 0.003) vertical reaction force when transferring to the high seat (48.6%) compared with the one of same height (44.5%). The leading hand experienced the lowest peak vertical force when transferring to the high target seat height (same=39.6%; high = 36%).

The target seat height was found to have no effect upon the mean and peak horizontal forces. However, in both cases these forces were significantly greater under the trailing hand (mean: same = 7.1%; high = 7.6%; peak: same = 10.2%; high = 10.4% as compared to the leading hand (mean: same = 5.9%; high = 5.4%; peak: same = 8.8%; high = 8.6%) during the lift phase of the transfer.

The peak vertical reaction force under the trailing hand and feet occurred earlier than the force under the leading hand when transferring, independent of the target seat height.

The authors concluded that their results demonstrated that though the lower extremities supported a significant portion of the body weight during a SPT, most of the body weight was supported by the UEs. Peak vertical reaction forces were always higher and occurred earlier underneath the trailing hand when compared with the leading hand during sitting transfers, and mean vertical forces were always similar between leading and trailing hands independent of target seat height. However, as the height of the target seat was raised and individual hand forces were recorded, the mean (+4.7%) and peak (+4.1%) vertical forces recorded under the trailing hand increased; the mean (-1.6%) and peak (-3.6%) vertical reaction forces under the leading hand declined. Raising the height of the target chair did not affect the horizontal forces under both hands.

The authors surmised that the highest peak vertical reaction force seen under the trailing hand when transferring to a high target seat versus a lower target seat, may be the reason for the higher EMG activity of the anterior deltoid and pectoralis major muscles of the trailing arm (described in Gagnon, Nadeau, Noreau, Eng, & Gravel, 2009 elsewhere in this NCA Evidence Section). These muscles may have to generate counterbalancing explosive moments of shoulder flexion and shoulder adduction to offset the elevated forces under the trailing hand early during the lift phase of the transfer.

The main objective of this trial was to characterize movement patterns of the trunk and UEs during sitting pivot transfers to three different seat heights in persons with SCI. The secondary objective of this study was to compare angular displacements and velocities measured at the trunk and UEs during the lift phase of a transfer to three different seat heights.

Ten males (age = 41.0 years (9.3); height = 1.74 m (0.08); body mass = 79.4 kg (17.6)) with complete sensory-motor thoracic SCI (T4-T11 ASIA A) following a traumatic injury participated in this study. All participants were at least two years post-SCI, long-term manual wheelchair users, able to independently execute sitting pivot transfers between seats of similar height without human or technological assistance required, and routinely used this type of transfer in daily life. Furthermore, none of the participants presented signs and symptoms of musculoskeletal impairments affecting the trunk or UE joints or exhibited any other condition that might alter their ability to transfer.

Participants were asked to transfer from one custom-made instrumented width- and height-adjustable chair to another one placed at a 90˚ angle, in a sitting position with feet in a position of preference. Both seats were initially set at a height of 50 cm for all participants (task 1), which closely replicated the height (mean (SD)) of the participants’ wheelchairs and cushions (53.0 cm (1.7)). The target seat was then lowered to 40 cm (task 2), and then raised to 60 cm (task 3). These last two conditions were selected to mimic, for example, the height of a regular toilet seat (task 2) and that of a bed (task 3). The dominant right UE always acted as the leading limb whereas the non-dominant left UE acted as the trailing limb for all transfers. After a familiarization period, three transfer trials per experimental task were recorded for each participant. Initial hand, feet and buttocks positions were constant across the trials of a given task for each individual. Study participants were encouraged to use their usual transfer methods.

Custom programs were used to quantify angular displacement and velocity of the trunk, shoulder, elbow and wrist joints. Specific values were only reported for the lift phase of the transfer (defined as the period from seat-off to seat-on of the transfer), but the angular displacement and velocity profiles of various parts of the body (trunk, shoulder, elbow and wrist joints) were performed across all phases of the transfer. Furthermore, angular displacement and velocity data were time normalized. The mean curves for each participant’s three trials were averaged for each task, and group mean curves were calculated by averaging all individual means, again for each given task.

The authors reported that the shoulder of the leading upper extremity reached its peak extension angular displacement and velocity values when transferring to the high target seat whereas peak flexion angular displacement and velocity were found at the trailing upper extremity at the same time. At the trailing elbow, additional elbow extension was observed as the height of the target seat was raised. Additionally, peak elbow extension velocity reached its maximal value during transfer to the high seat. Similarly, the leading upper extremity attained its most elevated elbow extension velocity during transfer to the higher seat.

The authors believed that the shoulder and elbow were key to the dynamics of the upper extremity during SPTs. In particular, they speculated that the very fast angular velocities attained during leading shoulder extension, together with the large extension movement simultaneously sustained by this joint when transferring to the higher target seat, might jeopardize leading shoulder joint integrity.

^aGagnon D, Nadeau S, Noreau L, Eng JJ, Gravel D. Electromyographic patterns of upper extremity muscles during sitting pivot transfers performed by individuals with spinal cord injury. J Electromyogr Kinesiol. 2009;19(3):509-520. doi:10.1016/j.jelekin.2007.12.005

The main objective of this study was to describe the electromyographic (EMG) recruitment patterns of shoulder and elbow muscles bilaterally during SPTs to target seats of three different heights (low, same, high) among individuals with SCI. All participants had sustained their SCI at least two years prior to the study, used manual wheelchairs, were able to independently transfer between seat heights that were equal, routinely used a SPT in their daily activities (reported number of SPTs/day were 19±7); and could tolerate at least 60 minutes of activity with rest periods.

Ten males with traumatic thoracic level complete sensory-motor ASIA A spinal cord injuries (T4-T11) volunteered for this study (age = 41 ± 9.3 yr; height = 1.74 ± 0.08 m; mass =79.4 ± 17.6 kg). None of the participants experienced signs or symptoms of secondary musculoskeletal impairment affecting their upper extremities or trunk nor did they manifest any other impairment interfering with their ability to perform transfers.

Participants transferred from an initial force-sensing seat toward a height-adjustable target force-sensing seat. The leading and trailing hands were each placed on additional distinct hand force-sensing surfaces attached to the side of the initial and target seats. Each participant initially transferred three times from a seat of 50 cm (which closely replicated the mean height of the wheelchair sitting surface for the experimental group (53.0 ± 1.66 cm)), to a target site of the same height (same). Then the target seat and leading hand surface heights were raised to 60cm (high) and three additional SPTs were performed. Finally, the target seat and leading hand surface heights were lowered to 40 cm (low) and three more SPTs were performed. Participants were encouraged to use a natural, self-selected transfer technique, especially in terms of movement amplitude and velocity. The dominant (right) upper extremity always acted as leading arm and the non-dominant (left) upper extremity acted as the trailing arm for all transfers. The bilateral muscles that are the prime movers during transfer activities were recorded by surface EMG electrodes: long head of the biceps brachii, long head of the triceps brachii, anterior fibers of the deltoid, clavicular fibers of the pectoralis major and latissimus dorsi. Each phase of the transfer was time-and amplitude-normalized.

Mean and peak EMG values were similar across the lift phase of the three transfer conditions (high, same low) for most of the muscles tested. However, mean EMG values of the biceps (P = 0.02) at the leading upper extremity, as well as the deltoid (P = 0.01) and pectoralis major (P = 0.03) at the trailing one, were predominantly active when transferring to a high target seat compared to a target seat of the same height, and even to one of low height for the first two muscles. For peak EMG values, the pectoralis major (P = 0.04) of the trailing upper extremity was more elevated when transferring to the high target seat than when transferring to a target seat of the same height. Neither mean nor peak EMG amplitude values were significantly lower during transfers to a lower target seat than during transfers to a seat of the same height.

The authors concluded that the relative EMG intensity (mean and peak values) during the lift phase of the transfers confirmed that transferring to a high target seat requires higher relative demand for the muscles generating shoulder flexion and elbow extension moments (biceps, anterior deltoid, pectoralis major) than transferring to the other target seat heights. The authors theorized that it is possible that transferring to a high target seat exacerbates the risk of developing secondary musculoskeletal impairments at the trailing upper extremity, especially at the shoulder joint. Unexpectedly, transferring to the low target seat required similar muscular effort to that required for transferring to a seat of the same height.

The purpose of this study was to compare the humeral elevation workspace during a typical day for individuals with SCI (injury level C6-L1) who use a manual wheelchair and matched able-bodied controls. Those included in the study were between 18-70 years of age and had functional range of motion in both shoulders, defined as active humeral thoracic flexion, abduction of at least 150˚ and the ability of the participant to touch the opposite shoulder, the back of his/her neck and his/her low back. Among exclusion criteria was a self-reported previous diagnosis of a complete supraspinatus tendon tear or a complete tear seen during a MRI. However, participants with SCI who had unilateral supraspinatus complete tears were still eligible to be followed for the contralateral shoulder. Additionally, controls were also excluded if they had any musculoskeletal or neurological disorder which might have impacted shoulder health or changed the individual’s ability to walk independently.

Participants were provided wireless inertial measurement units (IMUs) to wear on each lateral arm, as well as their anterior torso. The devices were to be worn for at least two typical days, excluding bathing and swimming, as the participants went about their regular routines. The units were removed for sleeping. The calculated humeral elevation angles ranged between 0-180˚, with 0˚ indicating the arm was down and aligned with gravity and 180˚ indicating the arm was raised overhead and aligned with gravity. The percentage of daily wear time each participant spent in five humeral elevation bins were calculated (0˚-30˚, 30˚-60˚, 60˚-90˚, 90˚-120˚, and 120˚-180˚). Data in which the thorax deviation angle was more than 30˚ were eliminated in order to allow humeral elevation angles to be interpreted similarly to humerothoracic elevation angles. Data were also excluded from analysis if the functional calibration postures were not completed properly or if at least eight hours of data were not collected after the elimination of non-wear time. Data were included if one or two complete days were collected; if two days were included all data were combined before the calculation of the percent of time in humeral elevation bins.

Thirty-four participants with SCI who used a manual wheelchair and 34 age (±2.5 years) and sex matched, able-bodied adults were enrolled. There were no statistical differences between the two groups in terms of self-reported weight, height, and dominant hand. Data (SD) were collected for an average of 11.4 (2.1) and 11.9 (1.3) hours for the SCI and control cohorts, respectively. Additionally, on average 18.3(14.0) and 28.0 (10.3) percent of the day was excluded because the trunk was at or over 30˚ for the SCI and control cohorts, respectively.

Participants with SCI spent significantly more time in 30˚-60˚ of humeral elevation than all other elevations bins on both their dominant and non-dominant sides (p<0.001). The SCI cohort spent 63% and 59% of their daily wear time (approximately 7 hours per day) at these elevations, on their dominant and non-dominant sides, respectively. The controls also spent the greatest amount of daily wear time in this elevation bin at 50% and 48% on their dominant and nondominant arm respectively, which was significantly lower than the SCI cohort for both arms (dominant: p < .0001, non-dominant: p = 0.003).

For the SCI cohort, the second largest percentage of time was spent in 60˚-90˚ of humeral elevation (approximately 20% of their day for both arms). Controls spent their second largest percentage of time in 0˚-30˚ of elevation for both arms, which was significantly higher than the amount of time the SCI cohort spent in this elevation range (p<0.001). Individuals with SCI spent comparable amounts of time in 0˚-30˚ and 60˚-90˚ of elevation, while controls spent significantly more time in 0˚-30˚ than 60˚-90˚ of humeral elevation on the dominant (p<0.001) and non-dominant (p<0.0001) sides. On average, participants in both cohorts spent less than 3% of their day (<25 minutes) in elevations over 90˚ for both arms.

There were no significant differences between cohorts for the 60˚-90˚, 90˚-120˚and >120˚ humeral elevation bins or between dominant and non-dominant arms for each cohort and each elevation bin. Pain did not have a significant effect on the percentage of time an individual spent in any humeral elevation bins for both dominant and non-dominant arms. There were no main effects of sex, age, injury level, or years of manual wheelchair use on either arm.

The authors noted that participants with SCI, as well as controls spent the majority of their day (~80%) in elevation angles between 0˚ and 60˚. However, they specifically stated that individuals with SCI spent significantly more time in humeral elevations previously found to be associated with supraspinatus tendon compression (30˚-60˚) than controls. The authors stated that this difference could in part be due to differences in the arm elevation work space during mobility, as manual wheelchair propulsion results in humeral elevation of approximately 25˚-55˚ at self-selected speeds while when walking, the humeral elevation angles are much lower.  However, the authors note that this positional difference in humeral elevation during mobility is unlikely to be the only contributor to the findings of this study because manual wheelchair users move about 3 km less than able-bodied individuals and only spend a small amount of their day actually propelling themselves (estimates range from 16 to 54 minutes per day). And while the authors note that manual wheelchair users may not place their arms in a neutral resting position of 0˚-30˚ as do the able-bodied, but instead on their wheelchair arm rests in 30˚-60˚ of humeral elevation, they also state that their data may suggest that injury to the supraspinatus tendon due to tendon compression of the SCI cohort occurs due to increased time between 30˚-60˚ of humeral elevations. This comparison to controls may promote understanding of the different ways in which the upper extremities are used during the day when the option to use the lower extremities is removed.

The purpose of this study was to report the daily percentage and consecutive durations manual wheelchair (MWC) users and matched able-bodied individuals (controls) spent static and dynamic across the humeral elevation workspace.

Forty-four manual wheelchair users with SCI (10 females, age: 42.8±12.0 years, time since injury: 12.3 ± 11.5 years, injury level C6-L1) and 44 age- and sex-matched controls (±3 years) were enrolled. Inclusion criteria for individuals in the manual wheelchair cohort included being between the ages of 18 and 70, use of a manual wheelchair as a main mode of mobility, functional upper extremity range of motion defined as active humeral thoracic flexion and abduction of at least 150˚ and the ability of the participant to touch the opposite shoulder, the back of his/her neck and his/her low back. Participants were independent in their mobility and self-care. Exclusion criteria for this cohort included previous bilateral supraspinatus tendon tears occurring prior to the SCI. The inclusion criteria for the sex- and age-matched ±3 years) able-bodied controls included the same age and functional parameters of the upper extremity as the manual wheelchair cohort. Additionally, the matched controls had to have the ability to walk independently with no reliance on an orthotic, prosthetic, or gait aid. Exclusion criteria for the matched controls included any documented musculoskeletal or neurological disorders that would be expected to impact shoulder health or change ability to walk independently or a diagnosis of unilateral or bilateral supraspinatus tears prior to enrollment.

Pain was measured on a continuous scale for the manual wheelchair cohort using the Performance Corrected Wheelchair User Shoulder Pain Index (PC-WUSPI) for both the right and left shoulders. Participants were provided wireless inertial measurement units on each of their lateral arms and torso to wear on the arms for two typical days (at least 8 hours), excluding bathing and swimming, as they went about their regular routines. The units were removed for sleeping. The average humeral elevation angle was calculated for each second (possible angles ranged between 0-180˚). Each second of the data was classified as static or dynamic in one of the humeral elevation ranges (0˚-30˚, 30˚-60˚, 60˚-90˚, 90˚-120˚ and >120˚). Two primary outcome measures were calculated based on the second-by-second data: the percentage and total duration of the full day that each arm was static or dynamic in each of the five humeral elevation ranges, and the average consecutive duration of static and dynamic periods in each humeral elevation range[3].

Thirty-three participants in the manual wheelchair cohort collected 2 days of useable data and 11 participants in this cohort collected 1 day of useable data. Forty participants in the control cohort collected 2 days of useable data; the second day of controlled participant data was excluded in four cases. The manual wheelchair and control cohorts averaged 9.1± 2.0 hours and 8.3± 1.3 hours of data collected per day, respectively. Overall an average of 8.7 h was used to estimate the time spent in static or dynamic periods in each humeral elevation range.

There was a significant effect of cohort on the percentage of daily time spent in the static or dynamic state in each humeral elevation range (p < 0.001). Post-hoc examination revealed that the manual wheelchair cohort spent significantly more time in the dynamic use of the dominant arm in the 60˚-90˚ and 90˚-120˚ ranges of humeral elevation than the matched controls. On average, the upper extremities of the manual wheelchair users were dynamic approximately 30 minutes more per day in the range of 30˚ - 90˚ of humeral elevation than those in the control group and approximately 40 minutes more per day than the control group in the static humeral elevation position of 30˚-60˚. The control cohort spent a significantly higher percentage of the day dynamic in 0˚-30˚ of humeral elevation on both dominant and non-dominant sides. There were no differences between dominant and non-dominant arms for either cohort. For the manual wheelchair cohort, there were also associations of decreased dynamic time in multiple humeral elevation ranges as age increased. For both cohorts, none of the outcome measures were significantly different for those with and without pain.

On the dominant side, the manual wheelchair users exhibited longer consecutive durations of dynamic use than controls in 30˚-60˚, 60˚-90˚ and 90˚-120˚ elevation ranges. The control participants demonstrated significantly longer average consecutive dynamic periods in 0˚-30˚ than manual wheelchair users while using both upper extremities. There were no differences found between the two groups in average consecutive static periods in each range of humeral elevation.

The authors stated that the results of this study supported the premise that different distributions of static and dynamic periods can be observed when comparing manual wheelchair users and matched controls across humeral elevation ranges. The authors noted that these results may highlight a specific risk for manual wheelchair users, who spent a larger percentage of their day in the dynamic state of humeral elevations over 60˚. Dynamic activities in this state were noted to potentially include, but not be limited to, transfers and accessing standard height counters and shelves from a seated position; activities that include loading or working with the arm away from the body. In addition to more daily time in the 60˚-120˚ range, manual wheelchair users also exhibited longer consecutive periods of dynamic time in this humeral elevation; however, the difference was not large (a matter of minutes) and it is unknown whether this additional time in higher elevations over days, months and years could cause cumulative pain and pathology. No differences between groups were found in the average consecutive periods of static time in each humeral elevation range. The authors concluded that these results may demonstrate meaningful differences that occur between those individuals who perform activities of daily living from the seated as opposed to the standing position.

^aKoontz A, Toro M, Cooper RA. The Impact of Transfer Setup on the Performance of Independent Transfers: Final Report. Report Prepared for U.S. Access Board, Washington, DC. April 17, 2012. Accessed 7/19/2021 at: https://www.herl.pitt.edu/ab/ABTransferSetupReportPhaseI.html

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Toro ML, Koontz AM, Cooper RA. The impact of transfer setup on the performance of independent wheelchair transfers. Hum Factors. 2013;55(3):567-580. doi:10.1177/0018720812460549

The purpose of this study was to determine how select environmental factors affect transfers among current community-dwelling wheeled mobility device users. More specifically, this project attempted to determine acceptable ranges of vertical height differences that may occur in wheeled mobility device non-level transfers. Those who participated in the study were required to be at least 18 years of age, be able to independently perform a transfer to/from a wheeled mobility device with or without a transfer assist device, and own a wheeled mobility device that they had been using for at least one year. Participants were excluded from the study if they had significant upper-extremity pain or injury that would inhibit the ability to perform transfers or experienced a recent history of pressure sores.

A custom-built, modular transfer station was designed for this study that included a height adjustable platform. Initially, the platform was adjusted to be level with the participant’s wheeled mobility device seat, with no side guard or front grab bar in place. The participants were asked to position themselves next to the platform as they normally would to prepare for a transfer. Each participant was asked to perform a transfer from the wheeled mobility device to the station and back to the wheeled mobility device. Participants were then asked to perform five protocols in random order (with rest breaks), in which they were asked to perform transfers with a front grab bar and/or side bars, or no equipment. The vertical height protocol took the height of the platform incrementally higher and lower than the participant’s seat. The amount of vertical distance that the seat was raised or lowered each time depended on the participant’s perceived and observed transfer abilities. The maximum and minimum heights the participant could transfer to and from the platform were recorded.

Participants were asked to attempt only transfers they felt were comfortable and safe. If participants began to slip or fall during a transfer, they were spotted and the transfer was declared “unattainable.” Participants could quit the study at any time if they were fatigued or if they felt pain that affected their ability to transfer.

A large number of the participants were veterans who participated in organized sports-related events; however, the authors stated that research had shown that their daily activity levels apart from the time of the event did not differ from that of community-dwelling adult wheeled mobility device users.

Ninety-five men and 25 women participated in the study. These participants experienced a broad variety of disabilities, including spinal cord injuries (SCIs) ranging from C3 to L4, multiple sclerosis (MS), cerebral palsy, post-polio, lower extremity amputation, stroke, amyotrophic lateral sclerosis, muscular dystrophy, osteogenesis imperfecta, traumatic brain injury, as well as other conditions. Their average age was of 47.7 ± 15.3 years. Eighty- four participants used manual wheelchairs, 29 used PWCs, 5 used scooters, and 2 used power-assist chairs. The study population as a whole had been using a wheeled mobility device for 14.9 ±12.1 years (range 1-59 years). Wheelchair seat plus cushion height was 54.8±3.4 cm (21.6 ± 1.4 inches) at the edge; median height was 55.8 cm (22 inches); the range was 43.2-63.5 cm (17-25 inches). Eighteen percent of the participants used assistive technology for the transfer: transfer board 14, lift 3, cane 3, and walker 2.

Of the 120 participants, 116 attempted to determine the lowest/highest transfer heights (without use of side guard/front grab bars/gap) that could be managed; 111 completed the task and five were unable to transfer to the adjustable platform at any height. The majority of participants, 92% (CI [86%, 96%]; 107/116) were able to transfer to a highest height of 55.8 cm (22 inches) with no gap or obstacle present, similar to the median wheeled mobility device seat height. Fewer numbers of subjects could transfer above and below this height. Only 89% of study individuals could transfer uphill 2 inches; only 76% of individuals could transfer uphill 3 inches; and only 63% of individuals could transfer uphill 4 inches; only 86% of individuals could transfer 2 inches downhill; only 78% could transfer three inches downhill; and only 69% could transfer four inches downhill (relative heights attained).

Because over 90% of independent wheeled mobility device users managed a transfer (with no gap or obstacle) at a height very close to the median height of the participants’ own wheeled mobility device, the authors concluded that transfers are easiest to achieve when the height of the transfer surface is at the same height as the wheeled mobility device seat (seat height + cushion). They also stated that height differentials of 2” above and below wheeled mobility device height, pose serious transfer-related accessibility problems for wheeled mobility device users. Per the authors, these conclusions were generalizable to a population of active, community dwelling wheeled mobility device users.

Van Drongelen S, Van der Woude LH, Janssen TW, Angenot EL, Chadwick EK, Veeger DH. Mechanical load on the upper extremity during wheelchair activities. Arch Phys Med Rehabil. 2005 Jun;86(6):1214-20. doi: 10.1016/j.apmr.2004.09.023. PMID: 15954062.

The purpose of this study was to determine the net moments on the glenohumeral joint and elbow joint during wheelchair activities, including those of reaching. Seventeen males participated in this study; five who were able-bodied (age 22±3 years), eight who were paraplegic (age 39 years old ±12 years; time since injury: 14± 10 years; level of injury level: T3-T12) and four who were tetraplegic (age: 28±5 years; time since injury: 7±6 years; level of injury: C6-7). No participant had a current history of shoulder problems. Two subjects with paraplegia and one subject with tetraplegia had an incomplete lesion. Except for age between the able-bodied and the paraplegic group, no differences were found for subject characteristics.

Net moments around the elbow and the glenohumeral joint (GHJ) were used to quantify the mechanical load on those joints. A reaching task was performed by placing different bottles on a platform, 0.5m off the ground. The bottles varied in mass (0.1, 0.75, 1.5kg). At the start of each trial, all subjects sat in an instrumented wheelchair and held the bottle at their lap. They then placed the bottle on the platform in front of them and took it back to the starting position. For this task, the exerted hand force was the force needed to compensate for the gravitational force on the bottle.

The peak shoulder and elbow moments for the three trials of placing a bottle on the shelf were calculated. With the increasing weight of the bottles, the net moment on the GHJ increased from 5.8 to 12.7 Nm; the net moment on the elbow increased from -1.1 to -5.2Nm. A flexion moment in the elbow was needed to hold up the weight, whereas a mainly flexion moment in the shoulder was needed to hold up the arm in front of the body. For a higher weight, significantly higher shoulder and elbow moments were found (P<.001). No significant differences in the net joint moments were found between the three groups of individuals.

The authors stated the results demonstrated that the net moments of the shoulder and elbow during the described reaching activities  are dependent on the mass of the object being moved. The moment on the shoulder joint during reaching with the empty bottle was comparable to wheelchair propulsion at a low speed; the shoulder moments reaching with a weight of 1.5kg were almost identical to the moments for propelling on a slope of 3% (propulsion results were determined in a separate aspect of this investigation).

The authors noted that these results imply that no essential differences were found in the kinematics and external forces studied among those who are able-bodied and those individuals who are  paraplegic/tetraplegic. They also stated that for subjects with a high spinal lesion level, different strategies may be necessary to stabilize the joint as a result of partial muscle paralysis and that this compensation activity may lead to high muscle stress and/or a high joint reaction force.

The authors further stated that the risk for musculoskeletal injuries is not only affected by the peak forces occurring during a task, but also by the frequency, the duration, the direction of the force, and the point of force application of a given task.

^aVan Drongelen S, van der Woude LH, Janssen TW, Angenot EL, Chadwick EK, Veeger DH. Glenohumeral contact forces and muscle forces evaluated in wheelchair-related activities of daily living in able-bodied subjects versus subjects with paraplegia and tetraplegia. Arch Phys Med Rehabil. 2005 Jul;86(7):1434-40. doi: 10.1016/j.apmr.2005.03.014. PMID: 16003677.

The purpose of this study was to estimate the differences in glenohumeral contact and shoulder muscle forces between able-bodied individuals and individuals demonstrating paraplegia and tetraplegia during reaching activities performed from a wheelchair. Per the authors, the load on the shoulder has often been quantified as net joint moments, which do not necessarily reflect the magnitude and distribution of muscle forces and the stability requirements in the shoulder. Compared with net shoulder moments, glenohumeral contact forces might be a more accurate indicator of mechanical load at the shoulder joint because contact forces reflect the sum of the external forces and the muscle forces around the joint. The compression force on the joint surface may cause damage to the joint surface, whereas the muscle forces can be high to stabilize the joint and therefore may lead to soft-tissue damage.

A convenience sample of seventeen males participated in this study; five who were able-bodied (age 22±3 years), eight who were paraplegic (age: 39 years old ±12 years; time since injury: 14± 10 years; level of injury level: T3-T12) and four who were tetraplegic (age: 28±5 years; time since injury: 7±6 years; level of injury: C6-7). Two of the research participants with paraplegia and one participant with tetraplegia experienced incomplete lesions. Of the participants with tetraplegia, one subject had no tricep muscle tension at all (manual muscle test score= 0), two subjects were unable to act against gravity (manual muscle test score = 2), and one subject was unable to act against resistance (manual muscle test score =3). Participants were required, among other criteria, to experience no current shoulder pain and no cardiovascular disease. Except for age between the able-bodied and the paraplegic group, no differences were found for subject characteristics.

Participants were asked to perform a reaching task by placing a 1.5 kilogram (kg) bottle on a platform 0.5m high with their right hand. The bottle had a ring under the cap so that the individuals with tetraplegia could grasp it. At the beginning of the task, all the participants sat in a wheelchair with the bottle in their lap. They then placed the bottle on the platform, held it there, and then returned the bottle back to their laps.

The authors compared the glenohumeral contact force of reaching with that of level wheelchair propulsion and a weight relief lift. For both peak and mean values, performing a lift was accompanied by a significantly (P<.001) higher glenohumeral contact force when compared with reaching (peak glenohumeral contact forces for weight-relief lifting were 100% higher than reaching). However, reaching caused a significantly (P<.001) higher peak and mean glenohumeral contact force when compared with level wheelchair propulsion. (Peak glenohumeral contact forces for reaching were twice as high as for level wheelchair propulsion.)

During the reaching task, the muscles necessary to elevate the arm forward (deltoid/deltoideus) and to stabilize the arm (infraspinatus, supraspinatus, serratus anterior) were active. Further, the muscles necessary to hold the bottle upright, such as the brachioradialis and biceps brachii muscles, were active. The muscles that produced the largest peak force during the reaching task were the deltoid, the brachialis, and the trapezius muscles. When expressed as a percentage of their maximum force, the brachialis and the deltoid muscles were the muscles with the most load during this task. The peak relative force of these muscles exceeded 15% of their maximum on average. The range of relative force of the other active muscles was between 5% and 15%. No differences were found among the three groups of participants.

The authors believed it was difficult to determine those activities that are most taxing to an individual in terms of developing an overuse injury.

Weiner DK, Long R, Hughes MA, Chandler J, Studenski S. When older adults face the chair-rise challenge. A study of chair height availability and height-modified chair-rise performance in the elderly. J Am Geriatr Soc. 1993;41(1):6-10. doi:10.1111/j.1532-5415.1993.tb05939.x

The goal of this study was to validate the clinical observation that small increases in chair height may significantly improve chair rise performance. Twenty-two volunteers were recruited from inpatients from a Veterans Administration Medical Center Extended Care and Rehabilitation Center (ECRC; n=14) as well as an Aging Center registry of community-dwelling elderly (n=8). All participants had the ability to stand independently and the ability to bear full weight on the lower extremities in the standing position. Mean age was 72 years (range: 64 - 105).

In previous research, the authors determined that the mean height of an armless kitchen /dinette type chair was approximately 17 inches. Subjects were asked to rise from such a chair with a firm surface and no slope to the seat. Subjects were asked to arise from six different seat heights: 17, 18, 19, 20, 21, and 22 inches. A unique random chair-height sequence was employed for each subject. Subjects were not allowed to use their hands to push off the chairs; otherwise the chair-rise strategy employed by the subjects was not controlled. No practice trials were provided, and subjects were given only one opportunity to rise at each height. Ten seconds was allowed to initiate a successful chair rise. A trial was considered successful if the subject, without the use of the hands, was able to stand upright from a sitting position. Subjects were given a minimum of 5 minutes rest between trials, but otherwise could rest as long as necessary.

Two subjects (ECRC residents) were unable to complete the chair rise task at any height. Nine were able to perform the task at all heights. As chair height increased from 17 to 22 inches, percent successful rises increased from 41% to 91%. Adding 1 inch of height to the 17-inch standard increased successful rises by 44% (from nine to 13). Adding 2 inches to the standard chair increased successful rises 77% (from nine to 16), and increasing 3 inches from the standard height increased successful chair rises 111% (from 9 to 19). Furthermore, in the 20 subjects able to complete the chair-rise task, mean self-reported difficulty score decreased by at least half as chair height was increased.

Moreover, of the 11 individuals who could not rise at the standard 17-inch chair height, four were successful at 18 inches and seven at 19 inches.

The authors noted that though two people in the study were unable to rise from even the highest height because of severe long-standing proximal muscle weakness, based on results, they believed seating height may need to be more closely scrutinized in locations frequented by frail elders. Augmentation of seat height by small increments facilitates chair rise performance.

4. Medicare Evidence Development & Coverage Advisory Committee (MEDCAC)

A MEDCAC meeting was not convened on this issue.

5. Evidence-Based Guidelines

Paralyzed Veterans of America Consortium for Spinal Cord Medicine. Preservation of upper limb function following spinal cord injury: a clinical practice guideline for health-care professionals. J Spinal Cord Med. 2005;28(5):434-470. doi:10.1080/10790268.2005.11753844

The Consortium for Spinal Cord Medicine, comprised of 17 organizations, developed these guidelines. Consultant methodologists (affiliated with Mt. Sinai School of Medicine) searched the international literature appropriate to the subject matter as well as graded and ranked the quality of research and conducted statistical meta-analyses and other specialized studies, as needed. Based on this information, each section of the Guidelines was written by expert panel members and then reviewed and modified as required, by clinical experts from each of the consortium’s organizations as well as their governing boards, and other select clinical experts and consumers. The work was also reviewed to consider antitrust, restraint of trade and health policy matters.

Among its many suggestions, the Consortium recommended that individuals with SCI who complete independent transfers, should perform level transfers wherever possible. It is further stated, that transfers should be made to surfaces that are at equal height or downhill, as uphill transfers increase forces in the upper limb. It was noted that the only way to ensure this type of transfer is through seat elevation.

The Consortium stated that evidence exists that transfers can lead to upper limb injury, because in a transfer, the shoulders must not only support the weight of the body, but also shift the trunk mass between the outreached hands. It observed that during transfers, research had shown pressure to be 2.5 times greater than that recorded when the shoulder was not bearing weight.

The Consortium maintained that the increase in pressure was likely due to the shift in body weight from the trunk through the clavicle and scapula and across the subacromial tissues to the humeral head. Further, it noted that the increased pressures stress the vasculature of the rotator cuff and could contribute to tendon degeneration.

6. Professional Society Recommendations / Consensus Statements / Other Expert Opinion

^aKoontz A, Toro M, Cooper RA. The Impact of Transfer Setup on the Performance of Independent Transfers: Final Report. Report Prepared for U.S. Access Board, Washington, DC. April 17, 2012.
Accessed 7/19/2021 at: https://www.herl.pitt.edu/ab/ABTransferSetupReportPhaseI.html  

This reference is in part discussed above. Besides studying the impact of transfer setup on the ability of study participants to perform transfers with vertical height differentials, the authors also performed an expert review of the available literature regarding transfers and the impact of setup.

Literature data bases were searched until June 2009. Though none of the scored articles were believed by expert reviewers to present strong or very strong evidence, it was thought that there was a consensus among studies that transfers to higher surfaces implied greater exertion of the upper limbs.

Schiappa V, Piriano J, Bernhardt L, et al. RESNA Position on the Application of Seat Elevation Devices for Power Wheelchair Users Literature Update (2019). 2019. Accessed on 3/15/2022 at https://www.resna.org/Portals/0/Documents/Position%20Papers/RESNA_App%20of%20Seat%20Elevation%20Devices%202019.pdf

A Rehabilitation Engineering & Assistive Technology Society of North America (RESNA) Position Paper is an official statement by RESNA. Position Papers are not intended to be formal, scientific meta-analyses. Rather, they use evidence and expert opinion to summarize best practices for Assistive Technology (AT) devices, evaluation, and service delivery. Position Papers provide a rationale for decision-making and professional skills for practitioners; and explain the medical necessity of AT devices and services for policy makers and funding sources.

It is RESNA’s position that power seat elevation devices are medically necessary, as this technology enables certain individuals to:

• Facilitate reach biomechanics, safety and range
• Improve transfer biomechanics, safety and independence
• Enhance visual orientation and line-of-sight
• Support physiological health, safety and well-being.
  • Decrease hyperlordotic position of the neck
  • Promote stable seated positioning
  • Reduce symmetric tonic neck reflex (STNR) activity
  • Improve safety with performance/participation in ADLs.
• Promote communication, social engagement, self-esteem and integration.
• Improve wheelchair pedestrian safety.

The Position Paper also states that a licensed, certified medical professional (i.e. physical or occupational therapist) should be involved with the assessment, prescription, trials and training in the use of the equipment to maximize safe use and functioning from the power seat elevation device. It is recommended this service be provided by an AT professional with the knowledge, skills and training in the provision of PWCs and power seating options such as an accredited supplier that employs a RESNA certified Assistive Technology Professional (ATP) who specializes in wheelchairs and who has direct, in-person involvement in the wheelchair selection.

In discussing the use of power seat elevation devices to improve transfer biomechanics during both SPTs and sit to stand transfers, RESNA summarizes by stating that the ability to change the seat height of the wheelchair in relation to the height of the surface being transferred to, can improve transfer biomechanics and efficiency, increase safety, reduce injury and fall risk and promote or maintain independence.

7. Public Comment

Public comments sometimes cite the published clinical evidence and give CMS useful information. Public comments that give information on unpublished evidence such as the results of individual practitioners or patients are less rigorous and therefore less useful for making a coverage determination.

CMS uses the initial public comments to inform its proposed decision. CMS responds in detail to the public comments on a proposed decision when issuing the final decision memorandum. All comments that were able to have personal health information redacted may be viewed in their entirety by using the following link: https://www.cms.gov/medicare-coverage-database/view/ncacal-public-comments.aspx?ncaid=309&ncacaldoctype=all&status=all&sortBy=status&bc=17

Initial Comment Period:  August 15, 2022 - September 14, 2022

During the initial 30-day public comment period following the release of the tracking sheet, CMS received 3,601 timely comments. Of these 3,601 comments, 57 were not published on the CMS website due to excessive personal health information content; however, all comments that were in scope and timely were considered for the proposed decision. Seventy-eight comments discussed only topics that are outside the scope of this national coverage analysis. Of the 3,523 in-scope comments, 3,468 supported reasonable and necessary coverage of seat elevation equipment for Group 3 PWCs. No commenters indicated an objection to reasonable and necessary coverage; and 55 commenters did not state a clear position on either aspect.

Most of the comments supported coverage of seat elevation equipment. Also, more than 2,000 of the commenters shared personal experiences using wheelchairs or shared their experiences as caregivers, family members, friends, neighbors, work and school colleagues and others in their communities.

The majority of comments were provided by wheelchair users, caregivers and other individuals. Comments were also provided by many advocacy organizations and individual advocates, professional societies and member organizations, state agencies, assistive technology and DME manufacturers and their employees, DME suppliers and their employees, health systems, hospitals, rehabilitation and other healthcare providers as well as individual healthcare professionals, providers of home and community-based services and other school and community professionals.

Many commenters provided references for our deliberation of this NCA. All such references were assessed for inclusion in our evidence review.

Second Comment Period:  February 15, 2023 - March 17, 2023

During the second 30-day public comment period, after the posting of the proposed decision memorandum, CMS received 2,133 timely comments, including one comment from an advocacy organization related to a neurological disease that included an attachment of comments from more than 500 of the association’s members representing individuals and caregivers/family of individuals. Of the 2,133 timely comments, 3 were not published on the CMS website due to extensive personal health information content; however, all comments that were in scope and timely were considered for this decision. Thirty comments only discussed topics that are outside the scope of this NCA. Of the 2,103 in-scope comments, the vast majority generally supported a benefit category determination of durable medical equipment as well as reasonable and necessary coverage of seat elevation equipment on PWCs. No commenters indicated an objection to reasonable and necessary coverage of power seat elevation equipment; and 30 commenters did not state a clear position on either aspect.

Most commenters also discussed other reasons that individuals use seat elevation equipment in addition to transfers. Many also submitted specific recommendations for CMS to add or modify the proposed criteria for reasonable and necessary coverage to include (1) non-weight-bearing transfers and, (2) reaching overhead to complete ADLs, IADLs and/or MRADLs. Additionally, some commenters provided recommendations for modifying the requirement for a specialty evaluation.

Many commenters also discussed seat elevation with respect to reducing cervical spine strain and injury, reductions in strain, injury, time, cost, and/or burden to caregivers (paid and unpaid). The majority of commenters also discussed the physical and mental health or psycho-social benefits of conducting eye-level conversations and having vertical visual access to the world. Many described seat elevation equipment on PWCs as “vital,” “necessary,” “essential,” and not a “convenience item” or “luxury item.” Many spoke in both broad and specific terms about how PWCs and seat elevation equipment provide independence, safety for transfers and daily activities, meaning their use reduces falls and injuries or increases safe functioning in the home and community. Many commenters also discussed PWCs and seat elevation equipment in terms of access and participation in home activities, school, community and employment. Also, many of the commenters shared personal experiences using wheelchairs or shared their experiences as caregivers, family members, friends, neighbors, work and school colleagues and others in their communities. Finally, many commenters discussed the financial costs of PWCs, seat elevation equipment, other required equipment and/or home modifications.

The majority of comments were provided by users of wheelchairs, caregivers and other individuals. Comments were also provided by many advocacy organizations and individual advocates. In addition, many comments were provided by health care professional societies and member organizations, state agencies including state Medicaid agencies, assistive technology and wheelchair manufacturers and their employees, DME suppliers and their employees, health systems, hospitals, rehabilitation and other healthcare providers as well as individual healthcare professionals, providers of home and community-based services and other school and community professionals.

Many commenters provided references for our deliberation of this NCA. All such references were assessed for inclusion in our evidence review.

Below is a more detailed description of comments with responses.

Comments and Responses:

General

Comment: Many comments were received from individuals who use PWCs as well as their family members, friends, caregivers, advocates and community members.

Response: We sincerely thank these commenters for openly sharing with us the burdens that their medical conditions impose. We have learned a great deal from these comments and are appreciative of the time and effort expended by all of the interested parties.

Power Wheelchair Groups

Comment: In response to our question in the proposed decision regarding whether the BCD and NCD should apply to users of Group 2 PWCs, many commenters specifically requested that individuals who use Group 2 PWCs be allowed coverage of associated power seat elevation equipment. In addition, many commenters stated that CMS should cover power seat elevation equipment on all PWCs generally, some specifying that the decision should be based on individual need, not broad diagnoses or categories/groups of PWCs. A smaller number of commenters also specifically mentioned Groups 1, 4 or 5 PWCs.

Response: As noted above, CMS finds that that the evidence is sufficient to determine that power seat elevation equipment is reasonable and necessary for individuals using complex rehabilitative power-driven wheelchairs under certain conditions. Complex rehabilitative power-driven wheelchairs are defined in 42 CFR 414.202, and include both Group 2 PWCs with power options that can accommodate rehabilitative features (for example, tilt in space) and Group 3 PWCs. Individuals who use these type of power wheelchairs are expected to use them for most, if not all, mobility related needs in the home.

In order to be covered under the final NCD, beneficiaries using a Group 2 complex rehabilitative power-driven wheelchair power wheelchair would need to meet the conditions of coverage in the NCD, as noted above:

1. The individual has undergone a specialty evaluation that confirms the individual’s ability to safely operate the seat elevation equipment in the home. This evaluation must be performed by a licensed/certified medical professional such as a physical therapist (PT), occupational therapist (OT), or other practitioner, who has specific training and expertise in rehabilitation wheelchair evaluations; and,

2. At least one of the following apply:

There are also Medicare-covered power wheelchairs that are not designated complex rehabilitative power-driven wheelchairs. These wheelchairs may be used by individuals whose physical and functional challenges are different than individuals who require complex rehabilitative power-driven wheelchairs. DME MACs will have discretion to determine reasonable and necessary coverage of power seat elevation equipment for individuals who use Medicare-covered PWCs other than complex rehabilitative power-driven wheelchairs. This allows for individualized decision making based on the unique characteristics of each individual who requests power seat elevation equipment on a claim-by-claim basis.

Comment: One commenter asked if power seat elevation equipment would be appropriate for an individual who required maximum assistance or is dependent (i.e. requires total assistance) in his/her transfer. Many other commenters stated that a weight bearing transfer, either through the upper extremities or lower extremities, should not be the only criteria of coverage, as the equipment will also be useful to those who perform non-weight bearing or dependent transfers.

Response: In responding to this comment, at issue is the distinction between performing a lift and performing a transfer. A transfer is a dynamic effort in which an individual aids in the transfer and is able to bear some weight on at least one lower extremity or on the upper extremities. A lift involves moving a person who cannot bear weight on any extremity (Canadian Centre for Occupational Health and Safety, 2018). The transfer related evidence presented in Section VIII.B.3 of the NCA (Internal Technology Assessment) describes the movement of individuals who perform these maneuvers independently, with/without transfer aides. As part of this response, we offer additional discussion below of individuals and their caregivers who may use mechanical lifting devices. 

We emphasize that the decision to use power seat elevation equipment is unique to every individual and depends on individual, caregiver and environmental circumstances, which must be evaluated for safety. Furthermore, we recognize that it may not be possible to accommodate a mechanical lift device in all environments, especially those of the home. Moreover, while a mechanical lift device may fit and be used in one room of a home, it may not be available or able to be optimally situated in other rooms of that same home (depending on type of lift, size, etc.). Therefore, we believe that for certain individuals, both mechanical lift devices and power seat elevation equipment on PWCs are appropriate in their home

In our decision language we have attempted to reflect that seat elevation devices are useful to those who transfer; i.e. who are able to bear weight through either their arms and/or a lower extremity(s), so that independently or with assistance, the individual can move from one surface to another, in a safe manner. This movement will depend on a combination of unique characteristics, including body size, balance, strength, coordination, range of motion, spasticity and cognition. Because of the individual nature of these characteristics, we believe there is no ‘typical’ transfer that can be described while using power seat elevating equipment and consequently we believe that safety during a transfer must be determined for each unique person through an appropriate evaluation.

Though it is well known that manual handling of patients (lifting, moving, sliding, transferring, or otherwise caring for a patient without mechanical assistance), presents a danger to healthcare professionals, we are also aware that manual patient handling may increase the risk of injury, pain, and negative health outcomes to patients (Matz et al., 2019). For example, in one study of 108 post stroke patients 60 years or older, 64% developed hemiplegic shoulder pain, (a common stroke sequela), sometime during the 6-month post hospital discharge study period. In that study, advice was given to caregivers as needed, so that transfer assists did not pull on the hemiplegic arm. However, it is reported that nine caregivers lifted their patients by pulling on the hemiplegic arm, even though six of them had received advice about correct lifting techniques. Furthermore, the authors found that it was the patients who required help with transfers at the time of hospital discharge who were more likely to suffer hemiplegic shoulder pain, with 18 of the 31 (58%) patients who were dependent for transfers on discharge reporting hemiplegic shoulder pain compared to 21 out of 70 (30%) patients who were independent in transfers (p<0.01). This relationship in hemiplegic shoulder pain and transfer dependency was also seen at 8 weeks post-discharge (p<0.05). The authors stated that those patients who required help in transfers were particularly at risk from incorrect handling and were more likely to develop hemiplegic shoulder pain (Wanklyn, Forster &Young, 1996).

Caregivers, including family members and friends, who provide manual lifting aid to patients are expected to expend considerable physical effort, often in awkward positions, to help complete these maneuvers in a safe manner. Research examining the topic of patient transfers/lifts has determined that even under ideal conditions, a maximum weight limit of 35 pounds should be designated for safe patient handling. However, given that ideal conditions are not the norm, there may be no method to safely perform a manual lift of a patient. Lift equipment is known to help reduce the biomechanical load and physical stresses associated with patient lifting and transferring tasks (Kucera et al., 2019), as has been intuitively stated by numerous commenters to this NCA.

Multifaceted safe patient-handling programs have been recommended to the health care industry as they not only have been found to result in fewer and less severe injuries to caregivers (e.g. nursing staff), but can also improve the quality of care received by those patients who are physically dependent. These programs include, among other components, appropriate ergonomic assessments and lifting equipment and have been shown to improve the care provided to patients in the realms of: (1) physical functioning, (2) activity level, (3) ability to maintain activities of daily living, and (4) fall prevention (Nelson, Collins, Siddharthan, Matz & Waters, 2008). Recommended techniques for patient movement call for appropriate transfer surface heights (Canadian Center for Occupational Health, 2018; Ji, Littman, Hettiarachchige & Piovesan, 2023; Waters, Nelson, Hughes and Menzel, 2009) which may depend on caregiver and patient anthropomorphic characteristics as well as the technique being used. Therefore, we believe that the adjustable height of power seat equipment may allow for a more ergonomically correct maneuver in the home and thus provide an improved quality of care for the patient during some assisted and dependent transfers.

NCD Coverage Criteria

Comment: Many commenters requested that CMS include coverage for power seat elevation equipment on PWCs in order to aid individuals in the performance of MRADLs, thereby improving the pain of cervical hyperlordosis, allowing for improved line of sight and decreasing the risk of falls due to loss of balance.

Response: We have reviewed the evidence on this subject that indicates seated wheelchair users work in a different humeral elevation space than their standing counterparts. We believe this information reflects, at least in part, the reaching that is required during the day to access standard countertops, appliances, etc. Though perhaps not the sole cause of the shoulder pathology and pain so often experienced by wheelchair users, the information presented provides at least one likely mechanism of how frequent, repetitive reaching may increase the potential for shoulder injury and pain for those who perform their daily activities from a seated, rather than a standing position. We therefore believe that power seat elevation equipment will allow the wheelchair user to adjust his/her height to at least perform daily tasks in a workspace similar to that of those who stand, and in doing so, extend the functional capabilities of their upper extremities, by perhaps reducing the risk of pain and pathology (a more detailed discussion of our decision is provided in Section IX of the NCA).  

It has also been suggested that the use of power seating equipment for activities of daily living may decrease the wheelchair accidents that result in falls during reaching activities (Chen et al., 2011; Nelson et al.; 2003, Sung, Trace, Peterson, Sosnoff & Rice, 2019) as well as prevent/improve any neck pain that may result from repeated hyperextension as one looks up, out of range of a comfortable line of site (Kirby, 2004). Further research in this area is encouraged.

Comment: Several stakeholders requested that the power seat elevation equipment be provided by a supplier that employs a RESNA-certified Assistive Technology Professional (“ATP”) who specializes in wheelchairs and who has direct, in-person involvement in the wheelchair selection for the beneficiary.

Response: We remind our commenters that per 42 CFR §424.57(c)(24), “All DMEPOS supplier locations, whether owned or subcontracted, must meet the DMEPOS quality standards and be separately accredited in order to bill Medicare. An accredited supplier may be denied enrollment or their enrollment may be revoked, if CMS determines that they are not in compliance with the DMEPOS quality standards.”

The CMS Final DMEPOS Quality Standards (effective January 9, 2018), Appendix B, stipulate that a supplier of certain wheelchairs, including Group 2 PWCs with power options and Group 3 PWCs, shall employ (W-2 employee) at least one qualified individual as a Rehabilitative Technology Supplier (RTS) per location. A qualified RTS is an individual that possesses one of the following credentials: Certified Rehabilitative Technology Supplier (CRTS) or Assistive Technology Professional (ATP) (effective 1/1/2009). The duties of the RTS are to:

1. Coordinate services with the prescribing physician to conduct face-to-face evaluations of the beneficiary in an appropriate setting and include input from other members of the health care team (i.e., PT, OT, etc.);
2. Provide the beneficiary with appropriate equipment for trial and simulation, when necessary;
3. Maintain in the beneficiary’s record all of the information obtained during the assessment; and implement procedures for assembly and set-up of equipment as well as a process to verify that the final product meets the specifications of the original product recommendation approved by the prescribing physician.

We believe that the supplier standards contained in the DMEPOS Quality Standards are sufficient to help ensure quality service to individuals obtaining power seat elevation equipment without being restrictive in their delineation of Assistive Technology Providers, and do not need to be repeated in the NCD.

Comment: Several commenters requested that CMS modify the proposed specialty evaluation criterion to specify that the PT, OT, or practitioner may have no financial relationship with the supplier.

Response: Financial relationship requirements are not established through an NCD as part of reasonable and necessary coverage.

Comment: A few commenters wondered if a downhill transfer would be classified as an uneven transfer.

Response: A downhill transfer is considered an uneven transfer.

Other comments

Comment: A few commenters asked if this NCD would apply to other government sponsored insurance programs such as Medicare Advantage and state Medicaid programs, as well as private insurance.

Response: The NCD would apply to Medicare and Medicare Advantage but not to other programs, including private insurance. A Medicare NCD establishes whether or not an item or service is covered (or non-covered) nationally under Title XVIII of the Act. The NCD is a controlling authority for Medicare contractors, Medicare Advantage Plans as specified in §417.414(b), and Administrative Law Judges as specified in §405.1060. NCDs are not controlling authorities outside of Title XVIII of the Act. 

Comment: Various commenters requested that CMS address a number of issues regarding classification of PWCs, general coverage of PWCs, modifications to NCD 280.3 (Mobility Assistive Equipment), providing coverage for standing equipment and telehealth opportunities for therapy and the power seat elevation specialty evaluation.

Response: We appreciate commenters concerns about these issues; however, these requests are outside the scope of this NCD analysis.

Comment: Several commenters have cited a personal need for various types of mobility equipment other than power seat elevation on PWCs.

Response: Although these comments are not within the scope of this policy decision, we would like to remind interested parties that Medicare covers many different types of mobility assistive equipment (e.g. scooters) and limb prostheses. Therefore, we encourage those who wish items of DMEPOS to discuss their individualized needs with their physicians.

Furthermore, to find Medicare suppliers of medical equipment, it may be useful to use the Medicare.gov “Search for Medical Equipment and Suppliers” website at https://www.medicare.gov/medical-equipment-suppliers. To find prosthetists, this same site may be used where the “equipment search” is for limb prostheses.

Should it be necessary, complaints regarding DMEPOS can be submitted by any of the following means:

(1)     Contact your supplier; or
(2)     Call Medicare at 1-800-MEDICARE (1-800-633-4227). TTY users can call 1-877-486-2048; or
(3)     If you received a competitively bid item in a competitive bidding area, call 1-800-MEDICARE and ask the 1-800-MEDICARE representative to send your complaint to the Competitive Acquisition Ombudsman. This Ombudsman responds to individual and supplier questions, issues, and complaints, and helps make sure your complaint is resolved.

Once you file your complaint, your supplier must let you know they received your complaint and are investigating it within 5 calendar days. The supplier must send you the result of your complaint and their response in writing within 14 calendar days.

IX. Analysis of a Reasonable and Necessary Determination

NCDs are determinations by the Secretary with respect to whether or not a particular item or service is covered nationally under title XVIII of the Social Security Act (§1869(f)(1)(B)) by Medicare (§1862(l) of the Act). Among other things, in order to be covered by Medicare, an item or service must fall within one or more benefit categories contained within Part A or Part B, and must not be otherwise excluded from coverage. As discussed in detail in Section IV of this decision, we find that power seat elevation equipment on PWCs falls within the benefit category for DME.

When making NCDs, it is important to consider whether the evidence is relevant to the Medicare population. In considering the generalizability of the results of the body of evidence to the Medicare population, it is necessary to consider at least the age, race and gender of the study participants.

This section of the decision memorandum provides an analysis of the evidence we considered during our review. The evidence includes the published medical literature and guidelines pertaining to our evidence questions. For details of each of the clinical trials, see the Evidence discussion in section VIII of this decision memorandum.

The following questions guided our review and analysis of the evidence below:

1. Is the evidence sufficient to demonstrate that power seat elevation equipment associated with a power wheelchair can improve the mobility limitation(s) related to wheelchair transfers that may constrain certain beneficiaries as they attempt to accomplish their MRADLs in customary locations in the home? These limitations may prevent the individual from accomplishing the MRADLs entirely, place the individual at reasonably determined heightened risk of morbidity or mortality secondary to the attempts to participate in MRADLs, and/or, prevent the individual from completing the MRADLs within a reasonable time frame.


2. Is the evidence sufficient to demonstrate that power seat elevation equipment associated with a power wheelchair can improve and/or reduce the pain and /or pathology associated with reach that may constrain certain beneficiaries as they attempt to accomplish their MRADLs in customary locations in the home? These limitations may prevent the individual from accomplishing the MRADLs entirely, place the individual at reasonably determined heightened risk of morbidity or mortality secondary to the attempts to participate in MRADLs, and/or, prevent the individual from completing the MRADLs within a reasonable time frame.

The analysis below evaluates power seat elevation equipment on PWCs to determine if its use is reasonable and necessary to help compensate for the mobility limitations that are experienced by certain Medicare beneficiaries either during transfers conducted from a seated or standing position and/or while reaching to accomplish MRADLs from the power wheelchair in customary locations of the home.

National Coverage Determination (NCD) 280.3, Mobility Assistive Equipment (MAE) states that “...MAE is reasonable and necessary for beneficiaries who have a personal mobility deficit sufficient to impair their participation in mobility-related activities of daily living (MRADLs) such as toileting, feeding, dressing, grooming, and bathing in customary locations within the home….”. Though that NCD does not pertain to seat elevation equipment, it states that the purpose of the generated coverage algorithm is to provide the appropriate MAE to “correct the mobility deficit” of the Medicare beneficiary. Mobility limitations that significantly impair the ability of beneficiaries to participate in one or more MRADLs in the home are those that:

Transfers

Wheelchair users must be able to execute transfers so that mobility can be accomplished. There are many different ways an individual can achieve a transfer depending on bodily impairments. For example, those whose lower extremities are too weak to raise their body weight from a chair, may use the strength of their arms to push their buttocks up and pivot around to another surface. Others, who may be able to achieve and maintain a standing position for a short amount of time, may raise themselves from a seated position, and pivot over a targeted surface, before seating themselves again. Regardless of how a transfer is performed, these maneuvers need to be accomplished so that MRADLs may be carried out in customary areas of the home.

We are aware that survey results have been published to convey the difficulties of performing non-level transfers. In one study of 112 wheeled mobility device users with diverse conditions (e.g. SCI, cerebral palsy, multiple sclerosis, amputation, Guillan-Barre, and other conditions), 38.4% of these individuals acknowledged that transferring to a surface higher than that of their own mobility device impacted their functional abilities. Of those individuals, 90.5% felt their participation in their community was limited when surfaces higher than their wheeled mobility device were encountered. These individuals used various wheeled mobility devices, including manual wheelchairs, PWCs, manual-power assist wheelchairs, and scooters as their primary wheeled mobility device (Koontz, Bass & Kulich, 2021).

Authors have published reports describing the usage patterns of persons who employ PWCs equipped with power seat elevation to accomplish transfers. For example, in one small pilot study of PWCs, three of nine participants whose wheelchairs were equipped with these devices reported using this equipment to facilitate transfers (Ding et al., 2008). In Sonenblum et al., 2021, 67% of a sample of 24 individuals with various disabilities (polio, muscular dystrophy, inclusion body myositis, cerebral palsy, multiple sclerosis, osteogenesis imperfecta, and other conditions) who had available to them a power operated seating system for various lengths of time, elevated to perform SPT transfers, sit-to-stand transfers, and dependent transfers at least once. Ten of the study participants used their wheelchair in an elevated position every single day of the study, while the remaining 14 had at least one day in which they did not use the elevating feature at all. Self-reporting suggested these individuals typically used their seat elevator in the home.

Moreover, in Mesoros et al., 2022, a retrospective study of self-reported outcomes (n= 1733 PWC users; 265 with seat elevating equipment) gathered through the Functional Mobility Assessment questionnaire (FMA)[4], it was demonstrated that those with seat elevating equipment on PWCs had significantly higher total FMA scores (indicating a higher satisfaction with overall functional mobility) and transfers scores. Furthermore, of those individuals with Group 3 wheelchairs, individuals with seat elevating equipment (n=240) also had significantly higher total FMA and transfer scores than those without (n=661).

While the above studies are of interest, they do not supply sufficient evidence to address our question regarding whether or not the home use of power seat elevation equipment on PWCs can improve the constraints that mobility limitations impose while performing a wheelchair transfer. We have found research that describes the specific biomechanical and electrophysiologic impacts of this equipment and demonstrates the consequences of its functional application. As mentioned above, we considered research that describes functional outcomes of transfers accomplished from various types of wheeled mobility devices and four-legged stationary chairs because we believe the motion and forces generated during the performance of these movement tasks (sitting transfers/ standing transfers,) provides information that describes how seat elevation equipment associated with PWCs affect a transfer from one surface to another.

Seated Transfers
In 2005, the Consortium for Spinal Cord Medicine Clinical Practice Guidelines (2005) published a recommendation regarding transfers in an effort to preserve upper limb integrity among individuals with SCI. This recommendation advised that those who experience a SCI and who transfer between surfaces using arm function, perform level or downhill transfers when possible, as the performance of an uphill transfer increased forces on the upper extremities. This recommendation however, appears to be significantly based on data obtained from a study of able-bodied males (Wang, Kim, Ford & Ford, 1994) and therefore does not generalize to the Medicare population who use PWCs.

Nevertheless, since 2005, this recommendation has been strengthened with biomechanical and electromyographic evidence obtained from wheelchair users who perform SPTs. Specifically, in ^aGagnon et al., 2008, it was found that the highest vertical reaction force value experienced during a SPT occurred under the trailing hand while accessing the higher target seat (i.e. during performance of an uphill transfer). The mean vertical reaction forces were also higher under the trailing hand when transferring to the higher target seat compared with a seat of the same height, even though the mean vertical forces under the leading hand were slightly lower. This finding indicates that transferring to a higher seat may require added effort of the trailing upper extremity, in that these forces may be associated with the high mechanical demands needed to initiate the lift phase of the transfer and optimize joint stability.

Additionally, ^aGagnon et al., 2009, notes that during a SPT, the electromyographic recruitment pattern mean intensity values of the biceps of the leading UE as well as the deltoid and the pectoralis major of the trailing UE were significantly greater when transferring to a high target seat in comparison to level and low target seats. This result may indicate that the biceps of the leading UE experiences an increased mechanical demand to support and pull the body’s weight to the higher target seat. Similarly, the deltoid and the pectoralis muscle may experience increased demand as the trailing UE supports and pushes the body weight to the elevated target surface. It is also possible that these forces potentiate the development of musculoskeletal injuries at the shoulder joint.

Moreover, in ^bGagnon, et al. (2008), though patterns of angular displacement and velocity were generally comparable among subjects with a SCI while transferring to high, low and same level target seats in a SPT, some differences of note were found. For example, the leading shoulder reached peak extension angular displacement and velocity when transfers to the highest target height were made; peak flexion values were found in the trailing UE at the same time. At the trailing elbow, peak elbow extension velocity was maximal during transfer to the high target seat and similarly the leading elbow attained its maximal extension velocity during the transfer to the high target seat. These combinations of movements, particularly of the shoulder, might jeopardize joint integrity and become a source of pain for the weight bearing joints of the upper extremities.

Finally, in Gagnon et al., 2005, ten spinal cord injured males were all able to perform a level transfer without difficulty. However, when asked to perform a posterior transfer in various support configurations onto an elevated surface of 10 cm, nine of the ten subjects could do so, but the success of this maneuver depended on hand placement. Seven subjects were able to perform the transfer when both hands were placed on the lower surface, five subjects were able to perform the transfer with one hand on the lower and one hand on the higher surface, and only three subjects were able to perform the transfer with both hands on the elevated surface. This result may demonstrate that constraints of UE placement create varying demands upon the transfer abilities of wheelchair users as they lift and shift their bodies from one surface to another.

The above evidence collectively indicates that performing SPTs to a target seat higher than the initial one, is likely more demanding of the upper extremities, particularly the shoulder, than performing a level SPT. We recognize that there are distinct limitations noted of the research. Sample sizes are generally small, and inter-subject variability may have been high as participant movement strategies were generally not constrained. Though subjects were encouraged in most studies to use their normal techniques to transfer, because researchers generally relied on laboratory set-ups, the investigative surroundings may not have mimicked that of the usual environment in which the subjects performed transfers. Within the studies noted, all of those represented above demonstrated SCIs. Though individuals with SCI represent a significant group within the wheelchair users’ population, they are not representative of the full population and the generalizability of these studies may be at risk.

Therefore, we sought corroboration of the increased UE demands imposed on wheelchair users during uneven transfers as compared to even transfers, from studies that demonstrated the functional capabilities of individuals performing SPTs to elevated versus level surfaces.

Toro et al, 2013 and ^aKoontz et al., 2012, reported the functional transfer capabilities of a generalized population of individuals with a broad variety of disabilities (e.g. SCI, multiple sclerosis, cerebral palsy, post-polio syndrome, traumatic brain injury, muscular dystrophy, stroke, spinal stenosis, rheumatoid arthritis, etc.) who performed level/non-level transfers of various vertical height differences from different types of wheeled mobility devices. This study of functional transfer capability demonstrated that over 90% of this varied population could transfer to a surface at a height similar to the median seat to floor height of their wheeled mobility devices. Fewer numbers of subjects could transfer above and below this height. For example, 89% of study individuals could transfer uphill 2 inches; 76% of individuals could transfer uphill 3 inches; and 63% of individuals could transfer uphill 4 inches. We believe these functional findings of SPTs indicate that uneven transfers as compared to even transfers require more exertion of at least the upper extremities when they are performed and therefore are in accord with the conclusions cited in the biomechanical and electromyographic studies (these studies are noted above). Based on the totality of the evidence, power seat elevation equipment that can provide the ability to perform a level transfer in situations where vertical height differentials exist between transfer surfaces, might help to mitigate the difficulty of accomplishing an uneven transfer as well as decrease the potential of shoulder injury and pain for those who repetitively are faced with these obstacles, thereby improving the mobility deficits of certain individuals who use a power wheelchair.

Sit to stand transfers
Some wheelchair users are able to come to a standing position from a chair and perform a standing transfer (e.g. standing pivot transfer). At times, the UEs are used to offset weakness in the legs, as are other compensatory maneuvers during this weight-bearing activity (Butler, Nene & Major, 1991; Sanford, Echt & Malassigne, 2000).

The study by Toro et al., 2013 and ^aKoontz et al., 2012, includes a few study participants who may have performed a standing transfer from their wheeled mobility devices in order to perform the required level/nonlevel transfers. The data to separately study these few individuals is not available.

We found no studies that described the ability of wheelchair users to perform a sit to stand transfer of any type from incremental wheelchair seat heights. Therefore, we expanded our search criteria and considered studies of individuals who attempted to rise (successfully or not), from traditional and otherwise stationary chair furniture. The investigation by Finlay et al., 1983, showed that frail elderly subjects who were unable to arise from an armchair without assistance, gained increased independence in their transfers if allowed to change from the sit to stand positions from an elevated height rather than the lower height of standard furniture. However, the results of this study may be confounded by the use of arm rests that would not be positioned as those on a power wheelchair. Still, Weiner et al., (1993) demonstrated a similar finding in 13 subjects evaluated who could not rise from a 17-inch standard armless chair; four could rise when the chair seat height was increased by one inch, three more could rise when the chair seat height was increased by 2 inches, and three more when the chair height was increased by 3 inches. We believe that the study by Burdett et al, 1985, does not provide useful information on the topic because of its extremely small sample size.

Similar to our analysis of the studies of seated transfers, we find the conclusions from these studies of sit to stand transfers are limited by their small sample size, lack of specificity and potential variety in the diagnoses of the subjects, as well as the unconstrained methods of rising that may have been used. The subjects in Findlay et al., (1983), and Weiner et al., (1993) were members of a community presumed equivalent to either a skilled or non-skilled nursing home. While the exact nature of their disabilities is unknown, they most likely represent a frail elderly community. A challenge with the studies performed, and used in this analysis, is that it is not clear which study subjects fulfill criteria for PWCs. Some of the study participants would likely be functional ambulators though the specifics of that act (e.g. distance, duration, speed, assistive technology used) were not observed or recorded by the investigators. For example, in Findley et al., (1983) and Weiner et al (1993), only the sit to stand movement was studied. A sit to stand movement is a different task than a sit to walk movement in mechanics and control (van der Kruk et al., 2021). Therefore, we do not believe the study participants’ ability to ambulate influenced the results of these studies as it relates to this analysis. We believe that many of the subjects studied may exhibit weakness patterns similar to that of individuals with neuromuscular disease (albeit without spasticity) and myopathy and likely share characteristics of the Medicare population who utilize PWCs. Further, this evidence demonstrates that elevating the seat height for those whose lower limbs are weakened, decreases extremity efforts required to change one’s position from sit to stand and functionally improves the ability to rise from a seated position in order to place oneself in a position to accomplish standing transfer. Moreover, Weiner et al. 1993, specifically demonstrates that elevating seat height even in an armless chair, without a push off from the upper extremities, allows the sit to stand transfer to be accomplished more easily by many who cannot perform this task at lower seat heights. Consequently, to the extent individuals may not have been able to rise from a lower wheelchair seat or would have repetitively placed injurious amounts of pressure upon their shoulders in order to accomplish a sit to stand transfer, based on this study raising the height of the seated position may mitigate these mobility impediments.

Therefore, based on the totality of the evidence reviewed, including the electromyographic, force related, kinematic and functional information gathered, we propose that the evidence is sufficient to conclude that power seat elevation equipment is expected to help reduce the transfer related mobility limitations of those individuals who use PWCs to move about their homes and thus are reasonable and necessary for certain Medicare individuals.

Reaching

The use of power seat elevation on PWCs can not only reduce the transfer related mobility limitation of individuals who use PWCs, but can also decrease mobility limitations related to reaching activities associated with MRADLs. For example, in Ding et al., 2008, it was noted that five out of nine subjects whose wheelchairs were equipped with seat-elevation functions reported using the seat elevator to reach things either at home, work, or in public. In Mesoros et al., 2022, the self-reported outcomes (n= 1733 PWC users; 265 with seat elevating equipment) gathered through the Functional Mobility Assessment questionnaire (FMA) of individuals with power seat elevating equipment on PWCs demonstrated significantly higher reach scores than those without seat elevating equipment; similar findings were demonstrated in those individuals with/without seat elevating equipment specifically on Group 3 PWCs.

In the ergonomic literature related to occupational injuries, it is accepted by many that there is an association between arm elevation at work and shoulder pain and disorders (Waersted, Koch & Veiersted, 2020). However, there has only been limited study of the connection between similar repetitive overhead reach and the performance of activities of daily living by those individuals who remain in the seated wheelchair position every day.  

As we have noted, shoulder pain is the most frequently reported type of musculoskeletal pain in wheelchair users and is thought mainly related to rotator cuff disorders (Liampas et al., 2021). Mechanical subacromial impingement, compression and/or abrasion of the rotator cuff tendons beneath the coracoacromial arch, has long been considered a mechanism for the development of rotator cuff pathology (Lawrence, Braman & Ludewig, 2020). Chronic overuse has been noted as one possible mechanism of this pain in users of wheelchairs (Liampas et al., 2021).

Clinically, the hallmark of impingement syndrome has been considered to be pain caused by subacromial rotator cuff compression in an arc of movement between 70˚ and 120˚ of humerothoracic elevation. However, this information is based on cadeveric investigations. More recent studies suggest that the rotator cuff insertion site is closest to the acromial arch at much lower humerothoracic elevation angles than previously thought, i.e. those being between 40˚ and 75˚. Though it is likely that other anatomic factors of the shoulder joint play into rotator cuff mechanics, the glenohumeral elevation angle has been consistently found to impact the available subacromial space during shoulder elevation motion and is thought to play into the pathology of the rotator cuff (Lawrence, Braman, Ludewig, 2020). However, pain provocation by injury to the rotator cuff and reproduced by clinical maneuvers in movement arcs of 70˚-120˚, may be the result of mechanisms other than just mechanical subacromial compression. For example, tendon injury due to mechanical subacromial compression occurring at lower angles may result in symptoms at higher angles where the muscle force required increases to counteract the rotational forces about the shoulder (Lawrence et al., 2017).

Rotator cuff pathology is not uncommon in the able-bodied; however, it occurs more frequently in the user of a wheelchair. In one study, paraplegic patients demonstrated a 4-fold higher prevalence for sustaining rotator cuff lesions than did sex and age matched able bodied individuals (63% vs 15%) (Akbar et al., 2010). Obviously, the seated positioning of wheelchair users means that a variety of activities of daily living are performed differently than for those who can stand. Objects need to be lifted to/from overhead more often, creating high moments that need to be counterbalanced with large muscular forces, potentially leading to pain and pathology of the upper extremity joints (Lawrence et.al., 2017).

In order to answer our evidentiary question regarding reaching to accomplish MRADLs, we cited two studies by van Drogelen and colleagues. These investigations demonstrated that the glenohumeral contact forces, glenohumeral joint moments, and muscular forces of the shoulder of paraplegic and tetraplegic individuals were found to be no different as compared to those of able-bodied persons while performing a reaching activity. This information however, does not aid us to draw conclusions relevant to our evidentiary question. In these studies, the platform to be reached was 0.5m high (approximately 20 inches) and it is not possible to determine the position of the arm during the task, except to state, as did the authors, that no movement above shoulder level occurred. Furthermore, the data obtained from the comparison of able-bodied individuals performing a reaching task seated from a wheelchair, as opposed to standing, does not represent the real-life conditions that pertain to our analysis.

Therefore, we believe it prudent to focus on the studies by Goodwin and colleagues who reported on various characteristics of the humeral elevation workspace that are used by those with spinal cord injuries and matched able-bodied controls during the course of a typical day. In ^aGoodwin et al., 2021, it is reported that the SCI cohort as compared to matched able-bodied controls, spent a significantly higher percentage of time in positions of humeral elevation similar to those associated with rotator cuff tendon compression (30˚-60˚) in both the dominant and non-dominant arms. In Goodwin et al., 2021, it was demonstrated that those using a manual wheelchair spent significantly more time in dynamic activities at 60˚-90˚ and 90˚-120˚ humeral elevation than did their age and sex matched counterparts. Those using a manual wheelchair also exhibited longer consecutive dynamic periods in 30˚-60˚, 60˚-90˚ and 90˚-120˚ on the dominant side than their matched controls.

There are limitations to both studies led by Goodwin. For example, the data collection periods in these small samples were short - one to two days - and may not have represented usual trends in a participant’s life even though “typical” days of activities were studied. Additionally, other factors that may influence shoulder injury, such as muscular strength, plane of shoulder elevation, shoulder load and scapular motion, were also not accounted for.

Nevertheless, these studies indicate that the SCI population who use a wheelchair spend a significantly higher percentage of time in humeral elevations (30˚- 60˚) associated with compression of the rotator cuff than do those individuals who are able-bodied. Furthermore, on the dominant side, it is demonstrated that the manual wheelchair users spend a larger part of their day using their upper extremity dynamically in the potentially painful humeral ranges of 60˚-90˚ and 90˚-120˚ than did their able-bodied counterparts. These movement arcs match those required to perform such activities of daily living like reaching into shelves and over high counters (Goodwin et al., 2021), as well as other functional activities (e.g. cooking) that may often require reach near or above shoulder height (Hastings & Goldstein, 2004).

We believe these findings indicate that the repetitive nature of reaching in order to access the vertical environment associated with many activities of daily living, is likely to contribute to the pain and pathology of the shoulder that is so frequently reported in wheelchair users. We understand that the evidence presented is concentrated in the population of individuals who experience spinal cord injuries and use manual wheelchairs. However, it is obvious that those who use a wheelchair will share the characteristic of working more than “normal” in elevated humeral workspaces. Based on the evidence, we believe that power seat elevation equipment can allow the wheelchair user to adjust his/her height to perform daily tasks in a workspace similar to those who stand, thereby extending the functional capabilities of their upper extremities. Consequently, we believe it reasonable and necessary to cover power seat elevation equipment on PWCs so that certain individuals can perform their mobility related activities of daily living associated with reaching, in customary locations in their homes.

Specialty Evaluation

We believe it is important that individuals receive appropriate equipment to best address their individual needs. RESNA (2019) noted: “A licensed, certified medical professional (i.e. physical or occupational therapist) should be involved with the assessment, prescription, trials and training in the use of the equipment to maximize safe use and functioning from the power seat elevation device. It is recommended this critical component be provided by an AT professional with the knowledge, skills and training in the provision of PWC’s and power seating options such as an accredited supplier that employs a RESNA certified Assistive Technology Professional (ATP) who specializes in wheelchairs and who has direct, in-person involvement in the wheelchair selection.”

Based on the totality of evidence presented, we believe it is appropriate to first require that all individuals who may receive power seat elevation equipment on PWCs undergo a specialty evaluation that confirms the individual’s ability to safely operate the seat elevation equipment in the home. This evaluation must be performed by a licensed/certified medical professional such as an occupational or physical therapist or other practitioner as recommended by the RESNA Position Paper, who should possess at a minimum, the education and work experience necessary to competently evaluate the needs of the power wheelchair user, coordinate and select the appropriate technology for the individual based on the prescriber’s orders, as well as provide training in the use, safe operation and maintenance requirements of the prescribed technology. We believe this is necessary to establish, as best as possible, that the individual receiving the power seat elevation equipment has been appropriately evaluated and educated to allow him/her to physically and cognitively be able to operate the equipment in the home without causing harm to themselves or others.

Summary

As a cohort, we believe that those who use complex rehabilitative power-driven wheelchairs to accomplish ambulation and/or MRADLs in their homes are most likely to require power seat elevation equipment to preserve the function of their shoulders. Moreover, with the expansion of the benefit category, we agree that some users of PWCs, other than those designated as complex rehabilitative power-driven wheelchairs, may also benefit from power seat elevation equipment.

Therefore, we believe power seat elevation equipment is reasonable and necessary for individuals using complex rehabilitative power-driven wheelchairs, as defined at 42 CFR §414.202, when the following conditions are met:

1. The individual has undergone a specialty evaluation that confirms the individual’s ability to safely operate the seat elevation equipment in the home. This evaluation must be performed by a licensed/certified medical professional such as a physical therapist (PT), occupational therapist (OT), or other practitioner, who has specific training and experience in rehabilitation wheelchair evaluations; and,

2. At least one of the following apply:

a. The individual performs weight bearing transfers to/from the power wheelchair while in the home, using either their upper extremities during a non-level (uneven) sitting transfer and/or their lower extremities during a sit to stand transfer. Transfers may be accomplished with or without caregiver assistance and/or the use of assistive equipment (e.g. sliding board, cane, crutch, walker, etc.); or,

b. The individual requires a non-weight bearing transfer (e.g. a dependent transfer) to/from the power wheelchair while in the home. Transfers may be accomplished with or without a floor or mounted lift; or,

c. The individual performs reaching from the power wheelchair to complete one or more mobility related activities of daily living (MRADLs) such as toileting, feeding, dressing, grooming and bathing in customary locations within the home. MRADLs may be accomplished with or without caregiver assistance and/or the use of assistive equipment.

In addition, the DME MAC has discretion to determine reasonable and necessary coverage of power seat elevation equipment for individuals who use Medicare covered PWCs other than complex rehabilitative power-driven wheelchairs. Allowing Medicare contractors to make these reasonable and necessary decisions provides the best mechanism to make power seat elevation equipment available to individuals who need it, as it will allow for individualized decision making based on the unique medical needs and functional deficits of each individual who requests this equipment.

Health Disparities
During the past 20 years there has been increasing evidence that demonstrates health disparities for people with disabilities (Iezzoni et al., 2021). Several studies have attempted to determine whether inequalities exist in wheelchair customizability among those who use PWCs.

In Hunt et al., 2004, a convenience sample survey of 155 power wheelchair users was studied to determine if there were disparities in wheelchair customizability within the thirteen Model Spinal Cord Injury Systems who participated in this study. Survey information was obtained from the participants via telephone, in-person interviews and the national database. PWCs were divided into three categories: the customizable PWCs were PWCs with either programmable controls and at least one of the following features: (1) the ability to accommodate an advanced seating system such as tilt in space or standing; (2) a suspension system; or (3) a high torque motor and stronger frame. The second category of wheelchair was standard power chairs with programmable control; the third category was standard PWCs. It was found that the percentage of standard programmable (46%) and customizable wheelchairs (54%) used by the sample population was similar. No one received standard PWCs without programmable controls. However, minorities with low socioeconomic backgrounds (low income, public funding, less education) were more likely to have standard programmable PWCs. Older individuals were also more likely to have standard programmable PWCs.

In Groah, Ljungberg, Lichy, Oyster & Boninger, 2014, a cross-sectional study was performed at six Spinal Cord Injury Model System centers. The pertinent aim of this study was to determine if individuals with SCI were receiving PWCs (Groups 3 and 4) with customizability and programable controls (depending on need), and if not, to determine if disparities exist based on funding source. Data was collected by self- report questionnaire and face to face interview. It was reported that for 134 power wheelchair users with a SCI, the proportion of individuals who received customizable PWCs with programmable controls from Workers Compensation /U.S. Department of Veterans Affairs (n =13) was 100%. The proportion of individuals who received customizable PWCs from other funding sources was 95.1% private insurance/prepaid plans (n =41), 86.0% Medicaid/Department of Vocational Rehabilitation (n =43), 83.8% Medicare (n=31), and 50.0% self-pay (n= 6). Differences in the type of wheelchair provided were independent of age, gender or race. The authors concluded that disparities in wheelchair procurement by insurance provider exist. However, the authors also stated that their findings needed to be correlated with long term risks, such as overuse injuries, breakdowns and participation.

In Myaskovsky et al., 2017, a cross sectional cohort study was performed in order to assess the association of race to the quality of wheelchair for veterans with SCI whose wheelchair was prescribed and paid for by the Veterans Affairs Healthcare System (VA). (The VA prescribes more than 3600 wheelchairs annually to those with SCI). Data was collected from Veterans by structured face to face questionnaire or by mail at three VA Medical Centers affiliated with academic medical centers.

To evaluate power wheelchair quality, research assistants coded speed, range, and customizable options (e.g., power tilt and power recline). Those wheelchairs of the highest quality category were defined as being most programmable, customizable and possessed the ability to obtain the highest speeds. Analyses of the data obtained were restricted to white and African American (AA) participants.

The authors found that although the estimated odds of getting higher quality wheelchairs were lower for African Americans compared to white Veterans, those racial differences were not statistically significant. However, other wheelchair characteristics were found to be predictive of wheelchair quality in power wheelchair users. For example, the quality of PWCs varied by income in white Veterans, with those who were poorer receiving lower quality equipment. In contrast, for AA Veterans, power wheelchair quality varied only by study site. (Veterans with amputated limb(s) were also studied for this investigation; however, there was no wheelchair quality variation found in this group.)

The ability of people who are mobility impaired to successfully regain that function in the home depends on access to appropriate equipment, including wheelchairs, regardless of socioeconomic characteristics. The right wheelchair must allow for safety and security, as well as independence. By providing coverage of power seat elevation equipment for PWCs for those for whom it is reasonable and necessary, we are providing beneficiaries with additional management opportunities to help improve the mobility limitations they experience.

X. Conclusion

CMS finds that power seat elevation equipment on Medicare-covered PWCs falls within the benefit category for DME. This BCD expands the scope of the proposed benefit category decision based on consideration of public comments on the proposed decision memorandum. Section 1861(n) of the Act defines what items are considered to be DME. 42 CFR 414.202 provides additional details on the definition of DME.

CMS finds in this national coverage analysis that that the evidence is sufficient to determine that power seat elevation equipment is reasonable and necessary for individuals using complex rehabilitative power-driven wheelchairs, as defined at 42 CFR §414.202, when the following conditions are met:

1. The individual has undergone a specialty evaluation that confirms the individual’s ability to safely operate the seat elevation equipment in the home. This evaluation must be performed by a licensed/certified medical professional such as a physical therapist (PT), occupational therapist (OT), or other practitioner, who has specific training and experience in rehabilitation wheelchair evaluations; and,

2. At least one of the following apply:

In addition, the Durable Medical Equipment Medicare Administrative Contractor (DME MAC) has discretion to determine reasonable and necessary coverage of power seat elevating equipment for individuals who use Medicare covered PWCs other than complex rehabilitative power-driven wheelchairs.

See Appendices B and C for NCD Manual language. Revisions to Appendix C also include technical updates to the narrative background to reflect the current regulations at 42 CFR §§414.202, 414.114, and 414.240.

APPENDIX A

General Methodological Principles of Study Design
(Section VIII of the Decision Memorandum)

When making national coverage determinations, CMS evaluates relevant clinical evidence to determine whether or not the evidence is of sufficient quality to support a finding that an item or service is reasonable and necessary. The overall objective for the critical appraisal of the evidence is to determine to what degree we are confident that: 1) the specific assessment questions can be answered conclusively; and 2) the intervention will improve health outcomes for patients.

We divide the assessment of clinical evidence into three stages: 1) the quality of the individual studies; 2) the generalizability of findings from individual studies to the Medicare population; and 3) overarching conclusions that can be drawn from the body of the evidence on the direction and magnitude of the intervention’s potential risks and benefits.

The methodological principles described below represent a broad discussion of the issues we consider when reviewing clinical evidence. However, it should be noted that each coverage determination has its unique methodological aspects.

Assessing Individual Studies

Methodologists have developed criteria to determine weaknesses and strengths of clinical research. Strength of evidence generally refers to: 1) the scientific validity underlying study findings regarding causal relationships between health care interventions and health outcomes; and 2) the reduction of bias. In general, some of the methodological attributes associated with stronger evidence include those listed below:

• Use of randomization (allocation of patients to either intervention or control group) in order to minimize bias.
• Use of contemporaneous control groups (rather than historical controls) in order to ensure comparability between the intervention and control groups.
• Prospective (rather than retrospective) studies to ensure a more thorough and systematical assessment of factors related to outcomes.
• Larger sample sizes in studies to demonstrate both statistically significant as well as clinically significant outcomes that can be extrapolated to the Medicare population. Sample size should be large enough to make chance an unlikely explanation for what was found.
• Masking (blinding) to ensure patients and investigators do not know to that group patients were assigned (intervention or control). This is important especially in subjective outcomes, such as pain or quality of life, where enthusiasm and psychological factors may lead to an improved perceived outcome by either the patient or assessor.

Regardless of whether the design of a study is a randomized controlled trial, a non-randomized controlled trial, a cohort study or a case-control study, the primary criterion for methodological strength or quality is to the extent that differences between intervention and control groups can be attributed to the intervention studied. This is known as internal validity. Various types of bias can undermine internal validity. These include:

• Different characteristics between patients participating and those theoretically eligible for study but not participating (selection bias).
• Co-interventions or provision of care apart from the intervention under evaluation (performance bias).
• Differential assessment of outcome (detection bias).
• Occurrence and reporting of patients whodo not complete the study (attrition bias).

In principle, rankings of research design have been based on the ability of each study design category to minimize these biases. A randomized controlled trial minimizes systematic bias (in theory) by selecting a sample of participants from a particular population and allocating them randomly to the intervention and control groups. Thus, in general, randomized controlled studies have been typically assigned the greatest strength, followed by non-randomized clinical trials and controlled observational studies. The design, conduct and analysis of trials are important factors as well. For example, a well-designed and conducted observational study with a large sample size may provide stronger evidence than a poorly designed and conducted randomized controlled trial with a small sample size. The following is a representative list of study designs (some of that have alternative names) ranked from most to least methodologically rigorous in their potential ability to minimize systematic bias:

Randomized controlled trials
Non-randomized controlled trials
Prospective cohort studies
Retrospective case control studies
Cross-sectional studies
Surveillance studies (e. g., using registries or surveys)
Consecutive case series
Single case reports

When there are merely associations but not causal relationships between a study’s variables and outcomes, it is important not to draw causal inferences. Confounding refers to independent variables that systematically vary with the causal variable. This distorts measurement of the outcome of interest because its effect size is mixed with the effects of other extraneous factors. For observational, and in some cases randomized controlled trials, the method in that confounding factors are handled (either through stratification or appropriate statistical modeling) are of particular concern. For example, in order to interpret and generalize conclusions to our population of Medicare patients, it may be necessary for studies to match or stratify their intervention and control groups by patient age or co-morbidities.

Methodological strength is, therefore, a multidimensional concept that relates to the design, implementation and analysis of a clinical study. In addition, thorough documentation of the conduct of the research, particularly study selection criteria, rate of attrition and process for data collection, is essential for CMS to adequately assess and consider the evidence.

Generalizability of Clinical Evidence to the Medicare Population

The applicability of the results of a study to other populations, settings, treatment regimens and outcomes assessed is known as external validity. Even well-designed and well-conducted trials may not supply the evidence needed if the results of a study are not applicable to the Medicare population. Evidence that provides accurate information about a population or setting not well represented in the Medicare program would be considered but would suffer from limited generalizability.

The extent to that the results of a trial are applicable to other circumstances is often a matter of judgment that depends on specific study characteristics, primarily the patient population studied (age, sex, severity of disease and presence of co-morbidities) and the care setting (primary to tertiary level of care, as well as the experience and specialization of the care provider). Additional relevant variables are treatment regimens (dosage, timing and route of administration), co-interventions or concomitant therapies, and type of outcome and length of follow-up.

The level of care and the experience of the providers in the study are other crucial elements in assessing a study’s external validity. Trial participants in an academic medical center may receive more or different attention than is typically available in non-tertiary settings. For example, an investigator’s lengthy and detailed explanations of the potential benefits of the intervention and/or the use of new equipment provided to the academic center by the study sponsor may raise doubts about the applicability of study findings to community practice.

Given the evidence available in the research literature, some degree of generalization about an intervention’s potential benefits and harms is invariably required in making coverage determinations for the Medicare population. Conditions that assist us in making reasonable generalizations are biologic plausibility, similarities between the populations studied and Medicare patients (age, sex, ethnicity and clinical presentation) and similarities of the intervention studied to those that would be routinely available in community practice.

A study’s selected outcomes are an important consideration in generalizing available clinical evidence to Medicare coverage determinations. One of the goals of our determination process is to assess health outcomes. These outcomes include resultant risks and benefits such as increased or decreased morbidity and mortality. In order to make this determination, it is often necessary to evaluate whether the strength of the evidence is adequate to draw conclusions about the direction and magnitude of each individual outcome relevant to the intervention under study. In addition, it is important that an intervention’s benefits are clinically significant and durable, rather than marginal or short-lived. Generally, an intervention is not reasonable and necessary if its risks outweigh its benefits.

If key health outcomes have not been studied or the direction of clinical effect is inconclusive, we may also evaluate the strength and adequacy of indirect evidence linking intermediate or surrogate outcomes to our outcomes of interest.

Assessing the Relative Magnitude of Risks and Benefits

Generally, an intervention is not reasonable and necessary if its risks outweigh its benefits. Health outcomes are one of several considerations in determining whether an item or service is reasonable and necessary. CMS places greater emphasis on health outcomes actually experienced by patients, such as quality of life, functional status, duration of disability, morbidity and mortality, and less emphasis on outcomes that patients do not directly experience, such as intermediate outcomes, surrogate outcomes, and laboratory or radiographic responses. The direction, magnitude, and consistency of the risks and benefits across studies are also important considerations. Based on the analysis of the strength of the evidence, CMS assesses the relative magnitude of an intervention or technology’s benefits and risk of harm to Medicare beneficiaries.

APPENDIX C
Medicare National Coverage Determinations Manual

Draft

This draft NCD is subject to formal revisions and formatting changes prior to the release of the final NCD contractor instructions and publication in the Medicare National Coverage Determinations Manual.

Table of Contents
(Rev.)

280.1 - Durable Medical Equipment Reference List (Rev. Issued: XXX, Effective: May 16, 2023)

The durable medical equipment (DME) list that follows is designed to facilitate the A/B MAC (HHH) and DME MACs processing of DME claims. This section is designed as a quick reference tool for determining the coverage status of certain pieces of DME and especially for those items commonly referred to by both brand and generic names. The information contained herein is applicable (where appropriate) to all DME national coverage determinations (NCDs) discussed in the DME portion of this manual. The list is organized into two columns. The first column lists alphabetically various generic categories of equipment on which NCDs have been made by the Centers for Medicare & Medicaid Services (CMS); the second column notes the coverage status.

In the case of equipment categories that have been determined by CMS to be covered under the DME benefit, the list outlines the conditions of coverage that must be met if payment is to be allowed for the rental or purchase of the DME by a particular patient, or cross-refers to another section of the manual where the applicable coverage criteria are described in more detail. With respect to equipment categories that cannot be covered as DME, the list includes a brief explanation of why the equipment is not covered. This DME list will be updated periodically to reflect any additional NCDs that CMS may make with regard to other categories of equipment.

When the A/B MAC (HHH) or DME MAC receives a claim for an item of equipment which does not appear to fall logically into any of the generic categories listed or has not been addressed in the processes outlined in regulations at 42 CFR §§414.114 and 414.240, the A/B MAC (HHH) or DME MAC has the authority and responsibility for deciding whether those items are covered under the DME benefit.

These decisions must be made by each A/B MAC (HHH) and DME MAC based on the advice of its medical consultants, taking into account:

• The Medicare Claims Processing Manual, Chapter 20, “Durable Medical Equipment, Prosthetics and Orthotics, and Supplies (DMEPOS).”

• Whether the item has been approved for marketing by the Food and Drug Administration (FDA) and is otherwise generally considered to be safe and effective for the purpose intended; and,

• Whether the item is reasonable and necessary for the individual patient.

The term DME is defined as equipment which, according to 42 CFR §414.202:

• Can withstand repeated use; i.e., could normally be rented and used by successive patients;

• Effective with respect to items classified as DME after January 1, 2012, has an expected life of at least 3 years;

• Is primarily and customarily used to serve a medical purpose;

• Generally is not useful to a person in the absence of illness or injury; and,

• Is appropriate for use in a patient’s home.

Durable Medical Equipment Reference List