We Got Your Back!

Q1: Considering the clinical needs of SCI patients, what should a wheelchair back be designed to do?

Mike Babinec, OTR/L, ATP, product manager, power wheelchair electronics/seating & positioning, Invacare Corp.:

Above all, wheelchair backs used with the spinal cord injured population need to be comfortable and need to provide the appropriate level of support for function.

Any wheelchair back that effectively meets the needs of a spinal cord injured individual needs to provide positioning support for atrest postures, as well as functional support during activities of daily living and mobility. Just as important as supporting posture for function is preventing poor postures — with their resultant long-term ill side effects.

Recent changes in wheelchair back provision (are leading) to back upholstery with newer fabrics giving increased attention to management of heat and moisture build-up — important for skin integrity, sitting tolerance, and comfort.

Jay Doherty, OTR, ATP, clinical education manager, Quantum Rehab:

A well-crafted wheelchair back will assist in maintaining proper pelvic position and natural spinal curves. This will assist in aligning and supporting the joints so that maximal mobility and range of motion is available during all functional activities. Also, the back should lock in solid enough to prevent flex, which leads to loss of energy and increased fatigue while propelling the wheelchair.

Elizabeth Stevens, MA, OTR/L, ATP, clinical/educational director, The Comfort Company:

The physical abilities of those with spinal cord injury, just as those with other mobility-limiting conditions such as cerebral palsy or multiple sclerosis, fall on a spectrum.

This range of physical strengths and challenges, along with lifestyle requirements, will determine how the back support needs to perform in order to maximize his/her functional independence. It may need to provide control only to the sacral-lumbar spine to avoid sacral sitting and increased pressure, or to the entire trunk and allow for the attachment of other positioning devices (laterals, chest harness, head support, etc.).

Tom Whelan, VP clinical content & research, Sunrise Medical:

The back must be available in many heights so the level of support can be matched to the user. There should be varying levels of lateral contour to match the user’s level of trunk control and functional stability.

The back should be easily modified to support the shape of the user’s spinal posture. For the more involved user with postural deformities, the back’s ability to accept secondary postural supports, such as lateral supports and headrests, is important. The back system should be as light as possible if the user is independent in manual propulsion. How easy the back is to remove and reattach may be very important to users that need to fold or collapse their own chair, for example transfer independently into the car and drive. A properly fitted wheelchair back provides a stable support for the trunk that enhances function and facilitates proper posture. A firm back may enhance propulsion efficiency by providing a stable base to push from.

Q2: How do different back heights – low, mid, high – impact client functionality?

Whelan : The height of the back is a reflection of the user’s level of involvement. A low thoracic injury who has control of the muscles in the upper trunk and upper extremities may need a back that barely rises above the lumbar spine. The back’s main purpose is to provide proper pelvic and lumbar support, while not interfering with trunk and arm use.

At the other end of the spectrum, a person who is quadriplegic may need a much taller back that at a minimum supports the spine up to the apex of the kyphosis of the thoracic spine. If the user is in recline or tilt, the back should support the entire trunk, and a headrest should be available. A back that is too tall may limit upperextremity function, while a back that is too low may not support an optimal posture and may not provide sufficient stability for function.

Babinec: Low backs (low thoracic) can promote function by facilitating an upright posture through the correct lumbar-sacral postural support. In addition, low backs do not interfere with upper-extremity range of motion, and they allow some trunk rotation for function without back cane interference.

Mid-level back heights allow for additional postural support to compensate for impaired balance while not interfering with upperextremity function. These backs are often measured to the inferior angle (bottom) of the scapula.

High backs provide full back support and are used most often with tilt and/or recline systems. These backs are often measured to the acromion process (tip of the shoulder).

Doherty: The higher back provides the additional support the consumer needs when in a fully tilted or reclined position. The individual with a high spinal cord injury often has the need for lateral trunk supports to provide trunk stability for functional activity. The higher backrest allows this component to be added.

The mid-height backrest can still allow lateral trunk supports to be utilized in many cases, so the client does not need to give up lateral stability. This will provide improved stability for greater functional outcome.

The low-height back is traditionally used with very active individuals. The firm back support provides pelvic and lumbar support, but allows their upper trunk and upper extremities full range of motion for optimal performance in their daily activities.

Stevens : As we all know, there is a lot of “gray” area when it comes to rehab, and an example where (traditional back-height wisdom) is not the rule would be with my pediatric school-based population. While the child may demonstrate the appropriate trunk control that would warrant a lower back support, school transportation will not bus the child unless they are outfitted with a chest harness. When fitting a chest harness, the back height needs to be to the top of the shoulder. So in this case, the requirements of the environment in which the child functions “wins” over basic seating and positioning rules.

Q3: What are important factors for providers to consider when assessing SCI clients for wheelchair backs?

Babinec: In addition to geometry (trunk width, hip width, back height), trunk balance, upper-extremity function, wheelchair type anticipated (manual vs. power, tilt vs. recline), sensation, skin integrity, posture/postural alignment, postural flexibility, hip range of motion, and level of lateral support needed are some considerations of a wheelchair back assessment.

Doherty: The most important thing is to be sure the backrest provides the support and functionality it was intended to. Although the client may require a certain height backrest for support, they may abandon the back if the height interferes with daily activities that are important to them. Always go over the pros and cons of the equipment being provided so the individual can make the most informed decision possible.

Stevens : Providers should consider five main factors:

  • The degree of trunk support required for the individual to have maximum dynamic sitting balance and functional upper-extremity use. This will determine the general height and lateral support requirements of the back.
  • The degree of accommodation or correction needed for skeletal deformities (e.g., scoliosis or kyphosis) and what support mechanism would work best (e.g., adjustable laterals, custom mold/foam in place, cut-out/build-up layers of foam, etc.).
  • The type of mobility system that will be used. For those who manually propel, the back support must be kept as light and low as possible. For those using power mobility or dependent mobility systems, the weight of the back support becomes less of a concern, but positioning for pressure redistribution or access to switches moves to the forefront.
  • Hardware, hardware, hardware! How much adjustability (depth, angular) does it have, and is it quick and easy to adjust in the field? Are there too many pieces and parts involved that will require lots of maintenance?
  • Last but certainly not least is the user’s lifestyle. What are their activities of daily living? How does the client transfer? Will the client be driving? What is their current equipment and how is it working for him or her? As someone brilliant once said, “If it ain’t broke, don’t fix it.”

Whelan : Like all technology assessment, matching the right product to the right user is best accomplished by a proper evaluation. A proper evaluation is best done by a team involving the treating or a specialist clinician, the RTS and the user. The team will discuss and document information that evaluates the client’s medical condition, posture, lifestyle, environment and goals.

Technology selection is almost always a series of trade-offs. Sometimes the user’s functional needs are at odds with postural goals.

For example, a back may be available that supports an appropriate upright posture that benefits respiratory and digestive function, but compromises the individual’s stability when propelling on ramps. Where possible the back solution should be tried or simulated to identify such issues.

This article originally appeared in the SCI Handbook: September 2009 issue of Mobility Management.

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