SCI Forum Reports
What About Cushions?
November 9, 2004
- Factors influencing wheelchair cushion choice
- Key Cushion Concepts
- How do I know when my cushion is worn out?
- What cushion is right for me?
- High risk skin- Why is it high risk?
- Should I have more than one cushion?
- What about other seating: sports equipment, car, theater, airplane?
- Types of cushions
- Cushion Manufacturers
November 9, 2004 - What is the best wheelchair cushion for you? Should you have more than one cushion? Should you sit on a cushion in the movie theater? On an airplane?
According to Jennifer Hastings, a physical therapist at the Puget Sound VA, the answer to all of these questions is: "It depends." Hastings is a board certified clinical specialist in neurologic physical therapy who specialized in SCI rehabilitation for over 13 years and established the wheelchair seating clinics at both the VA and Harborview Medical Centers.
- Individual body type. Consider your body type before injury, whether you have an upper motor neuron (UMN) or lower motor neuron (LMN) injury, how long ago you were injured, how much muscle atrophy (shrinkage) has occurred. "UMNs will have spasticity-muscle contraction in your paralyzed limb-that maintains more muscle tissue, generally better circulation, and healthier skin," Hastings said.
Body weight also matters, and in this case, "more isn't necessarily worse," she continued. "If you're really thin and sitting on just bone, even if you're light, you'll have different cushion needs than a person who weighs more" and has more padding.
- Postural deformities. "This is a nice clinical term that simply means you're shaped differently than average," Hastings explained. There are a variety of causes. An ischiectomy-surgical removal of part of the pelvic bone during flap surgery-creates a postural deformity because is results in an asymmetrical posterior. Range of motion (ROM) limitations can also cause asymmetries that play out to the seating surface.
- Personal skin situation. General health, skin history, movement, sensation, and age all affect skin health, strength and integrity. If you have a history of problems such as eczema or psoriasis, SCI tends to make these conditions worse. Scar tissue from prior skin breakdown or other injury needs more protection because it is not a strong as normal skin.
Movement, such as shifting around or transferring in and out of the chair, can put more stress on skin. But it is also very beneficial to change positions. Sensation can be good for skin because it signals discomfort and causes you to shift position.
General health is frequently overlooked in the cushion selection process. Nutrition and hydration must be adequate for good skin health. Any chronic condition that decreases circulation to the skin, such as diabetes or atherosclerosis, is a concern. "Some things you have control over," Hastings remarked. "If you have skin breakdown and you smoke, we can do all sorts of dressings, but to heal you have to quit smoking."
Age is also important. "Skin is an organ that gets thinner and less elastic as you age, and as a result less able to tolerate stress," she continued. "Padding that comes from subcutaneous fat also gets thinner. That's normal aging. With paralysis some of these processes accelerate."
"While clinicians think about skin protection and postural issues when selecting cushions for clients, you, the user, need to think about personal issues such as comfort, weight, maintenance, and aesthetics," Hastings said. "Both clinician and user need to be thinking about function ."
- Skin protection. Skin can be protected by distributing weight across the seating surface, decreasing shear (friction), and promoting heat exchange and airflow. Moisture, from perspiration or urine, can cause skin wounds, and bigger people are often warmer and may need more airflow in their cushions. Offloading-removing weight-from specific, at-risk areas like the ischial tuberosities (sitting bones) can be accomplished with cutouts in the cushion. "But there's no such thing as eliminating pressure, you just redistribute it," Hastings added.
"Originally clinicians thought a bigger surface area was better because it spread the weight around," Hastings said. "But some of those big cushions set the body up in a poor alignment, which can create pressure problems very quickly. This brings us to postural support."
- Postural Issues. Sound wheelchair seating principles include maintaining proper position and posture in the chair and controlling the pelvis so it stays in one position. The pelvis must be neutral and not tilting forward or back, with the goal of approximating the pelvis position that occurs when standing.
- Function . Hastings acknowledged that when clinicians are so focused on keeping people firmly positioned in the chair, other functions, such as transfers, may be neglected. "A postural cushion that keeps you in a good sitting position but makes it harder to do your own transfers is impeding function. We need to define function for each person, and then ask if this cushion is making the person more or less functional."
- Personal user issues. The issue of comfort is complicated for people who can't feel what they are sitting on. "A lot of people touch the cushion with their hand and say 'that feels soft,'" Hastings said. "But I also encourage you to think about comfort above the seat-your neck, back and shoulders."
When using your wheelchair cushion on a different surface it is important to think about the design of your cushion. "Interface-only" cushions have no shape of their own but take the shape of what is under and on top of them. "That cushion can go in any chair." Hastings said. "But a cushion with a lot of shape to it may be a problem if it's in the wrong chair."
Hastings listed some other personal user issues: cushion weight (for manual chairs that must be hoisted in and out of a car several times a day); maintenance ("a high-maintenance cushion is not a good choice for a low-maintenance person"); appearance ("If you think it's ugly, don't even try it-it'll end up in the closet.").
Much the same way you know when your jeans or shoes are worn out, i.e., how do they compare to their condition when new? "Here's a hint: you might not remember," Hastings said. She advises people to weigh, measure and photograph their cushions when new.
It's worn out when:
- Foam -It is compressed; retains the imprint of your seat stays after getting off it; little crumbs of foam rub off; or it smells.
- Sealed get pad -Edges or seals are cracked or pealing, or viscous gel feels hard anywhere. Some brands respond to warm water soak; if not, "it's toast."
- Contour base -The contour has changed. Check the edges: if it's slanting some way that it's not designed to, it's not doing its job.
- Roho cushion -Get in the habit of testing the cushion by pinching each pod. If you can feel anything inside the pod, the cushion should no longer be used.
- Air-based -It is losing air without a discernible hole that you can patch.
And don't forget about bathroom equipment (such as toilet seats), Hastings warned. "It wears out too, and usually isn't replaced often enough. It's not nearly as expensive to replace as a cushion."
"It depends on your needs," Hastings repeated.
Contoured postural cushions are designed to provide postural support and distribute pressure optimally when the user is seated in the proper position. "If you shift your posture a lot on a postural cushion, that's not good," she cautioned. "It can create increased pressure areas instead of providing pressure protection. You need to think about who you are and how you move and sit."
The chair-cushion interface is important. Hastings' bias: choose the chair configuration first, based on the client's postural needs; then pick the cushion.
- Is the problem shear? (Shear occurs when skin stays put and the body moves inside it; shear is not the friction on the surface of the skin.) A postural cushion with significant control may increase shear, Hastings warned.
- Is the problem strictly pressure? If so, a seating evaluation with a pressure mapping system can show how best to redistribute pressure away from "hot spots."
- Is the problem moisture? A cushion with better air exchange may be the answer. Cushions that wrap around and hold the user snuggly may be the worst choice.
- Is the problem a postural deformity? In this case, Hastings recommends a full seating evaluation, with pressure mapping and assessment of posture and range-of-motion.
The cushion should fit the chair, "so if you have two different size or shape wheelchairs, you need two different cushions," Hastings said.
- Sports equipment -Most sports equipment is set up very differently than a daily wheelchair, "so your daily-use cushion shouldn't work in them," Hastings explained. Unless you use only an interface cushion, you need a different cushion for the sports chair, "but you may only need a good quality foam cushion."
Your cushion needs depend on how much you move and slide around in the seat and how long you're in it. "You need to be careful. If you're tight in the equipment, that's good," she continued. "In a mono-ski, you're sitting inside a shell and it should fit just like a ski boot, with no movement between the body and the bucket." She recommends trying the equipment for 20 minutes and then checking your skin, including the non-seating areas like the back of the legs.
- Car -What do you drive? How long? Do you do pressure releases? Hastings warned against using a daily-use wheelchair cushion for driving because the sitting position is different in the car.
Some cars-like a new Mercedes or Corvette-don't need cushions because those car seats distribute pressure better than any wheelchair cushion, she said. "But don't turn the seat heaters on! If you drive a 15-year old Geo, it's a different story."
"It's important to do pressure releases in the car," she added. "If you don't know how, get someone to show you."
- Movie seats -Again, it depends on the seats. Some discount theaters with old seats demand a cushion. Any seat that reclines will put the user in a position different than the wheelchair, so using the wheelchair cushion is "probably not a good idea," Hastings said. "You could actually be creating more pressure problems."
- Airplane seats -A cushion and/or lumbar support may be necessary in coach class. A first class seat, on the other hand, is probably better than sitting in your wheelchair cushion.
- Foam -Lightweight, inexpensive, low maintenance, and featuring good air exchange and pressure distribution, foam comes in many varieties (flat, contoured, multi-density). Disadvantages: a shorter lifespan than other types; it soaks up moisture and retains odors and heat; and it provides minimal relief for bony prominences.
"If you're in a good chair, have an upper motor neuron injury, no skin problems, no incontinence, and you're well-hydrated and don't smoke, you can probably get along with a basic foam cushion like the one that comes with wheelchair," Hastings said.
- Honeycomb -Made by Supracore , these are lightweight, machine washable, low maintenance, and mildly contoured for support and pressure distribution. They can only be modified with a special "hot knife," however.
- Air cushions -Features include excellent pressure distribution, good air flow, easily cleanable, and light weight. However, they can leak or puncture, especially with smokers, and they may be unstable for certain postures and body types. Example: Roho High Profile.
- Hybrids -These cushions combine air and foam or air and gel, and provide: stable support; light weight; adjustable for postural corrections and accommodations; skin protection; and easy maintenance. Examples: Jay Seating and Positioning by Sunrise ; Infinity Seating Technology by Invacare ; Floam Technology by Otto Bock ; Flexseat by Flofit Medical (tested on rugby players); and Solo by Varilite .
- Custom fabricated -Used more in children than adults (unless an adult has significant postural deviations), these can be either carved or molded. Each cushion is unique, addressing the specific needs of the person it is made for. When done right, it has excellent pressure distribution. Modifiable only by the manufacturer, this can be an expensive option.
- Ride cushions -A new type of custom-molded product that is marketed as taking all pressure off the ischial tuberosities. Hastings cautioned, however: "Remember-there is no such thing as eliminating pressure, it just gets moved. Some sensate people sitting on this cushion have found the pressure on the backs of their thighs uncomfortable." This cushion won't retain water and can be easily cleaned; it is very lightweight and is custom shaped in the user's wheelchair, which is an advantage It is currently quite pricey (about $900) and intended for those who have not found success with other seating.
- Dynamic cushions -This is a battery-powered cushion that combines air and hydraulics and features alternating inflation and deflation without user input, which keeps pressure from building up in any one area. Very expensive and too heavy for manual chairs, Hastings admits to a bias against them because they do not provide stable postural support.
Sunrise Medical http://www.sunrisemedical.com
Roho Medical Products: http://www.roho.com/medical/index.jsp
Ride Designs (division of Aspen Seating): http://www.ridedesigns.com/
Otto Bock Rehab: http://www.ottobockus.com/
Flofit Medical: http://www.flofitmed.com/