Safe seating: Preventing injury; getting comfort

When and where do you sit for the longest periods of time? Many people respond in terms of cars, restaurants […]

When and where do you sit for the longest periods of time? Many people respond in terms of cars, restaurants or airplanes. If you use a wheelchair, however, you probably have a different point of view. In fact, you might spend 16 or more hours a day sitting and that could be cause for concern.

If you live and work from a wheelchair and your seating system is inappropriate for you, you might be at risk of a major health hazard. A pressure-related wound can cause a chain reaction of infections, hospitalizations, surgeries and months of bed rest.

The most vulnerable sites for pressure-ulcer formation in people who sit for long periods are the areas of highest compression, usually bony areas. Roughly 80 percent of ulcers (or pressure sores) develop over the base of the spine (sacrum), the top of the thigh bone (greater trochanter) and the two sit-bones at the bottom of the pelvis in the buttocks (ischial tuberosities). Wounds to the greater trochanter appear at the lower and outer edges of the hips, over the bony areas. Wounds at either ischial tuberosity are usually near the crease separating the buttocks from the thighs (gluteal fold). Occasionally, a wound appears at the back of the knee (popliteal).

Commercial/Custom Seating
Commercial seating—such as deep contour gel or air-flotation technology—can be effective in preventing wounds, but such technologies require vigilant maintenance. Commercial seating is usually sized for a wheelchair. It can be perfect for a symmetrical person, (which no one is) but difficult to customize when the pelvis is higher on one side (pelvic obliquity) or when the pelvis is further back on one side (pelvic rotation).

Customizing commercial seating can cause problems for people who have compromised, fragile skin or positioning challenges, such as sacral sitting or spasticity-related hip extension. People who have spina bifida, a spinal cord injury, or multiple sclerosis are likely to lack feeling (be insensate) in the area. They can not feel when the cushion need air or is over-inflated and they won’t sense when gel is pushed out of the areas where it’s most needed.

People often seek custom seating after they’ve tried various commercial options. A custom, pressure-relieving seat can suspend bony prominences above the hard surface of the seat, helping to prevent pressure ulcers. Custom seating is specifically made to accommodate anatomy, such as pelvic obliquity, while transferring the weight to healthy tissues. Custom seating is best designed and fabricated by checking the skin and using force-sensing array equipment (sometimes called pressure mapping). Such equipment provides a kind of topographical guide to each person’s body.

Because custom seating is specific to each person’s anatomy, it must be in the same position each time you use it. Once you are in the seat, self transfers can be challenging. That’s because the seat’s contours—which offer suspension, encourage good blood flow, and provide postural support—can sometimes become barriers to a smooth and energy-efficient self-transfer.

By itself, a carefully chosen, well-made seat can’t prevent wounds. If you’ve had a pressure wound in the past, you’re at risk of developing additional sores. Furthermore, the wound site—even when healed—has only 80 percent of the strength and durability it did before the sore occurred.

One key to preventing a wound is persistent, habitual shifts of your weight. Shifting promotes robust blood flow to weight-bearing tissues. Although shifting requirements vary by person, current guidelines recommend shifting one’s weight every 15 to 30 minutes, for at least 30 seconds at a time. To raise blood flow to normal, unloaded levels, the pressure relief should last one to three minutes.

Manual pressure-relief techniques depend on your abilities and upper-body strength. A complete push-up, using the armrests on the wheelchair and lasting one to three minutes, is difficult, if not impossible, for most of us. But you can accomplish a good weight shift using the “nap in your lap” technique. This requires you forward as far as you can while lifting your ischials off the seat. A power weight-shift system, such as a tilt-in-space power wheelchair, is recommended when manual pressure relief is not possible. Although powertilt systems are effective and easy to use, tilting back at least 65 degrees every half-hour for one to three minutes can be daunting or inconvenient. Some even view it as anti-social. Yet when you consider the relative inconvenience of weight-shifting against a wound-related hospital stay, you’ll see that developing a weight-shifting routine is well worth the effort.

Seeing Is Believing
If you can’t feel the results, Force-sensing equipment helps you find out if you’re physically shifting weight off bony prominences.

Here’s how it works. A seating provider puts a sensing mat between you and your seat then places a computer monitor where it will be easy for you to view. The mat provides information in the form of an active, dynamic and colorful movie, so you can easily see which weight-shifting techniques work best for you.

A seating provider you trust will become one of your most important health-care professionals. You’ll have the best seating results when you find and schedule appointments with that person. Return to your seating professional every six months for an assessment of your seating needs. Schedule an appointment immediately whenever your weight or health changes.

Double your impact - support quality journalism - give nonprofit, give now