Seating & Positioning
Proper seating and positioning is critical for people using mobility devices. Learn more about seating and positioning issues from Ottobock — the expert in mobility solutions for you and your loved ones.
Sitting all day is hard work—something you surely know if you’re a wheelchair user. If you’re an able-bodied caregiver, however, you may not have given it much thought—until an endless car trip leaves you feeling stiff, aching and exhausted. Read on to find out more about seating and positioning issues.
Seating & Positioning Issues
The natural, healthy alignment of the human body is all about function and comfort. Good posture promotes normal functioning of organs and greater efficiency of muscles, which minimizes fatigue.
Good posture is especially important to anyone who uses a wheelchair. In a sitting position, the natural curves of the back and neck should be supported. The shoulders, pelvis and knees should ideally be level. In that symmetrical position, muscles are in balance, ready to flex when needed and relax in between.
Poor posture brings on fatigue by making poor use of the skeleton’s structure. Muscles tire more quickly because they have to work harder. Prolonged, poor posture creates more strain on the spine, neck, hips and knees. That can lead to a cascade of structural problems—joint pain, reduced flexibility, asymmetrical muscle tightness, and deformity.
If you suffered a loss of bone or muscle below your waist, or have an abnormal spine or pelvis, you may need a special cushion and back support system and may not be able to achieve a level pelvis or level shoulders.
Problems with Posture
When your pelvis.....
Tilts back, you may experience problems with: Swallowing, breathing, digestion, reduced volume when speaking, neck and shoulder pain, localized pressure on skin
Tilts forward, you may experience problems with: Spinal muscle fatigue, bladder control, foot placement, localized pressure on skin
Tilts to one side, you may experience problems with: Instability, limited range of motion, localized pressure on skin
2. Skin integrity—and protecting it
2. Skin integrity—and protecting it
Skin that bears weight in a wheelchair lives in hostile territory. Pressure, shear, moisture and heat combine to create ideal conditions for the development of decubitus ulcers. In fact, a landmark study found that at least 20 percent of wheelchair users have a skin breakdown in any one year, which means that virtually every user is likely to encounter a skin problem within four to five years.
Ottobock specializes in seating and positioning products for users at high risk for skin-integrity issues. You are considered at high risk of skin-integrity issues if any of three statements is true as relates to sitting in your chair.
You have a history of redness and/or the presence of open wounds on your seated surface.
You cannot do an effective, independent weight shift on a consistent basis.
You have impaired sensation and don't check your skin daily and don't practice consistent weight shifts.
The good news is that most pressure ulcers—localized injuries to the skin and/or underlying tissue, usually over a bony prominence—are preventable. For that reason, anyone who spends their days in a wheelchair needs three types of skin protection as it relates to their wheelchair seating system.
Pressure in this case is the force on tissue pinched between bone and the external support surface (wheelchair upholstery or wheelchair seating surface). It can cut off the supply of blood and oxygen to an area and eventually cause tissue to break down. Pressure management relies on physics to assist with defending against pressure ulcers. You can reduce peak pressure by spreading the weight over a larger area.
Pressure = Force (body weight) / Area (weight-bearing area)
When you are seated on a firm, flat surface, all of your weight rests on bones on the underside of your pelvis (ischials), making you a potential candidate for decubitus ulcers.
To reduce this peak pressure it might be a good idea to redistribute or share this concentrated load over the whole of your underside surface for example your buttocks, undersurface of thighs and don't forget your feet if possible. Your back may also be able to take a lot of load while you are sitting. Your health care professional should help you with this at the time of your assessment and prescription.
Because those bony curves are your low points, a cushion improves load bearing by allowing you to sink into it as much as 2.5 inches without hitting bottom. Armrests and footplates at the proper height can bear some of your weight. So can back support that matches the curve of your spine.
Shear, which damages tissue with distorting forces, refers to the forward-and-back motion of the ischials against tissue under pressure. For active people, recesses or a liquid layer under the ischials allow movement of bony prominences which are intended to reduce high shear forces.
Heat and Moisture Management
People who are active or overweight or who have certain medical conditions generate a lot of heat and may perspire heavily on support surfaces. This can be more than uncomfortable: it can create a climate that can help lead to decubitus ulcers. Cushions that allow air and moisture to pass through help skin stay cooler and thereby contribute to a healthier seating environment.
To maximize your full potential, you have to be able to reach the world. Seating systems, positioning aids and accessories can help make it possible for wheelchair users to achieve a correct, comfortable and safe seating position in most everyday environments.
Products & Materials
Seating and positioning products come in a broad variety of types and styles, from simple off-the-shelf wheelchair cushions to custom seating. They’re also made out of a variety of materials.
Products by Level of Need
Three general categories of seating and positioning products meet increasing levels of need.
For those who have symmetrical posture and low to moderate risk of developing sores, standard cushions and backs may provide adequate comfort.
Seating to accommodate more complex postures or skin integrity needs that cannot be met with off the shelf seating solutions. Ottobock’s NUTEC Modular Seating is highly customizable and adjustable for kids and adults who have specific positioning requirements.
Seating to accommodate the fixed asymmetrical posture of people who require significant postural support. For OBSS cushions, Ottobock uses a fitting system with 3-D electronic imaging to capture the user’s shape. Then a computer-controlled digital carver replicates every curve in producing a foam mold.
SHAPE Custom Contoured Seating
Our digital ‘SHAPE’ Seating Systems have been trusted for over 20 years, aiming to prevent further postural deterioration ideally as part of a ’24 hour postural management programme.
SHAPE Seating Systems are the only solution for patients with complex needs as the design and accessories can be fully customised to suit the needs of the user.
Materials make the difference
Cushions and backs are made with a variety of materials to provide support, distribute weight and protect skin. Ottobock cushions and backs feature several unique materials.
An ultralight patented material, is a “low-memory” foam that automatically flows around bony prominences, reducing pressure by allowing weight to be supported by broader body surfaces. Floam adjusts to the shape of the user and holds practically any shape.
Rest Suspension Foam
Developed by and exclusively available through Ottobock, has outstanding pressure distribution that makes it virtually impossible to bottom out. It also helps absorb shock and dampen vibrations. Unlike most foams, it does not compress and tested at three times the industry standard for durability.
Technology and a unique, breathable foam allow air and moisture to pass through. Optimal airflow helps heat and moisture dissipate so you feel cooler.
An ultra-thin liquid layer in the cover that reduces shear forces and helps maintain skin integrity.
The tilt-in-space feature on some wheelchairs plays an important role in seating and positioning for some users. With tilt-in-space, the user rotates back, maintaining the same seat-to-back and seat-to-leg angles.
Tilting back 5 to 15 degrees can use gravity to help position the user for better posture.
Researchers have determined that 45 degrees of tilt (midway between horizontal and vertical) is needed for effective pressure management. That angle reduces pressure by one-third by distributing weight over a larger area. Tilting at various degrees throughout the day also provides relief.
Other Supporting Elements
Headrests come in numerous styles and sizes with an array of mounting options.
Lateral Thoracic Supports
If you need lateral thoracic supports, which support the upper sides of the trunk, the swingaway style adds convenience. If you live in a cooler climate, adjustable brackets and pads can compensate for the added thickness of winter clothing.
Cushion covers are made from assorted materials. If the cover material does not stretch, you won’t benefit from any self-molding foam inside. Incontinence-proof covers will protect the cushion but also can leave the user soaking in urine, which will aggravate any skin problems.
Other factors besides posture, skin health, and function
If two or more options seem equal on The Big 3 of posture, skin health, and function, look at a few other factors:
Comfort. How does it feel to the user?
Fit. Cushions and backs come in multiple sizes because the wrong size will cause strain over time.
Adjustability. “Low-memory” foam automatically flows around bony prominences. Some products allow you to position pouches filled with “low-memory” foam for more support and weight distribution where you need it.
Integration. Some cushions and backs are designed to work together.
Safety. Is the user stable?
Ease of use. Will the user or caregiver have any trouble with it?
Maneuverability. Any problems with movement for the user or the wheelchair?
Durability. Whatever you buy probably will be used for years, so it better hold up.
Get the right solution
You have individual needs that require an individual solution. To get the right seating and positioning for you, start by getting an assessment from a physiatrist (a physician who specializes in physical medicine and rehabilitation) or a Physical or Occupational Therapist who specializes in seating who will work alongside a Rehabilitation Technology Specialist (RTS) in helping you obtain the best solution.
To make sure you’re fit in the right system, you should have a thorough hands-on evaluation to determine:
Range of motion and flexibility in the spine, pelvis and leg joints
Postures that are flexible and those that are fixed
Cause(s) of seating and positioning challenges
The level of risk for issues with skin integrity
Functional needs and limitations
The specialist may take photographs to document your condition as well as measurements to ensure your wheelchair is the right size and is adjusted properly for you.
Be your own best advocate and make sure you get:
A solution that accommodates changing needs. What can you anticipate in the future—a child’s growth or loss of muscle mass with a degenerative condition?
A trial of the proposed solution before the physiatrist writes the final prescription.
Instruction on how to use the equipment.
Focus on causes, not symptoms
Wheelchairs are notorious for frustrating caregivers. The caregiver positions the user in the wheelchair, but soon the user is sliding or slouching or leaning. The caregiver readjusts the user, who repeatedly gets into the same unnatural position. The caregiver may use pads and supports to discourage sliding or to keep a leg from sliding off a footplate, but nothing seems to work.
Efforts to help by restricting movement tend to be misguided. People often spend time trying to control the device user when they should be adjusting the wheelchair. More often than not, there’s something wrong with the wheelchair, and discomfort compels the user to escape from an uncomfortable position.
Instead of trying to conquer a recurring misalignment, think of it as a symptom. Then try to figure out what causes it.
Common symptoms and possible causes
Sliding out of seat - Limited hip flexion, increased extensor tone, posterior pelvic tilt with kyphotic posture, tight hamstrings
Slouching (posterior pelvic tilt) - Weak trunk muscles, limited hip flexion, decreased lordosis, increased thoracic kyphosis, tight hamstrings
Falling forward (anterior pelvic tilt) - Tight hip flexors, tight quadriceps, tightened spinal extensor, weak abdominals, increased lumbar lordosis, forward sloping seat, backrest too vertical, excessive lumbar contour
Leaning (pelvic obliquity) - Pain in opposite hip, asymmetrical muscle strength or tone, scoliosis, inadequate support in seat, overly wide wheelchair, arm support(s) too high or too low
Windswept legs (pelvic rotation) - Unsupported trunk, inadequate posterior pelvic support, seat too high for foot propulsion, footrest height not adjusted for asymmetrical hip flexion, asymmetrical muscle tone in trunk and/or legs, asymmetrical hip abduction, adduction or flexion, difference in leg length, posterior dislocated hip