Sliding forward in a wheelchair, often resulting in a slumped posture known as sacral sitting, presents a serious safety challenge for older adults and their caregivers. This poor positioning occurs when the pelvis tips backward, causing the person to slide out of the seat and rest weight on the tailbone rather than the hips. Sacral sitting increases the risk of skin breakdown, particularly pressure injuries on the lower back, and can lead to falls from the chair. Maintaining an upright posture is also important for proper respiratory function and digestion, making the prevention of sliding a primary goal in elderly care.
Proper Seating and Posture Techniques
Addressing the fundamentals of seating is the necessary first step before implementing specialized equipment. Proper positioning begins with ensuring the pelvis is seated fully to the back of the chair, which prevents the backward tilt that initiates sliding. The goal is a neutral pelvic alignment where the hip bones are level and the spine is straight.
The feet must be positioned flat and securely on the footrests, or the floor if the chair is configured for foot propulsion. Incorrect footrest height alters pressure distribution on the thighs and hips, encouraging the user to shift and slide. The correct adjustment ensures the knees are bent near a 90-degree angle, with the thighs parallel to the seat surface.
Trunk alignment is equally important, as a supported torso minimizes the forward slump. If the wheelchair seat depth or width is incorrect, the user may lean or slide to find a more comfortable or stable position. Regular repositioning involves frequently checking and adjusting the person’s posture on a set schedule to prevent prolonged pressure and correct early signs of sliding.
Specialized Seating Aids and Supports
When proper technique alone is insufficient, specialized seating aids can physically alter the sitting surface to maintain a stable position. Anti-thrust cushions feature a raised front section or pommel that creates a barrier to forward migration, ensuring the pelvis remains back in the seat.
Wedge cushions are designed with an angled shape that is higher in the front than in the back, gently tilting the pelvis backward. This backward slope increases stability and counteracts the tendency to slump or slide forward. Contoured cushions often incorporate features like medial and lateral thigh supports, which help keep the legs aligned and the pelvis centered.
Beyond the seat, rigid back supports or lateral supports provide a solid foundation for the trunk. Unlike the flexible sling upholstery found on many standard wheelchairs, a firm backrest maintains the natural curves of the spine and prevents the upper body from collapsing forward. Lateral supports, which are cushions placed on the sides of the trunk, stabilize the torso and prevent leaning, which can lead to a shift in pelvic position and subsequent sliding.
Securement Devices and Safety Monitoring
Pelvic positioning belts are mechanical aids used to stabilize the pelvis, the foundation of good posture. These belts are intended for postural support, not as a physical restraint to prevent a person from leaving the chair. They are mounted to the wheelchair frame and positioned across the user’s pelvis, often at a 60- to 90-degree angle to the seat, to keep the hips securely back.
Correct fitting is achieved when the belt is snug across the bony structures of the pelvis, but not so tight that it causes skin irritation or restricts circulation. A poorly positioned belt, such as one mounted at a 45-degree angle, can allow a person to slide underneath it, creating a serious risk of injury or strangulation. Chest harnesses are also used for trunk support to encourage an upright posture, but they must be fitted carefully to avoid being classified as a restraint.
The use of any device that limits movement requires careful ethical consideration and should be a measure of last resort after exploring all alternatives. If a positioning device is deemed necessary, it requires a comprehensive assessment and frequent monitoring of the user’s skin integrity, comfort, and circulation. A wheelchair tray, when used correctly, can serve as a positioning aid to support the arms and trunk. However, using the tray to block a person from standing constitutes a physical restraint, highlighting the fine line between support and restriction.