the need

The upholstery on most sling-back wheelchairs sags after a few months of use. Sitting in a wheelchair with sagging upholstery causes poor posture that, over time, can lead to back pain, neck pain, and spinal and pelvic deformities.

better back support

back support shaping system

back support shaping system

the solution

Affordable, lightweight, and adaptable, the PAXBACKTM is the perfect solution for poor posture and resulting injuries. Easily attached to sling-back upholstery, this accessory adds comfort and improved posture and mobility to the wheelchair user.

project goal

The goal of this project was to develop an affordable, lightweight, comfortable, orthopedically correct, and easily adjustable back support designed to work with existing sling-back upholstery. Unlike commercially available back supports, which must be removed to fold the wheelchair, cannot be added to existing sling upholstery, and are unable to conform to the contours of different individuals, the back support shaping system was designed to adjust to the different activities of the wheelchair user.

phase 1 prototype development & clinical testing

In January 1993, Beneficial Designs developed a back support system that consists of support pads that hook onto the upright frame members of a wheelchair behind the sling-back upholstery. One support pad is contoured to fit the lower back, while the other, consisting of two smaller pads connected by a tension strap, is designed to provide support for the upper back. The horizontal tension straps on each support can be adjusted to customize the amount of support the pad provides.

Sixty-nine subjects participated in a short term clinical evaluation of back support prototypes and provided feedback to optimize the design specifications. The Back Support Shaping System improved comfort, spinal posture and wheelchair mobility in the majority of subjects, and 70% reported it was more effective than any back support they had used before

phase 2 long-term clinical testing

In June 1994, 40 subjects wore the back supports for a year and evaluated them for durability, posture, comfort, and function. Their comments were used to develop the back support shaping system into a design suitable for commercial marketing. The back support shaping system was shown to improve posture, comfort, and function.

The low back support is now being manufactured by PinDot Products by Invacare Corporation as the PaxBac, and was introduced at the March 1996 International Seating Symposium held in Vancouver.

PaxBac by PinDot Products


This project was funded by the National Center for Medical Rehabilitation in the National Institute of Child Health and Human Development at the National Institutes of Health through Small Business Innovation Research Phase I Grant #1 R43 HD29983-01 and Phase II Grant #2 R44 HD29983-02.