Ann Rehabil Med.  2011 Dec;35(6):897-906. 10.5535/arm.2011.35.6.897.

The Influence of Backrest Inclination on Buttock Pressure

• Park UJ
• Jang SH

• KMID: 2266817
• DOI: http://doi.org/10.5535/arm.2011.35.6.897

Abstract

OBJECTIVE
To assess the effects of backrest inclination of a wheelchair on buttock pressures in spinal cord injured (SCI) patients and normal subjects. METHOD: The participants were 22 healthy subjects and 22 SCI patients. Buttock pressures of the participants were measured by a Tekscan(R) pressure sensing mat and software while they were sitting in a reclining wheelchair. Buttock pressures were recorded for 90degrees, 100degrees, 110degrees, 120degrees and 130degrees seat-to-back angles at the ischial tuberosity (IT) and sacrococcygeal (SC) areas. Recordings were made at each angle over four seconds at a sampling rate of 10 Hz.
RESULTS
The side-to-side buttock pressure differences in the IT area for the SCI patients was significantly greater than for the normal subjects. There was no significant difference between the SCI patients and the normal subjects in the buttock pressure change pattern of the IT area. Significant increases in pressure on the SC area were found as backrest inclination angle was changed to 90degrees, 100degrees and 110degrees in the normal subjects, but no significant differences were found in the SCI patients.
CONCLUSION
Most of the SCI patients have freeform posture in wheelchairs, and this leads to an uneven distribution of buttock pressure. In the SCI patients, the peak pressure in the IT area reduced as the backrest angle was increased, but peak pressure at the SC area remained relatively unchanged. To reduce buttock pressure and prevent pressure ulcers and enhance ulcer healing, it can be helpful for tetraplegic patients, to have wheelchair seat-to-back angles above 120degrees.

Keyword

Wheelchair; Pressure ulcer; Backrest; Inclination

MeSH Terms

Buttocks
Humans
Posture
Pressure Ulcer
Spinal Cord
Ulcer
Wheelchairs

Figure

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  Fig. 1 Buttock pressure distribution in IT-SC areas as displayed on monitor.

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  Fig. 2 Changes in the buttock peak pressure of the IT area according to seat-to-back angle in normal subjects and spinal cord injured patients.

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  Fig. 3 Changes in the buttock peak pressure of the SC area according to seat-to-back angle in normal subjects and spinal cord injured patients.

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  Fig. 4 Patterns of change in average pressure for normal subjects and spinal cord injured patients. The pressure change pattern of the disabled in gray box from 90° seat-to-back angle is similar to that of normal subjects from 105°.

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  Fig. 5 Paterns of change in peak pressure for normal subjects and spinal cord injured patients. The pressure change pattern of the disabled group in gray box from 90° seat-to-back angle is similar to that of the normal group from 105°

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