Relationship of spine deformity and pelvic obliquity on sitting pressure distributions and decubitus ulceration.

The distribution of pressure points in 16 patients with paraplegia, nine with ulcers, and six who were ulcer free were compared with the distribution in 15 normal individuals using an instrument capable of simultaneously measuring multiple pressure points under the buttocks and thighs. The nine patients with ischial and sacral decubiti showed redistribution of their sitting pressures posteriorly, asymmetrical loading of the ischiae, and higher than normal pressures under the sacrococcygeum. These abnormal pressures were associated with unbalanced scoliosis, pelvic obliquity, and the loss of physiological lordosis following a spinal fusion. We defined four criteria of risk for decubitus ulceration.