Patterns of vertebral ossification and pelvic abnormalities in paralysis: a study of 200 patients.

To clarify the characteristics, extent, and frequency of spinal ossification and abnormalities of the sacroiliac joint, symphysis pubis, and hip in paralysis, routine radiographs of the lumbar spine, pelvis, and abdomen were retrospectively evaluated in 95 quadriplegic, 105 paraplegic, and 100 age-matched control patients, with attention to age and race and to spinal level and duration of paralysis. The spinal radiographs were evaluated for presence of osteophytes, syndesmophytes, paravertebral ossification, and flowing hyperostosis characteristic of diffuse idiopathic skeletal hyperostosis (DISH); the pelvic radiographs were used to measure the widths of the sacroiliac joint, hip, and symphysis pubis articulations and evaluate for presence of enthesopathy. Bone formation around vertebral bodies was often seen in quadriplegic (n = 41 [43%]) and paraplegic (n = 46 [44%]) patients. In quadriplegic patients, four distinct vertebral ossification patterns were evident: osteophytosis, paraspinal ossification resembling that found in psoriasis, syndesmophytosis, and flowing ossification similar to that in DISH. In paraplegic patients, osteophytosis was most frequent. Vertebral ossification in quadriplegic patients was significantly associated with age (P < .01) and increased in frequency and severity with increasing age.