Radiographic assessment of anatomic deviations in lumbar spondylolysis.

A series of 202 patients (133 men, 69 women) with spondylolysis were examined with respect to radiographic variables describing lumbosacral lordosis, size of lumbar vertebrae, transverse processes and disc height. An age-standardized and sex-stratified comparison was made with a control group of 170 subjects (68 men, and 102 women) without lumbar spine disorders. The difference in lumbosacral lordosis between the spondylolysis and control groups was considered to be secondary to olisthesis, and to lack an etiologic role for the genesis of lysis. The lengths of the transverse processes and their distances to the crista iliaca posterior demonstrated no differences between the groups and therefore did not seem relevant to the context of the pathogenesis of spondylolysis. The fifth lumbar vertebra in the spondylolytic patients was more wedged and less wide than in the controls. The question of the primary or secondary nature of this change has not yet been clearly elucidated, and should be given further attention. The spondylolytic patients demonstrated a decrease in the height of the L5-S1 disc much earlier than the controls, and the degree of narrowing of the disc space was much more marked.