Management of severe spondylolisthesis in children and adolescents.

Forty-three patients with a fifth lumbar-first sacral spondylolisthesis of 50 per cent or greater were reviewed. Four had been treated non-operatively; eleven, by arthrodesis; eighteen, by decompression and arthrodesis; and ten, by reduction and arthrodesis. The angle of slipping (measurement of the kyphotic relationship of the fifth lumbar to the first sacral vertebra) was found to be as important a measurement as the percentage of slipping in measuring instability and progression of slipping. Hamstring tightness did not correlate with neural deficit. Arthrodesis alone, even in the presence of minor neural deficits, tight hamstrings, or both, gave relief of pain and resolution of neural deficits and tight hamstrings. Our experience with a limited number of patients suggests that management by postoperative extension casts may achieve a significant reduction in percentage of slipping and in angle of slipping. Progression of the spondylolisthesis may occur following a solid arthrodesis.