Osteoporotic spondylolisthesis: a case report.

STUDY DESIGN: A case of spondylolisthesis caused by osteoporosis is described. OBJECTIVES: To describe the different etiologies of spondylolisthesis, and to report a new cause of pathologic spondylolisthesis previously unreported in the literature. SUMMARY OF BACKGROUND DATA: The literature on the etiology of spondylolisthesis is reviewed. Pathologic spondylolisthesis has been described with structural abnormalities, such as Paget's disease and tumors, but not with osteoporosis. METHODS: A clinical and radiographic interpretation of the reported case is presented. RESULTS: De Novo development of a spondylolisthesis at L5-S1 occurred by gradual elongation of the pars interarticularis over a period of 3 years. CONCLUSION: The reported case adds to the literature on spondylolisthesis by describing another etiology for this conclusion. Osteoporotic spondylolisthesis may well be identified more frequently in the future given the high prevalence of osteoporosis in the elderly.