Influence of Spondylolysis on Clinical Presentations in Patients With Lumbar Degenerative Disease

Background: There is insufficient current information regarding the prognosis of patients with lumbar spondylolysis when bone union is not achieved. To examine the number, age, and surgically treated levels of patients with lumbar degenerative disease who underwent lumbar spine surgery, and to compare the results between patients with spondylolysis and without spondylolysis, a cross-sectional study was performed. Methods: Patients with degenerative lumbar disease who underwent lumbar spine surgery were retrospectively reviewed (n=354). The prevalence of spondylolysis was determined using CT images. Patients were divided into a spondylolysis group and a non-spondylolysis group, and the patients’ age, sex, and surgically treated levels were compared between the two groups. Results: The prevalence of lumbar spondylolysis in the 354 patients was 6.50% (23/354). The patients’ age was significantly lower in the spondylolysis group (54.2 ± 13.5 years) than in the non-spondylolysis group (63.8 ± 14.2). The number of surgically treated levels was significantly lower in the spondylolysis group (1.33 ± 0.56 levels) than in the non-spondylolysis group (1.70 ± 0.87). The percentage of patients who underwent surgery at L5-S1 was significantly higher in the spondylolysis group; whereas the percentage of patients who underwent surgery at L3-L4 or L4-L5 was significantly higher in the non-spondylolysis group. Conclusions: Our results suggest that the presence of spondylolysis may not increase the incidence of degenerative lumbar spinal disorders requiring spinal surgery. However, spondylolysis patients frequently have severe degenerative disease at one level caudal to the spondylolysis, and infrequently have multilevel lumbar degenerative disease requiring spinal surgery.