Large Lumbar Lordosis is a Risk Factor for Lumbar Spondylolysis in Patients with Adolescent Idiopathic Scoliosis.

Study design A retrospective, single-center, observational study. Objective The aim of this study was to determine the prevalence and the characteristics of AIS patients with concomitant lumbar spondylolysis. Summary of background data The prevalence and features of lumbar spondylolysis in patients with adolescent idiopathic scoliosis (AIS) are unclear. Methods We included 357 patients with AIS who underwent correction and fusion surgery. Preoperative CT images were used to assess the existence of lumbar spondylolysis. Cobb angles of the curves, parameters of spinal alignment, Lenke classification, and the presence of low back pain were compared between patients with and without spondylolysis. Results Of the patients included in the study, 6.1% had lumbar spondylolysis. They had significantly greater lumbar lordosis (LL) and sacral slope (SS) than those without lumbar spondylolysis. Logistic regression analyses and receiver-operating characteristic curves showed that LL was a significant risk factor (odds ratio: 1.059; 95% confidence interval: 1.018-1.103; P = 0.005) of associating lumbar spondylolysis with a cut off value of 56.5 degrees (area under the curve [AUC]: 0.689; sensitivity = 63.6%, specificity = 71.0%). Conclusion We should be vigilant for lumbar spondylolysis in AIS patients whose LL and SS are large, especially with LL larger than 56.5 degrees.Level of Evidence: 3.