Scoliosis, type-2 diabetes and total laminectomy at the 4th lumbar vertebra are independent risk factors for post-laminectomy fracture around the isthmus.

Abstract Objective: We aimed to identify the risk factors and clinical outcomes for post-laminectomy fracture around the isthmus, which can cause back pain or radiculopathy. Methods: We performed a retrospective cohort study involving all patients who underwent laminectomy splitting the spinous process for lumbar spinal stenosis between 2010 and 2014. The primary outcome measure was post-laminectomy fracture around the isthmus. Clinical outcomes were evaluated based on reoperation rate. To evaluate risk factors for fracture, the following parameters were collected: (1) patient characteristics and concomitant type-2 diabetes, (2) lumbar scoliosis and sagittal alignment parameters, and (3) surgical data, such as rate of total laminectomy. Logistic regression analysis was performed to identify the independent risk factors for post-laminectomy fracture. Results: twelve of the 92 patients suffered a post-laminectomy fracture around the isthmus. Logistic regression analysis revealed that diabetes (odds ratio [OR], 15.41; 95% confidence interval [CI], 2.93–80.98; p=0.001), L4 total laminectomy (OR, 14.68; 95% CI, 1.51–142.76; p=0.021), and lumbar scoliosis (OR, 5.72; 95% CI, 1.16–28.21; p=0.032) were independent risk factors. The fracture group included 2 patients (16.7%) who required reoperation at the decompression level for recurrent leg pain, whereas the non-fracture group included 2 (2.5%) who underwent reoperation at a level different from the index procedure. Conclusions: Post-laminectomy fractures around the isthmus were significantly associated with scoliosis, type-2 mellitus, and total laminectomy at L4. Total laminectomy at L4 is best avoided to reduce the risk of post-laminectomy fracture in patients with scoliosis or type-2 diabetes.