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

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 diabetes mellitus, (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 mellitus (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, diabetes 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 diabetes mellitus.