Disc herniation after lumbar fusion.

Study Design: Eight patients with a herniated disc after lumbar spinal fusion are reported. Their clinical features, imaging studies, and management are reported.

Objectives: To identify the incidence and features of disc herniation above a spinal fusion, and to describe their management.

Summary Of Background Data: Late complications of lumbar spinal fusions have been reported in the literature, but disc herniation has not been specifically addressed in detail. The motion segment above a spinal fusion undergoes additional stresses, as documented by increased pressure and excessive motion, resulting in degenerative changes. These factors likely predispose to disc herniation.

Methods: Of 601 consecutive lumbar fusion cases over an 8-year period, herniated nucleus pulposus above the fusion was diagnosed in 8 patients. The clinical findings and imaging studies were reviewed, including a myelogram computed tomography scan, a magnetic resonance image with positive documentation of the herniation, or both. The management of these cases was reviewed.

Results: Eight patients (1.3%) (4 men and 4 women) were identified, whose average age was 56.4 years. Nonoperative treatment failed in six patients. Two of these patients underwent simple discectomy, and the remaining four underwent discectomy and fusion. All four patients went on to fusion. The average time from disc herniation onset to fusion was 28.4 months.

Conclusions: Herniated disc after lumbar spinal fusion was found in approximately 1.3% of patients. Although rare, this entity that should be considered when patients complain of recurring back pain after a lumbar spinal fusion.