Long-term vertebral changes attributable to postoperative lumbar discitis: a retrospective study of six cases.

UNLABELLED: A clinical, plain radiographic, and magnetic resonance imaging retrospective followup study was done on six patients with postoperative septic L4-L5 lumbar spondylodiscitis to identify the characteristic long-term radiographic findings predicting the clinical outcome. The mean followup was 12 years (range, 9-13 years). Three patients had moderate low-back pain and two were handicapped. One patient had slight peroneal weakness. Flexibility of the lumbar spine was restricted to some extent in all patients. Laminectomy for spinal stenosis (L4-L5) had been done in one patient and reoperation because of recurring disc herniation was done in two patients. Partial or total bone marrow depletion and corresponding enhancement of fat signals in relation to adjacent vertebral bodies, narrowing of the intervertebral disc space, and irregularity or cavitations affecting one or both end plates were long-term findings of magnetic resonance imaging. Plain radiographs and magnetic resonance imaging scans revealed a complete bony fusion in one patient and partial fusion in one patient. In two patients, residual disc protrusion or herniation in relation to the surgically treated disc was evident; three affecting L3-L4 and two affecting L5-S1 disc levels. Septic postoperative lumbar discitis severely hampers clinical recovery after disc operations and results in long-term changes as seen on magnetic resonance imaging scans. LEVEL OF EVIDENCE: Therapeutic study, Level IV (case series--no, or historical control group). See the Guidelines for Authors for a complete description of levels of evidence.