Postlaminectomy Spinal Stenosis after Lumbar Discectomy / 대한척추외과학회지

ABSTRACT

STUDY DESIGN: Retrospective study OBJECTIVES: To investigate the type of postsurgical spinal stenosis in patients who had undergone a primary laminectomy and discectomy for a herniated lumbar disc, and to evaluate the clinical outcomes of the revision operation. SUMMARY AND LITERATURE REVIEW Spinal stenosis occurs frequently after a laminectomy and discectomy. Facet joint arthritis, hypertrophy of the ligamentum flavum, iatrogenic instability, postsurgical scarring or any combination of these conditions can cause spinal stenosis. MATERIALS AND METHODS: Twenty-four patients, who had postsurgical spinal stenosis were reviewed. Patients with a simple recurrent disc herniation without a spinal stenosis were excluded. The mean age was 52.5 years (range 31~70). There were 19 males and 5 females. The primary discectomy were performed at L4-5 in 21 patients, L5-1 in 2 patients, and both L4-5 and L5-1 in 1 patient. The mean interval between the first discectomy and revision surgery was 11.6 years (range 2.7~40). The anatomical site of the spinal stenosis, combined herniated disc, height of the disc space, segmental instability, hypertrophy of facet joint and thickening of the ligamentum flavum in radiographs was evaluated. The clinical outcome was measured using the Oswestry disability index. RESULTS: Lateral spinal stenosis was observed in all patients. Eight patients showed both central and lateral stenosis. The lateral stenosis was caused by hypertrophy of the facet joint in 20 patients and a thickening of the ligamentum flavum in 8 patients. Nineteen patients showed herniated lumbar disc, including disc protrusion in 8 patients, disc extrusion in 9 patients, and disc sequestration in 2 patients. A loss of disc height was observed in 12 patients, segmental instability in 5 patients, and spondylolisthesis in 3 patients. All the patients received posterior decompression and posterolateral fusion with pedice screw instrumentation. Eighteen patients received a discectomy simultaneously. The average Oswestry score at the last visit was 24.4. CONCLUSIONS: Postlaminectomy spinal stenosis resulted from a lateral spinal stenosis associated with facet joint hypertrophy. Recurrent disc herniation also contributed to the novel development of symptoms. A wide decompression and fusion provided good clinical outcomes.