Study design: A retrospective follow-up study was conducted in patients who underwent decompressive laminectomy for degenerative lumbar spinal stenosis.
Objectives: To describe the long-term outcome of decompressive laminectomy performed for degenerative lumbar spinal stenosis, and to investigate preoperative factors that influenced outcomes, especially risk factors predisposing patients to poor results.
Summary of background data: The success rate of surgical treatment of decompressive laminectomy for lumbar spinal stenosis varies. Long-term follow-up investigations have indicated deterioration of outcome; however, the causes of deterioration have not been fully investigated, and there have been no reports with a minimum 10-year follow-up.
Methods: Of 151 patients who underwent decompressive laminectomy from 1980 through 1989, 37 were followed up for a minimum of 10 years. The mean age at surgery was 60.9 +/- 8. 2 years (range, 43-76), and the average follow-up period was 13.1 +/- 2.1 years (range, 10.1-17.4). The results were evaluated by the criteria of the Japanese Orthopedic Association Lumbar Score, and the outcome was classified as excellent at more than 75% improved score; good, 50-75%; fair, 25-49%; and poor, 0-24% or less. Information about impairment of activities of daily living was also obtained at follow-up. Associations between preoperative clinical and radiographic variables and clinical outcome were evaluated statistically.
Results: In all patients, the average score improvement of 55.2 +/- 31.6% was regarded as acceptable. The postoperative score and percentage of improvement of low back pain were lower than those of leg pain and walking ability. No impairment in activities of daily living was found in 62.2% of the patients. Rate of improvement was evaluated as excellent in 13 (35.1%), good in 8 (21.6%), fair in 8, and poor in 8 patients. Three patients required additional surgery because of disc herniation at the laminectomied segments. The patients with multiple laminectomy (P = 0.034) and more than 10 degrees preoperative sagittal rotation angle (P = 0.018) showed a significantly poorer outcome than the remainder of the patients.
Conclusions: Long-term follow-up showed that even without spinal fusion, more than half the patients were evaluated as excellent or good. Patients with more than a 10 degrees sagittalrotation angle who need multiple laminectomy, should be given information about the possibility of earlier deterioration of the outcome, and alternative or additional treatment such as concomitant spinal fusion with decompression may be considered.