[Long-term survival analysis after surgical management for degenerative lumbar stenosis]

The short- and mid-term symptom-relief of surgical treatment for lumbar stenosis is generally acknowledged, but the probability of a long-term reoperation remains to be studied. The purpose of this work was to determine the long-term risk of reoperation after surgical treatment of degenerative lumbar stenosis and to search for factors influencing this probability.

All patients who underwent from 1989 to 1992 surgical treatment for degenerative lumbar spine stenosis were included in this work. At last follow-up, we noted functional outcome using a specific self-administered questionnaire, patient satisfaction, lumbalgia and radiculalgia using a visual analog scale, SF36 quality-of-life, reoperation or not with time since first operation if performed and the reasons and modalities of the reoperation. The probability of reoperation was determined with the acturarial method. A Cox model was used to search for factors linked with the probability of reoperation; variables studied were: age, comorbid factors, extent of the release, posterolateral arthrodesis or not, extent of the potential fusion, use or not of instrumentation for arthrodesis.

The study included 262 patients. At last follow-up, 61 patients had died a mean 3.7+/-3 years after the operation; only one of these patients had a second operation 22 months after the first. Forty-four patients were lost to follow-up at mean 6.6+/-3 years. Among these 44 patients, four had a second operation during their initial follow-up at mean 47 months. One hundred fifty-seven patients were retained for this analysis at mean 15+/-1 years follow-up. Among these 157 patients, 29 had a second operation a mean 75 months after the first. There were four reasons for reoperating: insufficient release, destabilization within or above the zone of release, development or renewed zone of stenosis, development or renewed discal herniation. The risk of a second operation was 7.4% [95% CI 4.8-11.6], 15.4% [95% CI 10.7-21.1] and 16.5% [95% CI 11.7-219] at five, 10 and 15 years respectively after the first operation. Among the risk factors studied, only one had a significant impact on reoperation: extent of the zone of release (p=0.003). Compared with a release limited to one level, the risk of reoperation after release of three levels or more was five times greater [95% CI 1.8-12.7].