Revision surgery following operations for lumbar stenosis.

BACKGROUND: For carefully selected patients with lumbar stenosis, decompression surgery is more efficacious than nonoperative treatment. However, some patients undergo repeat surgery, often because of complications, the failure to achieve solid fusion following arthrodesis procedures, or persistent symptoms. We assessed the probability of repeat surgery following operations for the treatment of lumbar stenosis and examined its association with patient age, comorbidity, previous surgery, and the type of surgical procedure.
METHODS: We performed a retrospective cohort analysis of Medicare claims. The index operation was performed in 2004 (n = 31,543), with follow-up obtained through 2008. Operations were grouped by complexity as decompression alone, simple arthrodesis (one or two disc levels and a single surgical approach), or complex arthrodesis (more than two disc levels or combined anterior and posterior approach). Reoperation rates were calculated for each follow-up year, and the time to reoperation was analyzed with proportional hazards models.
RESULTS: The probability of repeat surgery fell with increasing patient age or comorbidity. Aside from age, the strongest predictor was previous lumbar surgery: at four years the reoperation rate was 17.2% among patients who had had lumbar surgery prior to the index operation, compared with 10.6% among those with no prior surgery (p < 0.001). At one year, the reoperation rate for patients who had been managed with decompression alone was slightly higher than that for patients who had been managed with simple arthrodesis, but by four years the rates for these two groups were identical (10.7%) and were lower than the rate for patients who had been managed with complex arthrodesis (13.5%) (p < 0.001). This difference persisted after adjusting for demographic and clinical features (hazard ratio for complex arthrodesis versus decompression 1.56, 95% confidence interval, 1.26 to 1.92). A device-related complication was reported at the time of 29.2% of reoperations following an initial arthrodesis procedure.
CONCLUSIONS: The likelihood of repeat surgery for spinal stenosis declined with increasing age and comorbidity, perhaps because of concern for greater risks. The strongest clinical predictor of repeat surgery was a lumbar spine operation prior to the index operation. Arthrodeses were not significantly associated with lower rates of repeat surgery after the first postoperative year, and patients who had had complex arthrodeses had the highest rate of reoperations.