The Risk of Getting Worse: Predictors of Deterioration After Decompressive Surgery for Lumbar Spinal Stenosis: A Multicenter Observational Study.

Objective: To investigate the frequency and predictors of deterioration after decompressive surgery for single and 2-level lumbar spinal stenosis.

Methods: Prospectively collected data were retrieved from the Norwegian Registry for Spine Surgery. Clinically significant deterioration was defined as an 8-point increase in Oswestry disability index (ODI) between baseline and 12 months' follow-up.

Results: There were 2181 patients enrolled in the study. Of 1735 patients with complete 12 months follow-up, 151 (8.7%) patients reported deterioration. The following variables were significantly associated with deterioration at 12 months' follow-up; decreasing age (odds ratio [OR] 1.02, 95% confidence interval [95% CI] 1.00-1.04, P = 0.046), tobacco smoking (OR 2.10, 95% CI 1.42-3.22, P = 0.000), American Society of Anesthesiologists grade ≥3 (OR 1.80, 95% CI 1.07-2.94, P = 0.025), decreasing preoperative ODI (OR 1.05, 95% CI 1.02-1.07, P = 0.000), previous surgery at the same level (OR 2.00, 95% CI 1.18-3.27, P = 0.009), and previous surgery at other lumbar levels (OR 2.10, 95% CI 1.19-3.53, P = 0.009).

Conclusions: Overall risk of clinically significant deterioration in patient-reported pain and disability after decompressive surgery for lumbar spinal stenosis is approximately 9%. Predictors for deterioration are decreasing age, current tobacco smoking, American Society of Anesthesiologists grade ≥3, decreasing preoperative ODI, and previous surgery at same or different lumbar level. We suggest that these predictors should be emphasized and discussed with the patients before surgery.