Risk factors for negative global treatment outcomes in lumbar spinal stenosis surgery: a mixed effects model analysis of data from an international spine registry.

OBJECTIVE

To determine risk factors for negative global treatment outcomes (GTO) as self-assessed by patients undergoing surgical treatment for lumbar spinal stenosis (LSS).

METHODS

Patients from the Spine Tango registry undergoing first-time surgery for LSS were analyzed. The primary outcome was GTO measured at the last available follow-up ≥3 months postoperatively using a single question rating how much the operation had helped the patient's back problem (negative=no change/operation made things worse). A 2-level logistic mixed effects model with the treating department as the random effect was used to assess factors associated with a negative outcome.

RESULTS

4,504 patients from 39 departments in ten countries were include. Overall, 14.4% of patients reported a negative GTO after an average follow-up of 1.3 years. In patients with dominant leg pain, negative outcome was associated with higher baseline back pain; in those with dominant back pain, it was associated with higher baseline back pain, ASA≥3, lower age, not having rigid stabilization, not having disc herniation, and the vertebral level of the most severely affected segment (L5/S1 vs L3/4). Four departments had significantly higher odds of a negative outcome, while one department had significantly lower odds. Three out of the four negative effects were related to two departments from one country.

CONCLUSIONS

LSS surgery fails to help at least one in 10 patients. High baseline back pain is the most important factor associated with a negative treatment outcome. Department-level and potentially country-level factors of unknown origin explained a non-negligible variation in the treatment results.