Risk Factors for Negative Global Treatment Outcomes in Lumbar Spinal Stenosis Surgery: A Mixed Effects Model Analysis...

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

Patients from the Spine Tango registry undergoing first-time surgery for LSS were analyzed. The primary outcome was global treatment outcomes 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.

A total of 4504 patients from 39 departments in 10 countries were included. Overall, 14.4% of patients reported a negative global treatment outcome 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 (American Society of Anesthesiologists) ≥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, whereas 1 department had significantly lower odds. Three out of the 4 negative effects were related to 2 departments from 1 country.

LSS surgery fails to help at least 1 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 nonnegligible variation in the treatment results.