Predictors for Unsuccessful Outcome of Lumbar Spinal Stenosis Surgery: A Secondary Analysis of the 2 Randomized NORDSTEN Trials.

STUDY

DESIGN

Observational cohort study.

OBJECTIVE

To evaluate potential predictors of unsuccessful outcomes after surgery in patients with lumbar spinal stenosis (LSS).

SUMMARY OF BACKGROUND DATA: LSS is a common cause of disability in adults and the leading indication for spine surgery in Norway. Despite advances in surgical techniques, nearly one-third of patients report either minor or no improvement or worsening of symptoms after surgery. Identifying predictors of unsuccessful outcomes is essential for improving patient selection and shared decision-making.

MATERIALS AND

METHODS

This secondary analysis used data from the 2 NORwegian Degenerative spondylolisthesis and spinal STENosis (NORDSTEN) randomized trials, which included 704 surgically treated patients with LSS, with (n=267) or without (n=437) degenerative spondylolisthesis. The Oswestry Disability Index (ODI) was the primary outcome measure. A reduction in ODI score of <30% from baseline to 2 years postoperatively was defined as an unsuccessful outcome. Multivariable logistic regression analysis was used to evaluate whether carefully selected baseline variables were associated with an unsuccessful outcome at 2-year follow-up.

RESULTS

Longer duration of radiating pain (>12 mo; OR: 2.58, 95% CI: 1.54-4.29), psychological distress (HSCL-25 ≥1.75; OR: 1.60, 95% CI: 1.01-2.53), and advanced disc degeneration (Pfirrmann grades 4-5; OR: 1.98, 95% CI: 1.26-3.12) were independently associated with an unsuccessful outcome. Commonly discussed factors such as age, BMI, smoking, ASA grade, and predominant back pain did not reach statistical significance for association with the outcome.

CONCLUSION

Among patients undergoing surgery for LSS, longer symptom duration, psychological distress, and advanced disc degeneration were associated with a higher risk of unsuccessful postoperative outcomes.