Prognostic Factors for Drop Foot Due to Lumbar Degenerative Diseases: The Impact of Surgical Timing on Postoperative Recovery.

Abstract

Retrospective clinical series. To investigate the prognostic factors for the improvement of drop foot caused by degenerative lumbar disease after surgery. Drop foot may be caused by lumbar spinal diseases and may affect daily life. There are limited data regarding predictors of drop foot, especially surgical timing. We retrospectively reviewed data from 87 patients with drop foot. Prognostic factors and precise timing of surgery affecting drop foot improvement were examined by multivariate logistic regression analysis. Forty patients (46.0%) recovered from drop foot after surgery. Age [odds ratio (OR)=0.93; 95% confidence interval (CI), 0.87-0.98; P=0.01], preoperative anterior tibialis muscle strength (OR=12.0; 95% CI, 2.41-59.9; P=0.002), and duration of drop foot before surgery (OR=3.59; 95% CI, 1.09-11.8; P=0.04) were significant prognostic factors. Two months was the most appropriate cutoff for surgery after appearance of symptoms. Age, preoperative tibialis anterior muscle strength, and duration of drop foot were statistically significant prognostic factors of recovery from drop foot. Surgery within 2 months after the onset of drop foot may improve postoperative outcome.