Predictive factors for residual leg numbness after decompression surgery for lumbar degenerative diseases

Background The purpose of this study is to evaluate the change patterns of leg numbness (LN) after lumbar decompression surgery (LDS), and to find the predictive factors that affect the recovery of numbness. Methods Patients who underwent LDS in our institution between August 2020 and July 2021 were prospectively enrolled in this study, and were followed by a 12-month follow-up. The degree of LN, leg pain (LP) and the disability were assessed using the visual analog scale (VAS) and oswestry disability index (ODI). Results A total of 314 patients finished the 12-month follow-up. The preoperative mean VAS-LN score was 3.49 [+ or -] 2.44, which decreased to 1.91 [+ or -] 1.30 at 3 months, to 1.29 [+ or -] 0.97 at 6 months and to 1.26 [+ or -] 0.96 at 12 months after surgery. The preoperative mean VAS-LP score was 6.05 [+ or -] 1.30, which decreased to 2.00 [+ or -] 0.86 at 3 months, to 1.02 [+ or -] 0.80 at 6 months, and to 0.49 [+ or -] 0.71 at 12 months after surgery. The preoperative mean ODI score was 27.90 [+ or -] 7.08, which decreased to 9.73 [+ or -] 3.09 at 3 months, to 6.72 [+ or -] 2.98 at 6 months, and to 4.57 [+ or -] 2.76 at 12 months after surgery. Via multivariate logistic regression analysis, only preoperative VAS-LN score (p < 0.001*) was identified as a significantly independent predictive factor for residual LN after operation. Conclusion Clinically significant improvement in LN was observed in the majority of patients within 6 months after LDS, and the improvement of VAS-LN was slower than the VAS-LP. High pre-operative VAS-LN score can independently predict the presence of residual LN after surgery at 12-month follow up. Keywords: Numbness, Decompression surgery, Lumbar degenerative diseases, Predictive factors