A prospective study of recovery from leg numbness following decompression surgery for lumbar spinal stenosis

Residual leg numbness (LN) following lumbar surgery can lower patient satisfaction; however, prospective studies are sparse. The purpose of this study was to evaluate recovery from LN following decompression surgery for lumbar spinal stenosis (LSS). A total of 145 patients with LSS were enrolled. All patients underwent decompressive surgery, with or without spinal fusion, followed by a 12 month prospective follow-up. The degree of LN and leg pain (LP) was assessed using the visual analog scale (VAS), a patient-reported outcome measure. Six patients dropped out, and we evaluated 139 patients (average age, 68.1 years). The average VAS-LN scores were 5.9 ± 2.6, 1.8 ± 2.3, 2.0 ± 2.5, 2.1 ± 2.6, 2.2 ± 2.5, and 2.1 ± 2.6, and the average VAS-LP scores were 5.7 ± 2.8, 1.2 ± 1.7, 0.9 ± 1.5, 1.4 ± 2.0, 1.4 ± 2.0, and 1.4 ± 1.9 preoperatively and at 2 weeks, 3, 6, 9, 12 months following the surgery, respectively. Significant improvement in VAS-LN and VAS-LP scores was observed during the first 2 weeks after the surgery. At 12 months after the surgery, the VAS-LN score was significantly greater than the VAS-LP score. The change in the VAS-LN score between the preoperative and 12 month-postoperative values was significantly smaller than that in the VAS-LP score. Multivariate logistic analyses revealed that preoperative symptom duration and preoperative dural sac cross-sectional area (DCSA) were the significant independent predictive factors for residual LN. Following lumbar decompression surgery, LN improved significantly during the first 2 weeks after surgery. However, the improvement in the VAS-LN score was less than in the VAS-LP score. Patients with longer preoperative symptom duration and narrow preoperative DCSA showed less LN improvement. Level 3.