Microendoscopic discectomy is widely performed as a minimally invasive surgery for patients with lumbar disc herniation in Japan. However, the reduced invasiveness in microendoscopic discectomy has not yet been fully evaluated. This is partly because effective scale has not been used to evaluate invasiveness. In this study, visual analogue scale was used prospectively to assess low back pain, leg pain and numbness. Microendoscopic discectomy was performed in 20 patients (10 men and 10 women). The average age was 34.1 years. Low back pain, leg pain and numbness were individually assessed in each patient for one week. After surgery scores for low back pain and leg pain were significantly reduced from 5.8±1.2 to 2.1±2.0 in 3 days and 7.0±1.5 to 0.2±0.3 in 1 day, respectively, whereas score for numbness of the legs was not reduced. Using the visual analogue scale to assess low back pain and leg pain could effectively evaluate the reduced invasiveness after microendoscopic discectomy within one week.
