Follow-up examinations performed a minimum of 2 years postoperatively showed that no neurovascular complications developed in 100 patients who underwent arthroscopic microdiscectomy for treatment of herniated discs at L3-4, L4-5, or L5-S1. By using a posterolateral approach, endoscopic control, and specially designed straight, upbiting, and deflectable forceps, it was possible to remove not only fragments located in the center of the nucleus, but also fragments that had migrated posteriorly and posterolaterally. Analysis of operative results by a modification of the Rush-Presbyterian-St. Luke's lumbar spine analysis system demonstrated that 88 of the patients attained excellent or good results and 12 attained poor or fair results. The outcome of surgery was not related to age, sex, or surgical level. The most common causes of an unsuccessful surgical outcome were lateral recess stenosis and sequestered fragments missed in the preoperative work-up.