97 patients with unilateral lumbar disc herniation were randomized to undergo lumbar microdiscectomy using either a traditional (control) or revised (test) technique, which focused on preserving as much of the ligamentum flavum as possible. The purpose of this study was to compare these two surgical approaches with respect to operative time, blood loss, pain and function. Results indicated that, although there were no significant differences between groups with respect to leg pain, operative time or blood loss, the test group yielded significantly better Oswestry scores at 12 weeks and 1 year post-operation. The revised procedure also resulted in significantly lower back pain scores at 3 days and 12 weeks postoperatively, however this significance was not maintained at 1 year. Both procedures were demonstrated to be safe, with no reports of reherniation, re-operation or infection.