Microsurgical Annular Restoration with a Z-Suture following Lumbar Microdiscectomy: A Retrospective Comparative Study on 763 Patients with a Mean Follow-up of 12.5 Years

Abstract

Background: Microdiscectomy for lumbar disc herniation (LDH) is one of the most common procedures performed by spine surgeons worldwide. It usually significantly reduces pain and restores both functional disability and health-related quality of life. The incidence of a postoperative recurrence, however, is encountered in 10 to 25%. A large annular defect is known to increase the risk of recurrence. A perioperative annular restoration may thus decrease the risk of recurrence. Methods: A retrospective study was performed comparing the risk of recurrence after lumbar single-level microdiscectomy with (study group) or without (control group) annular restoration using a Z-suture. Included patients were consecutively operated between May 1990 and April 1994 (control group) and September 1998 and December 1998 (study group). Subsequent LDH recurrence was recorded analyzing the patients' records and rereferrals until a mean follow-up of 12.5 years. Results: A total of n = 763 patients were included, of which 374 patients received a Z-suture (study group) and 389 patients served as controls (control group). The study groups did not differ in age (mean: 44.8 vs. 45.1 years; p = 0.86), gender (54.8 and 51.7% males; p = 0.38), or distribution of the lumbar segments (p = 0.46). Surgical time was significantly longer in the study group (81.6 vs. 69.3 minutes, p < 0.0001). The rate of reoperation for a local LDH recurrence was significantly lower in the study group at 3 months (0 vs. 1.8%, p = 0.02) and remained to show a clear trend at 12 months postoperative (2.1 vs. 4.6%, p = 0.07). At the time of last follow-up (mean: 8.3 vs. 16.6 years, p < 0.0001), local recurrence was observed in 21 out of 374 (5.6%) in the study group compared with 36 out of 389 (9.3%) in the control group (p = 0.06). The subsequent risk reduction of reoperation for local recurrence was 100, 54.3, and 39.8% after 3 months, 12 months, and at long-term follow-up using a Z-suture. There were no complications associated with the Z-suture in this series. Conclusions: Our data indicate that a Z-suture as annular restoration is safe and prolongs the surgery by ∼12 minutes. It reduces the recurrence rate at 3 and 12 months after microdiscectomy, while its impact on the long-term follow-up has to be interpreted with caution due to the longer follow-up of our control group. Therefore, annular defect restoration should be considered as an option to reduce the local recurrence rate for patients undergoing lumbar microdiscectomy.