Risk Factors for Early Reherniation after Lumbar Discectomy with or without Annular Closure: Results of a Multicenter Randomized Controlled Study

Abstract

Aim: Reherniation (RH) after lumbar discectomy (LD) is known as a failure and reported in the literature ranging from 3 to 18%. Different risk factors for RH have been discussed such as age, sex, BMI, smoking, type and size of annular defect, amount of removed disc volume, grade of disc degeneration, disc height, etc. The aim of this study was to identify preoperative demographic, radiological, and intraoperative surgical factors associated with early RH in patients undergoing one level LD with or without annular closure within 3 months after surgery. Methods: This study is based on the analysis of data of a postmarketing, prospective, multicenter RCT in Europa including patients undergoing standard LD with or without implantation of an annular closure device (ACD) (Barricaid®, Intrinsic Therapeutics, Inc., Massachusetts, United States). Enrollment of 554 patients in 21 Centers in Europa (DE, CH, AT, BE, NL, FR) started in 2010 and was completed by October 2014. A total of 276 patients were randomized to the ACD group and 278 patients to the control group. Results: Within 3 months after surgery, 20 (3.7%) patients had a symptomatic RH. 4 (1.5%) occurred in the ACD group and 16 (5.8%) in the Control group. Reoperation was performed in 3 patients in the ACD group and 9 patients in the Control group. Regarding the risk factors for RH, there was a trend with gender in the overall population (p = 0.077) – A 5.5% rate of RH was observed in females (12/219) in comparison to 2.5% (8/326) in male patients. A larger annular defect was a significant risk factor for RH overall (p = 0.017) and in the Control Group (p = .0.01). 21 (4%) patients had a defect size > 54 mm2 and 14.3% of these patients developed a RH. In the ACD group all 4 RH were found in patients with defects ≤ 54 mm2. Disc degeneration according to the classification of Kellgren and Lawrence showed a trend as a predictor for RH overall (p = 0.077) and was a significant risk factor in the Control group (p = 0.017). In addition the Pfirrmann classification correlated significantly with RH, both overall (p = 0.004) and in the Control group (p = 0.010). Out of 400 patients who showed a Pfirrmann Grade 2, 2.5% suffered RH, while 9.5% of the 95 patients with a Pfirrmann Grade 3 reherniated. Conclusion: Risk factors for early RH after LD in our study were large annular defect and disc degeneration. The ACD significantly reduces the risk for early RH. These results suggest that implantation of an ACD can prevent early RH after LD.