Effectiveness of an Annular Closure Device to Prevent Recurrent Lumbar Disc Herniation: A Secondary Analysis With 5 Years of Follow-up

Abstract

Importance: Patients with large annular defects following lumbar microdiscectomy for disc herniation are at increased risk for symptomatic recurrence and reoperation.

Objective: To determine whether a bone-anchored annular closure device in addition to lumbar microdiscectomy resulted in lower reherniation and reoperation rates vs lumbar microdiscectomy alone.

Design, setting, and participants: This secondary analysis of a multicenter randomized clinical trial reports 5-year follow-up for enrolled patients between December 2010 and October 2014 at 21 clinical sites. Patients in this study had a large annular defect (6-10 mm width) following lumbar microdiscectomy for treatment of lumbar disc herniation. Statistical analysis was performed from November to December 2020.

Interventions: Lumbar microdiscectomy with additional bone-anchored annular closure device (device group) or lumbar microdiscectomy only (control group).

Main outcomes and measures: The incidence of symptomatic reherniation, reoperation, and adverse events as well as changes in leg pain, Oswestry Disability Index, and health-related quality of life when comparing the device and control groups over 5 years of follow-up.

Results: Among 554 randomized participants (mean [SD] age: 43 [11] years; 327 [59%] were men), 550 were included in the modified intent-to-treat efficacy population (device group: n = 272; 270 [99%] were White); control group: n = 278; 273 [98%] were White) and 550 were included in the as-treated safety population (device group: n = 267; control group: n = 283). The risk of symptomatic reherniation (18.8% [SE, 2.5%] vs 31.6% [SE, 2.9%]; P < .001) and reoperation (16.0% [SE, 2.3%] vs 22.6% [SE, 2.6%]; P = .03) was lower in the device group. There were 53 reoperations in 40 patients in the device group and 82 reoperations in 58 patients in the control group. Scores for leg pain severity, Oswestry Disability Index, and health-related quality of life significantly improved over 5 years of follow-up with no clinically relevant differences between groups. The frequency of serious adverse events was comparable between the treatment groups. Serious adverse events associated with the device or procedure were less frequent in the device group (12.0% vs 20.5%; difference, -8.5%; 95% CI, -14.6% to -2.3%; P = .008).

Conclusions and relevance: In patients who are at high risk of recurrent herniation following lumbar microdiscectomy owing to a large defect in the annulus fibrosus, this study's findings suggest that annular closure with a bone-anchored implant lowers the risk of symptomatic recurrence and reoperation over 5 years of follow-up.

Trial registration: ClinicalTrials.gov Identifier: NCT01283438.

Conflict of interest statement

Conflict of Interest Disclosures: Dr Thomé reported personal fees from Intrinsic Therapeutics Honoraria as educational consultant during the conduct of the study; grants from BITPharma, BrainLab, DePuySynthes, Icotec, Idorsia, Pfizer, Signus Medical, and TETEC; and personal fees from BrainLab, DePuySynthes, Icotec, Medtronic, Nuvasive, Siemens, Signus Medical, Zeiss outside the submitted work. Dr Kuršumović reported receiving consulting fees from Intrinsic Therapeutics during the conduct of the study. Dr Klassen reported grants from Intrinsic Therapeutics outside the submitted work. Dr Bouma reported other from Intrinsic Therapeutic Research Support during the conduct of the study. Dr Bostelmann reported receiving support for travel from University Clinic Düsseldorf for travel coordinator meetings during the conduct of the study; and consulting fees from Intrinsic Therapeutics during the conduct of the study. Dr Arts reported receiving personal fees from Intrinsic Therapeutics during the conduct of the study; personal fees from Johnson and Johnson royalties, grants from Zimmer-Biomet, and personal fees from Nuvasive consultancy outside the submitted work; in addition, Dr Arts had a patent for EIT / Johnson and Johnson with royalties paid. Dr Miller reported receiving personal fees from Intrinsic Therapeutics during the conduct of the study. Dr Vajkoczy reported study support from Intrinsic Therapeutics the conduct of the study. Dr Brenke reported receiving grants from Intrinsic therapeutics during the conduct of the study. No other disclosures were reported.

Figures

Figure 1.. Enrollment and Randomization of Patients

A total of 276 patients were assigned to the device group and 278 patients assigned to the control group. Modified intention-to-treat population consisted of 272 patients with attempted device implant and 278 control patients. As-treated safety population consisted of 267 patients receiving the device and 283 receiving the control. In the as-treated safety population, failed device implantation in 5 patients from the modified intent-to-treat population resulted in assignment to the control group for analysis purposes.

Figure 2.. Index Level Symptomatic Reherniation Through 5 Years

Kaplan-Meier estimates in the modified intent-to-treat population through 5 years were 18.8% (SE, 2.5%) in the device group and 31.6% (SE, 3.0%) in the control group (log-rank P < .001).

Figure 3.. Index Level Reoperation Through 5 Years

Kaplan-Meier estimates in the modified intent-to-treat population through 5 years were 16.0% (SE, 2.3%) in the device group and 22.6% (SE, 2.7%) in the control group (log-rank P = .03).

Figure 4.. Cumulative Risk of Reoperation Through 5 Years

The Nelson-Aalen cumulative hazard for reoperation over 5 years was 0.172 (SE, 0.027) in the device group and 0.255 (SE, 0.034) in the control group (log-rank P = .03).