624 - Interim Results from a Prospective, Randomized Clinical Trail Investig...

General Session: Innovative Technologies

Presented by: G.J. Bouma - View Audio/Video Presentation (Members Only)

Author(s):

G.J. Bouma(1), P.D. Klassen(2), F. Martens(3), J. Fandino(4), Anular Closure RCT Study Group

(1) Sint Lucas Andreas Ziekenhuis, Amsterdam, Netherlands
(2) St. Bonifatius Hospital GmbH, Lingen, Germany
(3) Onze Lieve Vrouziekenhuis, Aalst, Belgium
(4) Kantonsspital Aarau AG, Aarau, Switzerland

Abstract

Introduction: While reported rates of reherniation after primary lumbar discectomy vary, Carragee et al found the reherniation rate among patients with anular defect widths wider than 6mm was 27%, compared to a 1% rate of reherniation in patients with slit or fissure type defects.While aggressive discectomy may reduce recurrence risk, less favorable outcomes such as disc collapse, back pain, and accelerated disc degeneration are associated with this technique. Closing massive anular defects after limited discectomy may provide effective treatment for reducing reherniation rates while negating the need for aggressive nucleus removal.The current study seeks to compare clinical outcomes of patients with a higher risk of reherniation due to larger anular defects treated with and without an anular closure device (ACD).

Methods: Interim data from an ongoing, prospective, randomized study was reviewed for adverse events, symptomatic reherniations, and reoperations at the index level. SAEs occurring within 30 days of the index surgery were considered peri-operative. Similar to the definition used by Carragee et al to define their 'massive defect' group, a key inclusion criterion for the study was an anular defect ≥ 6mm wide. Additional inclusion/exclusion criteria included: six weeks conservative care, no prior surgery, minimum Oswestry and leg pain (40/100). Symptomatic reherniations were reported by the site. Kaplan-Meier survivorship was estimated based on time to symptomatic reherniation, and compared to the data presented by Carragee et al. Randomization (1:1, Barricaid:Discectomy-only) is performed intra-operatively, following discectomy and confirmation of anular defect size (minimum 4x6mm, maximum 6x10mm). The Barricaid® ACD consists of a polyester mesh that occludes the anular defect, and is held in place by a titanium bone anchor.

Results: Enrollment of the study was completed in October of 2014 with 554 subjects. This interim safety analysis was performed in February 2015 and complies with the statistical analysis plan. 448 subjects were past one year, 287 past two years and 88 passed 3 years. Similar numbers of patients in each group had reported an adverse event (Barricaid 64%=178/276, Control 62%=171/278), with fewer device and/or procedure related serious adverse events (SAE) reported for Barricaid patients (21 vs 36). The Barricaid group had 56% fewer symptomatic reherniations (20 vs 45), 37% fewer reoperations at the index level (31 vs 49), and 76% fewer reoperations following recurrence including repeat reoperations (10 vs 41). The rates of serious peri-operative adverse events can be found in the following table:

Discussion: This interim report of an ongoing RCT provides an initial analysis showing a lower rate of peri- and post-operative serious adverse events for high-risk patients treated with an ACD. This analysis must be confirmed upon the completion of the trial. Longer-term follow-up is needed to confirm improved clinical outcomes for anular closure compared to discectomy alone and to further provide information regarding potential reductions in healthcare spending.

Table 1