Initial Two-Year Safety Data for an Annular Closure Device: Interim Results from a Multicenter, Prospective, Randomized Clinical Trial

Objective Lumbar discectomy is the most frequently performed spine surgery, generally resulting in acute relief of symptoms from herniated or bulging discs. Longer term results are less positive, with many patients suffering recurrent herniations and/or continued degeneration. Limited nucleus removal results in reduced back pain, but more frequent reherniation, particularly in patients with large annular defects. Implantation of an annular closure device (ACD) may allow for the advantages of limited nucleus removal without increased reherniation risk. We report here interim results of an ongoing randomized clinical trial (RCT) of an ACD.

Methods The Barricaid® ACD (Intrinsic Therapeutics; Woburn, Massachusetts, United States) consists of a polyester mesh that occludes the annular defect, and is held in place by a titanium bone anchor. This CE-marked device is being studied in a postmarketing RCT in Europe (http://clinicaltrials.gov/ct2/show/NCT01283438). Randomization (1:1, Barricaid:Discectomy-only) is performed intraoperatively, following discectomy and confirmation of annular defect size (minimum 4 × 6 mm, maximum 6 × 10 mm). Inclusion criteria include 6 weeks conservative care, no prior surgery, minimum Oswestry (40/100), and minimum leg pain (40/100). Reoperations and adverse events are tracked prospectively, and patients are followed at 6 weeks, 3 and 6 months, and annually until the last patient enrolled has reached 24 months.

Results Enrollment is complete with 554 patients enrolled through October 2014, with 448 past 1 year and 287 past 2 years at the time of this interim safety analysis (February 2015). Similar numbers of patients in each group have 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).

Conclusions This interim report of an ongoing RCT provides an initial view of safety and performance outcomes with use of an ACD compared with discectomy alone.