P123. 24-month outcomes of a prospective investigation of a novel mesh interbody spacer in single level fusions

BACKGROUND CONTEXT Interbody fusions are widely accepted as a successful method to treat lumbar degenerative disc disease (DDD).  Increasingly, surgeons are seeking interbody devices that are larger for stability and grafting purposes, but can still be inserted through less-invasive techniques. An investigational device exempt (IDE) trial of such a device is complete to 24 months. This novel, conformable mesh interbody fusion device when placed in the disc space through a small portal and filled with bone graft in situ may reduce the risk of trauma to surrounding structures while creating a large graft footprint that intimately contours to the patient's own anatomy. PURPOSE The purpose of this study is to evaluate the long-term results of a novel conformable mesh interbody fusion device. STUDY DESIGN/SETTING This investigation is a prospective, multi-center, single-arm, FDA and IRB approved IDE, performance goal trial. PATIENT SAMPLE A total of 102 adult subjects presenting with degenerative disc disease at a single level between L2 and S1 and unresponsive to six-months conservative care had instrumented lumbar interbody fusion. OUTCOME MEASURES Validated assessment tools include 100mm VAS for pain, Oswestry Disability Index (ODI) for function, single question survey for patient satisfaction, and computerized tomography (CT) scan for fusion. METHODS Subjects were enrolled across 10 geographically distributed sites. Pain/ODI surveys, physical evaluations, and imaging were performed serially through 24 months. Specifically, CT scans were done at 12 and, if not fused, 24 months. Independent radiologists assessed CTs for fusion. An independent committee adjudicated adverse events. Subjects with complete data at 24-months were included in the analysis. RESULTS Ninety-six (96, 94% follow up rate) subjects (57.0±12.0 y, 50.0% Female, Body Mass Index 30.6±4.9) reported average decreased low back pain (LBP) from baseline of 45.0± 26.6 at 6-weeks and 51.4±26.2 at 24-months. Right/left leg pain reduced by 28.9±36.7/37.8±32.4 at 6-weeks and 30.5±33.0/40.3±34.6 at 24-months. Mean ODI improved 17.1±18.7 from baseline to 6 weeks and 32.0±18.5 by 24-months. At 24 months, 91.7% of subjects rated their procedure as excellent/good. Fusion rates were 97.9% (94/96) at 12-months, and 99% (95/96) at 24 months. Mean operative time, estimated blood loss (EBL), length of stay (LOS) were 2.6±0.9 h, 137±217 mL, and 2.3±1.2 d, respectively. No device-related serious adverse events have occurred. CONCLUSIONS Clinically significant outcomes for pain, function, fusion and device safety are demonstrated in this population. Substantial clinical improvements occur by 6 weeks postop and continue to improve to 24-months. The successful outcomes observed in this trial support use of this novel device in an instrumented lumbar interbody fusion. FDA DEVICE/DRUG STATUS OptiMesh (Not approved for this indication)