BACKGROUND CONTEXT Interbody fusion with rigid cages are commonly employed in the surgical treatment of medically-refractory degenerative disc disease and spondylolisthesis. However, they require a certain degree of soft-tissue dissection and bone removal to accommodate placement of the cage. The SCOUT study is an on-going FDA IDE trial (clinicaltrials.gov NCT #: NCT02347410, IDE: G140140) investigating the safety and efficacy of a novel device for lumbar interbody fusion. It is exploring the use of an expandable bone graft-containing fabric mesh for use as the interbody spacer, a device that can be deployed through a delivery portal only 8mm in diameter. PURPOSE To report on 12-month follow-up data on patients participating in the SCOUT trial. STUDY DESIGN/SETTING Multiinstitutional prospective single-arm trial. PATIENT SAMPLE Skeletally mature adults, aged 21 to 80, with single-level symptomatic lumbar degenerative disc disease (levels L2–S1) requiring interbody fusion surgery. OUTCOME MEASURES Patient-reported satisfaction, VAS low back pain scores, ODI, and radiographic fusion rates at 12-month follow-up. METHODS All patients underwent either a MIS-TLIF or an open PLIF approach (determined by surgeon preference), and all received supplemental pedicle screw fixation. All patients had a minimum Visual Analogue Score (VAS) of 40mm (0-100 mm scale) and a minimum Oswestry Disability Index (ODI) of 40. All patients had a BMI RESULTS At most recent follow-up, 84 patients had undergone surgery, with 60 completing 6-month follow-up and 29 completing 12-month follow-up. Intraoperative and perioperative characteristics remained favorable in terms of estimated blood loss (mean: 129±150 cc), operative time (mean: 161±53 minutes), and length of stay (2.3±1.1 days). At twelve-month follow-up, all 29 patients (100%) demonstrated radiographic fusion, as defined by evidence of bridging bone on CT scan by two independent radiologists. Twenty of 29 patients (69%) reported “Excellent” satisfaction with their surgery and seven (24%) reported “Good” satisfaction. Compared to a baseline VAS low back pain score of 73.0±16.6 (Mean±SD) and baseline ODI of 54.0±12.1, there were significant improvements at both 6-months (VAS: 24.1±25.7, ODI: 25.3±20.4, p CONCLUSIONS At twelve-month follow-up, there are encouraging clinical and radiographic results for the use of an expandable fabric mesh device for lumbar interbody fusion. There is potential for such a system to provide good fusion and pain relief while minimizing tissue disruption.