A Prospective, Observational, Open-Label, Non-Randomized, Multicenter Study Measuring Functional Outcomes in a Novel Interspinous Fusion Device in Subjects with Low Back Pain: REFINE Study

Introduction Lumbar degenerative disease and the accompanying pain and dysfunction affect a significant number of patients in the USA and around the world. As surgery and innovation are moving towards minimally invasive treatments, this study looks to explore interspinous fixation as a standalone posterior approach to treat lumbar degenerative disc disease in the presence of neurogenic claudication and spinal stenosis. Methods This study was approved by an institutional review board (IRB) and is actively enrolling in a single-arm, multicenter, prospective, open-label fashion. Patients are followed with reporting at 3 months, and 12 months for primary endpoint analysis of efficacy and safety based on improved composite endpoints relative to baseline, with success defined as greater than 20 mm back pain reduction in Visual Analog Scale 100 mm (VAS) while standing or walking, greater than 20 mm leg pain reduction in VAS while standing or walking, Zurich Claudication Questionnaire (ZCQ) improvement of 0.5 or greater in two or three domains, Oswestry Disability Index (ODI) improvement of a least 10 points and no reoperations or revisions at the index level(s). Secondary endpoints included a multidimensional assessment in the Patient-Reported Outcomes Measurement Information System (PROMIS) 29 v2.1 and Patient Global Impression of Change (PGIC). Results In this interim 3-month analysis, 82% of patients reported they were improved from the procedure, while 65% of patients demonstrated clinical meaningful improvement in their pain and function, as defined by the VAS, ODI, and ZCQ. There was only one adverse event and no complications were identified at last clinic research follow-up visit. Conclusions This interim analysis of the first 20% of the enrolled patients out to 3 months was to determine safety of the procedure and report on adverse events, acknowledging the heterogeneity of surgical specialty. Further follow-up and greater numbers are needed as the study is ongoing.