Purpose We report our experience with a novel surgical device for the treatment of lumbar degenerative microinstability. Facet Wedge (DePuy Synthes, Raynham, Massachusetts, United States) is a novel technique of intra-articular lumbar facet fixation that provides a minimally invasive alternative to standard posterior fixation. Materials and Methods From November 2014 to July 2015, 38 patients underwent single-level Facet Wedge implantation. The main surgical indications included herniated disk (18 patients), spinal canal and foraminal stenosis (14 patients), and Meyerding grade I degenerative spondylolisthesis (6 patients). All the patients showed radiologic signs of microinstability: hyperintensity in both facet joints (facet fluid signal) in T2-weighted magnetic resonance imaging and a black disk as a sign of degenerative disease. No slippage was evident at dynamic radiograph. After a period of conservative treatment (minimum of 6 months), surgery was performed. All patients' follow-up lasted over at least 12 months. Results The low back visual analog scale score decreased significantly after surgery (from an average of 8.2 to 3.1 at final follow-up). Postoperatively, the Oswestry Disability Index showed a significant reduction (14.7 on average). No slippage or signs of adjacent segment degeneration was detected in neuroimaging follow-up. Conclusion Facet Wedge allows facet fixation in lumbar degenerative microinstability. To the best of our knowledge, this is the first clinical series reported in the literature on this novel device.