The Facet Wedge: a minimally invasive technique for posterior segmental intra-articular fusion

Abstract

Objective: Minimally invasive posterior segmental instrumentation and intra-articular fusion with the Facet Wedge device. Indications: All fusion indications in degenerative disc disease without significant translational instability, postnucleotomy syndrome, spondylarthrosis, discitis. Contraindications: Translatory instabilities, status after decompression with partial facet joint resection, spondylolysis in the affected segment. Surgical technique: Through a 3 cm skin incision, blunt transmuscular approach to the corresponding facet joint L1/2 to L5/S1. Opening of the joint capsule and visualisation of the intra-articular space. Cartilage removal and intra-articular implantation of the Facet Wedge device. Fixation of the implant by means of two angle-stable screws inserted in the corresponding facet joint parts. Postoperative management: Early mobilisation under thomboprophylaxis. Wearing a trunk-stabilizing brace for up to 12 weeks, depending on the type and extent of the procedure. No restrictions regarding walking distance, standing and sitting immediately postoperatively after pain. Results: In all, 27 patients (mean age 51.2 years, range 30–76 years) were enrolled in the prospective nonrandomized study from 02/2015 to 9/2017 with a total of 31 treated segments. In 23 cases a ventrodorsal surgical technique was used, in 4 cases a purely dorsal procedure with interposition of an intervertebral cage. Follow-up was 2 years. The Oswestry Score (ODI) improved from an average of 40.6% preoperatively to 16.6% postoperatively. The visual analog scale (VAS) for back pain improved from an average of 6.7 points preoperatively to 2.1 points 2 years postoperatively. During this observation period, 2 implant-specific complications were observed. One Facet Wedge had to be revised due to misplacement with early loosening. In another case, loss of correction occurred in a preoperatively existing first-degree spondylolisthesis with revision to a dorsal screw–rod system.