Good clinical outcomes and fusion rate of facet fusion with a percutaneous pedicle screw system for degenerative lumbar spondylolisthesis: minimally invasive evolution of posterolateral fusion.

Study Design. A retrospective clinical and radiographical study. Objective. To assess the clinical outcomes and fusion rate of facet fusion (FF) for degenerative lumbar spondylolisthesis (DLS). Summary of Background Data. On the basis of the long-term clinical and radiological follow-up studies of posterolateral fusion (PLF)—that is, intertransverse process fusion with pedicle screw instrumentation—for DLS, we recognized that FF alone would be sufficient for spinal fusion. Methods. Eighty-eight patients who underwent FF for single-level DLS were retrospectively reviewed after at least 1 year of follow-up. The control group comprised 21 patients who underwent conventional PLF. The operative technique involved a 5-cm midline skin incision, bilateral laminar fenestration, and FF with autologous bone harvested from the spinous process. Percutaneous pedicle screws were then inserted through the fascia. The fusion rate of FF was evaluated using computed tomography, and the change in the range of motion at the fused level was assessed on flexion-extension lateral radiographs. The Japanese Orthopaedic Association Back Pain Evaluation Questionnaire was used to assess the therapeutic effectiveness of FF. The results of the Roland-Morris Disability Questionnaire and the visual analogue scales of low back pain, buttock and lower limb pain, and buttock and lower limb numbness were evaluated. Results. The fusion rate was 88.6% (78/88 cases). Among 10 patients with inadequate fusion, the average range of motion significantly decreased from 14.4° preoperatively to 4.3° postoperatively. The Japanese Orthopaedic Association Back Pain Evaluation Questionnaire category scores demonstrated therapeutic effectiveness in 93.0% of the patients for walking ability and in 73.0% of the patients for low back pain. The average preoperative scores of the Roland-Morris Disability Questionnaire and the visual analogue scales of low back pain, buttock and lower limb pain, and buttock and lower limb numbness were significantly reduced postoperatively in the FF group. Conclusion. FF achieved good clinical outcomes that were superior to those of conventional PLF with a comparable fusion rate. It is useful for managing DLS and is a minimally invasive evolution of PLF. Conclusion. Level of Evidence: 3