406 Long-term Outcomes of Lumbar Facet Arthroplasty versus Spinal Fusion in the Treatment of Degenerative Spondylolisthesis and Stenosis

INTRODUCTION: Facet arthroplasty is a proposed alternative to lumbar fusion for treating degenerative lumbar spondylolisthesis and stenosis. Facet arthroplasty provides stabilization and preserves range of motion. METHODS: Patient-reported outcomes (PROMS), including Oswestry disability index (ODI), visual analog pain scales (VAS), and Zurich claudication questionnaires (ZCQ), were assessed at baseline and at multiple timepoints postoperatively. Flexion/extension range of motion (ROM) were radiographically evaluated at baseline, 12 months, and 24 months. Data were analyzed following an intention-to-treat model. RESULTS: A total of 299 patients were included (TOPS = 206, TLIF = 93). There were no significant differences at baseline. At 2 years, the TOPS group had a significantly greater proportion of patients report =30% improvement for ODI (93.8% versus 74.3%, p = 0.004) and =20-point improvement for VAS back (84.4% versus 61.8%, p = 0.014). At 1 year, TOPS group had a significantly greater proportion of patients report clinically significant improvements in all ZCQ categories (91.6% versus 78.5%, p = 0.012). In patients <65 years, the TOPS group had significantly improved PROMS compared to TLIF at 2 years; however, these differences were not observed in patients =65 years old. The TOPS groups preserved significantly more ROM at 12 (2.8° 95% CI 1.87; 3.74, p < 0.0001) and 24 (2.99° 95% CI 1.82; 4.15, p < 0.0001) months postoperatively compared to TLIF. ROM was similarly preserved in patients aged <64 and =65. The rate of adverse events did not differ significantly between groups (65.2% TOPS versus 61.5% TLIF). CONCLUSIONS: Facet arthroplasty preserves significantly more ROM and leads to improved PROMS compared to TLIF, particularly in younger patients. In older patients, the procedure improved outcomes significantly from baseline.