Geographic Variation in Disability After Posterior/Transforaminal Lumbar Interbody Fusion for Grade 1 Degenerative Lumbar Spondylolisthesis: A Five-Year Quality Outcomes Database Study

Introduction: Previous studies have suggested regional variation in disability after surgery for lumbar spondylolisthesis. However, long-term data regarding this geographic variability after PLIF or TLIF has not been well described.

Methods: We analyzed patients with lumbar grade 1 spondylolisthesis undergoing PLIF/TLIF from the 12 highest enrolling sites in the prospective Quality Outcomes Database. We analyzed baseline and 60-month postoperative outcomes. Differences in demographics, comorbidities, and ODI were compared across geographic regions of the United States with univariate and multivariate methods.

Results: Among the 608 patients who underwent surgery for grade 1 lumbar spondylolisthesis across 12 surgical sites, 385 underwent P/TLIF. Baseline and 60-month ODI values were available for 310 (80.5%). By geographic region, the Northeast had 15 patients across 3 centers, the West had 39 patients across 2 centers, the Midwest had 58 patients across 2 centers, and the South had 198 patients across 5 centers. Patients in the South tended to be younger, have higher BMI, have higher rates of coronary artery disease, have lower rates of at least college-level education, and have significantly worse mean±SD ODI at baseline (51.3±14.5) compared to the Northeast (44.7 ± 18.7), West (43.9 ± 15.4), and Midwest (40.9 ± 16.0) (p < 0.001). Patients in the South had the largest 60-month improvement in mean±SD ODI (25.9 ± 20.5), followed by the Midwest (21.2 ± 17.1), the Northeast (20.9 ± 24.0), and the West (13.3 ± 22.9) (p = 0.004). This resulted in similar 60-month ODI values across regions. Region did not predict baseline, change, or 60-month ODI scores in multivariate regression.

Conclusion : Among patients undergoing P/TLIF for grade 1 lumbar spondylolisthesis, those residing in the Southern United States had the worst disability at baseline but improved to a greater degree than other regions, resulting in similar 60-month ODI scores across all geographic regions.