288 Impact of Disc Degeneration on Clinical Outcomes After Fusion for Grade 1 Spondylolisthesis: A 5-year QOD Study

INTRODUCTION: Disc degeneration with loss of disc height can be an indication to fuse patients with lumbar spondylosis. However, its relevance for spondylolisthesis is unknown. METHODS: The Quality Outcomes Database was queried for adult patients who underwent fusion for single-level degenerative grade 1 lumbar spondylolisthesis. Pfirrmann grade at the level to be fused was assessed on preoperative sagittal T2-weighted MRI. VAS-back pain (BP-VAS), VAS-leg pain (LP-VAS), and ODI were collected preoperatively and at 3, 12, 24, 36, and 60 months postoperatively. RESULTS: The query returned 395 patients. Mean age (95% CI) was 60 (58.9-61.1) years; 39.5% were male. None had a Pfirrmann grade 1 disc. One (0.3%) had a grade 2 disc, 53 (13.4%) had a grade 3 disc, 245 (62%) had a grade 4 disc, and 96 (24.3%) had a grade 5 disc. Posterior-only approach was performed in 92.6%; interbody graft was placed in 92.7%. Mean BP-VAS (95% CI) at baseline, 3 months, 12 months, 24 months, 36 months, and 60 months were 7.1 (6.8-7.3) (n = 343), 3.1 (2.8-3.3) (n = 353), 2.9 (2.6-3.2) (n = 305), 3.2 (2.8-3.5) (n = 283), 3.5 (2.9-4.1) (n = 107), and 3.7 (3.3-4.0) (n = 324). Mean LP-VAS (95% CI) were 6.7 (6.4-7.0) (n = 392), 2.3 (2.0-2.6) (n = 353), 2.2 (1.9-2.6) (n = 306), 2.6 (2.2-2.9) (n = 284), 2.8 (2.2-3.4) (n = 107), and 2.8 (2.4-3.1) (n = 322). Mean ODI (95% CI) were 49.4 (47.8-51.1) (n = 392), 27.4 (25.3-29.5) (n = 347), 22.9 (20.6-25.2) (n = 313), 22.4 (20.1-24.8) (n = 291), 22.4 (18.3-26.4) (n = 97), and 25.9 (23.7-28.2) (n = 325). Utilizing linear regression, Pfirrmann grade was not associated with improvements in VAS-BP, VAS-LP, or ODI at any time point in unadjusted and adjusted analyses (p > 0.05). CONCLUSIONS: Patients who undergo fusion for single-level grade 1 spondylolisthesis are likely to experience significant and sustained improvements in pain and function regardless of severity of disc degeneration.