Spinopelvic Outcomes of Distal Lumbar Short-Segment Fusion in Recurrent Lumbar Disc Herniation: A Preoperative and Postoperative Comparative Analysis with Roussouly Classification

Abstract

OBJECTIVE: This study aimed to assess the effects of distal lumbar short-segment fusion (dSSF) on spinopelvic parameters and sagittal alignment in patients with recurrent lumbar disc herniation, with outcomes analyzed according to Roussouly classification. METHODS: A retrospective single-center cohort study included 38 patients with recurrent lumbar disc herniation who underwent open L4-L5 or L5-S1 dSSF between January 2015 and December 2023. Preoperative and postoperative spinopelvic parameters, including global lumbar lordosis (gLL), proximal lumbar lordosis, distal lumbar lordosis (dLL), pelvic tilt, sacral slope, and pelvic incidence-lumbar lordosis (PI-LL) mismatch, were measured using Nucleus Software. Patients were categorized into Roussouly types (RTs) (RT-1 to RT-4). Statistical analyses employed paired ttests or Wilcoxon signed-rank tests for spinopelvic parameter comparisons and chi-square tests for RT distribution, with significance set at P < 0.05. RESULTS: The cohort (20 females, 18 males; mean age 44.34 +/- 10.38 years) showed significant postoperative improvements in gLL (44.60 degrees +/- 17.64 to 48.70 degrees +/- 12.16, P = 0.027), dLL (25.00 degrees +/- 10.17 to 27.70 degrees +/- 6.70, P = 0.009), and PI-LL mismatch (13.19 degrees +/- 17.50 to 3.40 degrees +/- 5.56, P = 0.008) in RT-1 patients (n = 19). RT-2 became predominant postoperatively (P = 0.006). Pelvic tilt and sacral slope changes were insignificant across all groups. RT-2, RT-3, and RT-4 showed minimal spinopelvic parameter alterations, indicating limited impact in nonhypolordotic profiles. CONCLUSIONS: dSSF significantly enhances gLL, dLL, and PI-LL mismatch, particularly in RT-1 patients, suggesting improved sagittal balance in hypolordotic spines. Larger prospective studies with clinical outcomes are warranted to validate long-term efficacy.