L5 Vs. Pelvic Fixation As the Lowest Instrumented Vertebra in Long-Segment Fusion for Adult Spinal Deformity: A Systematic Review and Meta-Analysis Publisher



Bagherzadeh S ; Roohollahi F ; Bales NJ ; Pradhan A ; Bauer S ; Baker KE ; Vignollesjeong J ; Saleh D ; Rubio DS ; Kim P ; Aziz W ; Greenberg M ; Rostami M ; Alikhani P
Source: Spine Deformity Published:2026

Abstract

Purpose: To compare radiographic outcomes, patient-reported outcomes (PROs), and complications between L5 and sacropelvic fixation as the lowest instrumented vertebra (LIV) in long-segment fusion for adult spinal deformity (ASD). Methods: Following PRISMA 2020 guidelines, PubMed, Web of Science, Scopus, and Embase were searched for studies comparing L5 vs. pelvic fixation in ASD. Studies with Newcastle–Ottawa Scale (NOS) ≥ 7 were included. Extracted data included demographics, radiographic parameters [pelvic tilt (PT), lumbar lordosis (LL), sagittal vertical axis (SVA)], complications, and PROs [Scoliosis Research Society (SRS) and Oswestry Disability Index (OD)]. Meta-analysis used standardized mean differences (SMD) and odds ratios (OR). Heterogeneity was assessed with I2, and publication bias with Egger’s test. Results: Nine studies (1196 patients; mean age 67.5 years; mean follow-up 36.5 months) were included. Pelvic fixation achieved better sagittal correction: lower PT (SMD 0.88, p = 0.005), higher LL (SMD − 0.76, p < 0.001), and lower SVA (SMD 0.82, p = 0.016). PROs were similar at baseline and follow-up (all p > 0.05). L5 fixation had shorter operative time (SMD − 0.78, p = 0.005) but higher distal junctional failure (DJF) risk (OR 2.62, p = 0.002). Predictors of DJF with L5 LIV included older age, extensive fusion, high pelvic incidence, facet degeneration, and poor baseline sagittal balance. Conclusions: Pelvic fixation provides superior sagittal correction with comparable PROs and overall complications, while L5 fixation carries a 2.6-fold higher DJF risk. LIV selection must be individualized; pelvic fixation is strongly recommended for patients with advanced age (> 66 years), high pelvic incidence (> 52°), or severe sagittal malalignment to mitigate mechanical failure. PROSPERO ID Number: CRD420251129518. © The Author(s), under exclusive licence to Scoliosis Research Society 2026.