L4-sparing versus L4-L5 spinopelvic fixation in traumatic spinopelvic dissociation: A randomized controlled trial
In brief
L5-iliac fixation matches traditional method and cuts surgery time by 17 minutes
In a randomized trial of 112 patients with traumatic spinopelvic dissociation, L5-iliac fixation with transiliac-transsacral screws achieved the same vertical stability as the standard L4-L5-iliac construct while reducing operative time by about 17 minutes and blood loss by roughly 90 mL. Neurological recovery, functional scores and overall complication rates were similar, and a 4% implant-failure rate was deemed acceptable.
- Journal
- North American Spine Society journal (Q1)
- Published
- 6 July 2026
- Study design
- Randomized controlled trial
- Evidence level
- Level 1, High (CEBM 1b)
- Authors
- Mehrdad Zamani, Seyed Taher Mousavi, Hossein Hushmand, Sina Ghasemi, Ali Dezhpasand, Kowsar Bagtashi Baktash, et al.
- PMID
- 42602861
- DOI
- 10.1016/j.xnsj.2026.100926
Why clinicians should know about it
- Picked for Orthopedics and Sports Medicine (top studies of the week, 16 August 2026): RCT comparing L5‑iliac vs L4‑L5‑iliac fixation in spinopelvic dissociation
Abstract
BACKGROUND: Traumatic spinopelvic dissociation (SPD) requires surgical stabilization, traditionally with L4-L5-iliac fixation. Recent biomechanical evidence suggests L4 fixation may be unnecessary. This randomized controlled trial compared clinical and radiological outcomes of L5-iliac versus L4-L5-iliac constructs in SPD patients. METHODS: Between January 2020 and December 2023, 112 patients with traumatic SPD (Roy-Camille type II/III) were randomized to L5-iliac with transiliac-transsacral (TTS) screws (intervention, n = 56) or L4-L5-iliac with TTS screws (control, n = 56). Primary outcome was residual vertical displacement at 24 months. Secondary outcomes included operative time, blood loss, neurological recovery (Gibbons score), functional outcomes (Iowa Pelvic Score and Majeed Score), complications, and implant failure. Follow-up rate at 24 months was 85.7% (96/112). RESULTS: At 24 months, mean vertical displacement was 3.1 mm (standard deviation [SD] 1.7) in the L5-iliac group versus 3.3 mm (SD 1.8) in the control group (mean difference -0.2 mm; 95% confidence interval [CI] -0.9 to 0.5), demonstrating noninferiority (upper CI limit 0.9 mm < noninferiority margin of 2.0 mm; p for noninferiority = 0.008). Operative time was significantly shorter in the L5-iliac group (91.4 vs. 108.7 minutes; mean difference -17.3 minutes; 95% CI -24.1 to -10.5; p < .001). Blood loss was reduced (298 vs. 387 mL; p < .001). Implant failure (rod or screw breakage) occurred in 2 patients (4.1%) in the L5-iliac group versus 1 patient (2.1%) in the control group (p = .58). No significant differences were observed in neurological recovery, functional scores, or other complication rates. CONCLUSIONS: L5-iliac fixation with adjunctive TTS screws is noninferior to traditional L4-L5-iliac fixation for traumatic SPD, with significantly shorter operative time and reduced blood loss. The 4.1% implant failure rate in L4-sparing constructs appears acceptable. L4 fixation may be safely omitted.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.