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 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.