Minimally Invasive Inline Spinopelvic Fixation Without Offset Connectors for Unstable Sacral Fractures: Technical Description and Preliminary Clinical Experience

BACKGROUND: Spinopelvic fixation (SPF) is widely used for unstable sacral fractures with spinopelvic dissociation; however, conventional constructs often require complex implant configurations and extensive soft-tissue dissection. We evaluated the feasibility and clinical outcomes of a minimally invasive SPF (MIS-SPF) technique using an inline construct without offset connectors for the treatment of unstable sacral fractures. METHODS: The study included 5 consecutive patients with nonosteoporotic AO Spine Sacral Injury Classification Type C fractures who underwent MIS-SPF using an inline construct between September 2024 and March 2026. The construct consisted of lumbar pedicle screws connected to cranial iliac screws using bilateral longitudinal rods, whereas the caudal iliac screws were directly connected using a transverse rod. Perioperative variables, clinical outcomes, radiographic bone union, neurological recovery, and complications were retrospectively evaluated. RESULTS: The mean operative time was 200.2 ± 87.5 minutes, and the mean estimated blood loss was 154.6 ± 76.9 mL. When limited to the L4-iliac SPF procedures, the mean operative time was 149.0 minutes. Four patients completed at least 12 months of follow-up. All achieved radiographic bony union and regained independent ambulation. The mean Gibbons score improved from 3.3 ± 0.5 preoperatively to 2.0 ± 0.0 at final follow-up. No implant failure, surgical site infection, or revision surgery was observed. CONCLUSIONS: In this preliminary case series, MIS-SPF using an inline construct without offset connectors was feasible and demonstrated encouraging short-term clinical and radiographic outcomes. Further comparative and biomechanical studies are warranted to clarify its role in the treatment of unstable sacral fractures. CLINICAL RELEVANCE: This technical report describes a simplified minimally invasive SPF technique using an inline construct without offset connectors, which may facilitate surgical procedures while providing stable fixation for unstable sacral fractures.