Transsacral Bar Fixation for Osteoporotic H-Type Sacral Fractures: A Viable Alternative to Spinopelvic Fixation

Background: Fragility fractures of the pelvis (FFP) are an increasing challenge in aging societies. Among these, FFP type 4B ("H-shaped" sacral fractures) represent the most unstable subtype, characterized by bilateral sacral ala fractures with transverse dissociation. Optimal fixation strategies remain debated, as spinopelvic fixation provides maximal stability but is invasive, while iliosacral screws often fail in osteoporotic bone. Trans-sacral bar (TSB) fixation has been proposed as a less invasive alternative, though evidence for its use in FFP 4B remains limited. Methods: We conducted a retrospective single-center study of 31 elderly patients (mean age 77.9 years; 87.1% female) with CT-confirmed FFP type 4B fractures treated between 2015 and 2022 using navigation-guided TSB constructs. Surgical configurations included hybrid fixation (TSB + bilateral iliosacral screws, n = 25) and dual-bar fixation (n = 6). Outcomes included perioperative complications, implant survival, radiographic healing, pain, and mobility at 3 and 12 months. Opportunistic CT-derived Hounsfield units (HU) were used to assess bone quality. Results: All patients had severe osteoporosis (mean HU 75.8 ± 30.1). Mean operative time was 71 min, and mean hospitalization was 9.1 days. No intraoperative or postoperative complications occurred, and no implant loosening, migration, or revision surgeries were required. At 3 months, mean pain score was 1.9, further decreasing to 1.1 at 12 months; 60.9% of patients reported complete pain resolution. Mobility improved in most cases, with 80.6% discharged with a walker or crutches. Radiographic follow-up confirmed stable healing in all patients. Conclusions: Navigation-guided TSB-based fixation provided stable osteosynthesis with excellent implant survival, significant pain relief, and early mobilization in elderly patients with FFP type 4B fractures. Hybrid and dual-bar constructs both achieved reliable outcomes. TSB fixation thus represents a safe and effective alternative to spinopelvic fixation in this fragile population. Larger multicenter prospective studies are warranted to confirm these findings and refine fixation strategies.