Minimally Invasive Lumbopelvic and Transiliac-Transsacral Fixation for a Pathological Sacral Fracture Due to Metastatic Breast Cancer: A Case Report.

INTRODUCTION: Pathological sacral insufficiency fractures in patients with metastatic cancer are uncommon yet disabling, characterized by poor bone quality, high lumbosacral mechanical demand, refractory pain, and loss of ambulation. We report a fully minimally invasive combined transiliac-transsacral and lumbopelvic construct for metastatic spinopelvic instability. CASE REPORT: A 53-year-old woman with stage IV triple-negative breast cancer and multifocal osteolytic metastases developed refractory low lumbar and sacral pain after a ground-level fall. Imaging showed a pathological H-shaped sacral fracture with bilateral ala involvement, a transverse S1 component, and a stable anterior pelvic ring. After conservative management failed, she underwent a two-stage procedure under a single anesthetic: Percutaneous transiliac-transsacral screw fixation, followed by minimally invasive posterior lumbopelvic fixation with bilateral L5 pedicle screws and cement-augmented S2-alar-iliac screws connected by precontoured rods. Operative time was 325 min, with estimated blood loss below 50 mL and no complications. She sat at 24 h, walked with assistance by the 4th post-operative day (visual analog scale 0/10 at rest), and was discharged on day 5. At 3 months, she ambulated pain-free with a single cane, without neurological deficit, with adequate hardware position and no residual metabolic activity on positron emission tomography-computed tomography. CONCLUSION: In selected oncologic patients with unstable pathological sacral fractures, a combined transiliac-transsacral and lumbopelvic construct, performed using minimally invasive techniques, can provide immediate stability while minimizing soft-tissue morbidity and supporting pain control, early mobilization, and continued multidisciplinary oncologic care.