Lumbopelvic Fixation is Effective for Treating Pain and Function in Spinopelvic Dissociation from Unstable Pathologic Sacral Fractures

Introduction: Spinopelvic dissociation from pathologic sacral fractures can be a debilitating condition, resulting in significant skeletal and neurologic pain and functional impairment. In the setting of metastatic disease with prior or planned radiotherapy (RT) and/or chemotherapy, obtaining a successful union is particularly challenging. Thus, the objective of this study was to determine the effectiveness of lumbopelvic fixation for the treatment of U- or H-type pathologic sacral fractures.

Methods: Patients with metastatic disease presenting with U- or H-type pathologic sacral fractures treated with lumbopelvic fixation at a single institution between January 2019 and February 2024 were included. Primary outcome measures were pre- and postoperative sacral visual analog scale (VAS), presence of radiculopathy, and ambulatory status.

Results: 16 patients were included (mean age 62.8 ± 11.8 years, follow-up (FU) 14.3 ± 9.7 months, length of stay 6.5± 4.0 days). Upper instrumented level was L3 in 1 patient, L4 in 14 patients, and L5 in 1 patient. An S2 alar iliac trajectory was used in all patients. 9 patients (56.2%) received supplemental transiliac-trans-sacral screw or bilateral cement-augmented iliosacral screws. A completely percutaneous approach was performed in 12 patients (75.0%). Mean pre-operative sacral VAS was 6.9 ± 2.3, which decreased to 2.1 ± 2.3 at 3-week postoperative FU (p < 0.001), and 0.4 ± 1.0 at final FU (p < 0.001). All 16 patients had radicular symptoms preoperatively compared to only 1 patient (6.3%) at final FU (p < 0.001). Ambulatory status improved compared to preoperative baseline by 3-week postoperative FU in 12 patients (75.0%) and in 14 patients (87.5%) at final FU. Ambulatory status remained unchanged in the remaining 2 patients (12.5%). 2 patients (12.5%) died of progression of disease prior to 6-month follow-up. There were 4 postoperative complications among 4 patients (25.0%) within 30 days: pulmonary embolism, prolonged urinary retention, delirium, and superficial hematoma, which all resolved by final FU. There was 1 reoperation at final FU (6.3%) for a set screw disengagement.

Conclusion : Lumbopelvic fixation is effective for providing immediate skeletal and radicular pain relief and improves ambulatory function among patients with metastatic disease presenting with spinopelvic dissociation from a U- or H-type pathologic sacral fractures.