The association between lumbopelvic fixation and improved pain and function in patients with unstable pathologic sacral fractures.

OBJECTIVE: Spinopelvic dissociation from U- or H-type pathologic sacral fractures can be debilitating and often results in chronic pain and functional impairment. In the setting of metastatic disease with prior or planned radiotherapy (RT) and/or chemotherapy, obtaining a successful fracture union is particularly challenging. This study sought to determine the effectiveness of lumbopelvic fixation for the treatment of U- or H-type pathologic sacral fractures. METHODS: The authors reviewed data from patients with metastatic disease who presented with U- or H-type pathologic sacral fractures recalcitrant to nonoperative management and were treated with lumbopelvic instrumentation at a single institution between January 2019 and November 2024. Primary outcome measures were pre- and postoperative sacral pain (assessed using a visual analog scale [VAS]), ambulatory status, and opioid use in morphine milligram equivalents (MMEs). RESULTS: Twenty-two patients (mean age 63.4 [SD 12.8] years) met the inclusion criteria and had a mean of 14.5 (SD 9.2) months of follow-up. Seventeen patients (77.3%) underwent RT prior to surgery with a mean biologically effective dose of 59.1 (SD 14.6) Gy. The mean preoperative sacral VAS pain score was 7.5 (SD 2.2), which decreased to 2.2 (SD 2.2) at 3 weeks postoperatively (p < 0.001) and 0.4 (SD 1.1) at final follow-up (p < 0.001). All 22 patients had radicular symptoms preoperatively, compared to 2 patients (9.1%) at final follow-up (p < 0.001). Improvement in ambulatory status relative to preoperative baseline was evident in 15 patients (68.2%) at 3 weeks and in 19 patients (86.4%) at final follow-up. The mean preoperative daily opioid use was 156.1 (SD 154.9) MMEs, which decreased to 77.0 (SD 92.7) MMEs at 6 weeks postoperatively (p = 0.048) and 59.1 (SD 97.5) MMEs at final follow-up (p = 0.018). There was 1 reoperation (4.5%) at the final follow-up for a set-screw disengagement. CONCLUSIONS: Patients with metastatic disease who present with spinopelvic dissociation from U- or H-type pathologic sacral fractures use fewer opioid medications for axial and radicular pain and have better ambulatory function following lumbopelvic fixation. Larger, prospective studies are needed to confirm the authors' findings.