Novel Standalone Motion-Sparing Pelvic Fixation Prevents Short-Term Insufficiency Fractures After Midsacrectomies Without Sacrificing Normal, Mobile Lumbar Segments Traditionally Used for Stabilization.

Abstract

Sacrectomy is often the treatment of choice to provide the greatest chance of progression-free and overall survival for patients with primary malignant bone tumors of the sacrum. After midsacrectomy, the stability of the sacropelvic interface is diminished, resulting in insufficiency fractures. Traditional stabilization involves lumbopelvic fixation but subjects normal mobile segments to fusion. The purpose of this study was to determine whether standalone intrapelvic fixation is a safe adjunct to midsacrectomy, avoiding both sacral insufficiency fractures and the morbidity of instrumenting into the mobile spine. A retrospective study identified all patients who underwent resection of sacral tumors at 2 comprehensive cancer centers between June 2020 and July 2022. Demographic, tumor-specific, operative characteristics and outcome data were collected. The primary outcome was presence of sacral insufficiency fractures. A retrospective data set of patients undergoing midsacrectomy without hardware placement was collected as a control. Nine patients (5 male, 4 female), median age 59 years, underwent midsacrectomy with concomitant placement of standalone pelvic fixation. No patients developed insufficiency fractures during the 216 days of clinical and 207 days of radiographic follow-up. There were no adverse events attributable to the addition of standalone pelvic fixation. In our historical cohort of partial sacrectomies without stabilization, there were 4/25 patients (16%) with sacral insufficiency fractures. These fractures appeared between 0 and 5 months postoperatively. A novel standalone intrapelvic fixation after partial sacrectomy is a safe adjunct to prevent postoperative sacral insufficiency fractures in patients undergoing midsacrectomy for tumor. Such a technique may allow for long-term sacropelvic stability without sacrificing mobile lumbar segments.