Factors Associated With Spinopelvic Fixation Mechanical Failure After Total Sacrectomy

Study Design. We retrospectively analyzed factors associated with spinopelvic mechanical failure after total sacrectomy. Objective. To find the rate and type of mechanical fixation failure after total sacrectomy and to identify the associated risk factors. Summary of Background Data. Although rigid fixation has been achieved, mechanical failure is sometimes encountered in reconstruction after total sacrectomy. The incidence and factors associated with spinopelvic fixation mechanical failure after total sacrectomy are still not clear. Methods. The study comprised 63 patients who underwent spinopelvic reconstruction after total sacrectomy. The potential risk factors for fixation mechanical failure after total sacrectomy were evaluated, which included age, sex, body mass index, type of tumor (benign or malignant), and adjuvant treatment received (e.g., chemotherapy, radiation therapy). The surgery-related factors included the classification of tumor resection (en bloc or piecemeal resection) and the type of iliosacral resection. Adoption of anterior spinal column fixation (ASCF), posterior pelvic ring fixation (PPRF), four-rod technique (FRT) of spinopelvic fixation (SPF), and structural or morselized bone grafting after total sacrectomy in patients were considered reconstruction-related factors. Cox regression models were used to analyze associations between postoperative fixation failure and risk factors for all models. Results. Postoperative fixation mechanical failure occurred in 25% of patients (16/63) who underwent total sacrectomy. Univariate analysis showed that the factors associated with spinopelvic fixation mechanical failure after total sacrectomy were the non-adoption of FRT of SPF and ASCF, the adoption of Type II sacroiliac resection, and female sex, whereas multivariate analysis demonstrated similar results, except for the adoption of Type II sacroilliac resection. Conclusion. FRT connection of SPF and ASCF should be adopted in reconstruction after total sacrectomy, especially in female patients. Level of Evidence: 3