Clinical Significance of Preoperative Embolization for Non-Hypervascular Metastatic Spine Tumors

Objective : The efficacy of preoperative embolization for hypervascular metastatic spine disease (MSD) such as renal cell and thyroid cancers has been reported. However, the debate on the efficacy of preoperative embolization for non-hypervascular MSD still remains unsettled. The purpose of this study is to determine whether preoperative embolization for non-hypervascular MSD decreases perioperative blood loss. Methods : A total of 79 patients (36 cases of preoperative embolization and 43 cases of non-embolization) who underwent surgery for metastatic spine lesions were included. Representative hypervascular tumors such as renal cell and thyroid cancers were excluded. Intraoperative and perioperative estimated blood losses (EBL), total number of transfusion and calibrated EBL were recorded in the embolization and non-embolization groups. The differences in EBL were also compared along with the type of surgery. In addition, the incidence of Adamkiewicz artery and complications of embolization were assessed. Results : The average age of 50 males and 29 females was $57.6{\pm}13.5$ years. Lung (30), hepatocellular (14), gastrointestinal (nine) and others (26) were the primary cancers. The demographic data was not significantly different between the embolization and the non-embolization groups. There were no significant differences in intraoperative EBL, perioperative EBL, total transfusion and calibrated EBL between two groups. However, intraoperative EBL and total transfusion in patients with preoperative embolization were significantly lower than in non-embolization in the corpectomy group (1645.5 vs. 892.6 mL, p=0.017 for intraoperative EBL and 6.1 vs. 3.9, p=0.018 for number of transfusion). In addition, the presence of Adamkiewicz artery at the index level was noted in two patients. Disruption of this major feeder artery resulted in significant changes in intraoperative neuromonitoring. Conclusion : Preoperative embolization for non-hypervascular MSD did not reduce perioperative blood loss. However, the embolization significantly reduced intraoperative bleeding and total transfusion in corpectomy group. Moreover, the procedure provided insights into the anatomy of tumor and spinal cord vasculature.