Surgical treatment of spinal metastases from renal cell carcinoma-effects of preoperative embolization on intraoperative blood loss

The objective of this paper is analyzing the effects of preoperative embolization on intraoperative blood loss in spinal surgery for renal cell carcinoma (RCC) metastasis and identifying factors contributing to an increased blood loss in the surgical procedure. A retrospective analysis was performed in patients who were treated in for spinal metastasis from RCC between 2011 and 2016. Factors analyzed were reduction of tumor blush, timing of embolization, selective vs. superselective approach, surgical factors, and tumor volume and localization. Parameters were statistically correlated with intraoperative blood loss (hemoglobin (Hg) decrease, blood loss in milliliters, number of transfused blood bags). Twenty-five patients with 34 surgical interventions were included. Seventeen cases were treated superselectively and 11 treated selectively. Mean perioperative blood loss was 2248 ± 1833 ml. Higher blood loss was detected for vertebra replacement compared to percutaneous procedures (Hg decrease 4.22 vs. 2.62, p < 0.05). Blood loss increased with increasing tumor volumes (0-50 ccm/50-100 ccm/> 100 ccm) for Hg loss (3.29/3.64/4.24 mg/dl, NS), blood loss in milliliters (1291/2620/4971 ml, p < 0.001), and number of transfusions (1.2/3.4/7.0, p < 0.001). Stratifying by the grade of embolization, no significant differences were found between the groups (> 90%/90-75%/75-50%) for Hg loss, blood loss, or number of transfusions. Endovascular embolization for RCC metastasis of the spine is a safe procedure; however, in this cohort, patients undergoing embolization did not show a reduced blood loss in comparison to the non-embolized cohort. Additional factors contributing to an increased blood loss were tumor size and mode of surgery.