Role of Intraoperative Cell Salvage in Metastatic Spine Tumor Surgery

Abstract

Background Intraoperative blood loss is one of the major problems faced during the surgical management of metastatic spinal diseases. Presently, this is replenished by allogeneic blood transfusion, placing severe strain on the limited blood resource all over the world. We feel that this problem can be addressed by introducing the use of salvaged blood in spine tumor surgery. We conducted the study to evaluate the feasibility of using intraoperative cell salvage (IOCS) in combination with leukocyte depletion filter (LDF) in eliminating tumor cells from blood salvaged during metastatic spine tumor surgery (MSTS). This is with the view to pave the path for use of IOCS–LDF in musculoskeletal oncological surgery. Methods A total of 50 consecutive patients with known primary epithelial tumor, who were offered surgery for metastatic spinal disease at our university hospital, were recruited. Blood samples were collected at three different stages during surgery: stage A, from the operative field before IOCS processing, stage B, after IOCS processing, and stage C, after IOCS–LDF processing. Three separate 15 mL samples (5 mL each) were taken at each stage. The samples were examined by a cell block technique using immunohistochemical monoclonal antibodies to identify tumor cells of epithelial origin in the blood samples. We hypothesized that the proportion of patients with tumor cells negative in stage C is much smaller or negligible than that in stage A. To test this hypothesis, the proportion of patients with tumor cell negative in stages A and C was compared using two-sample proportion test. The difference in that proportion between stages A and B was also compared. Results Of the 50 patients, 10 were excluded for not fulfilling the inclusion criteria leaving 40 patients. Malignant cells of epithelial origin were detected in the samples taken from stage A, that is, the operative field before IOCS processing in 16 out of the 40 patients and in the samples from stage B, that is, the transfusion bag postcell-saver processing in 4 out of 40 patients. No viable malignant cells were detectable in any of the blood samples taken from stage C where the salvaged blood was filtered with LDF. Therefore, the proportion of patients with negative tumor cells in the samples taken from operative field was 60% (95% CI: 43–75%) and that in the samples taken from the transfusion bag post-IOCS processing was 90% (95% CI: 76–97%). All patients (100%) had negative tumor cells in the samples which were processed and filtered with both IOCS and LDF. Proportion test revealed that there was a significant difference between the proportion of patients with negative tumor cells in stages A and C ( p < 0.01), providing the evidence that IOCS–LDF was able to eliminate all the tumor cells in salvaged blood. This significant difference was also observed between stages A and B ( p < 0.01), indicating IOCS alone could be adequate for removing tumor cells. Conclusions The findings support the notion that IOCS–LDF combination works effectively in eliminating tumor cells from salvaged blood so this technique can possibly be applied successfully in spine tumor surgery and further be extended to the whole musculoskeletal tumor surgery.