Summary. Our meta-analysis showed that pooled mean blood loss during spinal tumour surgeries was 2180 ml. Standardised methods of calculating and reporting intra-operative blood loss are needed as it would be beneficial in the pre-operative planning of blood replenishment during surgery. Introduction. The vertebral column is the commonest site of bony metastasis, accounting for 18,000 new cases in North America yearly. Patients with spinal metastasis are often elderly, have compromised cardiovascular status, poor physiological reserve and altered immune status, all of which render them more susceptible to the complications of intra-operative blood loss and associated transfusion. Currently no consensus exists regarding the expected volume of blood lost during metastatic spine tumour surgery with various papers quoting anywhere between 1L to 6L. Knowledge of the expected blood loss prior to surgery however is important as it facilitates pre-operative planning, intra- and post-operative management of fluid balance and blood transfusion. We conducted a meta-analysis of published literature on spine tumour surgery to answer the question: “What is the expected blood loss in major spinal tumour surgery for metastatic spinal disease?”. Methods. A comprehensive online search of the English literature using Medline, Embase, and the Cochrane Central Register of Controlled Trials was performed. We included articles published from 31 January 1992 until 31 January 2012. This initial online search yielded 98 relevant articles. Two senior investigators independently reviewed all abstracts. The full text of articles that were deemed eligible for further consideration obtained and reviewed. Eighty five articles were excluded at this stage, largely due to lack of clear blood loss data, leaving 13 eligible articles. A hand search of the reference lists of relevant articles yielded 5 more articles. A total of 18 articles were included in the final meta-analysis of blood loss data. Disagreements regarding eligibility of articles for analysis were resolved by consensus. Selected articles for final analysis were independently graded according to the Centre for Evidence-Based Medicine (CEBM) Levels of Evidence. We evaluated the possibility of publication bias by obtaining a funnel plot (created by plotting the sample size against the effect estimate). The Egger's regression asymmetry test was used to assess the existence of publication bias. Results. Eighteen selected articles had a total of 785 patients who had undergone major spine tumour surgery for metastatic spinal disorders. The pooled estimate of the blood loss occurring during spinal tumour surgeries was calculated to be 2180ml (95%CI: 1805–2554ml). Apart from two studies which reported significant mean blood loss of more than 5500 ml, the resulting funnel plot suggested absence of publication bias. This was confirmed by Egger's test which did not show any small-study effects (p=0.119). However, there was strong evidence of heterogeneity between studies with I2=90% (p<0.001). Conclusions. The expected blood loss of a patient undergoing major surgery for spinal tumour constitutes more than a third of the circulating blood volume in a typical cancer patient with significantly impaired physiological reserve. Moreover, cases of catastrophic blood loss exceeding 5L exist in almost every series evaluated in this paper, with some reaching as much as 17–18L. Blood loss is a significant problem during spine tumour surgery and concerted effort is needed to address it

Summary. This is the first ever study to report the successful elimination of malignant cells from salvaged blood obtained during metastatic spine tumour surgery using a leucocyte depletion filter. Introduction. Catastrophic bleeding is a significant problem in metastatic spine tumour surgery (MSTS). However, intaoperative cell salvage (IOCS) has traditionally been contraindicated in tumour surgery because of the theoretical concern of promoting tumour dissemination by re-infusing tumour cells into the circulation. Although IOCS has been extensively investigated in patients undergoing surgery for gynaecological, lung, urological, gastrointestinal, and hepatobiliary cancers, to date, there is no prior report of the use of IOCS in MSTS. We conducted a prospective observational study to evaluate whether LDF can eliminate tumour cells from blood salvaged during MSTS. Patients & Methods. After Institutional Review Board (IRB) approval, 21 consecutive patients with metastatic spinal tumours from a known epithelial primary (defined as originating from breast, prostate, thyroid, renal, colorectal, lung, nasopharyngeal) who were scheduled for MSTS were recruited with informed consent. During surgery, a IOCS device (Dideco, Sorin Group, Italy) was used to collect shed blood from the operative field. Salvaged blood was then passed through a leucocyte depletion filter (RS1VAE, Pall Corporation, UK). 15-ml specimens of blood were taken from each of three consecutive stages: (i) operative field prior to cell saver processing (Stage A); (ii) transfusion bag post-cell saver processing (Stage B); (iii) filtered blood after passage through LDF (Stage C). Cell blocks were prepared by the pathology department using a standardised laboratory protocol. From each cell block, 1 haematoxylin and eosin (H&E) slide, and 3 slides each labelled with one of the following monoclonal mouse cytokeratin antibodies AE1/3, MNF 116 and CAM 5.2 were prepared. The cytokeratin antibodies are highly sensitive and specific markers to identify tumour cells of epithelial origin. These slides were read by one of two consultant pathologists who were provided full access to information on operative notes, but were blinded to the actual stages from which the slides were derived. Results. One case was excluded when the final diagnosis was revised to infection instead of metastatic spine tumour. Of the remaining cases, 7/21 tested positive for tumour cells in Stage A, 2 positive in Stage B. No specimen tested positive for tumour cells in Stage C. In 5 cases, posterior instrumentation without tumour manipulation was performed. Discussion/Conclusion. In this first-ever study of cell saver use in spine tumour surgery, we prove that leucocyte-depletion filters (LDF) can effectively eliminate tumour cells from blood salvaged during MSTS. It is now possible to conduct a clinical trial to evaluate IOCS-LDF use in MSTS. Our results are consistent with published results of similar studies performed on IOCS and LDF use outside the field of orthopaedic surgery. Spinal metastases originate from a myriad of primary cancers across various organ systems. If LDF can remove tumour cells from blood salvaged during surgery for spinal metastasis of different histological origin, then the finding can likely be extrapolated to several other fields of surgery where IOCS and LDF have not yet been attempted such as: neurosurgery, otolaryngology and general musculoskeletal oncology. Our results form a proof-of-concept for a paradigm shift in thinking regarding autotransfusion during spine tumour surgery

Summary

There is emerging evidence of successful application of IOCS and leucocyte depletion filter in removing tumour cells from blood salvaged during various oncological surgeries. Research on the use of IOCS-LDF in MSTS is urgently needed.