title: Intraoperative cell salvage in metastatic spine tumour surgery reduces potential for reinfusion of viable cancer cells.
abstract: This study aimed at evaluating our hypothesis that tumour cells, which pass through the intraoperative cell salvage (IOCS) machine, lose viability due to possible injury to the cell membrane during centrifugation and filtration, enabling safe reinfusion even without filtration.
  
  
  
  Thirteen patients who underwent metastatic spine tumour surgery (MSTS) at our institution were recruited. Blood samples (5 ml each) were collected at five different stages during surgery, namely, stage A and B: from patients' vein during induction and at the time of maximum tumour manipulation; stage C, D and E: from the operative blood prior to IOCS processing, after IOCS processing and after IOCS-LDF (leucocyte depletion filter) processing, respectively. The samples were then analysed for viability of tumour cells using microwell-based culture.
  
  
  
  The median age of the patients was 65 years (range 37-77 years). The most common primary tumour was lung, followed by breast, hepatocellular and renal cell carcinoma. The median blood loss was 680 ml (range 300-1500 ml). Analysis of cultured blood samples showed that CTC-containing clusters were developed from some samples before IOCS-LDF processing (stage A: three patients, stage B: three patients and stage C: one patient). None of the samples from stages D and E generated clusters after culture, suggesting the absence of viable cancer cells after IOCS processing.
  
  
  
  The salvaged blood may contain some tumour cells after processing with IOCS machine, but these cells are damaged and hence unable to replicate and unlikely to metastasise. The results of this study support the hypothesis that salvaged blood in MSTS is safe for transfusion.
authors.affiliation: Department of Orthopaedic Surgery, University Orthopaedics, Hand and Reconstructive Microsurgery, 1E, Kent Ridge Road, Singapore, 119228, Singapore. naresh@doctors.org.uk.
authors.forename: Naresh
authors.initials: N
authors.lastname: Kumar
authors.affiliation: Department of Orthopaedic Surgery, University Orthopaedics, Hand and Reconstructive Microsurgery, 1E, Kent Ridge Road, Singapore, 119228, Singapore.
authors.forename: Aye Sandar
authors.initials: AS
authors.lastname: Zaw
authors.affiliation: BioSystems and Micromechanics (BioSyM) Inter-Disciplinary Research Group, Singapore MIT Alliance for Research and Technology (SMART), National University of Singapore, Singapore, 138602, Singapore.
authors.forename: Bee Luan
authors.initials: BL
authors.lastname: Khoo
authors.affiliation: BioSystems and Micromechanics (BioSyM) Inter-Disciplinary Research Group, Singapore MIT Alliance for Research and Technology (SMART), National University of Singapore, Singapore, 138602, Singapore.
authors.forename: Sayantani
authors.initials: S
authors.lastname: Nandi
authors.affiliation: Department of Biomedical Engineering, National University of Singapore, 2 Engineering Drive 3, Singapore, 117581, Singapore.
authors.forename: Zhangxing
authors.initials: Z
authors.lastname: Lai
authors.affiliation: Department of Orthopaedic Surgery, University Orthopaedics, Hand and Reconstructive Microsurgery, 1E, Kent Ridge Road, Singapore, 119228, Singapore.
authors.forename: Gurpal
authors.initials: G
authors.lastname: Singh
authors.affiliation: Department of Biomedical Engineering, National University of Singapore, 2 Engineering Drive 3, Singapore, 117581, Singapore.
authors.forename: Chwee Teck
authors.initials: CT
authors.lastname: Lim
authors.affiliation: Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117597, Singapore.
authors.forename: Jean Paul
authors.initials: JP
authors.lastname: Thiery
mesh_terms: D000328:Adult; D000368:Aged; D002469:Cell Separation / Q000379:methods*; D006801:Humans; D008875:Middle Aged; D009362:Neoplasm Metastasis; D057725:Operative Blood Salvage / Q000379:methods*; D013125:Spinal Neoplasms / Q000601:surgery*
keywords: Circulating tumour cells (CTCs); Intraoperative cell salvage; Leucocyte depletion filter; Metastatic spine tumour surgery; Microwells