Special Poster Session 50th International Society for the Study of the Lumbar Spine Annual Meeting 2024

Introduction:

Allogeneic blood transfusion (ABT) is the current standard of blood replenishment for metastatic spine tumour surgery (MSTS) despite known complications. Salvaged blood transfusion (SBT) addresses majority of such complications that is related to ABT. However, surgeons remain reluctant to employ SBT in MSTS despite ample laboratory evidence. This can be due to a current lack of literature regarding the long-term outcomes of SBT in MSTS patients. This prompted our team to conduct a prospective clinical study to ascertain the long-term clinical outcomes of intraoperative cell salvage (IOCS) in MSTS.

Methods:

Our prospective study included 98 patients who underwent MSTS from 2014 to 2017. Patients were divided into three groups based on their BT type: no blood transfusion (NBT), ABT and SBT. Primary outcomes assessed were overall survival (OS) and tumour progression (TP), that was evaluated using RECIST (v1.1) employing follow-up radiological investigations at 6, 12, 24, 36 and 48 months. The primary tumours of MSD were also subgrouped based on vascularity and analysed.

Results:

Our study had a total of 98 patients [53:45(M/F)] with a mean age of 60 years old at the time of surgery. All three BT groups were comparable for demographics and tumour characteristics (p=0.215). Overall median blood loss was 400 mL [IQR 200-900 mL] and overall median BT was 620 mL (IQR: 110 – 1600 mL) for patients receiving BT. 33 (33.7%) patients received SBT, 39 (39.8%) received ABT and 26 (26.5%) had NBT. Comparison of total blood loss among the three groups revealed no significant difference between SBT and ABT (p=0.052). There was also no significant difference between the OS of patients who underwent ABT or SBT, as compared to NBT (p=0.136). However, OS was better in SBT than in ABT group, represented by our adjusted survival curve (Figure 1). Subgroup analysis with the vascularity of the primary tumours also showed a significant association with risk of death on the adjusted survival curve (Figure 2). On multivariate analysis, SBT did not show any increase in 4-year tumour progression [Adjusted HR 0.57; 95% CI 0.14-2.22; p=0.423]. Total blood loss was also not associated with tumour progression [Adjusted HR 0.51; 95% CI 0.15-1.65; p=0.26].

Discussion:

MSTS patients whom had SBT were associated with a decreased risk of death compared to ABT and NBT. Improved OS for SBT compared to ABT can be attributed to ABT-related immunosuppression which increases the likelihood of postoperative complications. Dividing the primary tumour into subgroups based on their vascularity also showed tumour vascularity to be a significant factor in OS, with highly vascular tumours showing significant increase in risk of death. However, our study did not find any factor that had significant association with TP. This may due to TP being determined by inherent primary tumour characteristics, instead of factors discussed in our paper.

This will be the first long term prospective study to report on the clinical outcomes of SBT in comparison with control groups in MSTS and affirms the clinical role of SBT in MSTS.