Hidden blood loss and its influencing factors after cement augmentation for vertebral metastasis

Introduction Few studies have focused on the risk factors for hidden blood loss (HBL) during cement augmentation surgery for pathologic vertebral compression fraction (PVCFs). Method From January 2014 to December 2020, the clinical data of 169 PVCF patients (283 levels) who underwent cement augmentation were retrospectively analysed. HBL was calculated according to the linear Gross formula using the patient's average Hct during the perioperative course and PBV. Multivariate linear regression analysis was performed to evaluate the independent factors associated with HBL. Results The mean HBL was 448.2 ± 267.2 ml, corresponding to 10.8% ± 6.2% of the patient blood volume (PBV). There were significant differences between pre- and postoperative haematocrit (Hct) (P < 0.001) and Hb (P < 0.001), and 132 patients developed anaemia postoperatively, while 79 patients had anaemia preoperatively (P < 0.001). Multivariate linear regression revealed that bone lesion quality (p = 0.028), number of PVCFs (p = 0.002), amount of bone cement (p = 0.027), bone cement leakage (p = 0.001), and percentage of vertebral height loss (VHL) (p = 0.011) were independent risk factors for HBL. Conclusion In conclusion, patients with lytic vertebral destruction, larger amounts of bone cement, greater amounts of bone cement leakage, more PVCF(s), and greater percentages of VHL may be more prone to HBL.