Is surgery for multiple myeloma-related spinal involvement associated with higher blood loss compared to spinal metastases?

[PURPOSE] Multiple myeloma (MM) is a hematologic malignancy often presenting with diffuse osteolysis of bone in the vertebral column. So far, little is known about the risk of perioperative blood loss in spinal surgery, as MM-related spinal lesions are often grouped with spinal metastases (SPMs). A more definitive understanding of bleeding risks for myeloma specifically will improve surgical planning and treatment. This study aims to assess the bleeding index (BI) and visually estimated blood loss (EBL) in MM patients versus SPM patients undergoing oncological spine surgery.

[METHODS] In this retrospective propensity-score-matched case-control study, we included 119 patients with MM and 119 patients with spinal metastases (SPM) who underwent oncological spine surgery between January 2002 and December 2022. A Wilcoxon signed-rank test was used to compare intraoperative bleeding values in MM and SPM patients, presented as BI and EBL.

[RESULTS] MM patients had significantly higher bleeding scores (BI 5.6) compared to SPM patients (BI 3.9) (p = 0.02). The visual EBL was significantly higher in MM patients (850 ml) compared to SPM patients (600 ml) as well (p = 0.039). The BI of MM patients was comparable to hormone-dependent breast cancer (BI 5.1) and renal cell carcinoma (BI 4.95) primary tumor types. No significant differences were found when the bleeding risk was subdivided per surgical procedure in MM (p = 0.647) or SPM patients (p = 0.403).

[CONCLUSION] This study demonstrated that the BI and EBL are significantly higher in MM compared to SPMs. MM lesions have an intraoperative bleeding risk comparable to SPMs traditionally regarded as hypervascular.