Characterization and prognostic implications of significant blood loss during intracranial meningioma surgery

Meningiomas consist of neoplastic arachnoidal cells imbedded in the meninges, and constitute 13–26% of primary intracranial tumors (1,2). Most meningiomas are slow growing and benign, and tend to compress or envelop the adjacent structures rather than invade them. Because a relatively clear operative plane is available, surgery aimed at total resection of the tumors is the main therapeutic option. While the surgical removal of intracranial meningiomas can reduce mass effects and may even be curative, the process is not without adverse events. In particular, meningioma resection is frequently accompanied by substantial blood loss, and preoperative embolization may be required to control surgical bleeding (3,4). This is an issue because significant surgical bleeding, i.e., ≥500 mL, is associated with morbidity and mortality in cases that undergo major non-cardiac surgery (5-7). There remains no universally accepted definition of excessive blood loss in the neurosurgical field. Moreover, the incidence of meningiomas increases with age, and elderly patients are particularly vulnerable to anemia and the detrimental effects of blood loss owing to their limited physiological reserves (8,9). Excessive bleeding during operations can also lead to the need for transfusions of red cells, platelets, or coagulation factors, thus increasing the potential for infection transmission and immunological reaction. Considering these various factors, it is important to predict significant blood loss and guide clinical management decisions in patients undergoing intracranial meningioma surgery