Post-operative hematoma after surgery for intracranial meningiomas: causes, avoidable risk factors and clinical outcome.

Intracranial meningiomas are mainly benign lesions amenable for surgical resection. However, removal of an intracranial meningioma carries a higher risk of post-operative hemorrhage compared to surgery for other intracranial neoplasms. Because avoidance of post-operative hematoma is of vital interest for neurosurgical patients, the aim of this retrospective study was to analyze risk factors of post-operative hematoma associated with meningioma surgery. Two hundred and ninety six patients with intracranial meningiomas, operated between June 1998 and June 2002, were included in this study. Patients who developed a space-occupying post-operative intracranial hemorrhage and were treated surgically were identified. Data of patients with and without hematoma were retrospectively analyzed to identify risk factors associated with post-operative hematoma. Variables analyzed included patients' age, invasion of venous sinus by the meningioma, tumor vascularization, arachnoidal infiltration, pre-operative prophylaxis of thromboembolic events, peri-operative coagulation abnormalities, residual tumor, location and histology of the tumor. Outcome of patients with post-operative hematoma was assessed according to the Glasgow Outcome Scale (GOS) at discharge and at three months. 21 patients (7.1 %) of 296 patients developed a post-operative intracranial hematoma requiring surgical evacuation. Age was significantly higher in the hematoma group 62.4 +/- 14.0 years compared to patients without post-operative hematoma 56.1 +/- 12.0 (p < 0.05; t-test). Patients older than 70 years had a six-fold increased risk to develop a post-operative hematoma (Chi2 test, 95% CI 1.949-13.224). Patients with post-operative hemorrhage had significant lower post-operative prothrombin time, fibrinogen and platelets immediately after surgery and lower platelets at day 1. None of the other parameters, including pre-operative routine coagulation values, differed significantly between patients with and without post-operative hemorrhage. Three patients with post-operative hematoma showed platelet dysfunction and three patients showed decreased FXIII activity. Of those patients with post-operative hemorrhage at three months follow up three patients (13%) succumbed from reasons not directly related to hemorrhage, one patient remained GOS 2 (4.3%), four patients (17.4%) were GOS 3 and 15 (65.4%) patients had favorable outcome (GOS 4 [one patient] and GOS5 [14 patients]). Meningioma surgery carries a higher risk for post-operative hematoma in the elderly. Thrombocytopenia and other hemostatic disorders were frequently associated with post-operative hemorrhage after meningioma surgery, while no surgical factors could be defined. Extending coagulation tests and specific replacement therapy may prevent hematoma formation and improve the patients outcome.