Analysis of the risk factors for development of post-operative extradural hematoma after intracranial surgery.

Objective: Post-operative extradural hematoma (EDH) is a relatively common complication in patients undergoing intracranial operations. The risk factors associated with the occurrence of EDH are not well described in the literature. The objective of this study was to identify the risk factors and the incidence of post-operative EDH adjacent and regional to the craniotomy or the craniectomy site.

Method: This was a retrospective study of 24 (2.6% of total) patients who underwent extradural hematoma evacuation after primary intracranial supratentorial surgery between January 2005 and December 2011. During this period, 941 intracranial operations were performed. The control group (72 patients) was selected on the basis of having undergone the same pre-operative diagnosis and treatment within 2 months of the operations for the 24 hematoma patients. The Glasgow Coma Scale score and operation character (emergency or elective) of the hematoma and control group were individually matched to minimize pre-operative conditional bias. The ages of both groups were individually matched with similar ages within 10 years of each other to minimize age bias.

Result: Univariate analysis showed that the significant pre-operative and intra-operative factors associated with post-operative EDH were an intra-operative blood loss of greater than 800 mL (p=0.007), maximal craniotomy length of greater than or equal to 100 mm (p=0.001), and craniotomy area of greater than or equal to 71.53 cm2 (p=0.018). In multivariate analysis, intra-operative blood loss exceeding 800 mL (median of total patients) placed a patient at significantly increased risk for post-operative EDH.

Conclusion: The data did not examine established risk factors for post-operative hematoma, such as thrombocytopenia, anti-coagulant and anti-platelet therapy, and a history of heavy alcohol consumption and/or tobacco intake. Recognizing the limitations of the study, large intra-operative blood loss and wide craniotomy area are implicated with an increased risk of post-operative EDH after intracranial surgery.