Incidence, risk factors and outcomes of seizures occurring after craniotomy for primary brain tumor resection

OBJECTIVE To determine the incidence, risk factors and outcomes of early post-craniotomy seizures. METHODS This was a retrospective cohort study of all patients who underwent craniotomy for primary brain tumor resection (2002-2011) and admitted postoperatively to the intensive care unit. The patients were divided into 2 groups depending on the occurrence of seizures within 7 days. RESULTS One-hundred-ninety-three patients were studied: 35.8% had preoperative seizure history and 16.6% were on prophylactic antiepileptic drugs (AEDs). Twenty-seven (14%) patients had post-craniotomy seizures. The tumors were mostly meningiomas (63% for the post-craniotomy seizures group versus 58.1% for the other group; p=0.63) and supratentorial (92.6% for the post-craniotomy seizures versus 78.4% for the other group, p=0.09) with tumor diameter=3.7+/-1.5 versus 4.2+/-1.6 cm, (p=0.07). One (3.1%) of the 32 patients on prophylactic AEDs had post-craniotomy seizures compared with 12% of the 92 patients not receiving AEDs preoperatively (p=0.18). On multivariate analysis, predictors of post-craniotomy seizures were preoperative seizures (odds ratio, 2.62; 95% confidence interval, 1.12-6.15) and smaller tumor size <4 cm (odds ratio, 2.50; 95% confidence interval, 1.02-6.25). Post-craniotomy seizures were not associated with increased morbidity or mortality. CONCLUSION Early seizures were common after craniotomy for primary brain tumor resection, but were not associated with worse outcomes. Preoperative seizures and smaller tumor size were independent risk factors.