Risk of perioperative seizures in patients undergoing craniotomy with intraoperative brain mapping

Background. The identification of risk factors associated with perioperative seizures would be of great benefit to the anesthesiologist in managing brain tumor patients undergoing craniotomy with intraoperative brain mapping.
Methods. A series of 316 supratentorial craniotomies for tumor resection, in which intraoperative brain mapping was used, were analyzed. From January 2005 to December 2010 the occurrence of intraoperative and immediate postoperative clinical seizures was prospectively recorded into a database. Demographic data, tumor characteristics, preoperative seizure control, intraoperative events and anesthetic management were evaluated as risk factors for intraoperative clinical seizures. Additionally, the association between intraoperative clinical seizures and immediate postoperative seizures was evaluated. In order to determine the best predictors of intraoperative and immediate postoperative clinical seizures, a multivariable analysis by logistic regression was performed.
Results. Younger age, location of the tumor in the frontal and parietal lobe, brain mapping conducted under general anesthesia and non physiologic values of arterial carbon dioxide (PaCO2) during brain mapping were independent positive risk factors for the development of intraoperative clinical seizures. Location of tumor in the frontal lobe, antiepileptic polytherapy, intraoperative seizures requiring pharmacologic treatment during brain mapping, and blood on postoperative CT scan were independent positive risk factors for the development of immediate postoperative seizures.
Conclusion. Clinical seizures are common intraoperative and postoperative complications of supratentorial craniotomies with intraoperative brain mapping. The identification of those patients at higher risk of seizures may guide intraoperative and postoperative medical management.