The Risk of Seizure After Surgery for Unruptured Intracranial Aneurysms: A Prospective Cohort Study

BACKGROUND: We aimed to identify a group of patients with a low risk of seizure after surgery for unruptured intracranial aneurysms (UIA). OBJECTIVE: To determine the risk of seizure after discharge from surgery for UIA. METHODS: A consecutive prospectively collected cohort database was interrogated for all surgical UIA cases. There were 726 cases of UIA (excluding cases proximal to the superior cerebellar artery on the vertebrobasilar system) identified and analyzed. Cox proportional hazards regression models and Kaplan-Meier life table analyses were generated assessing risk factors. RESULTS: Preoperative seizure history and complication of aneurysm repair were the only risk factors found to be significant. The risk of first seizure after discharge from hospital following surgery for patients with neither preoperative seizure, treated middle cerebral artery aneurysm, nor postoperative complications (leading to a modified Rankin Scale score >1) was <0.1% and 1.1% at 12 months and 7 years, respectively. The risk for those with preoperative seizures was 17.3% and 66% at 12 months and 7 years, respectively. The risk for seizures with either complications (leading to a modified Rankin Scale score >1) from surgery or treated middle cerebral artery aneurysm was 1.4% and 6.8% at 12 months and 7 years, respectively. These differences in the 3 Kaplan-Meier curves were significant (log-rank P<.001). CONCLUSION: The risk of seizures after discharge from hospital following surgery for UIA is very low when there is no preexisting history of seizures. If this result can be supported by other series, guidelines that restrict returning to driving because of the risk of postoperative seizures should be reconsidered.