The risk factors of postoperative infarction after surgical clipping of unruptured anterior communicating artery aneurysms: anatomical consideration and infarction territory

Purpose An anterior communicating artery is a common location for both ruptured and unruptured intracranial aneurysms, and microsurgery is sometimes necessary for their successful treatment. However, postoperative infarction should be considered during clipping due to the complex surrounding structures of anterior communicating artery aneurysms. This study aimed to evaluate the risk factors of postoperative infarction after surgical clipping of unruptured anterior communicating artery aneurysms and its clinical outcomes. Methods The data of patients who underwent microsurgical clipping of an unruptured anterior communicating artery aneurysm in our hospital between January 2008 and December 2020 were retrospectively analyzed. The patients’ demographic data, anatomical features of the anterior communicating artery complex and aneurysm, surgical technique, characteristics of postoperative infarction, and its clinical course were evaluated. Results Notably, among 848 patients, 66 (7.8%) and 34 (4%) patients had radiologic and symptomatic infarctions, respectively. Univariate and multivariate logistic regression analyses showed that hypertension (odds ratio (OR), 1.99; p = 0.022 ), previous stroke (OR, 3.89; p = 0.009 ), posterior projection (OR, 5.58; p < 0.001 ), aneurysm size (OR, 1.17; optimal cut-off value, 6.14 mm; p = 0.002 ), and skull base-to-aneurysm distance (OR, 1.15; optimal cut-off value, 11.09 mm; p < 0.001 ) were associated with postoperative infarction. In the pterional approach, a closed A2 plane was an additional risk factor (OR, 1.88; p = 0.041 ). Infarction of the subcallosal and hypothalamic branches was significantly associated with symptomatic infarction ( p = 0.001 ). Conclusion Hypertension, previous stroke, posteriorly projecting aneurysms, aneurysm size, and highly positioned aneurysms are independent risk factors for postoperative infarction during surgical clipping of an unruptured anterior communicating artery aneurysm. Additionally, a closed A2 plane is an additional risk factor of postoperative infarction in patients undergoing clipping via the pterional approach.