Anterior choroidal artery aneurysm case series: a clinical decision algorithm for endovascular and surgical treatment using a novel classification system.

Anterior choroidal artery (AChA) aneurysms represent 2-5% of intracranial aneurysms. The proximity of the origin of the AChA to the aneurysm neck poses a risk of thromboembolic complications following treatment. AChA occlusion can result in significant neurological deficits. We present a case-series of patients with AChA aneurysms and their treatment outcomes. We describe how treatment was chosen based on aneurysm and patient-specific factors to minimize risks, enhance efficacy of treatment, and improve patient outcomes. We retrospectively reviewed 27 patients who underwent treatment for AChA aneurysms at a single institution from 2015-2024. Clinical presentation, aneurysm characteristics, procedural details, and follow-up data were collected. Twenty-seven AChA aneurysms (median diameter 2.94 mm), were treated in 29 procedures. Treatments included clipping (11 aneurysms), flow diversion (13), or coiling (5). The five coiled aneurysms were ruptured at presentation. Three patients experienced permanent infarction (10.3%), two in the setting of vasospasm after coiling and one after flow diversion in a patient who proved to have resistance to clopidogrel. At a median follow-up of 4.73 months (IQR = 1.23-14.03), 25 patients (93%) had favorable functional recovery (mRS 0-2). Patients treated for AChA aneurysms experienced favorable functional outcomes by utilizing surgical and endovascular techniques carefully chosen based on aneurysm and patient-specific factors. Two patients did not achieve independence post-coiling due to disability from their initial subarachnoid hemorrhage. There were no treatment related causes of unfavorable functional outcomes.