Pseudoaneurysms as a complication of stereoelectroencephalography: Case series and clinical recommendations

Objective Stereoelectroencephalography (sEEG) is commonly employed in the workup for epilepsy surgery in patients with focal drug-resistant epilepsy (DRE). Intracranial hemorrhage is a known complication, with reported incidence rates ranging from .9% to 19.1%. Rarely, pseudoaneurysms have been reported in literature as a potential cause. This retrospective cohort study aims to describe the occurrence, clinical characteristics, and management of iatrogenic pseudoaneurysms following sEEG and the clinical outcome of the described cases.Methods A cohort of 395 patients (4067 depth electrodes) with DRE who underwent sEEG was retrospectively analyzed. The identified patients with pseudoaneurysms were analyzed in detail, focusing on timing of detection and location of the aneurysms, clinical characteristics, management strategies, and clinical outcome.Results A symptomatic iatrogenic pseudoaneurysm was identified in six of 395 cases (1.5%), with a per-electrode risk of .15% (6/4067); all occurred at the M2/M3 branches of the middle cerebral artery. All six cases presented with intracerebral or subarachnoid hemorrhage. Aneurysms were detected with combined cerebral computed tomographic angiography (CTA) and digital subtraction angiography (DSA) and treated without complications by surgical clipping or endovascular embolization. The depth electrode implantation and planned sEEG recording had to be either prematurely discontinued or canceled in four of six cases. No patients died; five experienced neurological symptoms and required prolonged hospitalization, with four needing additional rehabilitation.Significance Pseudoaneurysms following sEEG represent a serious complication with significant clinical consequences and warrant early detection and intervention. Occurrence is underreported in literature. It is recommended to use CTA and DSA when a pseudoaneurysm is suspected, particularly in cases of intraparenchymal or subarachnoid hemorrhage, and especially when depth electrodes are in close proximity to a blood vessel.