Pseudoaneurysm Formation after Stereoencephalography for Epilepsy.

Abstract

Introduction Stereoencephalography (SEEG) has emerged as the most common technique for invasive monitoring as part of the pre-operative workup for epilepsy surgery. The use of intracranial implants has the potential for vascular injury giving rise to pseudoaneurysm, followed by unpredictable, delayed hemorrhage. However, while this has been suspected in cases of severe, delayed hemorrhage after SEEG implantation, no case of confirmed pseudoaneurysm has been shown to arise secondary to a SEEG implant. Case Presentation A patient was evaluated over the course of two SEEG implantations before the decision to proceed with deep brain stimulation (DBS) of the anterior nucleus of the thalamus (ANT) to treat their drug-resistant epilepsy. Pre-operative imaging for DBS revealed a pseudoaneurysm proximal to an SEEG craniostomy site. The lesion was treated with excision and vascular bypass, and the patient ultimately underwent DBS as planned. Retrospective analysis strongly implicated the SEEG implantation in pseudoaneurysmal formation, most likely via arterial collision resulting from entry site deviation from the planned stereotactic trajectory. Conclusion Pseudoaneurysm may be a more prevalent complication of SEEG than existing literature would suggest, as the delayed formation of these lesions can allow them to escape recognition on routine postoperative imaging. Though likely still uncommon, this may suggest the prudence of additional radiological surveillance. This complication is potentially devastating if unrecognized and untreated, but otherwise does not preclude further surgical therapies for epilepsy.