High-How Bypass with Internal Carotid Artery to Middle Cerebral Artery Bypass Using Radial Artery Graft Through the Supramandibular-Subzygomatic Route for Giant Internal Carotid Aneurysm: Technical Case Report

BACKGROUND: A unique case of an internal carotid artery (ICA) giant aneurysm treated by high-flow bypass is presented. This patient had some anatomic variations in the neck region that posed problems for the high-flow bypass, and a new approach to address them is presented. CASE DESCRIPTION: A 55-year woman presented with diplopia, abducens nerve palsy, severe headache, and disordered consciousness. She had a giant ICA aneurysm (diameter, 32 nun). Although high-flow bypass was considered, this patient had 3 anatomic issues that posed problems: an elongated styloid process, a high carotid bifurcation, and a meandering external carotid artery. Thus, some changes had to be introduced to proceed with the high-flow bypass. A tunnel radial artery (RA) graft was made between the supramandibular and subzygomatic areas, and an ICA-RA-M2 anastomosis was performed. The patient's preoperative symptoms improved gradually after surgery. Magnetic resonance imaging and computed tomography showed good patency of the RA graft and no ischemic change. She was discharged without neurological deficits. CONCLUSIONS: This case provided 2 new methods for high-flow bypass: RA graft route and the anastomosis of the ICA in carotid bifurcation. To our knowledge, this is the first case report of a high-flow bypass with a tunnel created for the RA graft (supramandibular-subzygomatic route) and an ICA-RA-M2 anastomosis.