Internal Carotid Artery Exposure: An Anatomic Study of Endoscopic and Open Anterior Transfacial Approaches

Objective: The purpose of this study is to determine internal carotid artery exposure in an endoscopic endonasal approach compared with internal carotid artery exposure with a progressive anterior transfacial dissection.

Study Design: Anatomic, morphometric analysis of human cadaver heads.

Setting: Anatomy laboratory

Participants: Latex injected adult cadaver heads.

Main outcome measures: Internal carotid segments and length above the bifurcation were measured with an endoscopic approach, a superstructure maxillary swing (palate in native position), a complete maxillary swing with palatal split, and an anterior mandibular swing. Anatomic limits to the carotid space were compared with each approach.

Results: An endoscopic approach allowed visualization of 2cm on average of ICA at 4.4cm on average above carotid bifurcation. A superior swing approach allowed visualization of 3cm on average of ICA at 3.4cm on average above carotid bifurcation. A total maxillary swing approach allowed visualization of 4.5cm on average of ICA at 1.9 cm on average above carotid bifurcation. A mandibulotomy approach allowed visualization of 6.4cm on average of ICA at 0cm on average above carotid bifurcation.

Conclusions: The complexity of surgical procedures involving the skull base relates in part to the close relationship to neurovascular structures including the internal carotid artery. Internal carotid artery exposure in head and neck surgery can be important from a patient safety standpoint to ensure proximal and distal control to minimize bleeding complications. Anatomic limits can also be important if the ICA has neoplastic involvement that needs to be surgically addressed. The ICA in the parapharyngeal space can be difficult to dissect via an endoscopic approach given its lateral position in the coronal plane. The endoscopic approach showed the smallest portion of the ICA at the furthest point from the bifurcation suggesting the least amount of exposure. We were able to expose an additional centimeter with a superior swing technique, and another 2.5 cm with a superior maxillary swing. The mandibulotomy exposed the entire internal carotid artery and the bifurcation. When choosing between endoscopic, superior maxillary swing, and complete maxillary swing, the surgeon can consider the degree of exposure they need and where exactly in the skull base they need access to.