Exposure of the cervical internal carotid artery: Surgical steps to the cranial base and morphometric study

OBJECTIVE: Several studies have reported on approaches to increase exposure of the distal cervical internal carotid artery (ICA), but these studies have neither systematically addressed the anatomic aspects nor quantified the additional exposure of each maneuver. We describe surgical steps to expose the ICA region, quantify the additional exposure of each operative step, and discuss ways to minimize surgical morbidity. METHODS: The ICA was exposed in 10 formalin-fixed cadaveric heads using the following four steps: 1) anterior sternocleidomastoid approach, 2) retroparotid dissection and division of the digastric muscle, 3) section of the styloid apparatus, and 4) mandibulotomy. After completion of each step, the most distal level of ICA exposure was marked with a hemoclip and segment lengths were measured between each clip. RESULTS: Sectioning of the digastric muscle and sectioning of the styloid apparatus provided the most significant exposure of the ICA (14.15 and 15.08 mm, respectively) with minimal risks. Mandibulotomy added 10.20 mm in length and 20.65 degrees in width, but is a maneuver that must be weighed against the heightened risk of morbidity. CONCLUSION: Surgical exposure of the distal cervical ICA is associated with relatively high morbidity that increases with higher levels of exposure. Staged maneuvers have been shown to increase ICA exposure, especially in our systematic approach. The number of steps required varies depending on the level of lesion. Complete understanding of the surgical anatomy is essential to minimize surgical morbidity and to develop surgical expertise.