Skull base revascularization corridors to the high cervical, petrous, and cavernous internal carotid artery: microsurgical anatomy for optimizing surgical exposure.

Abstract

Revascularization enables the total removal of skull base tumors encasing the internal carotid artery (ICA) and can be used to treat complex aneurysms requiring parent artery occlusion when clipping is unfeasible. Authors of this study aimed to analyze the microsurgical anatomy involved in revascularization procedures involving the high cervical, petrous, and cavernous segments of the ICA in relation to the anterior circulation, with special emphasis on various skull base approaches to optimize the surgical exposure. They also aimed to assess the various surgical corridors used in revascularization procedures by incorporating necessary modifications to standard skull base approaches. Anterolateral skull base approaches were performed on 6 formalin-fixed, silicone-injected cadaveric human heads (12 sides). Skull base approaches, their combinations, and additional modifications were examined in terms of their ability to provide optimal access to donor and recipient arteries, distinct bypass segments, and clip placement through a single surgical corridor. Resection of the vaginal process of the tympanic part of the temporal bone after mobilization of the lateral pterygoid muscle and the mandibular condyle provided access to the distal part of the high cervical ICA and the initial posterior vertical segment of the petrous ICA. Additional removal of the styloid process increased access to the anastomotic site of the high cervical and petrous segments of the ICA, as well as the extracranial courses of the lower cranial nerves. The anterior petrosectomy offered broad access to the horizontal segment of the petrous ICA, while the anterior clinoidectomy provided extensive exposure of the clinoidal and supraclinoid ophthalmic ICA segments. An optimized surgical exposure achieved through targeted skull base modifications may allow safe anastomosis and adequate clipping room on the high cervical, petrous, cavernous, and supraclinoid ICA segments. Targeted skull base approaches establish reproducible and functionally robust corridors for bypass procedures involving the entire length of the ICA and the anterior circulation.