Broad Mobilization of the Internal Carotid Artery in Fisch Type B and C Approaches

Background: Fisch has described a series of lateral infratemporal fossa approaches (ITF) that are prototypic transtemporal approaches to the ITF. The Fisch type B and C approaches were developed to approach the petrous apex and clivus. Correct skeletonization of the internal carotid artery is necessary for wide exposure. Objective: We present broad mobilization of the internal carotid artery obtained after release in its different segments in Type B and C Fisch approaches. Methods: Cadaveric study. Fisch B and C approaches with skeletonization of the internal carotid artery were performed and measurements of carotid displacement were taken. Results: Type B approach: Skeletonization of ICA in its petrous portion from the cochlea and Eustaquian tube allows mobilization of 0.5 cm anteriorly; skeletonization of its attachment in the carotid foramen provides another 0.2 cm. Dissection ~3 cm in the upper parapharyngeal space with complete skeletonization and subperiosteal dissection from the entry zone in the skull base allows anterior displacement of 2 cm from the cochlea; this last step has the largest contribution in addressing its mobilization. In type C the complete liberation of the ICA in the parapharyngeal space (3–4 cm) to its cavernous portion allows anterior displacement of 4.5 cm. Conclusion: Release of the internal carotid artery from its parapharyngeal portion to the cavernous sinus allows a broad mobilization and therefore better access to the regions in which the ICA interposes as clivus, petrous apex and sellar region allowing for increased vascular control. When a lesion extends into the neck further mobilization can achieved with transcervical dissection of the parapharyngeal ICA.