Transzygomatic extended middle fossa approach for upper petroclival skull base lesions.

Central skull base lesions in the upper retroclival and petroclival regions can be challenging to access because of their location anterior to the brainstem. Several transpetrosal approaches have been developed to access the petroclival junction, including anterior petrosal (anterior petrosectomy), posterior petrosal (retrolabyrinthine, translabyrinthine, transcochlear), and combined petrosal approaches. The anterior petrosal approach is best suited for upper petroclival lesions located anterior and superior to the internal auditory canal and superior to the inferior petrosal sinus. This approach provides direct access to the anteromedial cerebellopontine angle, petrous apex, Meckel cave, and ventrolateral brainstem between the trigeminal root and the facial nerve. The authors describe their modification of an anterior petrosal approach, the so-called transzygomatic extended middle fossa approach, which incorporates a zygomatic osteotomy, anterior mobilization of the V3, and extensive middle fossa drilling. This exposure provides a wider surgical corridor for direct view of the clivus and ventral brainstem.