How to perform microscopic/endoscopic resection of large petrous apex lesions.

The endoscope and microscope can be used conjointly in certain sites, such as middle ear cholesteatoma or for resection of cerebellopontine angle tumours. Petrous apex tumours are classically accessed via a lateral otological approach, or, for the most anterior tumours, via an endonasal endoscopic approach. Surgical access via a lateral incision is limited inferiorly by the superior bulb of the internal jugular vein, medially by the labyrinth, facial nerve and internal auditory canal, superiorly by the dura mater, and laterally by the internal carotid artery. Via an anterior endonasal approach, the corridor formed by the internal carotid artery and the paraclival dura limits access to the posterior part of the petrous apex, restricting this approach to certain cholesterol granulomas or small cholesteatomas. None of these approaches, on its own, is sufficient in the case of an extensive petrous apex lesion. The objective of this technical note is to describe the combined microscopic/endoscopic approach comprising sequential use of the microscope and the endoscope via a lateral approach for the management of large petrous apex lesions.