Extended middle fossa approach for petroclival lesions.

A modification of the previously described transcochlear approach to extra- and intradural petroclival and clival lesions is described in this report. It is an approach from the middle cranial fossa. It involves unroofing and depression of the external ear canal, removal of the glenoid cavity of the temporo-mandibular joint, exentration of the middle ear ossicles, posterior mobilization of labryrinthine and tympanic segments of the facial nerve, and drilling of the petrous bone from an entirely lateral perspective. An extensive and low exposure of the petroclival region, posterior aspect of the cavernous sinus, upper and mid clivus and the cerebellopontine angle is obtained. The anterior surface of the brain stem upto the pontomedullary junction is exposed with minimal or no retraction of the temporal lobe of the brain. The vein of Labbe and sigmoid sinus drainage is unhampered. Anterior and posterior extension of the exposure is possible. Only a limited mastoidectomy and labyrinthectomy, necessary to facilitate exposure and mobilization of the facial nerve is necessary. The inferior limit of the exposure is set by the dome of the jugular bulb. Hearing is sacrificed. The technique and merits of the procedure are discussed in this report. The study is based on surgical experience of 4 cases.