Posterior Transpetrosal Approach

Abstract

  The posterior transpetrosal approach, which can provide a better ventral surgical view than the lateral suboccipital approach, is required for the surgical treatment of skull base lesions extending to the petrous bone. In this paper, the microsurgical anatomy of the mastoid and surgical manipulation involved in mastoidectomy are explained.

  The posterior transpetrosal approach for petroclival lesions has been reported from the 1970s to the early 1990s. This approach is typically performed in combination with other approaches, leading to several variations. The surgery is performed in the lateral position. The posterior neck muscles are retracted to avoid muscle injury. After the occipital bone and mastoid had been exposed, occipital craniotomy and mastoidectomy are performed. A triangular shape is drilled into the mastoid with the following anatomical landmarks as vertices : the posterior point of the root of the zygoma, mastoid tip, and asterion. Subsequently, the sigmoid sinus plate and mastoid antrum are exposed. After confirming the lateral semicircular canal inside the mastoid antrum, the superior and posterior semicircular canals are also exposed. Finally, the facial nerve and jugular bulb are identified.

  Precise anatomical knowledge and a safe skull base drilling technique are required to achieve success with the use of the posterior transpetrosal approach, resulting in a wide and shallow surgical field for skull base lesion.