Petroclival Meningioma: Posterior Petrosal Approach

Petroclival meningiomas are rare and account for less than 2% of all meningiomas. These tumors arise along the upper two-thirds of the clivus, superior to the jugular foramen and medial to the cranial nerves’ foramina at the petroclival junction. This anatomic location is uniquely difficult to approach surgically because it is very closely surrounded by multiple neurovascular structures, including the brainstem, basilar artery, cranial nerves (CNs) III-VIII, the cavernous sinus, and the sella.

This location also resides at the convergence of the supra- and infratentorial compartments, allowing petroclival meningiomas to span both spaces. This anatomic configuration may require radical skull base osteotomies or combined/staged approaches. Tumors of the lower one-third of the clivus, inferior to the jugular foramen, are primarily foramen magnum lesions and are discussed in the chapter dedicated to the Foramen Magnum Meningioma.

The natural history of petroclival meningiomas is presumed to be similar to that of other meningiomas, but it has not been well documented because of the relative rarity of these lesions. In some cases these tumors show evidence of slow, steady growth, but in others, growth is sporadic. Some lesions are followed unchanged for many years until they suddenly begin to enlarge, whereas others enlarge initially then stop growing. Some of these lesions never manifest any evidence of growth. Petroclival meningiomas often grow quite large before diagnosis, fur...