Petrous and Clival Meningiomas

Petrous and clival meningiomas represent about 2% of all intracranial meningiomas and about 10% of posterior fossa meningiomas that can extends from the posterior surface of the petrous to the petrous apex with the petroclival junction till the superior two-third of the clivus. The natural history is characterized by a slow progressive growth. Clinical presentation can be related to the mass effect on the cerebellum and brainstem causing headache and gait imbalance as main symptoms, or to cranial nerves impairment. There is no universally accepted comprehensive classification. Operatively, they could be classified, considering the dural site of attachment and the relationships with the acoustic-facial bundle and the trigeminal nerve. Although it is still a matter of debate, radiosurgery can be advocated for the treatment of small tumors without significant brainstem compression. Surgery is the treatment of choice for large tumors causing mass effect. Nowadays, the retrosigmoid approach is considered the keystone approach for these tumors even if other skull base approaches like the trans-cochlear, the Kawase and the combined approach are still preferred in selected cases. The philosophy of resection has changed in last 20 years from striving to obtain gross total resection using invasive skull base approaches to a maximal safe resection followed by adjuvant radiation treatment in order to reduce cranial nerves morbidity and improve patient’s functional outcome. Nevertheless, surgical morbidity in terms of cranial nerve impairment remains relatively high. Radiation therapies like single- or multi-session Gamma Knife and Cyber Knife radiosurgery, and conformal fractionated radiation therapies represent different options for the treatment of residual and recurrent tumors.