Microsurgery of Cerebellopontine Angle Tumors

The cerebellopontine angle (CPA) is a narrow area located between the cerebellum, the posterior surface of the petrous bone, and the brainstem. From a surgical point of view, it presents a significant challenge due to its intricate network of vessels and cranial nerves. In its early stages, a small tumor will cause only cochleovestibular symptoms. As the tumor progresses, it affects the function of the last cranial nerves. At the same time, the growth of the tumor causes progressive compression of the brainstem and cerebellum, which may be silent or manifest as headache and/or cerebellar ataxia, which should be considered warning symptoms. Several types of tumors can develop in CPA. This article will focus on the characteristics of the four most common tumors: vestibular schwannomas, meningiomas, epidermoid cysts, and facial nerve schwannomas. Vestibular schwannoma, by far the most common, will be used to illustrate treatment recommendations. The specifics of surgical management of meningiomas and epidermoid cysts are then discussed. For the purposes of this discussion, it is assumed that the decision to proceed with surgery has been made and that alternatives such as simple watchful waiting or radiation therapy have been ruled out.