Large and giant vestibular schwannomas compress the cerebellum, brainstem, and fourth ventricle; in other words, the degrees T4 and T5 tumors according to the Matties and Samii classification, as well as grade IV of the Koos classification. Large and giant vestibular schwannomas require microneurosurgical excision. The retrosigmoid transmeatal access serves as the basis for microneurosurgical resection. This chapter explains the microsurgical anatomy of the cerebellopontine angle and the steps involved in the retrosigmoid approach. We review the selection of the most appropriate treatment technique for each patient, along with its results, outcomes, and complications. Hydrocephalus is frequently associated, and the different types of hydrocephalus and their management are reviewed. The goal of treatment is to preserve the life of the patients, to decompress the brainstem, and to maintain the facial nerve function.