Retrosigmoid Microsurgery of Giant Vestibular Schwannoma

Giant vestibular schwannomas (defined by a maximum extrameatal diameter greater than 4 cm) usually represent up to 2% of all vestibular schwannomas in Western countries, but they may reach the majority in developing countries. The microsurgical removal of the lesion, with consequent decompression of the brainstem and of the surrounding neurovascular structures, is the cornerstone of giant vestibular schwannomas management. However, their size and their close relationship with important neurovascular structures may make the microsurgical resection very challenging, thus increasing the risk of postoperative morbidity (in particular facial nerve function) and mortality. As a consequence, there is still no clear consensus regarding the best treatment option: some authors consider the complete surgical removal as the final goal to be reached in 1, 2, or more stages; others believe that the so-called “functional sparing surgery policy” (based on a subtotal resection followed by early stereotactic radiosurgery of the tumor remnant or delayed stereotactic radiosurgery only in case of tumor progression) could be helpful to preserve facial nerve function in spite of higher rates of progression after incomplete resection. Here we present our technique for the microsurgical removal of giant vestibular schwannomas through the retrosigmoid approach. In addition, we briefly summarize the pros and cons of the different surgical approaches for vestibular schwannomas, report on the main postoperative complications (more frequent in large and giant tumors), and discuss the therapeutic strategies for achieving good functional outcomes when dealing with such challenging lesions.