[Experience of surgical management of trigeminal schwannomas that simultaneously spread to the middle and posterior cranial fossae].

INTRODUCTION: trigeminal schwannomas account for 0.07-0.36% of all intracranial tumors and 0.8-8% of all intracranial schwannomas. Different surgical approaches are used depending on the topographic anatomical variant of the tumor. Dumbbell-shaped tumors that spread both to the middle and posterior cranial fossae are the most challenging ones in terms of their resection. MATERIAL AND METHODS: Five patients with dumbbell-shaped trigeminal schwannomas were operated on at the Burdenko Neurosurgical Institute in 2011-2013. In four cases, tumor resection comprised two stages using the retrosigmoid suboccipital approach (RSA) and lateral extended transsphenoidal endoscopic approach (LETEA); in one case, the tumor was resected in a single session through the LETEA. If there were pronounced symptoms affecting the brainstem and/or cerebellum, tumor resection from the posterior cranial fossa through RSA was resected at the first stage (3 cases). If no symptoms were observed, tumor resection from the middle cranial fossa through LETEA was used as the first stage (2 cases). RESULTS: After two surgical stages, total, subtotal, and partial tumor resection was performed (one case each). Total tumor resection from the middle cranial fossa was achieved through LETEA in two cases. Aggravation of ipsilateral paresis of the craniocerebral nerve VI was observed after the surgery in two cases. No cases of nasal liquorrhea were observed after transnasal surgery. In one case, the cavernous segment of the internal carotid artery was damaged during LETEA, thus requiring endovascular occlusion of the damaged vessel to be performed. CONCLUSION: LETEA is an effective approach that allows resection of tumors from the middle cranial fossa and the cavernous sinus. Combined with RSA, this approach can be used for two-stage resection of dumbbell-shaped trigeminal schwannomas.