"Retrosigmoid approach"@en . "5f5580f15529a7a1292784393708e689" . "Vestibular schwannoma"@en . "V.M. Gerganov" . "Endoscope"@en . "Gerganov" . . "Assisted microsurgery"@en . "V.M." . "Intraoperative electrophysiological monitoring"@en .