Impact of video-endoscopy on the results of retrosigmoid-transmeatal microsurgery of vestibular schwannoma: prospective study
Abstract
Endoscopy-assisted microsurgery represents modern trend of treatment of the cerebellopontine angle (CPA) pathologies including vestibular schwannoma (VS). Endoscopes are used in adjunct to microscope to achieve better functional results with less morbidity.
Angled optics, magnification and illumination enable superior view in the operative field. Our prospective study (consecutive 89 patients with untreated unilateral sporadic vestibular schwannoma undergoing tumor resection via a retrosigmoid approach during 2008-2010; Endoscopy-assisted microsurgery: 39 cases/Grade 1: 2, Grade 2: 5, Grade 3: 9, Grade 4: 22, Grade 5: 1 and microsurgery: 50 cases/Grade 1: 1, Grade 2: 3, Grade 3: 9, Grade 4: 34, Grade 5: 3) proved endoscopic technique valuable for assessment of radicality of resection in the region of internal auditory meatus.
Improved information about critical structures and tumor itself helps the surgeon to preserve facial nerve and in selected cases also hearing. These techniques can help to decrease incidence of postoperative complications.
In the endoscopy-assisted microsurgery residual tumor in the fundus of internal auditory canal not observable with microscope was identified with endoscope in four cases and radicalized. There is a suspicious intrameatal tumor recurrence in one patient in the microsurgery group.
Neither mortality nor infection was observed. Adjunctive use of endoscope identified potential pathways for CSF leak formation, which was not observable with the microscope in five patients.
Improved cochlear nerve (p = 0.012), brainstem auditory evoked potentials and hearing (p = 0.001), facial nerve (p = 0.027) and excellent-very good (House-Brackmann 1-2) facial nerve function (p = 0.035) preservation were observed in the endoscopy-assisted microsurgery group.