OBJECTIVE:Endoscopes have been increasingly used during neurosurgical procedures. Previously, they have been shown to offer better visualization than the microscope in selected situations and frequently have allowed less invasive surgery. This study was undertaken to determine whether endoscopy is safe and effective during suboccipital surgery for vestibular schwannomas.METHODS:Ten patients with vestibular schwannomas underwent suboccipital transmeatal craniotomies for tumor excision. Endoscopy with a rigid glass lens endoscope (Hopkins telescope) was used during tumor removal to examine posterior fossa neurovascular structures and after excision to inspect the internal auditory canal.RESULTS:Complete tumor excision was achieved in nine patients. Endoscopy allowed improved identification of tumor and adjacent neurovascular relationships in all cases without the need for significant retraction of the cerebellum or brain stem. In addition, residual tumor at the fundus of the internal auditory canal (n = 2) and exposed petrous air cells (n = 3) not seen with the microscope were identified endoscopically. Operative time was not significantly increased by incorporating the endoscope.CONCLUSION:Posterior fossa endoscopy can be performed safely during surgery for tumor removal. Endoscope-assisted surgery for vestibular schwannomas may offer some advantages over standard microsurgery in selected cases. The advantages may include improved visualization, more complete tumor removal, and a lowered risk of cerebrospinal fluid leakage.