Surgical management of trigeminal schwannomas: defining the role for endoscopic endonasal approaches

Because multiple anatomical compartments are involved, the surgical management of trigeminal schwannomas requires a spectrum of cranial base approaches. The endoscopic endonasal approach to Meckel's cave provides a minimal access corridor for surgery, but few reports have assessed outcomes of the procedure or provided guidelines for case selection. A prospectively acquired database of 680 endoscopic endonasal cases was queried for trigeminal schwannoma cases. Clinical charts, radiographic images, and long-term outcomes were reviewed to determine outcome and success in removing tumor from each compartment traversed by the trigeminal nerve. Four patients had undergone endoscopic resection of trigeminal schwannomas via the transpterygoid approach (mean follow-up 37 months). All patients had disease within Meckel's cave, and 1 patient had extension into the posterior fossa. Gross-total resection was achieved in 3 patients whose tumors were purely extracranial. One patient with combined Meckel's cave and posterior fossa tumor had complete resection of the extracranial disease and 52% resection of the posterior fossa disease. One patient with posterior fossa disease experienced a sixth cranial nerve palsy in addition to a corneal keratopathy from worsened trigeminal neuropathy. There were no CSF leaks. Over the course of the study, 1 patient with subtotal resection required subsequent stereotactic radiosurgery for disease progression within the posterior fossa. Endoscopic endonasal approaches appear to be well suited for trigeminal schwannomas restricted to Meckel's cave and/or extracranial segments of the nerve. Lateral transcranial skull base approaches should be considered for patients with posterior fossa disease. Further multiinstitutional studies will be necessary for adequate power to help determine relative indications between endoscopic and transcranial skull base approaches.