Multimodality Management of Trigeminal Schwannomas

Abstract

Patients presenting with trigeminal schwannomas require multimodality management by a skull base surgical team that can offer expertise in both transcranial and transnasal approaches as well as radiosurgical and microsurgical strategies. Improvement in neurologic symptoms, preservation of cranial nerve function, and control of mass effect are the primary goals of management for trigeminal schwannomas. Complete surgical resection is the treatment of choice but may not be possible in all cases. Radiosurgery is an option as primary management for small- to moderate-sized tumors and can be used for postoperative residuals or recurrences. Planned surgical resection followed by SRS for residual tumor is an effective option for larger trigeminal schwannomas. The endoscopic resection is an excellent approach for patients with an extradural tumor or tumors isolated to the Meckel cave. A detailed analysis of a tumor and its surroundings based on high-quality imaging can help better estimate the expected outcome from each treatment. An expert skull base team should be able to provide precise counseling for each patient's situation for selecting the best option.

Image-guided endonasal endoscopic excision of Meckel’s cave trigeminal schwannoma from cavernous and petrous carotid artery

“…CT scan is always performed initially and may show widening of superior orbital fissure, foramen ovale or foramen rotundum, and also it depicts any erosions of the middle fossa and petrous apex. MRI is used to indicate the type of trigeminal schwannoma, adjacent anatomical structures and tumor volume [ 6 ]. Via imaging, the tumors are classified into six different types [ 7 ].…”

“…The choice of modality depends mainly on tumor-nerve anatomical situation. The former approach is more suitable for tumors that locate trigeminal nerve medially while the latter is more suitable for tumors that locate it laterally [ 6 ].…”

Trends in the Management of Non-Vestibular Skull Base and Intracranial Schwannomas

“…Transcranial approaches might then be chosen for tumors that displace the trigeminal nerve medially while endonasal techniques may be selected for tumors displacing the nerve laterally. 26 …”

“…Transcranial approaches might then be chosen for tumors that displace the trigeminal nerve medially while endonasal techniques may be selected for tumors displacing the nerve laterally. 26 The treatment aims of TS focus on improvement in neurologic symptoms, relief of mass effect, and preservation of cranial nerve function. After the application of skull base techniques, gross total resection (GTR) has been achieved in 69-87%.…”

“…Most of series report a tumor control rate greater than 80%, which is somewhat lower than that achieved with vestibular schwannomas. 3,26,[32][33][34] The incidence of tumor regression ranges from 34% to 87% and tumor stability from 8% to 50%. [32][33][34][35][36][37] A significant symptomatic improvement following SRS varies from 31% to 72% across the series, whereas the incidence of symptomatic deterioration varies from 0% to 27%.…”