Surgical treatment of dumbbell-shaped hypoglossal schwannoma via a pure endoscopic transoral approach

Abstract

Dumbbell-shaped hypoglossal schwannomas tend to cause lower cranial nerve deficits, facial paralysis and hearing loss. With appropriate preoperative evaluation and careful planning of the perioperative period, complete tumor resection can be achieved via the purely endoscopic transoral approach. The endoscopic transoral approach is an effectice choice for management of dumbbell-shaped hypoglossal schwannomas.

Giant recurrent dumbbell-shaped hypoglossal schwannoma in an elderly male: A case report

“…Certain neurologists consider that the extracranial portion of dumbbell-shaped hypoglossal schwannomas does not require resection; however, in our opinion, a complete surgical resection is indicated if the tumor becomes symptomatic or when marked growth is noted, according to the condition of the patient, and should be performed via a one or two stage procedure According to a previous study (12), a complete tumor resection is achieved in <30% of these dumbbell-shaped hypoglossal schwannomas. Although little is known with regard to the long-term natural history of residual hypoglossal schwannoma, the growth rate of schwannoma is generally considered to be slow, however, this growth will compress vessels and nerves, and more aggressive adherence will occur, causing complications such as dysphagia and respiratory disturbance (5).…”

“…Magnetic resonance imaging (MRI) is considered superior to computed tomography for the diagnosis of skull base tumors, as MRI accurately demonstrates the relationship between tumor location and the surrounding soft tissues (4). Although 39 cases of dumbbell-shaped, hypoglossal schwannoma have been described in the literature to date (3,(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15), only a small proportion of these cases (<30%) achieved a complete tumor resection (12), and no recurrent cases were reported. At present, the standard surgical technique used for the treatment of hypoglossal schwannomas is the far lateral approach with partial resection of the condyle, which exposes the hypoglossal canal (3,16).…”

Endoscopic Approach to Remove Intra-extracranial Tumors in Various Skull Base Regions

“…The expanded endoscopic approach has been used in skull base surgery over the last decade. [ 10 11 12 13 14 15 ] The feasibility of this approach for removing lesions in the skull base and its advantages of preventing surgical retraction of the brain and improving cranial nerve function have gradually been recognized by more and more neurosurgeons.…”

“…The operative techniques have been previously described in detail both by us and others in the field. [ 10 11 12 13 14 15 ]…”

“…In fact, the extracranial component usually remains. Based on our early experiences using endoscopic approaches to remove meningioma and schwannoma with intra-extradural growth,[ 10 11 12 ] here we present our findings from 10 years of experience by using a purely endoscopic transnasal or transoral approach (ETA) for intra-extracranial growing tumors in various skull base regions to demonstrate the outcome and evaluate feasibility and safety of this method.…”