Endoscopic Transoral Approach for Extracranial Hypoglossal Schwannoma

Abstract

Objective: Hypoglossal nerve schwannoma, especially when inside the extracranial region, is extremely rare. This report describes a new endoscopic transoral approach for the removal of extracranial hypoglossal schwannoma. Patients and Methods: Three patients (1 male and 2 females, aged 58–63 years) with extracranial hypoglossal schwannoma in the paroccipital condyle and the jugular foramen were treated solely by an endoscopic transoral approach. All patients presented signs of hypoglossal nerve paresis with hemiatrophy of the tongue. In addition, one of them had glossopharyngeal nerve paresis, and vagus nerve paresis was found in another patient. Results: In all patients, tumors underwent successful radical intracapsular removal by the endoscopic transoral approach, as confirmed by the postoperative examinations and MRI. No complications occurred during or after surgery, except that 1 patient had swallowing difficulties and a temporary right vagus palsy during the first day after surgery. All patients were followed up for 6 months, and the lack of any recurrence has been confirmed. Muscle bulk, motor and swallowing functions, and the vagus palsy improved in all patients. Conclusion: The endoscopic transoral approach is a safe and useful surgical technique for the removal of intracapsular tumors, including extracranial hypoglossal schwannomas, which involves minimal invasion.

Transoral Approach to the Jugular Foramen Region with Preservation of the Eustachian Tube

“…Through the transoral corridor, the entire pICA and the lower cranial nerves (IX to XII) deserve particular attention. 12,22 With a 0 scope or microscope, magnification can help better identify and preserve the vessels and lower cranial nerves when dividing the mass conducted through the transoral corridor. Moreover, intraoperative image guidance, doppler, and intraoperative neurological monitor could also provide additional assistance for identification and preservation of important neurovascular structures, further safeguards during the procedure.…”

“…The jugular foramen is subdivided into the pars nervosa and pars vascularis; the former being located at the anteromedial aspect, including the glossopharyngeal nerve and the inferior petrous sinus, whereas the latter being located at the posterolateral aspect transmitting the vagus and spinal accessory nerves (CN X‐XI), and the jugular bulb 9 . The technical feasibility of surgical access and resection of tumors arising in the JFR via an endonasal or transoral corridor has been reported in previous studies 7,10–13 …”

“…9 The technical feasibility of surgical access and resection of tumors arising in the JFR via an endonasal or transoral corridor has been reported in previous studies. 7,[10][11][12][13] In a cadaveric study, adequate exposure of the jugular foramen was achieved after nasopharyngectomy of variable extent. 14 The parapharyngeal internal carotid artery (pICA) lies at the anteromedial or anterolateral aspects of the jugular foramen when traveling upward prior to entry into the vertical petrous canal; and as such, the pICA may constitute a restricting factor for adequate exposure of the jugular foramen when conducted from an endonasal corridor.…”

“…A primary or multi-port auxiliary transoral approach has been occasionally adopted for addressing lesions arising from the JFR. 10,12,13 In our previous study, we also adopted the transoral corridor for resection of schwannomas arising from the retro-styloid compartment with extension into the JFR. 13 However, the anatomical relationship between the pICA and the JFR and technical nuances with preservation of the ET performed through the transoral corridor were not sufficiently appreciated.…”

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

“…Despite variations of the transcondylar approach or intradural approach combined with an extradural approach have been used, complete tumor resection was achieved only in 9 (28.1%) out of 32 cases in our own studies and in others studies. [ 10 21 22 23 ] Usually, the extracranial component remained. In this series, complete tumor resection was achieved in all the 14 patients using pure ETA, without creating additional permanent damage to cranial nerve.…”