[Management of patients with vestibular schwannoma type IV]

Vestibular schwannomas (VSs) are benign, slow-growing tumors that are classified by the Koos and Hannover grading scales. Despite extensive study, the management of large VS remains controversial.

Between 2003 and 2018, 61 patients with VS grade IV were treated in our institution. Patient data and radiological images were retrospectively analyzed. Additionally, we performed a subgroup analysis of patients with and without fourth ventricle distortions.

Most patients presented with multiple symptoms, like hearing loss in 55 patients (90 %), trigeminal nerve affection in 16 (26 %), facial nerve affection in 7 (12 %), ataxia in 27 (45 %), and symptoms associated with increased intracranial pressure caused by hydrocephalus in 4 patients (7 %). Patients with type IV b VS presented significantly more often with ataxia, tonsillar herniation, and hydrocephalus. Complete tumor resection was achieved in 48 patients (79 %) and near-total resection was achieved in 12 patients (20 %). During long-term follow-up, 90 % of the patients had favorable outcomes regarding facial nerve function (House and Brackman grade I-III). In six patients (10 %), a ventriculoperitoneal shunt was inserted. More than 90 % of the patients had > 70 % functional impairment based on the Karnofsky Index.

Large VS is often associated hydrocephalus, ataxia, multiple cranial nerve impairments, and clinical signs of increased intracranial pressure. Primary microsurgical resection, as the primary treatment option, is associated with good outcomes in patients with large VS.