Vestibular schwannoma: Clinical, Epidemiological and Biochemical perspectives

Vestibular schwannoma (VS) is a slow growing benign tumour originating in the Schwann cells surrounding the vestibulocochlear nerve. Over recent decades, the incidence rate for VS has steadily increased, with greater numbers of patients with smaller tumours being diagnosed. Today, it is estimated that around 1 in 500 people will suffer from VS in their lifetime. The most common symptom of VS is unilateral hearing loss, tinnitus or dizziness. The growth rate of the tumour is unpredictable and not related to degree of symptoms. The overall aim of this thesis was to provide new knowledge that could be used to improve routines for treatment and clinical guidelines for future patients with sporadic VS. A local clinical quality database was used to identify patients with VS treated at Uppsala University hospital. The information in the database of patients with VS was used to analyze postoperative complications after translabyrinthine surgery, hearing outcomes after hearing preservation middle cranial fossa surgery, both postoperative and after more than 10 years of follow up, and the risk of enduing a fall-related injury. The proteome of the human endolymphatic sac endolymph in six patients with VS was described. 13% of the translabyrinthine operated patients (93 of 700) suffered from one or more complications postoperatively. Increasing age and tumour size were both risk factors for postoperative facial nerve dysfunction. Greater tumour size increased the risk for intracranial hemorrhage. 60 out of 84 patients with VS operated on through middle fossa surgery had preserved hearing after surgery. After 10 years, the hearing had deteriorated symmetrically in the tumour ear and the contralateral ear. There was no increased risk for fall-related injuries among patient with VS compared to VS-free controls. Studying subgroups, an increased risk of fall-related injury was displayed among middle-aged patients before being diagnosed with VS and postoperatively in patients treated with middle fossa surgery. A total of 1,211 proteins were detected in the ES endolymph, of which 110 were unique for the endolymph. To further improve the knowledge regarding patients with VS, a joint national guideline program would be desirable.