Incidence of Vestibular Schwannoma in Patients with Unilateral Tinnitus: A Systematic Review and Meta-Analysis

OBJECTIVES: Vestibular schwannoma (VS) is a tumor of the vestibulocochlear nerve. Current literature indicates that 1.6% of patients undergoing magnetic resonance imaging of the internal auditory meatus (MRI IAM) for audiovestibular symptoms are diagnosed with a VS. However, there is limited research reporting on patients who present with unilateral tinnitus without asymmetrical hearing loss. This study is a systematic review and meta-analysis evaluating how many of those patients had a VS diagnosed on MRI IAM. DATABASES USED: Online searches of PubMed, Medline, and Embase databases were performed up to October 2022. METHODS: This meta-analysis was undertaken aligning with PRISMA guidelines. Articles reporting on patients having MRI IAM for unilateral tinnitus without asymmetrical hearing loss were included. Outcomes measures were patient demographics, VS cases, incidental findings, size, and management of tumor. A meta-analysis of proportions was performed using a random-effects model with the restricted maximum likelihood method. Quality assessment was performed using the Joanna Briggs Institute critical appraisal checklist. RESULTS: Seven case series were included in the review: a total of 1,394 patients. Seven patients had a VS, with a median size of 4 mm. The pooled detection rate for VS was 0.08% (95% confidence interval = 0.00-0.45). Subsequent management was reported in six cases of which four were actively monitored and two surgically excised. The most common incidental finding was sinus disease (49 patients). CONCLUSION: Our findings indicate that MRI IAM has a low diagnostic yield for VS detection in patients presenting with unilateral tinnitus without asymmetrical hearing loss, with mostly small tumors that are conservatively managed.