Cochlear FLAIR Signal Changes in Hearing Preservation Vestibular Schwannoma Surgery

Objective: Cochlear fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI) signal intensity has been shown to be elevated in patients with vestibular schwannomas (VS). This study evaluated the preoperative and postoperative cochlear signal on FLAIR sequences in patients undergoing hearing preservation surgery. Study Design: Retrospective chart review. Setting: Tertiary referral center. Patients: All patients undergoing middle cranial fossa or retrosigmoid craniotomy for VS at a single institution from September 2013 to January 2017 were screened. Hearing was graded according to the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) hearing classification. Inclusion criteria included preoperative AAO-HNS class A or B hearing and available preoperative and postoperative FLAIR sequences. Main Outcome Measure: Signal intensity of cochlear FLAIR signal was measured in the affected cochlea and normalized to the contralateral cochlea. Hearing preservation was defined as AAO-HNS class A or B postoperatively. Results: Eighteen patients met all inclusion criteria, and 12/18 experienced hearing preservation. There was no difference in preoperative FLAIR ratio between hearing preserved and nonpreserved groups (2.02 vs 2.32, p = 0.52). Postoperatively, FLAIR ratio was lower in the hearing preserved group compared to the nonpreserved group (1.19 vs 1.87, p = 0.033). Conclusions: The current study is the first to examine postoperative cochlear FLAIR changes in VS patients undergoing hearing preservation surgery. In our study population, abnormal hyperintense FLAIR signal normalized in patients experiencing successful hearing preservation, while those who lost hearing maintained abnormal signal. Future studies may investigate the role of FLAIR in guiding optimal timing of operative intervention in VS patients.