Author(s)
C. Blake Sullivan MD
Daniel Q. Sun MD
Raymund W. Kung MD
Megan Asklof
Marlan R. Hansen MD
Bruce J. Gantz MD
Affiliation(s)
Abstract:
Objective: To evaluate the association between signal changes during intra-operative audiologic monitoring and post-operative audiometric outcome in patients undergoing vestibular schwannoma (VS) resection via middle cranial fossa (MCF) approach.Study Design: Retrospective chart reviewSetting: Academic tertiary referral centerPatients: One hundred twenty five consecutive patients (mean age 48.6 years, range 16-67; mean tumor size 9.9mm, range 1.8-18.9 mm) who underwent MCF VS resection.Interventions: Intra-operative audiologic monitoring using auditory brainstem reflex (ABR) and direct cochlear nerve action potential (CNAP).Main outcome measures: Intra-operative ABR wave V and CNAP amplitudes and post-operative pure-tone average (PTA) and word recognition score (WRS).Results: On ABR, decreased wave V amplitude or absent waveform was associated with 65.3% and 81.1% increase, respectively, in post-operative PTA; and 63.8% and 82.3% decrease, respectively, in post-operative WRS. Similarly, decreased amplitude or absent waveform on CNAP was associated with 47.3 and 100% increase, respectively, in post-operative PTA; and 45.3% and 100% decrease, respectively, in post-operative WRS. Receiver-operating curve analysis showed that ABR combined with CNAP achieved the highest diagnostic accuracy in predicting post- operative hearing decline (sensitivity 70.3%, specificity 100%), and performed better compared to each modality alone (ABR: sensitivity 60.3%, specificity 92.4%; CNAP: sensitivity 57.9%, specificity 100%).Conclusions: Intra-operative ABR wave V and CNAP amplitude changes are associated with changes in post- operative hearing, and dual modality monitoring was more diagnostic of post-operative hearing decline compared to each modality alone during MCF VS resection. Overall, intra-operative ABR and CNAP were more specific than sensitive for post-operative hearing decline.Define Professional Practice Gap & Educational Need: There is a lack of contemporary knowledge in regards to intraoperative auditory monitoring during middle cranial fossa tumor removal and how these monitoring methods are related to postoperative hearing loss.Learning Objective: To demonstrate that dual modality auditory monitoring intraoperatively is a better predictor of postoperative hearing loss compared to single modality monitoring.Desired Result: Assess one's institutional techniques for monitoring auditory changes during middle cranial fossa tumor removal and that dual modality monitoring can be used as a more predictive guide to counsel patients about potential postoperative hearing loss.IRB or IACUC Approval: ApprovedLevel of Evidence: 4