(0952) Ossicular Chain Reconstruction Outcomes in Transmastoid Repair of Encephalocele

Introduction: Transmastoid repair has become a more commonly performed approach for repair of skull base defects. A downside of this approach is the possibility of difficult access the anterior tegmen tympani. In certain cases, the ossicles are involved with the encephalocele or may limit access to the defect and are removed. The purpose of this study is to evaluate the hearing outcomes of ossicular chain reconstruction in these patients in which ossicles were removed.

Methods: A retrospective chart review of patients undergoing transmastoid repair of spontaneous CSF leak or encephalocele from 2020-2023 was performed. Patient demographics, comorbid conditions, surgical factors, and audiologic data was obtained. Patients were separated into groups that had ossicular chain reconstruction and those that did not. Pre and postoperative audiologic data was compared both within the groups and between the two.

Results: In total, 32 patients were identified who underwent transmastoid repair of encephalocele or CSF leak. Of these patients, 6 underwent OCR for access to tegmen dehiscence. There was no difference in pre- or postoperative audiologic status between the OCR and native hearing group. Additionally, there was minimal change from the pre- to postoperative status for either group. Those with CSF leak had significantly worsened ABG preoperatively compared to those without, this resolved postoperatively.

Conclusions: There was no difference in audiologic outcomes for those undergoing OCR. Patients undergoing OCR not in the setting of chronic otitis media have good outcomes, similar to native ossicular chain. Further data collection is currently being performed.