Improving Resident Familiarity with the Translabyrinthine Approach to the Internal Auditory Canal

Objectives: To increase otolaryngology resident experience with drilling and dissection of the internal auditory canal (IAC) via a translabyrinthine approach.

Study Design: Pilot study involving temporal bone education and hands-on drilling with completion of pre- and post-drilling surveys.

Methods: Participants completed a pre-drilling survey assessing their familiarity with IAC anatomy and prior drilling experience using a 5-point Likert scale ranging from “strongly agree” to “strongly disagree.” They then watched a short oral and video presentation of IAC anatomy and drilling techniques. Following this, participants manipulated the nerves in the IAC on a prosected temporal bone. Using fixed cadaveric temporal bones with a previously drilled mastoidectomy and labyrinthectomy, participants then identified the IAC using cutting and diamond burrs. After drilling superior and inferior troughs, the IAC dura was divided and the facial, cochlear, and vestibular nerves were identified and dissected. Participants then completed a post-drilling survey assessing their familiarity with IAC anatomy and their satisfaction with the educational experience using the Likert scale described above. The session lasted for approximately 1 hour.

Results: Seven participants were included in this pilot study ranging in experience from PGY1 through PGY 5. The median number of translabyrinthine procedures previously observed during medical school and residency was 1, and the median number of times the IAC had been drilled in the temporal bone laboratory was 0. The percentage of residents who either agreed or strongly agreed that they were very familiar with IAC anatomy increased from 0 to 57% after the education session, and similarly the percentage of residents who either agreed or strongly agreed that they were confident identifying the facial nerve in the IAC increased from 43 to 86%. 100% of participants either agreed or strongly agreed that the drilling experience and nerve dissection improved their familiarity with this approach, and 100% of participants were very satisfied with the overall experience.

Conclusion: Residents participating in this pilot study reported limited experience with the translabyrinthine approach to the skull base and drilling the IAC during their training. A brief educational session and temporal bone laboratory drilling experience increased the reported familiarity with the approach, as well as improved understanding of IAC anatomy. Experiences such as this may enhance resident exposure to advanced lateral skull base approaches in a safe environment, and increase comprehension of the complex anatomic relationships of the IAC.