Transcanal Endoscopic Approach to the Mastoid Segment of Facial Nerve and the Role of the Pyramidal Eminence as a Landmark
Objectives: To study the feasibility of approaches in addressing the mastoid segment of facial nerve through transcanal route exclusively under endoscopic guidance and to verify the usefulness of the pyramidal eminence as a landmark.
Study design: The prospective experimental study
Setting: “Transcanal endoscopic temporal bone dissection lab” situated in the Surgiscope hospital, Chittagong, Bangladesh.
Materials: 4 (Four) cadaveric temporal bones.
Interventions: Two pure transcanal endoscopic approaches were applied to excavate the mastoid segment of facial nerve. In anterior-medial approach, the dissection was progressed from medial to the lateral direction through the retrotympanum focusing the anterior-medial side of the mastoid segment of facial nerve. Whereas in anterior-lateral approach, the dissection was progressed from lateral to the medial direction through the posterior canal wall focusing the anterior-lateral side of the mastoid segment of facial nerve. In both approaches, the pyramidal eminence was considered as an anatomical landmark to navigate the dissection for the excavation of the mastoid segment of facial nerve.
Main outcome measures: The efficacy of each approach in respect of the complete excavation of the mastoid segment of facial nerve and the worthiness of the pyramidal eminence as the landmark for navigating the dissection.
Results: In both transcanal endoscopic approaches, the entire mastoid segment of facial nerve could be exposed successfully. But in anterior-medial approach, the chorda tympani nerve was needed to be sacrificed. The search of the mastoid segment of facial nerve with the guidance of the pyramidal eminence was observed as effective and safe.
Conclusion: The entire mastoid segment of facial nerve could be successfully addressed through transcanal route under pure endoscopic guidance. The pyramidal eminence has appeared as an important landmark for such endeavor.
Bangladesh J Otorhinolaryngol; October 2019; 25(2): 108-115
Manuscripts submitted for publication in the Bangladesh Journal of Otorhinolaryngology must not have been previously submitted or published. Accepted papers become the permanent property of the Bangladesh Journal of Otorhinolaryngology. By submitting a manuscript, the authors(s) agree that copyrights for their articles are automatically transferred to Bangladesh Journal of Otorhinolaryngology, if and when the articles are accepted for publication.
The use, in this journal, of registered trade names, trade marks, etc. without special acknowledgement does not imply that such names, as defined by the relevant protection laws, be regarded as unprotected, and, thus, free for general use.
Authors who publish with this journal agree to the following terms:
Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).