Transcanal Transpromontorial Approach to the Internal Auditory Canal: Training on the Ovine Model

By June 7, 2019

Bonali, Marco1; Fermi, Matteo 1; Presutti, Livio 1
1 University Hospital of Modena, Department of Otorhinolaryngology, Head & Neck Surgery, Modena, Italy

The aim of the study is to describe the ovine model as training model for transcanal transpromontorial approach (TTA) to the internal auditory canal. This approach has recently been described to treat small symptomatic acoustic neuroma of the internal auditory canal and/or the cerebello-pontine angle (koos II and III), in selected patients.

Study design: Experimental ex vivo dissection study
Setting: Tertiary care hospital, preclinical experimental setting
Patients: 6-month old or older ovine previously studied with a CT scan imaging
Intervention: Transcanal transpromontorial approach to the internal auditory canal

Main Outcome Measure(s): Feasibility and reproducibility of the surgical approach to the IAC; Description of anatomic differences between the ovine model and the human; Description of surgical steps
Results: The ovine model is an appropriate training model for TTA. Different surgical steps can be trained on this model to get to the internal auditory canal such as: canalplasty, tympanomeatal flap, ossicular chain desarticulation, opening of the cochlea and the vestibule, identification of the dura and the cranial nerves into the canal. The epitympanic, retrotympanic and mesotympanic regions of the middle ear cleft showed anatomicals details close to the human. Both endoscopic and microscopic approach could be performed in all the specimens. The reproducibility of the surgical approach was high.
Conclusion: The present study described the inner ear and internal auditory canal anatomy in the ovine model. The ovine model was a viable option to perform surgical training on the TTA.