Anatomical Basis for Endoscopic Cochlear Implantation Via a Transmeatal Approach

WANG Bochen; LAI Yanbing; YU Youjun; ZOU Zhaohui; CHEN Kangsong; CHAI Bin; WANG Yuejian

doi:10.3969/j.issn.1672-2922.2017.019.

Abstract：Objective To describe a new endoscopic technique for cochlear implantation via a ear canal ap-proach, as well as its advantages and disadvantages. Methods Three human temporal bone specimens (6 ears) were used to simulate cochlear implantation and to measure relevant anatomical parameters under a surgical microscope. Results The round window niche was exposed, and implant electrodes implanted without opening the mastoid cells or damaging the chorda tympani nerve or facial nerve, under an endoscope in all cases. The distance was 5.47±0.11 mm between the lateral margin of round window and the junction of the chorda tympani nerve and the tympanic ring;and 5.62±0.43 mm between the inferior margin of round window and the groove for the inferior wall of the external auditory canal. The length of the inferior wall of the external auditory canal was 12.63±0.99 mm. Distance between the mastoid segment of facial nerve and the groove for the inferior wall of the external auditory canal was 4.65±0.50 mm. The length of the up-per wall of the external auditory canal was 17.02 ± 1.52 mm. Conclusion Endoscopic transmeatal approach for cochlear implantation is minimally invasive, safe, time saving and easy to learn. Its advantages in complicated cases include easi-er exposure of the round window, although its efficacy needs further clinical verification. Further research is needed to define its limitations and risk of complications.