Endoscopic Cochlear Implantation: A Prospective Study

Abstract

Objective: To assess the hypothesis that an endoscopic technique would allow a resident to: 1) be able to create a cochleostomy in a proper location and 2) understand how to more accurately place an electrode into the scala tympani. Method: Twenty cadaveric specimens had a posterior tympanotomy approach performed using standard microscopic techniques. After this approach, a prospective single-blinded, randomized study was performed with the resident completing 10 cochleostomies using only a microscope and 10 using only an endoscope. After the procedures were completed, both the resident and faculty expert reviewed the bones and assessed placement of cochleostomy, size of cochleostomy, and time to perform the cochleostomy. Results: The average time to the cochleostomy using the endoscopic technique was 5 min: 15 sec; with the microscope, this was 2 min: 41 sec. The average size of the cochleostomy with the endoscopic technique was 1.0 mm and with the microscope, it was larger than 1.0 mm. In terms of placement of the cochleostomy, only 5/10 (50%) were placed properly with the microscope but 8/10 (80%) were placed properly with the endoscope. This difference was statistically significant. Conclusion: This study points to some potentially significant advantages in using the endoscope vs the microscope for placement of the cochleostomy. While using the endoscope took longer to create the cochleostomy, the endoscope allowed a smaller cochleostomy with a more accurate placement, in this prospective, cadaveric study. Further study is warranted in the operating room with this technique, as endoscopic techniques may further enhance current microscopic placement.