The application of a 70° endoscope in performing transcanal middle ear surgery

Endoscopes increase the expediency of transcanal middle ear surgery. However, the application of a 70° endoscope is limited and seldom discussed, mainly because of its large angle. We introduce our experiences with the 70° endoscope in transcanal middle ear surgery.

This is a retrospective chart review of 127 patients with chronic otitis media who underwent middle ear surgery performed by the senior author in 2016 at a tertiary referral center. The types of eardrum perforation were classified as central, inferior, posterior, or anterior according to the main location of the hole. The demographics, surgical pictures, and operative records were reviewed.

In 15 ears of the 127 patients, the ossicles were recognized directly by a microscope. In another 112 ears, the ossicles could not be identified under a microscope. Without elevating the tympanomeatal flap, the ossicles could be recognized in 72 of these 112 ears with endoscopes, especially the 70° endoscope. In 35 of these 112 ears, an incision to extend the drum perforation or creation of a small tympanomeatal flap in the posterior-superior canal was made to observe the ossicles. However, 5 of these 112 ears were still noted to have a narrow and/or curved ear canal and preoperatively needed to undergo endaural incisions. Among the other 122 patients who first underwent attempted transcanal surgery, 15 ears changed to endaural incisions. The drum perforations were repaired directly through the perforation in 107 ears via the transcanal route. One year after surgery, the air-bone gap closure was 16.0 ± 11.8 dB, and the graft take rate was 91.3%.

With the help of a 70° endoscope, we can use the transcanal transperforation route to evaluate and reconstruct drum perforations and ossicular chains in appropriate patients. Hence, normal tissue injuries to the ear canal can be minimized.