Variations of chorda tympani nerve in endoscopic stapes surgery

Objective: To reveal the factors affecting the incidence of chorda tympani nerve )CTN) transection during middle ear surgery. Study Design: Prospective case review. Setting: Tertiary referral center. Patients: We analyzed 20 ears with otosclerosis that underwent stapes surgery during 2022-2023 Main Outcome Measure: To confirm CTN transection, intraoperative endoscopic video. We used the same video images to determine the anatomical variation of the CTN course in the middle ear and determine types of chord tympani. Results: 25% 5 cases type1 of chorda 65% 13 cases type2 10% 2 cases type3 CTN anatomical variants such as the “Attached Short type” and “Ultrashort type” showed a significantly higher CTN transection incidence Conclusion: Endoscopic ear surgery provides improved visibility, reduces the necessity for significant manipulation of the chorda tympani, and subsequently lowers the occurrence of CTN injury. Performing a preoperative assessment to determine the extent of stapes involvement and the anatomical position of the CTN course could assist in identifying patients who are at a higher risk of experiencing iatrogenic CTN transection.