Two cases in which taste function was restored by re-adaptation of the chorda tympani nerve during ear surgery

Abstract

Because the chorda tympani nerve (CTN) runs through the tympanic cavity, ear surgeons often encounter the CTN during middle ear surgery, which can cause postoperative taste disturbance. We reported two cases in which the CTN was unintentionally sectioned during surgery, and the stumps of the injured nerve were re-adapted to each other, resulting in recovery of taste function. In case 1, tympanoplasty was performed in the left ear with tympanosclerosis and the right ear with cholesteatoma, and the CTN was sectioned once during surgery on both sides. The stumps were then re-adapted, and both symptoms and findings of electrogustometry (EGM) improved after the surgeries. In case 2, after stapes surgery for right otosclerosis, a piston repeatedly fell off two times in 9 years, and stapedotomy was performed three times. The right CTN was sectioned during the initial surgery, and re-adaptation was performed. In the second and third revision surgeries, regeneration of the right CTN was microscopically confirmed, and both findings of EGM and symptoms improved. Even if the CTN is unintentionally sectioned during surgery, re-adaptation of the nerve ends may allow regeneration of the chorda tympani nerve and restoration of taste function.