Chorda Tympani nerve injury during tympanoplasty. Comparison of endoscopic and microscopic methods

Iatrogenic injury of the chorda tympani nerve (CTN) is a well-recognized complication of middle ear surgery The aim of the present study was to compare CTN injury occurring as a result of type 1 tympanoplasty performed using microscopic and endoscopic methods.

A retrospective study was conducted at our institution on patients diagnosed with chronic otitis and then treated with type 1 tympanoplasty surgery between January, 2013 and January, 2014 .The patients were divided into two groups; group 1 consisted of patients who underwent endoscopic tympanoplasty and group 2 consisted of patients who underwent microscopic tympanoplasty. At follow-up 3, 6 ,and 12 months after surgery patients were asked to complete a questionnaire that enquired about symptoms of CTN injury: changes in taste sensation, tongue numbness. and dry mouth.

There were 66 patients (33 males, mean age 30.4 ± 8.14 years (range: 8-56 years)) There were 25 patients in group I (endoscopic tympanoplasty) and 41 patients in group 2 (miscroscopic tympanoplasty). A total of 11 (16.6%) patients reported symptoms related to CTN damage: 1 (4%) patient in group and 10 (24%) patients in group 2. A metallic taste in the mouth was the most-common symptom, noted by 7 patients(63.6%), 1 (4%) in group 1 and 6(14.6%) in group 2. Ageusia/hypogeusia was reported by 4 patients (37.4%) all in group 2 Tongue numbness occurred in 2 patients (4.8%) in group 2. No patients had xerostomia.

Type I tympanoplasty performed with an endoscopic technique is minimally invasive,and is associated with less CTN manipulation and as a consequence less iatrogenic injury to the CTN.