Taste disorders and recovery of the taste function after middle ear surgery

Background: The incidence and the scale of recovery of the taste function after middle ear surgery is usually determined by the use of anamnestic data and electrogustometry.

Methods: Taste tests (regional chemical taste test, electrogustometry and subjective evaluation) were performed preoperatively, 2 to 3 weeks and 6 to 9 months after middle ear surgery. These results were evaluated by taking the scale of chorda tympani nerve (CTN) manipulation into consideration. Three groups were chosen: group 1: no or small CTN manipulation, n = 54; group 2: strong CTN manipulation, n = 14; group 3: severed CTN, n = 50. Methods: In a prospective study 118 patients were examined after middle ear surgery in the ENT-Department of the University of Rostock between 2001 and 2002. 61 females and 57 males, age from 7 - 81 years, were included.

Results: Complaints were observed in all three groups, mainly in groups 2 and 3. These included taste disorders, taste phenomenon and numbness of the tongue. Using regional chemical taste tests, the taste loss of group 3 could be proven for those patients with complaints in 64 % and for those patients without complaints in 27 %. The electrogustometry is more sensitive than chemical taste test. All patients had pathological thresholds after chorda cutting (78 % no thresholds; 22 % elevated thresholds). 68 out of 118 patients (58 %) had a second follow-up after 6 to 9 months after middle ear surgery. The complaints are declining in all groups. In groups 2 and 3 a recovery of taste function could be observed. Even if the number of patients with severed chorda, who suffer from taste disorders, diminishes, a recovery of the taste function could only be observed in 30 %.

Conclusions: The scale of chorda manipulation is important for the recovery of the taste function after middle ear surgery. The CTN should be preserved intraoperatively, especially when an operation of the contralateral ear is planned as well.