Long-term follow-up of chorda tympani function after middle ear surgery

Objectives: The aim of this prospective single center study was to document the incidence of postoperative taste problems after middle ear surgery with long-term follow-up to assess the evolution. Secondary goals were to evaluate the influence of the pathology and the degree of chorda tympani (CT) manipulation on its function. Methods: We used a questionnaire to prospectively assess subjective changes in taste in 40 patients undergoing middle ear surgery. We calculated chemical taste scores for the operated and contralateral side using a chemical taste test protocol. Intraoperative manipulation of the CT was also documented. Results: A significant correlation between chemical taste scores on the operated side and the indicated taste was found preoperatively and short-term postoperatively. No correlation was found 3 years after the surgery. A significant correlation between the chemical taste score at the operated side and the degree of CT damage was also found. The chemical taste score on the operated side significantly decreased if the CT was stretched without visible damage in comparison to slightly touched. Conclusion: Our results showed that a reduction in subjective taste was a relatively frequent yet transient complication after middle ear surgery. Compensatory mechanisms other than (partial) CT recovery co-existed and could explain the loss of correlation between chemical taste tests and subjective taste evaluation long-term postoperatively. Significant changes in chemical taste scores after CT manipulation suggest that surgeons' intraoperative evaluations of CT manipulation and stretching may be a good predictor of postoperative taste reduction.