Background: We have assumed that the Chorda tympani (HT) manipulation during stapes surgery for otosclerosis has negative impact on taste sensation, two point discrimination and fungiform papillae capillary network morphology.
Methods: After stapes surgery for otosclerosis, the surgeon graded the degree of manipulation of HT nerve as: (1) unmanipulated, (2) minimally manipulated, (3) moderately manipulated, (4) severely manipulated, or (5) severed. Patients undergoing stapes surgery were tested 1 day preoperatively, 1 and 6 months postoperatively. The taste was tested with taste strips for sweet, salty, sour and bitter. General sensation was tested with a static two-point discrimination. Narrow band imaging contact endoscopy (NBI) was used to determine the number of fungiform papillae (Npapillae) and the total score of blood vessel morphology (NBItotal). Tests were performed on ipsilateral (test) side of the tongue and on contralateral (control) side of the tongue.
Results: In our study, 52 patients with otosclerosis were included. Prior to planned correlation tests the assumptions have been tested, revealing there is no relationship between the data regarding the manipulation of the HT nerve, so statistical correlation tests were not performed. During the follow-up, statistically significant decrease of sweet (p = 0.003), salty (p = 0.035), sour (p = 0.036), and bitter taste (p = 0.013) within the test side during the follow-up was identified. A statistically significant impact on presence of dysgeusia for sweet was found 1 month postoperatively (p < 0.005). Postoperative decrease in two-point discrimination score was not statistically significant (p = 0.056). There was a statistically significant decrease of NBItotal (p = 0.005) and Npapillae (p = 0.009). On the control side of the tongue, no statistically significant changes were detected.
Conclusions: HT manipulation affects taste sensation as well as fungiform papillae capillary network density and its morphology. General sensation of the tongue is not influenced by HT manipulation.
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