Abstract: Objective: To investigate injury of the eustachian tube and middle ear by sinusitis in children and observe the recovery of the acoustic dysfunction after treatment for sinusitis. Methods: Examination of the ear, observation of the pharyngeal ostium of the eustachian tube， acoustic impedance tests, and pure tone audiometry were performed on 100 children with chronic sinusitis and 50 normal children. Of them, in 128 ears of 68 children sinusitis was found combined with ear diseases and then treated. Results: In children with sinusitis, the abnormal rate of the eardrum, the pharyngeal ostium of the eustachian tube , the function of the eustachian tube and the acoustic impedance tests was 64%, 62%, 63.5%, and 62.5%,respectively, and the rate of hearing loss was 47.5%. Compared with the normal children, the differences were statistically significant(P＜0.01). The differences of the incidence of middle ear disease and acute sinusitis, subacute sinusitis and chronic sinusitis were statistically significant between the two groups (P＜0.05). The acoustic dysfunction had a significant improvement after the treatment for sinusitis. Conclusion: The changes of the eustachian tube function caused by sinusitis lead to a significantly high incidence of middle ear disease.

Key words: Acoustic impedance tests, Sinusitis, Pure tone audiometry, Eustachian tube, Middle ear, Children