A Comparative Study of Eustachian Tube Functions in Normal and Diseased Ears with Tympanometry and Videonasopharyngoscopy

摘要

Eustachian tube is a bony and fibrocartilagenous tube extending from the antero-inferior part of middle ear cleft to lateral wall of the nasopharynx. Its main functions are ventilation of middle ear to equalize the middle ear pressure with atmospheric pressure and mucociliary clearance. The functioning of eustachian tube has a direct impact on normal middle ear function. As a corollary, dysfunction of eustachian tube inevitably leads to retraction of the tympanic membrane initially and sterile effusion and subsequent conductive deafness later. Secretory otitis media today is the most common cause of conductive deafness in children with an intact ear drum. Evaluation of function of eustachian tube assumes paramount importance in this scenario. To evaluate eustachian tube functions in normal and diseased ears with tympanometry and videonasopharyngoscopy and to compare the tympanometric tests of eustachian tube function with videonasopharyngoscopy and to assess their reliability. The study was conducted at Army hospital (R&R) Delhi Cantt from October 2005 to April 2007. Hundred (100) ears were examined and were divided into two groups, the control group with normal tympanic membrane on otoscopy and case group with complaints of diminished hearing and intact but retracted tympanic membrane. Their eustachian tube function was evaluated by tympanometric tests and videonasopharyngoscopy. Thereafter a comparison was made between the two. The study revealed that videonasopharyngoscopy was highly accurate and reliable test for eustachian tube function as compared to tympanometry. Slow motion video analysis of eustachian tube dynamics is a useful tool for further understanding the pathophysiology of tubal dysfunction.