Assessment of hearing efficiency following surgical intervention of oral submucous fibrosis by using tympanometry and audiometry- a prospective study.

Oral Submucous Fibrosis (OSMF) is a chronic insidious disease, affecting any part of the oral cavity and sometimes the pharynx. Although occasionally preceded by and/or associated with vesicle formation, it is always associated with a juxta-epithelial inflammatory reaction followed by fibroelastic changes of the lamina propria, with epithelial atrophy leading to stiffness of the oral mucosa and causing trismus and inability to eat. Symptoms of this disease include burning sensation of the oral mucosa, ulceration and pain, reduced movement and depapillation of tongue, blanching and leathery texture of oral mucosa, loss of pigmentation of oral mucosa, and progressive reduction of mouth opening. Advanced cases show signs of loss of hearing due to blockage of Eustachian tube (ET) and difficulty in swallowing because of esophageal fibrosis.1

Amongst structures communicating with the oral cavity the ET connects the middle ear cavity with the nasopharynx. Normal opening of the ET equalizes atmospheric pressure in the middle ear; closing of the ET protects the middle ear from unwanted pressure fluctuations and loud sounds. Abnormal or impaired ET functions (i.e., impaired opening or closing) may cause pathological changes in the middle ear. This in turn can lead to hearing disabilities. In OSMF, there can be failure of ET to effectively regulate air pressure. As ET function worsens, air pressure of middle ear falls and ear sounds are perceived as muffled and may cause impaired hearing. However there is a paucity of information related to the involvement by fibrosis of areas adjoining the oral cavity e.g. Ear, Oro-pharynx, and Pharynx.2

Several stu­dies have clinically evaluated the eustachian tube function by audiometry and tympanometry and have found its significant impairment in OSMF patients as compared to healthy controls. These studies substantiate both clinically and histologically that eustachian tube function and hearing ability is impaired in OSMF.3

Most of the  studies conducted so far include patients suffering from OSMF – Khanna and Andrade Grade IV only.  Also, limited number of studies appear to have compared the changes of ET functioning following surgical intervention of OSMF with that of pre surgical ET functioning. In this study we are trying to find out, the prevalence of ET dysfunction in different grades of OSMF patients. So, in our study we are trying to detect whether the surgical release of fibrous bands is of any help to improve hearing ability in such patients.4