Nasopharyngeal exposure to simulated gastric juice causes eustachian tube dysfunction in rats. Specifically, middle ear pressure regulation and mucociliary clearance of middle ear contents were disabled. These results support recent reports in the literature linking nasopharyngeal reflux to eustachian tube dysfunction and secondary development of otitis media.

Gastroesophageal reflux is a common problem in the newborn and preschool periods. Recent research suggests that it may be related to eustachian tube dysfunction and otitis media with effusion. The purpose of this experiment was to investigate the relationship between simulated gastroesophageal reflux and eustachian tube dysfunction. Rat middle ears were repeatedly exposed (transtympanically) to pepsin in hydrochloric acid or to phosphate-buffered saline solution. Their eustachian tube function was evaluated by assessing passive opening and passive closing pressures, and active clearance of positive and negative pressure. The passive pressure function tests showed variable results. The rats exposed to pepsin in hydrochloric acid had an impaired ability to clear positive and negative pressure from the middle ear as compared to the rats exposed only to phosphate-buffered saline solution. The results demonstrate that multiple middle ear exposures to pepsin in hydrochloric acid leads to eustachian tube dysfunction in rats.

These findings demonstrate that late-phase allergy leads to significant eustachian tube dysfunction and subsequent formation of effusion by impairing the ventilatory and clearance functions of the eustachian tube.

Gastroesophageal reflux may induce ET dysfunction.

Injury to the recurrent laryngeal nerve causes vocal fold paresis or paralysis resulting in poor voice quality, and possibly swallowing dysfunction and/or airway compromise. Injury can occur as part of a neurodegenerative disease process or can be due to direct nerve trauma or tumor invasion. Management depends upon symptoms, the cause and severity of injury, and the prognosis for recovery of nerve function. Surgical treatment techniques can improve symptoms, but do not restore physiologic motion. Gene therapy may be a useful adjunct to enhance nerve regeneration in the setting of neurodegenerative disease or trauma. Remote injection of viral vectors into the recurrent laryngeal nerve is the least invasive way to deliver neurotrophic factors to the nerve's cell bodies within the nucleus ambiguus, and in turn to promote nerve regeneration and enhance both nuclear and nerve survival. The purpose of this review is to discuss the potential role for gene therapy in treatment of the unsolved problem of vocal fold paralysis.