Functional evaluation of paratubal muscles using electromyography in patients with chronic unilateral tubal dysfunction

Eustachian tube dysfunction is closely related to the development of otitis media and result from several factors including inflammation within the nasal cavity and nasopharynx, adenoid hypertrophy, cleft palate and nasopharyngeal carcinoma. To some extent, eustachian tube dysfunction may be related to weakness of the paratubal muscles, such as the tensor veli palatini and levator veli palatini muscles. The aim of the study is to find out myogenic factors in eustachian tube dysfunction using electromyography (EMG), and to evaluate the clinical feasibility of EMG. Ten patients with unilateral eustachian tube dysfunction were included in this study. The healthy side of each patient was used as a control. EMG tests on paratubal muscles were conducted under the view of a 30° endoscope or fiberoptic laryngoscope. EMG on the tensor veli palatini showed decreased amplitudes on the affected side in one patient during phonation. EMG on the levator veli palatini showed decreased amplitudes on the affected side in two patients during both deglutition and phonation, one patient during phonation only, and two patients during deglutition only. The only patient who had decreased amplitude on EMG of the tensor veli palatini also had decreased amplitude on EMG of the levator veli palatini. In conclusion, although it is generally accepted that the tensor veli palatini plays a major role in opening the eustachian tube, reduced activity of the levator veli palatini may be related to eustachian tube dysfunction. When assessing eustachian tube function, EMG is useful for evaluating myogenic factors.