Prognosis of Epiglottic Inversion Dysfunction

Question

Answer

The epiglottis is a leaf-like, fibroelastic structure, positioned between the base of the tongue and the laryngeal aditus. During swallow it appears to invert to cover the aditus as the 'first valve' of airway closure. Its apparent movement is actually passive. Current evidence points to external forces moving the epiglottis (Perlman, 92). There are muscles attached to it, fibers from the aryepiglotticus and thyroepiglotticus, etc., but there is little evidence that the muscles actively contract at the time of inversion. When inverted, the epiglottis forms channels made up of the vallecula and a ramp-like alley to the pyriform sinuses along the lateral aspects of the aryepiglottic folds to the opening of the esophagus (Costa, 98). The epiglottis protects the airway through its participation in the formation of the valleculae and as an insertion point for the aryepiglottic folds, and lateral channels. In this context, the epiglottis is a secondary element in the protection of the airway.

There are three sequential stages in epiglottic movement during swallowing (Perlman, et al, 92; Costa, 98), as an upward epiglottic shift determined by hyoepiglottic ligament, associated with a simultaneous bending caused by the tongue backward projection, then a posterior rotation of the epiglottis, limited by the adjustment of the epiglottic tubercle to the vestibular fold, determined by laryngeal upward shift against hyoid bone, and, lastly, an eversion of the free extremity of the epiglottis beyond the horizontal plane. It participates, during swallowing and regurgitation, through the passive adjustment of the intralaryngeal posterior surface of the epiglottic tubercle to the vestibular folds. In association with these epiglottic movements there is a stretching of the aryepiglottic folds to allow for the transient formation of the lateral channels. The upward and forward movements of the larynx associated with the opening of the pharyngoesophageal transition, occurs synchronously with the oral ejection of the swallowed bolus. The increase in the laryngeal resistance, in which the epiglottis takes part, is only efficient when there is wide and synchronous opening of the pharyngoesophageal transition because there is a build up of pressure in the oral cavity transferred to the pharynx during this time.

From the discussion above, a dysfunction of epiglottic inversion may be due to direct trauma to the fibroelastic body (Kawana, et al., 98), prolonged presence of a tube displacing the epiglottis, or some destructive disease process (i.e., chondromalacia, tumor formation, atriovenous malformation, etc.) that would affect its passive role in the swallow sequence by either acting poorly as a cover or trapping test material. Barring this, one needs to look at lingual, hyoid or laryngeal function. Muscles of the floor of the mouth and of laryngeal suspension may be the culprits? Finally, middle pharyngeal constrictor dysfunction may play a role in unsuccessful epiglottic function (Yip, et al., 09).

It is perhaps better to ask whether epiglottic inversion isn't one of a constellation of signs and symptoms that have a poor prognosis initially, but may improve over time with proper medical attention and intensive rehabilitative intervention. I would use exercises and strategies for laryngeal elevation including the Shakir exercises, Mendelsohn, and even forced pitch. I would look at hyoid bone elevation in relation to floor of mouth muscular activity and provide exercises with the aim of improvement of strength and endurance. Lastly, I would discern whether pharyngeal function isn't a contributing factor (Yip, et al., 09), typically a disorder of asymmetric muscular activity. Of course, after any prolonged intubation, one must think of vocal fold mobility impairment as the glottis is the primary, and 'third valve', of airway protection. Thus the reason for the Mendelsohn and forced pitch.

References

Perlman, A.L., et al. (1992). The relationship of vallecular residue to oral involvement, reduced hyoid elevation, and epiglottic function. J. Speech and Hearing Res., 35. 734-741.

Costa, M.M. (1998). Videofluoroscopic evaluation of the functional significance of the epiglottis in adults. Arq. Gastroenterol. 35(3). 164-74.

Yip, H., et. al (2009). Can a fluoroscopic estimation of pharyngeal constriction predict aspiration? Otolaryn. - HNS, 135(2). 215-217.

Kawana, S., et al. (1998). Case Study: High, large epiglottis disturbs proper positioning of the laryngeal mask and cuffed oropharyngeal airway. Anesth. Analg.,87. 489-90.

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Mr. Charpied is the Director of the Department of Speech Pathology, in the Department of Otolaryngology - Head and Neck Surgery, with the University Rochester's School of Medicine and Dentistry and Strong Memorial Hospital. A clinically certified Speech Pathologist who specializes in voice and swallowing, Mr. Charpied has developed techniques and manuals on the diagnosis, treatment and management of voice and swallowing disorders. He teaches at Nazareth College, as well in the ENT resident program. His research interests include anatomy of the larynx, quantification of laryngeal function through image analysis, and the use of computers as a clinical tool. Besides publications and numerous abstracts, Mr. Charpied's introductory text for Speech Pathology students, Anatomic and Physiologic Elements of Human Communication," has been submitted for publication. He is currently completing a text titled, "Neurologic Basis of Human Communicative Behavior."