[Tracheal deformity observed in tracheostomized Duchenne muscular dystrophy patients who can speak with appropriately inflated cuff of tracheal tube].

Respiratory failure occurring during late adolescence is a major cause of death in Duchenne muscular dystrophy (DMD). A number of respiratory assistance techniques including tracheostomy and positive pressure mechanical ventilation have been utilized not only to prolong DMD patients' life but also to improve quality of their life. It is surprising that most of the tracheostomized DMD patients can speak under positive pressure ventilatory assistance. Preserved functions of glosso-pharyngo-laryngeal muscles in these patients presumably make it possible to control the air leak around tracheal tube, which does not necessitate tight inflation of the tube cuff. Recently we noticed that some patients are still able to speak even when the cuff is fully inflated. In order to understand the mechanism of this phenomenon, we visualized the topographical relationship between trachea and the tube cuff using computed tomography by filling the cuff with aqueous contrast medium. We obtained following findings: 1) Trachea is flat and deviated from normal midline position, and 2) the tube cuff is located eccentrically in trachea resulting in compression of one side of the inner wall and leaving open space on the other side. We conclude that the tracheal malposition and deformity underlie this strange phenomenon and tight inflation of the cuff to prevent air leak may result in unfavorable complications in DMD patients.