[The glosso-crico-arytenoid unit as a phonatory organ in sub-total reconstructive laryngectomy using the Labayle technic].

The present study was carried out in order to assess characteristics of vicarious voice in patients undergoing Labayle's reconstructive sub-total laryngectomy. This type of surgery, which permits air passage for both respiration and phonation, makes it possible to preserve pneumophonic coordination. During phonation the expiratory air column is used and sound is generated as it passes through a vibrating structure having a sphincteric function. In the opinion of the authors this structure is not only made up of the cricoid orifice, against which the base of the tongue presses like an operculum, but also of the mobile residual arytenoid and, at times, of the lateral walls of the pharynx. Thus a single dynamic unit is formed involving several structures and their synergism guarantees the neoglottic occlusion required for a speaking voice. In the present study, glottography gave no significant results. In phonation a rapid vibration of the neoglottid mucosa is obtained thus producing a phonetically valid acoustic phenomenon. However, this does not result in an electroglottographic recording of adduction. On the other hand, interesting data were recorded when comparing the morpho-functional aspects of the neoglottis with characteristics of the vibrating voice, as recorded by spectrography. Spectrographic tracings are markedly better in cases of valid occlusion of the glosso-pharyngeal-arytenoid unit and this may be achieved regardless of the mobility of the remaining arytenoid. It is thus clear that several patients with a fixed arytenoid, but having valid sphincteric action of the other structures (i.e. base of the tongue or pharynx), had excellent speech quality and intelligibility. Therefore, Labayle's surgery, which reconstructs a pharyngo-tracheal continuity and consequently restores natural breathing, makes speech continuity possible. Such subjects have mixed vocal output (periodic components together with noise) although, on the whole, the voice produced has the fundamental requirements for intelligibility (i.e. intensity, pitch, harmonic structure, emission time) and may thus be considered valid for interpersonal verbal communication.