Functional voice quality assessment in curative microsurgery of laryngeal malignancies. Postoperative voice rehabilitation based on the "laryngeal double valve function"

According to Negus and Pressman the sphincter systems of the vocal folds and the ventricular folds form a respiratory "laryngeal double valve function". Correspondingly, we found a physiological phonation system of the glottis and a pathological-compensatory one of the supraglottis. They appear to be regulated through an automatic phonatory control system with the glottal phonatory function evidently acting as sensor level. In order to confirm this hypothesis, objective voice analyses with glottal-relevant parameters of 26 voice-rehabilitated patients after minimally invasive laser surgery of glottal carcinomas are presented and integrated into a "hoarseness diagram" with the coordinates roughness and breathiness. Using statistically deliminated acoustic dusters, our data show a qualitative hierarchy of different postoperative phonation mechanisms. They demonstrate the influence of the vibratory capacity of glottal and supraglottal structures on the quality of the vibratory closure. Both functional parameters evidently determine the resulting voice quality in the sense of our hypothesis.