[CO2 laser cordectomy: analysis of morpho-functional results].

The authors have conducted a study of a large sampling of subjects who had undergone different types of cordectomy. The purpose of this study has been to analyze the anatomo-functional variables encountered with such procedures. In particular, the following were studied: post-surgical vocal recovery; type of glottic sphincter scarring, particularly as related to the extent of surgical excision; effect commissure synecchia has on the post-operative voice, again related to type of exeresis; different types of functional compensation related to the various surgical excisions and means by which the new scarring cord is built; severity of dysphonia resulting after each type of surgery. The study involved 69 patients who had undergone different types of cordectomy: from limited procedures--the so-called submucosal cordectomies for circumscribed, superficial neoplasms--to more radical ones, performed on tumours extending to the laryngeal ventricle of one or both sides. A history was taken of all the cases and they underwent videolaryngoscopy, psychoacoustic evaluation and voice spectrography. This study revealed the following: vocal recovery is achieved within 1-3 months after surgery, particularly when the exeresis was limited; longer recovery times were required for more radical surgery; with horizontal exeresis the prognosis for sphincteric recovery--characterized by a good neocord--is better than with procedures removing structures on the vertical plane (true vocal cord + ventricle + false cord) where scarring generally proves inadequate to re-establish a satisfactory sphincter; commissure synecchia is unusual in all types of surgery and is more frequent in bilateral forms. This is not specifically responsible for aggravating the dysphonia although, except in a few cases, it can make an important contribution in limiting the glottic opening and facilitating vocal sounds; as regards functional compensation, the observations show that the larynx is able to adapt to anatomic damage, the entire organ playing a part in reducing the air space to create a more or less valid phonatory sphincter, each part in its own way. Among the most noteworthy mechanisms for functional compensation we find the cord-neocord, the glottic mechanism at the false cords and ary-arythenoid compensation. There is no direct relationship between phonatory mode and neocord conformation since not all cases achieving a satisfactory neocord actually use glottic phonation. Although the Yanagihara spectrographic classification of dysphonia cannot distinguish between severe dysphonia and aphonia, it can be applied in the objective classification of limited post-cordectomy vocal compromise. In fact, spectrography is able to document that: Type II dysphonia--light--is unusual and was only found in 2 cases with a excellent neocord and a perfect pneumo-phonic picture; Type II dysphonia--moderate--is most often found in submucosal cordectomies and in other cases of monolateral exeresis with adequate scarring; Type IV dysphonia actually corresponds to the most important forms. It is present in all types of cordectomy and is most prevalent in those with a severe adductor deficit associated with inadequate or poorly balanced supraglottic functional compensation.