Radiotherapy contends with endoscopic surgery for the role of treatment of choice for Tis-T1 glottic cancer. The amount of vocal cord to be surgically removed logically depends on the surface and deep extension of the neoplasm. Thus, a prerequisite for proper management includes an analysis of the voice changes after each of the progressive types of cordectomy described in the European Laryngological Society Classification. Between January 1998 and December 2000, 89 patients with glottic cancer (8 Tis, 63 T1a, 18 T1b) underwent different types of endoscopic cordectomy. Perceptual analysis (GRBAS scale); objective analyses of jitter, shimmer, and noise-to-harmonics ratio; and subjective (Voice Handicap Index) evaluation of voice were performed in 51 patients. Statistical evaluation of preoperative and postoperative objective results by analysis of covariance, as well as perceptual and subjective data, showed significant voice improvement after type I and II cordectomies, with the voice attaining nearly normal parameters. By contrast, after type III, IV, and V cordectomies, the vocal outcome was not significantly different from the preoperative pattern. It can therefore be concluded that type I and II resections, whenever indicated, are adequate procedures even for professional voice users. By contrast, accurate counseling is mandatory before type III, IV, and V cordectomies.
Application of Water Quality Evaluation in the Cotai City Ecological Reserve in Macau: Taking the Single Factor Index Evaluation Method as an Example