Objective To observe the effect of immediate topical application of chitosan on preventing anterior giottic stenosis (AGS) after microsurgical resection of both vocal fold with CO<,2> laser , including the anterior commissure, in a canine model. Methods Sixteen canine larynges were injured by microresecting procedure of both vocal folds with CO<,2> laser. The dogs were randomly divided into two groups, chitosan group and control group. The chitosan and isotonic sodium chloride solution(control) were used for 5 minutes immediately after surgery. One week after the initial surgery, three dogs in each group were randomly selected , ultrastructure of fibroblast were examined with transmission electronic microscope and expression of basic fibroblast growth factor(bFGF) and traansforming growth factor betal (TGF-β1) were evaluated by enzyme-linked immunosorbent assay(ELISA). Three weeks after surgery, the rest dogs' glottic web were lysed and repeatedly treated with chitosan and isotonic sodium chloride solution respectively. The glottic wound healing and AGS formation were examined every week, and all larynges were harvested and examined histologically six weeks after the initial surgery. Results Transmission electronic microscope examination of the ultrasmcture of fibroblast indicated that chitosan inhibited the proliferation of fibroblast. Chitosan increased the expression of bFGF and TGF-β1, and bFGF and TGF-β1 in chitosan group, which was significantly higher than that in control group (z = -2.887 and -2.005, P =0.002 and 0.041). Chitosan decreased the extent of AGS formation. Three weeks after the surgery, the AGS lesion in the control group affected mean 49% of the length of the vocal folds from the anterior commissure to the vocal process, while chitosan group affected mean 7%, which was significantly less than the extent of web formation in the control group, (z = - 2. 619, P = 0. 008). The grade of collagen content in chitosan group was significantly lower than that in control group (P = 0. 003). Conclusion Chitosan is effective in preventing AGS after CO<,2> laser cordectomy.

Objective To explore the substantial resection limits of CO2 laser surgery for hypopharynx and the course of wound healing in animals,for the purpose of evaluating the clinic usefulness of transoral CO2 laser surgery in the treatment of selected hypopharyngeal carcinomas.Methods Twenty-three dogs were randomly assigned to two groups.Group one(11 dogs)received left piriform sinus resection,group two(12 dogs)received the resection of posterior wall of the hypopharynx.Six dogs in group one were killed immediately or 4,8,12,16,20 d post-operatively.Seven dogs in group two were killed immediately or 7,14,21,28,35,42 d post-operatively.The whole larynx and hypopharynx were taken out and the specimens were examined by naked eyes and under microscope.The other 5 dogs in each group were fed until the wound healed,the duration were observed.Results All the operations were successful and the results were satisfactory.In group one,the dogs could take food the day after operation;two dogs had slight cough during eating and recovered after five days.In group two,the dogs could take food the next day after operation,eight dogs had slight cough during eating and recovered after ten days.The excision dimensionwas satisfactory.In group one(resection of the lateral wall of piriform sinus),the size of raw surface was (7.5±0.8)cm2((-x)±s) and the healing time was(18.4±1.5)d.In group two(resection of the posterior wall of the hypopharynx),the wound surface was(7.0±0.5)cm2 and the healing time was(39.8±1.9)d.The healing time in group two was significantly longer than that in group one(t=19.535,P<0.01).Thepost-operative healing process were observed,including cellulose membrane coverage,granulation filling andepithelization.Conclusions Transoral CO2 laser was suitable for partial hypopharynx resection.Animalscan recuperate well with little complications.Although the course of wound healing was delayed,wound surface can recover with good laryngeal and deglutition functions.

OBJECTIVES: To explore the character of laryngoscopy finding, voice, and therapy of vocal fold fibrous mass. METHODS: Clinical data, morphology, voice character, surgery and pathology of 15 cases with vocal fold fibrous mass were analyzed. RESULTS: The morbidity of vocal fold fibrous mass might be related to overuse of voice and laryngopharyngeal reflex. Laryngoscopy revealed shuttle line appearance, smoothness and decreased mucosal wave of vocal fold. These patients were invalid for voice training and might be improved by surgery, but recovery is slow. CONCLUSIONS The morbidity of vocal fold fibrous mass might be related to overuse of voice and laryngopharyngeal reflex. Conservative treatment is ineffective for this disease, and surgery might improve.
Humans ; Laryngeal Diseases ; therapy ; Laryngoscopy ; Vocal Cords ; pathology ; Voice Quality ; Voice Training