Prevention of anterior glottic stenosis after CO2 laser cordectomy with chitosan

Objective To observe the effect of immediate topical application of chitosan on preventing anterior glottic stenosis （AGS） after microsurgical resection of both vocal fold with CO2 laser , including the anterior commissure, in a canine model. Methods Sixteen canine larynges were injured by microresecting procedure of both vocal folds with CO2 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 , uhrastructure of fibroblast were examined with transmission electronic microscope and expression of basic fibroblast growth factor（bFGF） and transforming 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 uhrasructure 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 CO2 laser cordectomy. Key words: Vocal cords; Adhesions; Chitosan; Postoperative complications