Mitomycin Does Not Prevent Laryngotracheal Repeat Stenosis after Endoscopic Dilation Surgery: An Animal Study

Objectives/Hypothesis: Conflicting data exist in the literature regarding the role of mitomycin in the prevention and treatment of laryngotracheal stenosis. The purpose of the study was to assess the value of mitomycin in preventing repeat stenosis after endoscopic dilation surgery of well-established stenoses. Study Design: Prospective controlled animal study. Methods: Laryngotracheal stenosis was induced in 16 dogs. After a period of 3 months the dogs underwent endoscopic dilation and were randomly divided into two groups. The control group received immediate topical application of normal saline. Dogs in the mitomycin group received immediate topical application of 0.5 mg mitomycin. The animals were then observed for 3 more months before euthanasia. The laryngeal lumens were measured endoscopically at baseline, before dilation, and before euthanasia. A comparison was made between the two study groups by means of the Wilcoxon rank-sum test for change in the percentage of stenosis attained by the endoscopic dilation. Results: Nine dogs were included in the control group, and seven in the mitomycin group. Group comparison for initial occlusion before endoscopic dilation using Wilcoxon rank-sum test showed no difference between the two groups (z = 0.16 [P = .87]). Three months after endoscopic dilation, no difference was observed between the two groups regarding the change in the percentage of occlusion (z = -0.21 [P = .83]). Conclusion: Mitomycin exerts a benefit equal to that of normal saline when applied to a well-established laryngotracheal stenosis in dogs and does not prevent repeat stenosis after endoscopic dilation surgery.