Objectives/hypothesis: Early topical application of mitomycin to a laryngotracheal lesion may prevent or reduce laryngotracheal stenosis (LTS).
Study design: Prospective controlled animal study.
Methods: LTS was induced in 60 dogs randomly assigned to four groups. Controls received an immediate topical application of normal saline. The suction-control group received an immediate application of normal saline followed by suction of secretions on day 2. The mitomycin group received immediate application of 0.7 mL mitomycin (0.2 mg/mL). The repeat-mitomycin group received an immediate application of mitomycin and a second application on day 2, after secretions were suctioned. The laryngeal lumens were measured endoscopically at baseline, day 12, and day 21. Animals were euthanatized if stenosis approximated 95% or at day 21.
Results: All dogs in the mitomycin groups survived to day 21, compared with 12 in the suction group and only 2 controls. No side effects of mitomycin were observed. At day 21, surviving controls had 85% and 95% stenosis. In the mitomycin group, median stenosis was 27% (interquartile range, 29% to 42%); in the repeat-mitomycin group, 30% (22% to 40%); and in the suction-control group, 84.5% (72.5% to 93.5%). The mitomycin group differed significantly from controls on day 12 (median difference = 85%, 95% CI = 80%-94%, P < .0001) and day 21 (difference = 63.9%, 95% CI = 58%-85%, P = .031).
Conclusion: A single topical application of mitomycin significantly reduces the severity of LTS in dogs. Reapplication after 2 days does not improve results. Prospective clinical studies are warranted to assess the efficacy in humans.