Randomized Controlled Trial of Balloon Dilation in Treatment of Subglottic Stenosis With a Rabbit Model

Objectives: Identify the effects of balloon dilation duration and topical ciprofloxacin-dexamethasone application in treatment of subglottic stenosis. Study Design: Randomized controlled trial. Setting: Animal research facility. Subjects and Methods: Forty-four rabbits underwent subglottic injury in an Institutional Animal Care and Use Committee–approved study. One week after injury, the subglottis of each rabbit was measured and treated with endoscopic balloon dilation for 2 rounds of short duration (SBD; 3 seconds), long duration (LBD; 30 seconds), or LBD with topical ciprofloxacin-dexamethasone application (LBD+C). The subglottis of each rabbit was remeasured at the study endpoint: 1 month postdilation or following development of life-threatening respiratory distress. Results: Of 44 rabbits, 35 (80%) survived to endoscopic balloon dilation, with 21 rabbits developing a grade III Cotton-Myer stenosis. Prior to dilation, there was no difference in stenosis rates among groups (all subjects, P =.99; grade III stenosis only, P =.52). Among grade III subjects, improvement in stenosis after dilation was –1% (SD, 21%) for SBD, 27% (SD, 38%) for LBD, and 58% (SD, 29%) for LBD+C (P =.01). Early euthanasia/death rates among grade III subjects were 85% for SBD, 63% for LBD, and 17% for LBD+C (P =.03). Time to early euthanasia/death was 5.0 days for the SBD group and 8.4 days for the LBD group (P =.04). Conclusion: SBD was inferior to LBD or LBD+C in multiple metrics. LBD+C offered significant improvements in stenosis size and mortality over the SBD group and had the lowest rate of early mortality. Further research is needed to identify optimal balloon dilation treatment duration.