Impact of Balloon Diameter on Dilation Outcomes in a Model of Rabbit Subglottic Stenosis

To determine the appropriate balloon size for dilation using a previously described reproducible survival animal model of subglottic stenosis.

Prospective animal study.

We conducted a prospective study including 16 New Zealand White rabbits. The airway of each animal was sized with an endotracheal tube (ETT), and subglottic stenosis (SGS) was endoscopically induced using Bugbee electrocautery to 75% of the circumference of the subglottis, followed by 4-hour intubation. Two weeks postoperatively, the rabbits' airways were sized and then dilated using a 6-, 7-, 8-, or 9-mm balloon, with four animals in each experimental group. Following dilation, animals were again sized and subsequently euthanized. The cricoid lumen was measured microscopically in each animal.

Prior to inducing stenosis, all animals were sized with a 3.5 ETT. After inducing injury but prior to dilation, airways showed grade 2 SGS that sized with a 2.5 ETT with no leak. Postdilation, animals dilated with 6- or 7-mm balloons (n = 8) sized with a 3.0 ETT, and animals dilated with an 8- or 9-mm balloon (n = 8) sized with a 3.5 ETT. Postdilation median cricoid lumen measurements were 12.5 mm² (6-mm balloon), 13.92 mm² (7 mm), 16.83 mm² (8 mm), and 17.15 mm² (9 mm); two cricoid fractures occurred in the 9-mm group.

The postdilation cricoid lumen diameter increased with increased balloon size, and the use of an 8-mm balloon achieved the largest cricoid lumen diameter without causing fracture. Further research is necessary to determine the ideal duration of dilation and optimal intervals between dilations.

NA Laryngoscope, 129:2409-2413, 2019.