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

Abstract

Objective To determine the appropriate balloon size for dilation using a previously described reproducible survival animal model of subglottic stenosis. Study Design Prospective animal study. Methods 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. Results 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. Conclusion 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. Level of Evidence NA Laryngoscope, 129:2409–2413, 2019

Quantitative Evaluation of Subglottic Stenosis Using Ultrashort Echo Time MRI in a Rabbit Model

“…Schweiger et al reported that balloon dilation procedure treated SGS in all rabbits, which underwent the treatment with an 8 mm diameter balloon, whereas it increased the airway diameter when a 6 mm diameter balloon was used, but it did not treat the SGS completely. 30 Lisy et al demonstrated that balloon dilation procedure avoided the need for tracheostomy in 80% of cases following balloon dilation. 36 However, in some cases balloon dilation had to be performed multiple times to treat SGS.…”

“…Subglottic stenosis was induced by cauterization of 75% of the posterior subglottic region followed by 4‐hour intubation carried out using a 3.5 mm ETT as shown in Figure 1B,C 30 . Intubation of the rabbits after cauterization was performed to exacerbate the development of stenoses.…”

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

“…Taken together, these data suggest that a longer duration of balloon dilation combined with topical ciprofloxacin-dexamethasone produces an improved clinical result as compared with a short duration of balloon dilation by decreasing restenosis severity without increasing perioperative complications. While there are no published guidelines for the ideal duration of subglottic balloon dilation, several studies cite a 30-second dilation 12,18 or to maintain balloon inflation until desaturation. 2,3 In this study, long-duration balloon dilation was defined as 30 seconds.…”

“…While there are no published guidelines for the ideal duration of subglottic balloon dilation, several studies cite a 30‐second dilation 12 , 18 or to maintain balloon inflation until desaturation 2 , 3 . In this study, long‐duration balloon dilation was defined as 30 seconds.…”

“…1 Although endoscopic balloon dilation has been consistently described as a valuable modality for treating pediatric subglottic stenosis, [1][2][3][4][5][6][7][8][9][10][11] there is no evidence-based consensus regarding its technical parameters. A recent study employed a live rabbit model to determine the appropriate balloon size required to address subglottic stenosis effectively and safely 12 ; however, the appropriate duration of balloon inflation remains unclear, as indicated by its variability among studies. [3][4][5][6][7]10,13 There is a theoretical risk that prolonged occlusion of the airway can lead to cardiopulmonary effects due to negative intrathoracic pressure or direct vagal stimulation, although a paucity of data on this subject exists in the medical literature.…”