Department of Otorhinolaryngology, Weill Medical College of Cornell University, New York Presbyterian Hospital, New York, New York 10021, USA.
Laryngoscope. 2010 Oct;120(10):2094-7. doi: 10.1002/lary.21066.
Endoscopic balloon dilation is increasingly popular as primary therapy for infants with subglottic stenosis. We aim to determine the maximum balloon diameter and pressure where no fracture of the cricoid would occur, minimum balloon size and pressures where a gross fracture of the cricoid occurs, and location of these fractures. We tested these objectives by performing balloon dilation in laryngotracheal complexes of eight euthanized adult male New Zealand white rabbits, with airway characteristics similar to a 3- to 9-month-old infant.
Subglottic airway diameter of each specimen was determined using endotracheal tubes (Cotton-Myer grading system). Preexistent subglottic disease was excluded by rigid endoscopy. Serial dilation with balloon catheters was performed, employing incremental balloon sizes and pressures, to determine balloon size and pressure, which resulted in a cricoid fracture. Locations of gross fractures were validated by two independent observers.
Airway diameter of all specimens was 5.4 mm (size 4.0 endotracheal tube). Four of the seven cricoid cartilages exhibited gross fractures. Dilation with balloon diameters less than 6.0 mm failed to induce a fracture despite maximal inflation to 16.0 atmospheres. The minimum balloon size required to create a fracture was 7.0 mm, at a pressure of 6.0 atmospheres. All fractures occurred at the anterior lamina of cricoid ring.
No fractures occurred when balloon dilation was performed with a balloon 0.6 mm or smaller than the measured subglottic diameter. Fractures of the cricoid occurred when balloon dilation was performed with a balloon 1.6 mm or larger than the subglottic diameter.
经内镜球囊扩张术作为治疗儿童声门下狭窄的首选治疗方法越来越受欢迎。本研究旨在确定不会发生环状软骨骨折的最大球囊直径和压力、会发生环状软骨完全骨折的最小球囊直径和压力，以及这些骨折的位置。我们通过对 8 例新西兰白兔的喉气管复合体进行球囊扩张来测试这些目标，这些白兔的气道特征与 3 至 9 个月大的婴儿相似。
使用气管内导管（Cotton-Myer 分级系统）确定每个标本的声门下气道直径。通过刚性内镜排除预先存在的声门下疾病。采用递增球囊大小和压力进行序贯球囊扩张，以确定导致环状软骨骨折的球囊大小和压力。通过两名独立观察者验证完全骨折的位置。
所有标本的气道直径均为 5.4mm（4.0 号气管内导管）。7 个环状软骨中有 4 个出现完全骨折。尽管最大充气至 16.0 个大气压，但直径小于 6.0mm 的球囊扩张未能引起骨折。导致骨折所需的最小球囊直径为 7.0mm，压力为 6.0 个大气压。所有骨折均发生在环状软骨环的前侧板。
当球囊扩张的球囊比测量的声门下直径小 0.6mm 或更小时，不会发生骨折。当球囊扩张的球囊比声门下直径大 1.6mm 或更大时，环状软骨会发生骨折。
