[A case of congenital laryngeal web with subglottic stenosis]

Evaluation of an asymmetric anterior glottic web in an excised canine larynx model

The main objective of the study is to model asymmetry within anterior glottic webs in excised larynges using sutures and apply aerodynamic and acoustic analyses. Anterior glottic webs (AGW) were modeled in eight excised larynges using sutures secured at the level of the glottis to mimic the scar tissue of the web. Each of the eight larynges were tested under three different pressure increments for each of the three models of AGW: symmetric, vertically asymmetric, and laterally asymmetric. Phonation threshold pressure (PTP) and flow (PTF) differed significantly across AGW conditions (p = 0.006 and p = 0.005, respectively). Additionally, vocal efficiency was significantly different among conditions (p = 0.005) as well as significantly lower in the asymmetric groups (p = 0.015 and p = 0.007). Perturbation measures were not significantly different across conditions. Correlation dimension (D2) was significantly different at PTP, 1.25 × PTP, and 1.5 × PTP (p = 0.003, p = 0.010, and p < 0.001, respectively) as well as significantly higher in the asymmetric groups at each pressure increment. The increased PTP, PTF, and D2 values as well as decreased vocal efficiency among the asymmetric conditions indicates a significant decrease in vocal function, and thus represents that asymmetries could be a contributing factor to the pathological symptoms associated with glottic webs.

An Excised Canine Model of Anterior Glottic Web and Its Acoustic, Aerodynamic, and High-speed Measurements

OBJECTIVES

This study aims to build an excised anterior glottic web (AGW) model and study the basic voice-related mechanisms of the AGW through investigating the acoustic, aerodynamic, and vibratory properties.

STUDY DESIGN AND METHODS

Overall, four conditions were tested for each of the eight canine larynges used. At baseline, 10%, 20%, and 33% occlusion (as determined by the placement of the suture), acoustic, aerodynamic, and high-speed video data were collected while each larynx was phonated in a soundproof booth.

RESULTS

The phonation threshold pressure (PTP) and the phonation threshold flow significantly increased as percent occlusion increased (P < 0.001). There were significant increases in jitter % and shimmer % from baseline group to AGW model groups at PTP, 1.25 PTP, and 1.5 PTP (P = 0.039, P < 0.001, P < 0.001, P < 0.001, P < 0.001, and P = 0.001, respectively). The fundamental frequency significantly increased as percent occlusion increased at all given pressures (P < 0.001). Correlation dimension (D2) was significantly higher in the AGW model groups than in the baseline group at PTP, 1.25 PTP, and 1.5 PTP (P = 0.002, P < 0.001, P = 0.01, respectively). High-speed videos revealed that, the left phase shift in the AGW model groups compared with the baseline at 1.25 PTP was significant (P = 0.027) and right phase shift at 1.5 PTP (P < 0.001).

CONCLUSIONS

We presented an anatomically similar model of a type 1 AGW and confirmed its validity through aerodynamic, acoustic, and high-speed video analysis in our study. We observed and investigated the glottic web movement, which may be a new explanation for the pathologic voice-related mechanism of AGW.

The butterfly procedure: a new technique and review of the literature for treating anterior laryngeal webs

Congenital laryngeal webs, subglottic stenosis, and laryngeal atresia result from various degrees of failure of airway recanalization as a spectrum. The symptoms also range from asymptomatic to dysphonia and severe airway obstruction. There are a number of methods for management of symptomatic patients. In this article, we discuss a new procedure that was used in the management of two anterior laryngeal web patients with relatively acceptable results.