Changes in rima glottidis area and lack of laryngeal epiglottic-glottic seal after unilateral cricoarytenoid lateralization ex vivo

Evaluation of two unilateral laryngoplasty techniques and their effect on arytenoid cartilage abduction in cats

OBJECTIVES

The aim of this study was to evaluate two unilateral laryngoplasty (arytenoid lateralisation) techniques for use in the surgical management of laryngeal paralysis in cats.

METHODS

Left cricoarytenoid abduction (lateralisation) was performed in 20 ex vivo cat larynges; 10 following complete cricoarytenoid disarticulation (group LAA-dis) and 10 following no cricoarytenoid disarticulation (group LAA-nodis). For both groups, left arytenoid abduction (LAA) was measured in the resting and postoperative larynges using image analysis software. Measurements were evaluated using the Mann-Whitney U-test. For both groups, dorsal images of the postoperative larynges were assessed visually for evidence of epiglottic coverage of the entrance to the larynx.

RESULTS

The mean percentage increase in LAA was 311.5% and 199.4% (P <0.006) for group LAA-dis (complete cricoarytenoid disarticulation) and group LAA-nodis (no cricoarytenoid disarticulation), respectively. In both groups, there was no evidence of a lack of epiglottic coverage of the entrance of the larynx for any of the postoperative larynges.

CONCLUSIONS AND RELEVANCE

Placement of a single, tensioned suture between the muscular process of the left arytenoid cartilage and the caudolateral aspect of the ipsilateral cricoid cartilage (unilateral cricoarytenoid lateralisation) resulted in abduction of the left arytenoid cartilage and a corresponding increase in the area of the rima glottidis on the operated side. The clinical significance of the difference in outcome between left cricoarytenoid abduction following complete cricoarytenoid disarticulation and abduction following no cricoarytenoid disarticulation remains unclear, and both might be considered appropriate for the surgical management of laryngeal paralysis in the cat.

Description and evaluation of a novel transoral endoscopic arytenopexy in canine cadavers

OBJECTIVE

To describe the transoral endoscopic arytenopexy (TEA) and evaluate its effects on the rima glottis area (RGA) and laryngeal epiglottic-glottic seal (LEGS). We hypothesize the TEA will be a feasible surgical technique and the TEA will provide a significant increase in RGA with minimal change to the LEGS.

STUDY DESIGN

Canine cadaveric model.

ANIMALS

Fifteen medium- to large-breed canine cadavers.

METHODS

Endoscopic photos of the larynx were taken with the epiglottis open for baseline RGA measurement and closed for baseline measurement of exposed RGA and LEGS. A custom endoscopic gag port (EGP) facilitated the TEA, performed by suturing the lateral aspect of the left arytenoid soft tissues to adjacent pharyngeal wall across the piriform recess. Endoscopic photos were repeated to measure changes in RGA and LEGS. A computerized planimetric analysis program was used to calculate baseline RGA and LEGS. The RGA was reported in % change from baseline. The LEGS was reported as intact or altered. A nonparametric Wilcoxon signed-rank test was used to compare baseline to post-TEA RGA.

RESULTS

The mean baseline RGA was 0.52 ± 0.28 cm³ and mean post-TEA RGA was 0.78 ± 0.37 cm³ (p-value < .0001). The LEGS remained intact post-TEA in all cadavers.

CONCLUSIONS

The TEA was technically feasible and resulted in an increase in RGA while maintaining the LEGS.

CLINICAL SIGNIFICANCE

The TEA may provide a minimally invasive addition to the established techniques for reducing airway resistance while minimizing the impact on the LEGS.

Effects of a novel, 3D printed bilateral arytenoid abductor on canine laryngeal airway resistance ex vivo

Background

Laryngeal paralysis is a disease process most commonly seen in older, large breed dogs. When both arytenoid cartilages are affected dogs can develop life-threatening respiratory compromise, therefore surgical intervention is recommended. While there are multiple surgical procedures that have been described to treat laryngeal paralysis, there remains a considerable risk for postoperative complications, most commonly aspiration pneumonia. The objective of this ex vivo experimental study was to evaluate the effects of a novel, 3D printed bilateral arytenoid abductor on laryngeal airway resistance in canine cadaver larynges. Laryngeal airway resistance was calculated for each specimen before (control) and after placement of a 3D printed, bilateral arytenoid abductor. The airway resistance was measured at an airflow of 10 L/min with the epiglottis closed and at airflows ranging from 15 L/min to 60 L/min with the epiglottis open. The effects of the bilateral arytenoid abductor on laryngeal airway resistance were evaluated statistically.

Results

With the epiglottis open, median laryngeal airway resistance in all larynges with a bilateral arytenoid abductor were significantly decreased at airflows of 15 L/min (0.0cmH2O/L/sec), 30 L/min (0.2cmH2O/L/sec), and 45 L/min (0.2cmH2O/L/sec) compared to the controls 15 L/min (0.4cmH2O/L/sec; P = 0.04), 30 L/min (0.9cmH2O/L/sec; P = 0.04), and 45 L/min (1.2cmH2O/L/sec; P = 0.04). When the epiglottis was closed, there was no significant difference in laryngeal resistance between the control (18.8cmH₂O/L/sec) and the abducted larynges (18.1cmH₂O/L/sec; P = 0.83).

Conclusions

Placement of a bilateral arytenoid abductor reduced laryngeal resistance in canine cadaver larynges compared to the controls when the epiglottis was open. With the epiglottis closed, there was no loss of laryngeal resistance while the device abducted the arytenoid cartilages. The results of this ex vivo study is encouraging for consideration of further evaluation of the bilateral arytenoid abductor to determine an appropriate material and tolerance of this device in vivo.