Effect of laryngoplasty on respiratory noise reduction in horses with laryngeal hemiplegia

Abstract

Summary Reasons for performing study: Laryngoplasty is the technique of choice for treatment of laryngeal hemiplegia, with the aim of improving airway function and/or eliminating respiratory noise. However, there are no quantitative data in the literature describing the effect of laryngoplasty on upper airway noise or its relationship to upper airway mechanics in horses with laryngeal hemiplegia. Objectives: To determine whether laryngoplasty reduces respiratory noise in exercising horses with laryngeal hemiplegia; and to establish whether the degree of upper airway obstruction can be predicted by upper airway noise, or the degree of arytenoid abduction correlated with airway obstruction and noise production. Methods: Six Standardbred horses with normal upper airways during maximal exercise were used. Respiratory sounds and inspiratory transupper airway pressure (Pui) were measured in all horses before and after induction of laryngeal hemiplegia and 30, 60 and 90 days after laryngoplasty. Inspiratory sound level (SL) and the sound intensity of the 3 inspiratory formants (F1, F2 and F3, respectively) were measured using a computer‐based sound analysis programme. The degree of abduction was graded by endoscopic visualisation 1, 30, 60 and 90 days post operatively. Linear regression analysis was used to determine correlations between Pui, sound indices and grades of arytenoid abduction. Results: In laryngeal hemiplegia‐affected horses, Pui, inspiratory SL and the sound intensity of F1, F2 and F3 were significantly increased. At 30 days following laryngoplasty, the sound intensity of F1 and Pui returned to baseline values. The sound intensities of F2, F3 and SL were significantly improved from laryngeal hemiplegia values at 30 days post operatively, but did not return to baseline at any measurement period. Sound level, F2 and F3 were significantly correlated with Pui (P<0.05), but the correlations were weak (r2= 0.26, 0.35 and 0.40, respectively). Grade of abduction and F2 were positively and significantly correlated (P<0.006, r2= 0.76). Grade of arytenoid abduction and Pui were not correlated (P = 0.12). Conclusions: Laryngoplasty reduced inspiratory noise in laryngeal hemiplegia‐affected horses by 30 days following surgery, but did not return it to baseline values. While upper airway noise and Pui were correlated, this relationship was insufficiently strong to predict Pui from noise in individual animals. The degree of arytenoid abduction was not correlated with Pui, but was positively correlated with noise production. Potential relevance: Laryngoplasty reduces upper airway noise in horses with laryngeal hemiplegia, but is not as effective as bilateral ventriculocordectomy in this regard, although respiratory noise reduction occurs more rapidly than with bilateral ventriculocordectomy. Residual noise during exercise cannot be used as a predictor of improvement in upper airway function in individual horses following laryngoplasty. The degree of arytenoid abduction obtained following surgery does not affect upp...

The impact of technology on the study of equine upper airway surgery

“…This method of evaluation is distinctly subjective in nature, and assumes a tight correlation between respiratory noise and airway obstruction. In fact, in horses with experimentally induced laryngeal hemiplegia, the correlation between residual airway obstruction following prosthetic laryngoplasty and residual noise is weak (Brown et al 2004). Therefore, the residual noise during exercise cannot be used as a predictor of improvement in upper airway function in individual horses following laryngoplasty.…”

“…Also, the success of this surgery for returning horses to racing has been well documented (Witte et al 2009). Prosthetic laryngoplasty reduces upper airway noise in horses with laryngeal hemiplegia, but is not as effective as bilateral ventriculocordectomy in this regard (Brown et al 2004). However, respiratory noise reduction occurs more rapidly than with bilateral ventriculocordectomy.…”

İki Tayda Sol Larengeal Hemipleji Olgusu

“…arış performansını olumsuz yönde etkileyen larengeal hemipleji, safkan ırklar başta olmak üzere bir çok yarış atı ırkında tanımlanmaktadır (1)(2)(3)(4).…”

Chirurgie de laryngoplastie chez le cheval debout

“…Elle est habituellement effectuée sous anesthésie générale avec le cheval positionné en décubitus latéral. Cette technique a été initialement décrite en 1970 (Marks et al 1970) et les résultats ont été objectivés par des études expé-rimentales (Brown et al 2004 ;Rakesh et al 2008). La perte d'abduction pendant la période post-opératoire immédiate ainsi que l'apparition de toux associée à des degrés variables de dysphagie, sont les complications les plus fréquemment rencontrées après cette procédure (Dixon et al 2003 ;Froydendund et al 2014 ;Biasutti et al 2016).…”

“…La perte d'abduction pendant la période post-opératoire immédiate ainsi que l'apparition de toux associée à des degrés variables de dysphagie, sont les complications les plus fréquemment rencontrées après cette procédure (Dixon et al 2003 ;Froydendund et al 2014 ;Biasutti et al 2016). La laryngoplastie est associée à une ventriculectomie (VE) uni ou bilatérale ou à une ventriculo-cordectomie (VCE) dans le but de réduire le bruit inspiratoire (Brown et al 2004;Robinson et al 2006). La chronologie des deux interventions pour optimiser l'efficacité de la laryngoplastie a également été étudiée (Perkins et al 2011).…”