Quantitative assessment of progressive laryngeal hemiplegia in a 4‐year‐old beagle

Abstract

Progression of unilateral laryngeal paralysis (LP) was quantified in an asymptomatic 4year-old beagle during spontaneous breathing stimulated with inhaled 10% CO 2 . Laryngeal evaluation was performed sequentially to track progression of LP over an 18-month period. Videos of the larynx during CO 2 -stimulated breathing were obtained under propofol anaesthesia. Maximal inspiratory normalised glottal gap area (NGGA) was determined on each occasion for left and right hemiglottis. Left NGGA was smaller than the right side throughout the period of follow-up. After 18 months, LP had progressed to such a degree that the left arytenoid was completely paralysed with no movement during inspiration. This case report demonstrates the possibility of early detection of LP, and quantification of progression. Early detection may allow regenerative surgical strategies for LP to maintain glottic area and reduce postoperative complication rates.

A model of transient laryngeal hemiplegia in dogs through conduction blockade of the recurrent laryngeal nerve

“…We have recently reported a case in which subclinical LP was identified using this methodology, and its progression quantified, in a Beagle. 11 LP results in slow but progressive atrophy of the CAD muscles, decrease in fiber diameter, loss of muscle fibers, fibrosis, and replacement of muscle fibers with fat, secondary to denervation. 12 Although surgical reinnervation procedures have been described in people, 13 success depends, at least in part, on the presence of viable CAD muscles and RLn if nerve-to-nerve anastomosis is performed.…”

“…A similar observation was reported previously in horses over a longer period of time following injury of an RLn, 21 and in a dog with subclinical left-side LP. 11 The compensatory increase in arytenoid abduction on the uninjured side probably mitigates the effects of unilateral LP until paradoxical adduction occurs, or until the disease progresses on the contralateral side.…”