Surgical and Conservative Management of Bilateral Dynamic Laryngeal Collapse Associated with Poll Flexion in Harness Race Horses

Abstract

Bilateral dynamic laryngeal collapse associated with poll flexion is a serious performance-limiting upper respiratory tract disorder that is overrepresented in NCT racehorses. Our results suggest that VFC is not the initiating event in this complex obstructive airway disorder for which there is currently no consistently effective treatment.

Bilateraler dynamischer Kehlkopfkollaps in Zusammenhang mit der Kopf-Halshaltung im Tölt bei einem Islandpferd

“…Bilateral dynamic laryngeal collapse has previously only been reported in harness racehorses, and Norwegian Coldblooded Trotters seem predisposed to this disorder relative to Standardbreds (Strand et al 2004, Fjordbakk et al 2008. The diagnosis can only be established while the affected individual is driven into the bit during high-speed treadmill videoendoscopy wearing a bridle and head check rein.…”

“…When the horse was allowed to trot with a lower head carriage, the sound and the airway collapse disappeared (Fig 3), but were easily and consistently reproduced when the horse was urged back into the tölting gait. The bilaterally symmetric vocal fold and arytenoid cartilage collapse was evaluated as "marked" according to a previously published grading scale (Fjordbakk et al 2008). No other dynamic abnormalities were noted during this examination.…”

“…Left sided arytenoid cartilage collapse, vocal fold collapse and axial deviation of the aryepiglottic folds are the most common disorders affecting the larynx (Tan et al 2005.These disorders are most often present regardless of head and neck position. Bilateral vocal fold and arytenoid cartilage collapse associated with poll flexion is a newly described disorder most frequently diagnosed in Norwegian Coldblooded Trotters (Strand et al 2004, Fjordbakk et al 2008). This disorder is often associated with other abnormalities of the upper respiratory tract, such as axial deviation of the aryepiglottic folds and dorsomedial deviation of the epiglottic margins, and has therefore recently been denoted bilateral dynamic laryngeal collapse (Fjordbakk et al 2008).…”

“…Bilateral vocal fold and arytenoid cartilage collapse associated with poll flexion is a newly described disorder most frequently diagnosed in Norwegian Coldblooded Trotters (Strand et al 2004, Fjordbakk et al 2008). This disorder is often associated with other abnormalities of the upper respiratory tract, such as axial deviation of the aryepiglottic folds and dorsomedial deviation of the epiglottic margins, and has therefore recently been denoted bilateral dynamic laryngeal collapse (Fjordbakk et al 2008). Norwegian Coldblooded Trotters are powerful harness racehorses that can be difficult to restrain.…”

“…Although they race with different types of head-checks enforcing "high" head and neck position, poll flexion occurs when they are restrained onto the bit. Correct diagnosis is only made videoendoscopically when the horse is driven into the bit by using full racing gear and long reins on the high-speed treadmill (Strand et al 2004, Fjordbakk et al 2008). This report describes the first case of bilateral dynamic laryngeal collapse diagnosed in an Icelandic Horse evident only during the töl-ting gait.…”