Dynamic laryngeal collapse associated with poll flexion as a complication of laryngeal tie‐forward surgery in three harness racehorses

Abstract

Objective To report dynamic laryngeal collapse (DLC) associated with poll flexion as a potential complication of the laryngeal tie‐forward procedure (LTFP) in harness racehorses. Study design Short case series. Animals Three harness racehorses. Methods Preoperative and postoperative medical records of all harness racehorses that underwent the LTFP were reviewed, as were high‐speed treadmill videoendoscopy recordings of 35 horses that returned for upper airway evaluation postoperatively. Results One standardbred and two Norwegian coldblooded trotters in which dorsal displacement of the soft palate had been initially diagnosed were found to have bilateral arytenoid cartilage and vocal fold collapse associated with poll flexion after the LTFP. These three horses were otherwise clinically normal when exercised in free head carriage. Conclusion Dynamic laryngeal collapse associated with poll flexion can occur as a complication after the LTFP in harness racehorses and should be considered as a differential in horses with persistence of airway problems after surgery. Clinical significance Postoperative DLC may be underdiagnosed in harness racehorses because this complication is obvious only when horses are driven with bit and reins during high speed treadmill or overground videoendoscopy.

Outcome analysis of 95 harness racehorses with confirmed dorsal displacement of the soft palate treated with laryngeal tie‐forward surgery

“…Additionally, the perceived recurrence rate of less than 6% reported by Woodie et al was based partially on horses with a presumptive diagnosis of iDDSP 8 , introducing the possibility of nonaffected horses falsely reducing the recurrence rate. Sporadically reported URT complications after LTF surgery include induction of VFC 25 and DLC associated with poll flexion 21 . In the current study, we diagnosed induction of VFC in four horses and induction of DLC in two horses at HSTE re‐evaluation after the LTF procedure (Table ).…”

“…Sporadically reported URT complications after LTF surgery include induction of VFC 25 and DLC associated with poll flexion. 21 In the current study, we diagnosed induction of VFC in four horses and induction of DLC in two horses at HSTE re-evaluation after the LTF procedure (Table S7).…”

“…Exercising endoscopy is considered the gold standard for diagnosing “dynamic” URT disorders, including iDDSP 5,6,18‐20 . Harness racehorses train and race with a relative high head/neck position due to the overcheck, and it is important to include periods of poll flexion during the HSTE examination 1,21 , which has been shown to induce iDDSP more frequently 1,18 . Significant disparities between resting and exercising endoscopy findings in relation to iDDSP have been thoroughly documented 1,5,6,20,22 .…”

Unilateral and bilateral compression of the epiglottis during poll flexion in harness racehorses

“…Exercise-related laryngeal disorders associated with poll flexion are often induced by changes in the relative positioning of the larynx and hyoid apparatus within the intermandibular space (McCluskie et al 2008;Fjordbakk et al 2013) and exacerbated by the increased negative inspiratory pressures caused by narrowing of the pharyngeal/laryngeal lumen width during poll flexion (Petsche et al 1995;Strand et al 2009), as predicted by the Bernoulli Principle and Venturi Effect. Upper respiratory tract disorders evident during poll flexion can be primary in nature (Strand et al 2004) or secondary to the increased regional airway pressure gradients occurring with other URT disorders (Strand & Skjerve 2012) and/or surgical interventions that alter laryngeal and/or hyoid conformation (Vermedal & Strand 2020).…”

Unilateral and bilateral compression of the epiglottis during poll flexion in harness racehorses

“…Exercise‐related laryngeal disorders associated with poll flexion are often induced by changes in the relative positioning of the larynx and hyoid apparatus within the intermandibular space (Fjordbakk et al., 2013; McCluskie et al., 2008) and exacerbated by the increased negative inspiratory pressures caused by narrowing of the pharyngeal/laryngeal lumen width during poll flexion (Petsche et al., 1995; Strand et al., 2009), as predicted by the Bernoulli Principle and Venturi Effect. Upper respiratory tract disorders evident during poll flexion can be primary in nature (Strand et al., 2004) or secondary to the increased regional airway pressure gradients occurring with other URT disorders (Strand & Skjerve, 2012) and/or surgical interventions that alter laryngeal and/or hyoid conformation (Vermedal & Strand, 2020).…”