Surgical and conservative management of bilateral dynamic laryngeal collapse associated with poll flexion in harness race horses.
OBJECTIVE
To test the hypothesis that in bilateral dynamic laryngeal collapse associated with poll flexion, vocal fold collapse (VFC) is the initial abnormal event that induces further laryngeal collapse, and that racing performance would therefore be substantially improved after bilateral ventriculocordectomy in affected individuals.


METHODS
Retrospective study.


METHODS
Twenty-six horses.


METHODS
Medical records (1998-2006) of harness racehorses admitted for high-speed treadmill videoendoscopy (HSTV) that had bilateral dynamic laryngeal collapse associated with poll flexion were reviewed. Race records, owner interviews, and follow-up HSTV were used to evaluate outcome after either surgical treatment including bilateral ventriculocordectomy or conservative management.


RESULTS
Bilateral dynamic laryngeal collapse, defined as bilateral VFC with concurrent arytenoid cartilage collapse (ACC), was identified in 26 horses. Norwegian Coldblooded Trotters (NCT) were overrepresented. Sixteen horses had surgical treatment and 10 were treated conservatively. Return to racing and racing performance was not improved within or between groups after the treatment. On follow-up HSTV of 6 surgically treated horses, there was no residual soft tissue collapse in the ventral portion of the rima glottidis; however, ACC and other abnormalities were still evident.


CONCLUSIONS
Bilateral ventriculocordectomy resolved VFC, but failed to stabilize the arytenoid cartilages or to significantly improve racing performance.


CONCLUSIONS
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.
Fjordbakk
Cathrine T
CT
Department of Companion Animal Clinical Sciences, Equine Teaching Hospital, Norwegian School of Veterinary Science, Oslo, Norway. cathrine.fjordbakk2@veths.no
Strand
Eric
E
Hanche-Olsen
Siv
S
D000818:Animals; D001193:Arytenoid Cartilage / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D001947:Breeding; D005080:Exercise Test / Q000662:veterinary; D005260:Female; D006734:Horse Diseases / Q000503:physiopathology / Q000601:surgery* / Q000628:therapy; D006736:Horses; D007818:Laryngeal Diseases / Q000503:physiopathology / Q000601:surgery / Q000628:therapy / Q000662:veterinary*; D007828:Laryngoscopy / Q000662:veterinary; D007830:Larynx / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D008297:Male; D010805:Physical Conditioning, Animal / Q000502:physiology*; D012189:Retrospective Studies; D016896:Treatment Outcome; D014827:Vocal Cords / Q000473:pathology / Q000503:physiopathology / Q000601:surgery