title: Surgical and conservative management of bilateral dynamic laryngeal collapse associated with poll flexion in harness race horses.
abstract: 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.
authors.affiliation: Department of Companion Animal Clinical Sciences, Equine Teaching Hospital, Norwegian School of Veterinary Science, Oslo, Norway. cathrine.fjordbakk2@veths.no
authors.forename: Cathrine T
authors.initials: CT
authors.lastname: Fjordbakk
authors.forename: Eric
authors.initials: E
authors.lastname: Strand
authors.forename: Siv
authors.initials: S
authors.lastname: Hanche-Olsen
mesh_terms: 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