Postoperative race performance is not correlated with degree of surgical abduction after laryngoplasty in National Hunt Thoroughbred racehorses.

OBJECTIVES To (1) assess the degree of arytenoid cartilage abduction lost after laryngoplasty (LP) in Thoroughbred National Hunt racehorses and (2) to correlate postoperative racing performance with degree of arytenoid abduction after LP. STUDY DESIGN Case series. ANIMALS National Hunt Thoroughbred racehorses (n=68). METHODS Grade of postoperative arytenoid abduction for National Hunt racehorses that had LP with ventriculocordectomy was assessed at 1 day, 6 days, and 6 weeks after LP. Race records were analyzed to ascertain if there was correlation between the degree of arytenoid cartilage abduction and various measures of race performance (return to racing postoperatively, total earnings in 5 races immediately postoperatively, and lifetime number of starts postoperatively). RESULTS Median postoperative arytenoid abduction was grade 2 on day 1 but had decreased to grade 3 by 6 weeks. Horses with grades 1, 2, and 3 abduction 1 day after surgery had median losses of 1, 1, and 0.5 abduction grades, respectively, at 6 weeks. Horses with grade 1 abduction on day 1 were significantly more likely to lose abduction by day 6 after surgery than horses with grade 3 abduction on day 1. There was no statistically significant correlation between the postoperative grade of arytenoid abduction at any time point and earnings in 5 races after surgery, likelihood of racing postoperatively, or total number of lifetime race starts postoperatively. CONCLUSIONS Horses with maximal (grade 1) surgical arytenoid abduction are significantly more likely to suffer postoperative loss of abduction than those with grade 3 abduction. Postoperative grade of abduction does not appear significantly correlated with markers of racing performance in National Hunt racehorses; however, very few horses with poor (grade 4 or 5) abduction were included and thus conclusions regarding racing performance in such horses cannot be drawn from this study. CLINICAL RELEVANCE Seemingly, most horses with grade 3 laryngeal abduction can race successfully and perhaps surgeons should not be disillusioned by the appearance of only moderate (grade 3) abduction in the long term after LP in racehorses.

[1]  N. E. Robinson.  Consensus statements on equine recurrent laryngeal neuropathy: conclusions of the Havemeyer Workshop , 2010 .

[2]  J. Rawlinson,et al.  Intra-articular stabilisation of the equine cricoarytenoid joint. , 2008, Equine veterinary journal.

[3]  C. Adreani,et al.  35 – Surgical Treatment of Laryngeal Hemiplegia and Hemiparesis , 2007 .

[4]  H. Erb,et al.  A comparison of laryngoplasty and modified partial arytenoidectomy as treatments for laryngeal hemiplegia in exercising horses. , 2006, Veterinary surgery : VS.

[5]  B. McGorum,et al.  Long-term survey of laryngoplasty and ventriculocordectomy in an older, mixed-breed population of 200 horses. Part 1: Maintenance of surgical arytenoid abduction and complications of surgery. , 2010, Equine veterinary journal.

[6]  B. M. Kraus,et al.  Laryngoplasty with ventriculectomy or ventriculocordectomy in 104 draft horses (1992-2000). , 2003, Veterinary surgery : VS.

[7]  A. Fürst,et al.  Spirometric and endoscopic assessment of surgical treatment in horses with laryngeal hemiplegia , 2003 .

[8]  D. Slone,et al.  Treatment of laryngeal hemiplegia in horses by prosthetic laryngoplasty, ventriculectomy and vocal cordectomy , 2002, Veterinary Record.

[9]  E. Parente,et al.  The effect of recurrent laryngeal neurectomy in conjunction with laryngoplasty and unilateral ventriculocordectomy in thoroughbred racehorses. , 2001, Veterinary surgery : VS.

[10]  J. R. Mcclure,et al.  Career racing performance in Thoroughbreds treated with prosthetic laryngoplasty for laryngeal neuropathy: 52 cases (1981-1989). , 2000, Journal of the American Veterinary Medical Association.

[11]  A. Wilson,et al.  In vitro evaluation of a novel prosthesis for laryngoplasty of horses with recurrent laryngeal neuropathy. , 2000, Equine veterinary journal.

[12]  N. E. Robinson,et al.  Efficacy of prosthetic laryngoplasty with and without bilateral ventriculocordectomy as treatments for laryngeal hemiplegia in horses. , 1996, American journal of veterinary research.

[13]  Russell Ap,et al.  Performance analysis after prosthetic laryngoplasty and bilateral ventriculectomy for laryngeal hemiplegia in horses: 70 cases (1986-1991). , 1994 .

[14]  E A Scott,et al.  Effect of laryngeal hemiplegia and laryngoplasty on airway flow mechanics in exercising horses. , 1986, American journal of veterinary research.

[15]  B. Goulden,et al.  Equine laryngeal hemiplegia. Part III. Treatment by laryngoplasty. , 1982, New Zealand veterinary journal.

[16]  J. Leslie,et al.  Use of a prosthetic device for surgical correction of laryngeal hemiplegia in horses. , 1970, Journal of the American Veterinary Medical Association.