Effects of unilateral laser-assisted ventriculocordectomy in horses with laryngeal hemiplegia.
BACKGROUND
Recent studies have evaluated surgical techniques aimed at reducing noise and improving airway function in horses with recurrent laryngeal neuropathy (RLN). These techniques require general anaesthesia and are invasive. A minimally invasive transnasal surgical technique for treatment of RLN that may be employed in the standing, sedated horse would be advantageous.


OBJECTIVE
To determine whether unilateral laser-assisted ventriculocordectomy (LVC) improves upper airway function and reduces noise during inhalation in exercising horses with laryngeal hemiplegia (LH).


METHODS
Six Standardbred horses were used; respiratory sound and inspiratory transupper airway pressure (Pui) measured before and after induction of LH, and 60, 90 and 120 days after LVC. Inspiratory sound level (SL) and the sound intensities of formants 1, 2 and 3 (Fl, F2 and F3, respectively), were measured using computer-based sound analysis programmes. In addition, upper airway endoscopy was performed at each time interval, at rest and during treadmill exercise.


RESULTS
In LH-affected horses, Pui, SL and the sound intensity of F2 and F3 were increased significantly from baseline values. At 60 days after LVC, Pui and SL had returned to baseline, and F2 and F3 values had improved partially compared to LH values. At 90 and 120 days, however, SL increased again to LH levels.


CONCLUSIONS
LVC decreases LH-associated airway obstruction by 60 days after surgery, and reduces inspiratory noise but not as effectively as bilateral ventriculocordectomy.


CONCLUSIONS
LVC may be recommended as a treatment of LH, where reduction of upper airway obstruction and respiratory noise is desired and the owner wishes to avoid risks associated with a laryngotomy incision or general anaesthesia.
Robinson
P
P
Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, Michigan 48824.
Derksen
F J
FJ
Stick
J A
JA
Sullins
K E
KE
DeTolve
P G
PG
Robinson
N E
NE
D000818:Animals; D005260:Female; D006429:Hemiplegia / Q000601:surgery / Q000662:veterinary*; D006734:Horse Diseases / Q000601:surgery*; D006736:Horses; D007825:Laryngectomy / Q000379:methods / Q000662:veterinary*; D053685:Laser Therapy / Q000379:methods / Q000662:veterinary*; D008297:Male; D019060:Minimally Invasive Surgical Procedures / Q000379:methods / Q000662:veterinary; D010805:Physical Conditioning, Animal / Q000502:physiology; D011312:Pressure; D012135:Respiratory Sounds / Q000662:veterinary*; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D014826:Vocal Cord Paralysis / Q000601:surgery / Q000662:veterinary*; D014827:Vocal Cords / Q000601:surgery