Histological evaluation of the equine larynx after unilateral laser-assisted ventriculocordectomy.
BACKGROUND
Trans-endoscopic laser surgery, such as unilateral laser-assisted ventriculocordectomy (LVC), has gained popularity in the treatment of RLN because a laryngotomy incision or general anaesthesia are not required. However, removal of the vocal fold and ventricle takes considerable laser energy and could cause collateral tissue damage, including injury to the adjacent laryngeal cartilages.


OBJECTIVE
To document the histological effects of laser surgery on laryngeal tissues in horses that have undergone LVC for the treatment of laryngeal hemiplegia (LH).


METHODS
Six horses were used: 4 with experimentally induced LH that had subsequently undergone LVC 6 months prior to euthanasia; and, 2 horses were used as controls. One of the control horses with naturally occurring LH was used to study the effect of neuropathy alone, whereas the other was subjected to euthanasia immediately following LVC to evaluate the acute effect of laser surgery. Using a band saw, each larynx was sectioned transversely at 5 mm intervals and evaluated histologically.


RESULTS
Acutely, LVC caused thermal damage to adjacent soft tissues but did not affect the histology of the laryngeal cartilages. Six months after LVC, laryngeal cartilages were histologically normal and there was squamous metaplasia of the repaired laryngeal mucosa, resulting in restitution of the mucosal integrity.


CONCLUSIONS
Using a diode laser in contact fashion at 20 W, LVC can be used to remove the laryngeal vocal fold and ventricle without causing laryngeal cartilage damage.


CONCLUSIONS
Laryngeal chondritis is an unlikely consequence of LVC.
Robinson
P
P
Department of Large Animal Clinical Sciences, Michigan State University, East Lansing, Michigan 48824, USA.
Williams
K J
KJ
Sullins
K E
KE
Arnoczky
S P
SP
Stick
J A
JA
Robinson
N E
NE
de Feijter-Rupp
H
H
Derksen
F J
FJ
D000818:Animals; D005260:Female; D006429:Hemiplegia / Q000473:pathology / Q000601:surgery / Q000662:veterinary*; D006734:Horse Diseases / Q000473:pathology / Q000601:surgery*; D006736:Horses; D007150:Immunohistochemistry / Q000662:veterinary; D007825:Laryngectomy / Q000009:adverse effects / Q000379:methods / Q000662:veterinary*; D007830:Larynx / Q000473:pathology / Q000601:surgery; D053685:Laser Therapy / Q000009:adverse effects / Q000379:methods / Q000662:veterinary*; D008297:Male; D012135:Respiratory Sounds / Q000662:veterinary; D016896:Treatment Outcome; D014826:Vocal Cord Paralysis / Q000473:pathology / Q000601:surgery / Q000662:veterinary*; D014827:Vocal Cords / Q000473:pathology / Q000601:surgery