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Abstract

Objective—To develop a technique for neodymium:yttrium-aluminum-garnet (Nd:YAG) laser ventriculocordectomy in standing horses and document healing in horses undergoing laser ventriculocordectomy.

Animals—6 horses between 2 and 32 years old.

Procedure—Under endoscopic guidance, the left laryngeal ventricle was everted with grasping forceps and excised with an Nd:YAG laser, using 60 watts of power in a noncontact fashion (6,403 to 9,197 Joules). Following removal of the ventricle, the vocal cord was photoablated. Horses were examined endoscopically 2, 7, 14, 21, 30, and 47 days after ventriculocordectomy, and 1 horse was euthanatized on each of these days. At necropsy, the larynx was removed intact and examined grossly. Samples were collected for histologic examination of the ventriculocordectomy site.

Results—Endoscopic examination revealed granulation tissue by day 7, the start of epithelialization by day 21, and healing by day 47. At necropsy, 4 horses were found to have a small amount of ventricular mucosa remaining dorsally and 1 additional horse was found to have a mucocele. Granulation tissue was identified grossly and histologically in the horses euthanatized between 7 and 30 days after surgery. Incipient reepithelialization was evident histologically on day 14, and complete reepithelialization of the surgery site was evident by day 47.

Conclusion and Clinical Relevance—Results suggest that ventriculocordectomy can safely be performed with an Nd:YAG laser in standing horses. (Am J Vet Res 2001;62:531–537)

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To determine the effects of 3 topically applied treatments (1% silver sulfadiazine cream [SSC], triple antimicrobial ointment [TAO], and hyperosmolar nanoemulsion [HNE]) on microbial counts, exuberant granulation tissue (EGT) development, and reepithelialization of contaminated wounds at the distal aspect of the limbs of horses.

ANIMALS 8 healthy adult horses.

PROCEDURES A 2.5 × 2.5-cm, full-thickness, cutaneous wound was created at the dorsal aspect of each metacarpus and metatarsus (1 wound/limb/horse), covered with nonadhesive dressing, and bandaged. Wounds were inoculated with bacteria and fungi the next day. Each wound on a given horse was randomly assigned to 1 of 4 treatment groups (SSC, TAO, HNE, or no topical treatment [control]). Bandage changes, culture of wound samples, treatments, photography for wound measurements, and biopsy were performed at predetermined time points. Time (days) until wound closure, number of EGT excisions, microbial counts, and scores for selected histologic characteristics were compared among groups.

RESULTS Median time to wound closure for all groups was 42 days. Time to wound closure and histologic characteristics of wound healing did not differ among groups. Least squares mean microbial counts were significantly higher for HNE-treated wounds on days 9 and 21, compared with SSC-treated and TAO-treated wounds, but not controls. Proportions of SSC-treated (7/8) or HNE-treated (5/8) wounds needing EGT excision were significantly greater than that of TAO-treated (1/8) wounds. The proportion of SSC-treated wounds with EGT excision was greater than that of controls (3/8).

CONCLUSIONS AND CLINICAL RELEVANCE None of the treatments resulted in more rapid wound closure, compared with that for untreated control wounds under the study conditions. When treatment is warranted, TAO may help to limit EGT formation.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine the effects of diode laser palatoplasty on the soft palate in horses.

Animals—6 clinically normal horses and 6 euthanized horses from another study.

Procedures—6 horses underwent diode laser palatoplasty (treated horses); 3 received low-dose laser treatment (1,209 to 1,224 J), and 3 received high-dose treatment (2,302 to 2,420 J). Six other horses received no treatment (control horses). The upper respiratory tracts of all treated horses were evaluated immediately following surgery (day 0) and on days 2, 7, 14, 21, 30, and 45. Horses were euthanized on day 45, and magnetic resonance imaging (MRI) of the head was performed. The soft palate was removed from treated and control horses, evaluated grossly, and scored for edema, inflammation, and scarring. Soft palates from all horses were sectioned for histologic and biomechanical evaluations.

Results—Endoscopic examination revealed a significant increase in soft palate scarring and decrease in edema and inflammation in treated horses by day 7. Gross postmortem findings corresponded with MRI findings. Gross and histologic examination revealed a significant increase in scarring, edema, and inflammation at day 45. Histologic evaluation of palatal tissue from high-dose–treated horses revealed full-thickness injury of skeletal muscle, with atrophy of muscle fibers; findings in low-dose–treated horses indicated superficial injury to skeletal muscle. After surgery, treated horses had a significant decrease in soft palate elastic modulus, compared with control horses.

Conclusions and Clinical Relevance—Laser palatoplasty resulted in soft palate fibrosis and skeletal muscle loss; however, the fibrosis did not result in an increase in soft palate elastic modulus.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine the extent to which a hydroxyapatite coating promotes pin stability in the third metacarpal bone during transfixation casting in horses.

Animals—14 adult horses.

Procedures—7 horses each were assigned to either an uncoated or hydroxyapatite-coated pin group. Three transcortical pins were placed in the third metacarpal bone of each horse and incorporated into a cast for 8 weeks. Insertion and extraction torque were measured, and torque reduction was calculated. Radiography was performed at 0, 4, and 8 weeks. Lameness evaluation was performed at 2, 4, 6, and 8 weeks. Bacteriologic culture of pins and pin holes was performed at pin removal.

Results—All horses used casts without major complication throughout the study. Insertion torque was higher in uncoated pins. There was no effect of group on extraction torque. Hydroxyapatite-coated pins had lower torque reduction. Five of 15 hydroxyapatite-coated pins maintained or increased stability, whereas all uncoated pins loosened. Pin hole radiolucency, lameness grades, and positive bacteriologic culture rates were not different between groups.

Conclusions and Clinical Relevance—Hydroxyapatite coating increased pin stability within the third metacarpal bone of horses during 8 weeks of transfixation casting but did not improve pin performance on clinical assessments. Clinical use of hydroxyapatite-coated transfixation pins may result in greater pin stability; however, further research is necessary to improve the consistency of pin osteointegration and elucidate whether clinical benefits will ultimately result from this approach in horses.

Full access
in American Journal of Veterinary Research