Transendoscopic contact neodymium:yttrium aluminum garnet laser correction of epiglottic entrapment in standing horses

Fifty-seven Standardbred and 44 Thoroughbred racehorses and 1 Thoroughbred polo mare with primary clinical signs of exercise intolerance or respiratory tract noise or combined exercise intolerance and respiratory tract noise were referred for laser correction of epiglottic entrapment. Significantly (P less than 0.001) more Standardbred than Thoroughbred racehorses were affected, compared with the observed hospital population during the same period. At referral, 14 horses did not have evident epiglottic entrapment and were returned to exercise without development of entrapment after treatment, which consisted of 1 week of rest and administration of anti-inflammatory medication. In 88 standing horses under sedation and topical anesthesia, epiglottic entrapment was corrected transendoscopically by use of a contact neodymium:yttrium aluminum garnet laser. In these 88 horses, 98% of entrapments were persistent, 92% were thick, 97% were wide, and 45% were ulcerated. Thirty-one percent of the horses had endoscopic evidence of epiglottic hypoplasia, and 8% had deviated epiglottic axis. Complete correction was achieved in 97% of the horses, Persistent dorsal displacement of the soft palate in 1 horse and severe epiglottic hypoplasia with thick, chronic entrapping membranes in 2 horses precluded successful transendoscopic correction with the horses in standing position. Most horses were treated on an outpatient basis, and all were able to be returned to exercise after 7 to 14 days of rest and treatment with anti-inflammatory medication. Entrapment recurred in 4 horses (5%), 3 of which had hypoplastic epiglottis. Dorsal displacement of the soft palate developed after surgery in 9 horses (10%) and continued in 4 horses (5%) that had displaced soft palate before surgery. All these horses had epiglottic hypoplasia. Laser correction of epiglottic entrapment in standing horses was safe, well tolerated, and effective. Laser surgery was an alternative to conventional surgery, and eliminated the need for general anesthesia and laryngotomy. It also reduced convalescence and postoperative complications.     

Transendoscopic axial division of epiglottic entrapment

Transendoscopic laser axial division of epiglottic entrapment can be performed in the standing horse with sedation and a local anesthetic, obviating the need for general anesthesia. The diode or Nd:YAG laser energy can be transmitted via a flexible fiber through the biopsy channel of the videoendoscope and can provide excellent cutting and hemostasis. Division of the membrane is performed with controlled strokes over the dorsal aspect of the membrane from the caudal edge of the entrapment toward the rostral tip, until the epiglottis is freed. Approximately 1,000 to 3,000 J are required to perform the procedure. Postoperative management consists of antimicrobial and systemic, as well as local anti-inflammatory, medication. The horse will require approximately 2 weeks of convalescence before returning to exercise.     

Treatment in the field of 27 horses with epiglottic entrapment

Twenty-seven horses were treated for epiglottic entrapment by using an oral, hand-assisted bistoury knife technique, under general anaesthesia; 26 of them returned successfully to racing, but one developed a permanently displaced soft palate. After the surgery 13 of the horses had an increased handicap rating and 13 had a decreased rating.     

Transendoscopic neodymium:yttrium aluminum garnet laser irradiation in horses

A neodymium:yttrium aluminum garnet (Nd:YAG) laser was used to study effects of applying laser irradiation transendoscopically to the corniculate process of the arytenoid cartilage in horses. Dosimetry was established initially in vitro in 10 corniculate cartilages that were irradiated and examined histologically to determine penetration depths at selected power settings. Eleven horses were given xylazine IV and butorphoral tartrate IV, and their left ventricle and corniculate process were irradiated. Six horses had left laryngeal hemiplegia and were euthanatized and necropsied 14 weeks after laser application and evaluation for upper airway stridor. Endoscopy was performed in the 5 other horses; they were euthanatized and necropsied at selected intervals to characterize the healing process. Healing was by second intention and was complete at 14 weeks. Two horses developed buds of granulation tissue along the laser incision, which resolved after a second laser application. Scar tissue formation resulted in left of midline displacement of the dorsal portion of the right corniculate process. The left ventricle healed without complications and was totally ablated. All horses had inspiratory stridor when exercised 14 weeks after laser irradiation.     

Treatment of epiglottic entrapment by transnasal axial division in standing sedated horses using a shielded hook bistoury

Objectives: To report use of a shielded hook bistoury developed for correction of epiglottic fold entrapment in standing sedated horses. Study Design: Prospective clinical study. Animals: Standardbreds (n=8), 3–19 years of age. Methods: Epiglottic fold entrapment was corrected during standing sedation using a shielded hook bistoury passed nasally into the pharynx. Owners, trainers, and referring veterinarians were contacted by telephone to establish outcome. Results: Axial division of the entrapping epiglottic fold was successful in all horses. No short‐ or long‐term complications occurred. Axial transection of the entrapping fold was performed rapidly (mean, 83 seconds between advancing the bistoury into the pharynx and transection of the entrapping fold). Conclusion: Transnasal axial division of the aryepiglottic fold can be accomplished safely using the shielded hook bistoury. The shield mechanism minimizes the risk of injury from the cutting blade to adjacent structures.     

Correlation of performance with endoscopic and radiographic assessment of epiglottic hypoplasia in racehorses with epiglottic entrapment corrected by use of contact neodymium:yttrium aluminum garnet laser

Epiglottic entrapment in 35 Thoroughbred and 44 Standardbred horses was corrected transendoscopically by use of a neodymium:yttrium aluminum garnet laser. Before surgery, the entrapped epiglottis was classified as hypoplastic or normal in each horse on the basis of endoscopic appearance alone. Using a digitizer, thyroepiglottic length was determined from lateral-view laryngeal radiographs. For 78 racehorses, earnings (less than $5,000 or greater than $5,000) were compared before and after surgery. Earnings category and racing performance after surgery were tested for association with endoscopically determined epiglottic hypoplasia and radiographically determined thyroepiglottic length. Endoscopy and radiography were useful methods of evaluating the epiglottis in horses with epiglottic entrapment. Mean (+/- SD) thyroepiglottic length for both breeds of horses with epiglottic entrapment was significantly (P = 0.0001) smaller (Thoroughbreds, 7.28 +/- 0.67 cm; Standardbreds, 7.21 +/- 0.62 cm), compared with thyroepiglottic length measured from control groups composed of clinically normal Thoroughbred (8.56 +/- 0.29 cm) and Standardbred (8.74 +/- 0.38 cm) racehorses. Both breeds of horses with epiglottic entrapment that had endoscopically apparent hypoplastic epiglottis had significantly (P less than 0.0001) smaller thyroepiglottic length (Thoroughbreds, 6.64 +/- 0.60 cm; Standardbred, 6.93 +/- 0.72 cm) than did horses with epiglottic entrapment that had endoscopically normal epiglottis (Throughbreds, 7.57 +/- 0.47 cm, Standardbreds, 7.36 +/- 0.50 cm). Significant difference was not detected in endoscopic appearance of the epiglottis among age, gender, or breed distributions.(ABSTRACT TRUNCATED AT 250 WORDS)     

Transendoscopic contact neodymium:yttrium aluminum garnet laser excision of tracheal lesions in two horses

Two male racehorses (1 Standardbred, 1 Thoroughbred) were examined because of intraluminal cervical tracheal lesions, located 60 to 70 cm from the nares. A contact neodymium:yttrium aluminum garnet laser with a chisel probe attached to the fiber end was used to transendoscopically debride a nonhealing tracheal ulcer and to excise a pyogranulomatous mass. In both horses, the surgical sites healed quickly and the lesions did not redevelop.     

Use of transendoscopic contact neodymium:yttrium aluminum garnet laser to drain dorsal epiglottic abscesses in two horses

A submucosal abscess, located on the dorsal surface of the epiglottis, was diagnosed in 2 Thoroughbred racehorses by use of endoscopy. Both horses had exercise intolerance. One horse had intermittent dorsal displacement of the soft palate, coughed while eating and galloping, and made an abnormal respiratory noise. Both abscesses were drained transendoscopically by use of a contact neodymium:yttrium aluminum garnet laser. Eleven days after surgery, the surgical sites appeared to have healed. Clinical signs resolved permanently, and both horses returned to successful racing careers.     

Dynamic epiglottic retroversion as a cause of abnormal inspiratory noise in six adult horses

This case report describes the endoscopic findings and outcome in 6 horses diagnosed with dynamic epiglottic retroversion (ER) during exercise. Horses included 2 showjumpers, one eventer, one pleasure riding horse and 2 Thoroughbred racehorses. All were adults (age range: 4–10 years). Dorsal angulation of the epiglottis was identified at rest in one horse. However, resting endoscopy was unremarkable in the remaining 5 horses. Exercising endoscopy was performed during high‐speed treadmill exercise in 3 horses and during ridden exercise in the other 3. Intermittent ER occurred during inspiration in all horses and the frequency increased with increasing speed. In 2 horses the epiglottis retroverted beyond the rima glottidis. All horses made an abnormal respiratory noise described as a ‘grunt’ when retroversion of the epiglottis occurred. Poll flexion was found to be an exacerbating factor in the nonracehorses. Two horses continued in work but abnormal inspiratory noise persisted. Surgical treatment, in the form of subepiglottic resection, was attempted in one horse. However, it never raced again after the procedure. Of the remaining horses, 2 were retired and the third was subjected to euthanasia.     

Evaluation of epiglottic augmentation by use of polytetrafluoroethylene paste in horses.

Epiglottic augmentation was evaluated in 7 horses, using 7 ml of polytetrafluoroethylene (polytef) paste injected submucosally on the ventral surface of the epiglottis. In 6 horses, an Arnold-Bruning intracordal injection syringe, specifically designed to inject polytef into paralyzed vocal folds in human beings, was used. At necropsy 60 days after surgery, group mean thickness measurement 20 mm from the epiglottic tip was 40% greater (P less than 0.01) and, at the epiglottic attachment of the aryepiglottic fold, was 29% greater (P less than 0.01) in the 6 polytef-augmented horses than in clinically normal nonsurgically treated controls. At necropsy, extensive epiglottic thickening was seen. This thickening was exclusively attributable to distention of submucosal areas in the ventral aspect of the epiglottis, with foreign body granulomata surrounded by fibrous connective tissue. In 1 horse, polytef paste was injected by use of a disposable syringe and needle. Excess ventral epiglottic swelling and exposed epiglottic cartilage was seen during subsequent endoscopy. At necropsy 60 days after surgery, the epiglottic contour remained deformed and a large deep mucosal ulcer was observed at the injection site. Histologic examination revealed necrotizing suppurative inflammation that extended into the epiglottic cartilage. Surgery was not technically difficult to perform through a laryngotomy, and all horses tolerated the procedure without apparent discomfort. Endoscopy performed after surgery revealed unremarkable and uniform response to the polytef paste in 4 horses, and in 3 horses, revealed excess swelling and inflammation of the ventral epiglottic tissue that resolved over time.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of a diode laser for use in induction of tendinopathy in the superficial digital flexor tendon of horses

Objective-To evaluate use of a diode laser to induce tendinopathy in the superficial digital flexor tendon (SDFT) of horses. Animals-4 equine cadavers and 5 adult horses. Procedures-Cadaveric SDFT samples were exposed to a diode laser at various energy settings to determine an appropriate energy for use in in vivo experiments; lesion size was assessed histologically. In vivo experiments involved laser energy induction of lesions in the SDFT (2 preliminary horses [0, 25, 75, and 87.5 J] and 3 study horses [0 and 125 J]) and assessment of lesions. Study duration was 21 days, and lesions were assessed clinically and via ultrasonography, MRI, and histologic evaluation. Results-Lesion induction in cadaveric tissues resulted in a spherical cavitated core with surrounding tissue coagulation. Lesion size had a linear relationship (R(2) = 0.9) with the energy administered. Size of in vivo lesions in preliminary horses indicated that larger lesions were required. In study horses, lesions induced with 125 J were ultrasonographically and histologically larger than were control lesions. At proximal and distal locations, pooled (preliminary and study horses) ultrasonographically assessed lesions were discrete and variable in size (mean ± SEM lesion percentage for control lesions, 8.5 ± 3%; for laser lesions, 12.2 ± 1.7%). Ultrasonography and MRI measurements were associated (R(2) > 0.84) with cross-sectional area measurements. Conclusions and Clinical Relevance-In vivo diode laser-induced lesions did not reflect cadaveric lesions in repeatable size. Further research is required before diode lasers can reliably be used for inducing tendinopathy.     

Endoscope-guided, transoral axial division of an entrapping epiglottic fold in fifteen standing horses

Objectives— To describe and evaluate the use of a transoral, endoscope-guided technique for transection of an entrapping epiglottic fold in sedated standing horses.
Study Design— Retrospective study.
Animals— Horses (n=16) with epiglottic fold entrapment (EFE).
Methods— Medical records (2005–2006) of 16 horses with EFE were reviewed to determine history, physical and endoscopic examination findings, postoperative complications, and outcome after axial division of EFE using a hooked bistoury, under an endoscopic-guided, transoral approach.
Results— EFE was confirmed by endoscopy. Axial division was successfully performed in 15 sedated, standing horses. One horse had to be anesthetized to complete the procedure. None of the horses made abnormal respiratory noise after surgery and all returned to their intended use. After surgery, 1 horse had a short, deformed epiglottis.
Conclusions— EFE can be axially divided safely and effectively using an endoscope-guided, transoral approach, with the horse sedated and standing.
Clinical Relevance— Endoscopic-guided, transoral axial division of EFE in sedated standing horses is an alternative choice to performing this procedure under general anesthesia.     

Comparison of intra-articular drilling and diode laser treatment for arthrodesis of the distal tarsal joints in normal horses

REASONS FOR PERFORMING STUDY: Anecdotal reports suggest that laser-facilitated arthrodesis of the distal tarsal joints improves the prognosis compared with intra-articular drilling but no objective comparisons have been performed. OBJECTIVES: To evaluate intra-articular drilling and laser-facilitated arthrodesis using in situ and in vivo techniques. METHODS: Fourteen cadaver limbs were evaluated in situ for chondrocyte viability after both surgical techniques. In vivo, one randomly selected limb was subjected to laser-facilitated arthrodesis and the other underwent intra-articular drilling in 6 normal horses. Clinical examinations were performed at 1, 3 and 5 months. Two horses were subjected to euthanasia at 1, 3 and 5 months. RESULTS: Significantly more chondrocyte death was observed with laser-facilitated arthrodesis compared to drilling, but the overall degree suggested only a focal effect. In vivo, both groups demonstrated minimal post operative morbidity. There was more evidence of arthrodesis seen at all time points with intra-articular drilling. CONCLUSIONS: This study demonstrated that changes associated with ultimate arthrodesis occur earlier after intra-articular drilling of the distal tarsal joints than laser-facilitated arthrodesis, although clinically affected horses may respond differently. POTENTIAL RELEVANCE: Intra-articular drilling may provide earlier arthrodesis of the distal tarsal joints, but not necessarily a better long-term result.     

Semiconductor diode laser transscleral cyclophotocoagulation for the treatment of glaucoma in horses: a retrospective study of 42 eyes

Objective To evaluate the outcome of diode laser transscleral cyclophotocoagulation (TSCP) for the treatment of glaucoma in horses. Procedure Medical records at The Ohio State University were reviewed. All horses that underwent diode laser TSCP between the years of 1995 and 2007 were included. Preoperative, procedural and clinical follow‐up data were collected, and telephone follow‐up was performed. Results Forty‐two eyes of 36 horses were included. Twenty‐four hours prior to surgery mean intraocular pressure (IOP) was 37.17 ± 13.48 mmHg (42 eyes). Forty‐one of 42 eyes (98%) were sighted and 39 of 39 (100%) of eyes were receiving topical glaucoma medication. At 3–5 weeks postoperatively the average IOP was 19.36 ± 12.04 mmHg (22 eyes). IOP remained significantly lower than pretreatment values at all periods of clinical follow‐up (P < 0.05). There was no significant difference in vision outcome, or the requirement for topical glaucoma medication relative to pretreatment values at any follow‐up period. Hyphema in 5 of 42 eyes was the only complication noted. Of the 27 eyes seen for clinical follow‐up, 2 were enucleated because of refractory elevation of IOP. Mean telephone follow‐up was 49 months. Twenty‐one of 22 owners contacted (95%) reported that the treatment had been of value, 14 of 22 eyes (64%) were receiving topical glaucoma medication, and 13 of 22 eyes (59%) were considered sighted. Conclusions Diode laser TSCP aided in the control of IOP and maintenance of vision but did not eliminate the need for topical glaucoma medication during the period of clinical follow‐up.     

Surgical correction of wry nose in four horses

Objective— To describe surgical techniques used for correction of congenital nasal deviation (wry nose) in horses (wry nose) and to report outcome.
Study Design— Retrospective study.
Animals— Horses (n=4), 5–17 months old with wry nose.
Methods— Nasal deviation was corrected by transecting the premaxillae/maxillae and nasal bones at their site of maximum curvature and realigning and stabilizing the bones in a more normal alignment using internal fixation. The nasal septum was removed during the same anesthetic period.
Results— For each horse, physical appearance was improved and respiratory stridor eliminated.
Conclusions— Wry nose can be corrected by transecting the premaxillae/maxillae and nasal bones and stabilizing the transected bones in a more normal alignment; the nasal septum can be removed concurrently.
Clinical Relevance— Surgical correction of wry nose may provide a good functional and cosmetic outcome.     

Surgical correction of entrapment of the large colon and caecum through a mesoduodenal rent with standing laparoscopic repair in a mare

A 12-year-old Tennessee Walking Horse mare displaying signs of severe colic for 48 h was found during an exploratory celiotomy to have entrapment of a cranially displaced large colon and the caecum through a rent in the mesoduodenum. The entrapment was relieved, and 24 h later, the mesoduodenal rent was closed laparoscopically, with the mare standing. The owner reported 6 months later that the mare had displayed no signs of colic since being discharged from the hospital 11 days after surgery.