Partial Arytenoidectomy in the Horse

Four horses were examined because of inspiratory dyspnea and noise resulting from an inability to abduct one or both arytenoid cartilages. Two unilateral arytenoidectomies were done following failure of laryngoplasty, and two bilateral arytenoidectomies were done to correct permanent arytenoid adduction caused by laryngeal ossification. The surgical procedure included submucosal dissection of the arytenoid cartilage and removal of the vocal fold, lateral ventricle (when present), and the arytenoid cartilage, excluding the muscular process. Excessive mucous membrane was pulled caudally from the opening of the larynx and carefully sutured to close the mucous membrane and smooth the rima glottis. Postoperative swelling was greatest between the 3rd and 7th days. Long-term results included one horse returned to normal function with no noise, one horse returned to normal function but with respiratory noise, one horse returned to light riding with reduced noise, and one horse salvaged for pasture use.     

Partial Arytenoidectomy in the Horse with and without Mucosal Closure

Left-sided partial arytenoidectomy was performed in eight horses to evaluate healing. Four horses underwent conventional partial arytenoidectomy with suture apposition of the mucosa. In four horses, most of the arytenoid cartilage, including overlying mucosa, vocal fold, and laryngeal saccule, were excised en bloc without mucosal closure. The horses were monitored clinically by endoscopic examination. One horse from each group was euthanatized at weeks 2, 4, 8, and 16. Complete necropsies with gross and histologic examination of the arytenoidectomy sites were performed. Postoperative complications such as coughing, dysphagia, and aspiration pneumonia were not encountered and problems with wound healing were minimal in both groups. The defect created by partial arytenoidectomy without mucosal closure initially filled to the level of the luminal surface with granulation tissue, with a gradual transition to mature fibrous connective tissue. Grossly, the defect appeared to be healed and was completely epithelialized by week 16 without apparent narrowing of the laryngeal lumen. Partial arytenoidectomy sites with mucosal closure healed in a similar pattern by week 8. Partial dehiscence of the dorsal portion of the sutured mucosa occurred in three horses.     

Partial Arytenoidectomy in Horses

Unilateral partial arytenoidectomy was performed in 22 horses. Six horses had arytenoid chondritis, 14 horses had idiopathic laryngeal hemiplegia (11 of which had been treated unsuccessfully by insertion of a laryngeal abductor muscle prosthesis), and two horses had laryngeal hemiplegia resulting from perivascular injection of an irritant drug. After surgery, eight horses (36%) developed a nasal discharge of food and/or water that was of clinical significance in only two of them. The operation resulted in marked improvement in exercise tolerance in all 20 horses tested, although two could not work because of severe exercise-associated coughing. Mild inspiratory stertor was present in eight horses and was excessive in one. It was concluded that the high incidence of problems related to swallowing rendered the method unacceptable. Modification of partial arytenoidectomy by silicon augmentation produced improvement in one horse.     

Video-Assisted Left Partial Arytenoidectomy by Diode Laser Photoablation for Treatment of Canine Laryngeal Paralysis

Objectives— To evaluate the clinical outcome of left partial arytenoidectomy by video-assisted laser diode photoablation as a surgical treatment for canine laryngeal paralysis (LP).
Study Design— Case series.
Animals— Dogs with bilateral LP (n=20).
Methods— After endoscopic diagnosis of bilateral LP, left partial arytenoidectomy was performed by photoablation of arytenoid cartilage tissue using a diode laser (600 μm diameter, 15 W power, 980 nm wave length) to increase the width of the rima glottidis. Outcome was evaluated endoscopically (1 and 6 months) and clinically (1, 6, and 12 months).
Results— No substantial complications occurred during photoablation or in the immediate postoperative period. Postoperative width of the rima glottidis ranged from 6 to 10 mm at its widest aspect. At 1 month, respiratory function after walking and short running appeared good. Clinical and endoscopic examination revealed good outcome at 1 and 6 months. At 6 months, there was no evidence of hypertrophic scar, hypertrophic granulation tissue, or stricture of the laryngeal glottis in any dog. Two dogs developed aspiration pneumonia after 12 months.
Conclusions— Partial arytenoidectomy using video-assisted diode laser photoablation appears to be an effective technique for treating LP.
Clinical Relevance— Partial arytenoidectomy by diode laser photoablation should be considered as an alternative technique for treatment of canine LP.     

Excision of Cutaneous Tumors in the Horse Using Histologic Guidance

A highly successful surgical technique for removing cutaneous tumors in humans was used in seven horses with cutaneous squamous cell carcinoma (n = 3) or sarcoid (n = 4). In humans, the complete underside of the tumor is evaluated histologically by processing horizontal sections from the tumor base, and orientation between the wound surface and the undersurface of the excised tumor is maintained by mapping both surfaces. The technique ensures that small foci of residual tumor can be located accurately and removed. Based on our experience, three modifications of the human technique are suggested for its use in horses. The equine patient should be placed under general anesthesia rather than using local anesthesia if the tumor is in a difficult position for standing surgery or the patient is uncooperative; useful information can be obtained from tissue processed in buffered formalin if frozen sections are not available; and optimal tumor size for this procedure is no larger than 3 x 2 cm.     

利用微卫星标记对蒙古马和纯血马遗传多样性的研究

通过13个微卫星座位对蒙古马和纯血马两大品种的60匹马进行了遗传检测。用8％非变性聚丙烯酰胺凝胶电泳分离PCR扩增产物，并用银染法显色。通过软件计算了各微卫星座位的等位基因频率、有效等位基因数(Ne)、多态信息含量(PIC)和杂合度(H)。结果13个座位中UCDEQ440变异最大，TKY16变异最小；纯血马的Ne、PIC和H的平均值均稍高于蒙古马；总群体的平均遗传分化系数是0．0429。这些研究将为今后我国培育优良品种马提供思路。     

Traumatic phacocele in an American Miniature Horse

An 18‐year‐old American Miniature Horse mare was presented with a complaint of a scleral swelling affecting the right eye and a history of suspected trauma 6 weeks prior to evaluation. Clinical findings included severe blepharospasm, a bulbous swelling of the dorsotemporal bulbar conjunctiva, and phthisis bulbi. Ocular ultrasound was recommended but declined. Enucleation was elected for the blind, painful eye and was performed standing. Gross and histopathologic examinations of the globe were consistent with extrusion of the lens to the episcleral space, which is classified as a traumatic phacocele when associated with naturally occurring trauma. The location of lens entrapment suggested globe rupture occurred at the limbus, which is described as one of the weakest points of the equine globe. Subconjunctival dislocation of the lens and development of a traumatic phacocele should be considered as a differential diagnosis for horses presenting with subconjunctival masses, apparent aphakia, and historical trauma.     

Distal Humeral Salter Harris (Type II) Fracture Repair by an Ulnar Osteotomy Approach in a Horse

Objectives: To report repair of a comminuted distal humeral type II Salter–Harris fracture using an ulnar osteotomy approach and locking compression plates (LCP). Study Design: Case report. Animal: A 3‐month‐old Standardbred filly with a type II Salter–Harris fracture of the distal humerus. Methods: Radiographic and computed tomography examinations were performed to assist surgical planning. The distal humeral fracture was approached by an ulnar osteotomy and repaired using a 7‐hole broad LCP and screws inserted in lag fashion. The osteotomy was subsequently repaired using a 7‐hole narrow LCP. Results: The distal humeral fracture was successfully approached and stabilized by an ulnar osteotomy approach. At 6‐month follow‐up, the filly was ambulating comfortably with a normal cosmetic appearance. Conclusions: An ulnar osteotomy approach was readily performed and allowed for repair of a type II Salter–Harris fracture of the distal humerus. Clinical Relevance: The equine distal humerus can be accessed readily using an ulnar osteotomy approach. LCPs allow for repair of complicated fractures that have previously been associated with a grave prognosis.     

Acute suprarenal occlusion in an American Miniature Horse

A 7-month-old Miniature filly was examined because of a 4-day history of abnormal posture, lethargy and weakness. On initial evaluation, the filly presented with an abnormal stiff gait in her hindlimbs associated with hindlimb ataxia and lumbar kyphosis. She showed hindlimb discomfort by weight shifting from one hindlimb to the other. A complete blood count revealed an acute inflammatory leukogram associated with hyperfibrinogenaemia. The measurement of the serum amyloid A concentration indicated anactive inflammatory process. Biochemistry and urinalysis results revealed a severe azotaemia associated with diluted urine despite clinical dehydration, consistent with acute renal failure. Medical treatment was initiated with fluid therapy and antimicrobials. The pain was managed with morphine sulphate only, to avoid further kidney damage. The filly maintained an abnormal gait during this time, became progressively more ataxic and uncomfortable, and developed colic episodes. Because the horse was unresponsive to pain management, euthanasia was elected by the client. Post-mortem examination revealed an occlusive thrombus within the abdominal aorta, firmly attached to the intima, partially recanalised and extending from the aorta 1 cm along the right renal artery. In the left and right kidneys, severe subacute neutrophilic pyelonephritis, with lymphoplasmacytic interstitial nephritis was noted. In the hindlimb muscles, multifocal myocyte necrosis and evidence of regeneration was present. To the authors’ knowledge, this is the first case of acute suprarenal occlusion to be described in a horse.     

Management of Chronic Diarrhea in an Adult Horse

Chronic diarrhea could be a challenge from both the diagnostic and therapeutic point of view. This case report will discuss the clinical approach to the evaluation of chronic diarrhea with the production of free fecal water in an adult horse. The discussion of this case report may provide further information and describe a possible therapeutic option with sulfasalzine, focusing on the nutritional management of chronic diarrhea in adult horses. Nutritional management could be of higher importance for horses that suffer from this problem because it improves the well-being of the hindgut environment. In the present case report, motility abnormalities were identified without other physiological disturbances of colonic function or a decrease in body weight, and the priority was the following: (1) rebalancing of the diet to the real nutritional requirements of the patient, (2) avoiding excess carbohydrate from both forage and concentrate, (3) selecting the right proportion between good quality first-cut meadow hay and grounded and pelleted meadow hay that helps to reduce mechanical and physical load of the colon and could help in the formation of more homogeneous digesta, (4) reducing the stress with adequate feed consumption time, meal size, and time spent in a overgrazed paddock, and (5) increasing the proportion of omega-3 fatty acids in the diet. With the nutritional plan and management and the initial use of sulfasalazine, the horse maintained a good quality of the feces with a reduced or absent production of the free fecal water.     

Epiglottic Entrapment A Transnasal Surgical Approach to Divide the Aryepiglottic Fold Axially in the Standing Horse

Transnasal, axial division of the aryepiglottic fold was performed to correct entrapment of the epiglottis in 20 sedated, standing horses, using a hooked bistoury and topical anesthesia. Presenting complaints included decreased exercise tolerance or loss of racing performance, abnormal respiratory noise, and coughing. The surgical procedure was technically easy to perform with a minimum of instrumentation. The horses were rested an average of 18 days before race training or riding was resumed. Evaluation of racing records or contact with owners indicated that most affected horses competed successfully after transnasal surgical correction of the entrapment.     

Dorsal Laminectomy in the Horse II. Evaluation in the Normal Horse

Subtotal dorsal cervical laminectomy was performed on nine normal horses to evaluate positioning, refine the surgical technique, and assess the immediate and long-term effects of this procedure in the horse. Funkquist type B laminectomies were performed at various levels from C3-C4 to C6-C7. Absorbable gelatin sponge or autogenous nuchal fat was placed over the exposed dura mater. Surgery times varied from 2 to 3 hours, and all horses recovered without complication. Rapid primary intention wound healing occurred, with two horses showing neck pain. All remained neurologically normal. The horses were euthanized 6 weeks, 3 months, or 6 months postoperatively. Myelograms performed just prior to euthanasia demonstrated normal or expanded dye column widths. Necropsy revealed that all surgical sites had healed well. The laminectomy membrane was soft and pliable and could be easily separated from the underlying dura mater when fat was used as interpositional material. When gelatin sponge was used, the laminectomy membrane was firmly bonded to the dura. Spinal cords at the level of laminectomy appeared normal and moved freely within the vertebral canal. Histological evaluation of the laminectomy sites and associated spinal cord revealed no abnormalities attributable to the surgery. It was concluded that dorsal cervical laminectomy can be performed in horses without untoward sequelae. The procedure may be useful for the treatment of equine cervical compressive myelopathies.     

Arthroscopy in the Horse

Veterinary Research Communications -