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Published by the Florida Association of Equine Practitioners, an Equine-Exclusive Division of the Florida Veterinary Medical Association Issue 3 • 2018

EQUINE NONULCERATIVE KERATOPATHIES DENNIS E. BROOKS DVM, Ph.D., DACVO

THE CHANGING FACE OF EQUINE DENTISTRY JACK EASLEY DVM, MS, DABVP/Eq., DAVDC/Eq.

OPTIONS FOR NECK IMAGING AMY L. JOHNSON DVM, DACVIM (LAIM & NEUROLOGY)

THE ELITE ATHLETE REHABILITATION R. D. MITCHELL DVM, MRCVS, DACVSMR, Cert. ISELP

56

th

ANNUAL OCALA

EQUINE CONFERENCE FEBRUARY 1-3, 2019 | OCALA, FLORIDA


The President's Line EXECUTIVE COUNCIL COREY MILLER

DVM, MS, DACT FAEP COUNCIL PAST PRESIDENT

cmiller@emcocala.com

ANNE L. MORETTA VMD, MS, CVSMT

maroche1@aol.com

JACQUELINE S. SHELLOW DVM, MS REPRESENTATIVE TO FVMA EXECUTIVE BOARD

jackie@shellow.com

ARMON BLAIR DVM

abeqdoc@aol.com

ADAM CAYOT DVM

adamcayot@hotmail.com

AMANDA M. HOUSE DVM, DACVIM

housea@ufl.edu

Dear Fellow Equine Practitioners, With September upon us, this marks the start of fall in Florida. Despite the slowdown of activities, the FAEP Council and FVMA continue to stay active, planning CE events for the next year that will be of benefit to practitioners in and outside of the state. While it is challenging developing these programs, it is extremely rewarding to see the efforts come to fruition. The FAEP hosted its annual Student Appreciation Day at the University of Florida College of Veterinary Medicine on August 25, featuring a day of hands-on labs for veterinary students interested in pursuing equine veterinary medicine. Students had the opportunity to learn about a variety of topics ranging from training Thoroughbreds to taking ultrasounds and X-rays to learning different types of therapies for horses. FAEP would like to thank UF CVM for partnering with us to provide students with this unique experience, along with all the site locations and sponsors: Boehringer-Ingelheim, Equine Medical Center of Ocala, Equine Performance Center, Florida Equine Veterinary Associates (FEVA), GoldMark Farm, Henry Schein Animal Health, Niall Brennan Stables, Ocala Equine Hospital, Peterson & Smith Equine Hospital, and Zoetis. The Promoting Excellence Symposium (PES) 2018 in Naples is just around the corner. Do not wait to register because wet lab seats are filling up fast. In addition to the Ultrasound Wet Lab being presented by world-renowned equine musculoskeletal system anatomist Dr. Jean-Marie Denoix, there will also be a packed lecture schedule on topics that include rehabilitation, surgery, endocrine disease and much more. With a total of 37 hours of world-class CE presented by nine distinguished national and international speakers, we encourage you to register and not miss out on this unique learning experience happening this October! The FAEP Council is also excited to announce that the 56th Annual Ocala Equine Conference (OEC) is confirmed for February 1-3, 2019, at the Ocala Hilton. It will feature the ever-popular pre-conference Ultrasound Wet Lab, along with some exceptional speakers who will share updates on current research and provide practical information for the equine practitioner. Looking ahead, I look forward to seeing many of you at PES 2018 in Naples in the coming month and at next year’s OEC!

PHILIP J. HINKLE EXECUTIVE DIRECTOR

phinkle@fvma.org

Ruth-Anne Richter, BSc (Hon), DVM, MS FAEP Council President

Opinions and statements expressed in The Practitioner reflect the views of the contributors and do not represent the official policy of the Florida Association of Equine Practitioners or the Florida Veterinary Medical Association, unless so stated. Placement of an advertisement does not represent the FAEP’s or FVMA’s endorsement of the product or service. FAEP | 7207 MONETARY DRIVE, ORLANDO, FL 32809 | PH: 800.992.3862 | FAX: 407.240.3710 | EMAIL: INFO@FVMA.ORG | WEBSITE: WWW.FAEP.NET

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Issue 3 • 2018


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EQUINE NONULCERATIVE KERATOPATHIES DENNIS E. BROOKS | DVM, Ph.D., DACVO

Corneal stromal abscesses

Focal trauma to the cornea can inject microbes and debris into the corneal stroma through small epithelial ulcerative micropunctures. A corneal abscess (Figure 1) may develop after epithelial cells adjacent to the epithelial micropuncture divide and migrate over the small traumatic ulcer to encapsulate infectious agents or foreign bodies in the stroma. Epithelial cells are more likely to cover a fungal than a bacterial infection. Reepithelialization forms a barrier that protects the bacteria or fungi from topically administered antimicrobial medications and interferes with both routine diagnostics and treatment. Some stromal abscesses may also be secondary to systemic disease with invasion of the iris, lens and corneal endothelium.

medical therapy. If reduced inflammation of the cornea and uvea are not found after two to three days of medical treatment, surgical removal of the abscess should be considered. Deep lamellar and penetrating keratoplasties (PK) are utilized in stromal abscesses near Descemet's membrane and eyes with a rupture of the abscess into the anterior chamber. Corneal transplantation eliminates sequestered microbial antigens and removes necrotic debris, cyotokines and toxins from degenerating leukocytes in the abscess.

Penetrating keratoplasty (PK) for deep corneal stromal abscesses

Corneal transplantation, such as penetrating keratoplasty (PK), is performed to restore vision, to control medically refractory corneal disease and to re-establish the structural integrity of the eye. PK is considered high risk for rejection in infected, vascularized corneal tissue with nearly all PKs in horses high-risk corneas. Fresh corneal grafts are preferred in horse PK but frozen tissue can be utilized. Vascularization of the grafts, indicating rejection, begins at five to 10 days postoperatively. Few equine PK grafts remain completely clear following their vascularization. They do form a very good therapeutic and tectonic function.

Squamous cell carcinoma and other corneal tumors

Figure 1: A dorsal corneal stromal abscess and hypopyon are present.

Preneoplastic epithelia dysplasia, intraepithelial carcinoma in situ and the invasive squamous cell carcinoma (SCC) (Figure 2) are common to the limbus and cornea of horses. Epithelial

Corneal stromal abscesses can be a vision-threatening sequelae to apparently minor corneal ulceration in the horse. A painful, blinding chronic iridocyclitis may result. Most stromal abscesses involving Descemet's membrane are fungal infections. The fungi seem "attracted" to the type IV collagen of Descemet's membrane. Both superficial and deep stromal abscesses do not heal until they become vascularized. The patterns of corneal vascularization are often unique suggesting that vasoactive factors are being released from the abscess that influences the vascular response. Medical therapy consists of aggressive use of topical and systemic antibiotics, topical atropine, and topical and systemic NSAIDs. Superficial stromal abscesses may initially respond positively to Figure 2: A thin layer of squamous cell carcinoma is present.

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dysplasia can be treated with topical 5-fluorouracil. Keratectomy and adjunctive therapies are needed for carcinoma in situ and SCC. Rapidly progressive and invasive SCC may necessitate enucleation. Limbal melanomas and hemangiosarcomas have also been reported in horses.

Corneal foreign bodies

of the endothelium is a proposed mechanism of this syndrome. The prognosis for a return to normal is poor. Hypertonic solutions (5% sodium chloride) may be beneficial in the early stages. Thermatokeratoplasty may be necessary to reduce the edema in severe cases. Endothelial cell reattachment and cellular hypertrophy can occur to resolve the condition in some horses.

Penetrating and perforating corneal foreign bodies (Figure Immune-mediated keratitis 3) cause varying degrees of keratitis and uveitis, and they are Several forms of immune-mediated keratitis (IMMK) are found common in horses. Superficial foreign bodies can be removed in in the U.S. and Europe (Figures 5 and 6). Epithelial, stromal under topical anesthesia and the subsequent ulcer treated and endothelial types are noted. Some are associated with a medically. Deep corneal stromal and penetrating foreign bodies “history of ocular trauma.� The etiology is presumed to be altered may cause severe uveitis/endophthalmitis and require more corneal immune privilege from abnormal exposure or expression aggressive care. of corneal antigens inducing autoimmune dysregulation. Nonulcerative superficial and nonulcerative recurrent forms of stromal keratitis are two types of IMMK. Stromal plasma staining may occur in some eyes. An endotheliitis with slight corneal edema is another deeper form of IMMK. These IMMK eyes may partially respond to topically administered

Figure 3: A small brown corneal foreign body is present.

Endothelial detachment following blunt trauma

Profound and persistent corneal edema may be present following blunt trauma to the globe of the horse (Figure 4). Detachment

Figure 4: Blunt trauma can cause corneal edema.

WWW.FAEP.NET |

Figure 5: Immune-mediated keratitis (IMMK) manifested by an eye with the deep stromal form of IMMK is present.

Figure 6: This form of IMMK with a vertical streak of edema is termed endotheliitis. FLORIDAAEP |

@FLORIDA_VMA | The Practitioner  5


Figure 7: Eosinophilic keratitis can mimic a tumor.

corticosteroids, NSAIDs, tacrolimus or cyclosporine A. They may require parenteral antibiotics, corticosteroids or NSAIDs. The endotheliitis form is particularly aggressive and difficult.

Eosinophilic keratoconjunctivitis

Figure 8: Calcific band keratopathy is calcium deposition in ill corneas.

Herpes keratitis

Multiple, superficial, white, punctate or linear opacities of the cornea, with or without fluorescein dye retention, are found associated with equine herpes virus 2 and -5. The focal punctate corneal opacities may be found at the end of superficial corneal vessels, and they may retain rose bengal stain.

Eosinophilic keratoconjunctivitis (EK) (Figure 7) has an unknown Varying amounts of ocular pain, conjunctivitis, fluorescein etiology, but it may be an immune-mediated disease. All ages statining and iridocyclitis are present. and breeds of horses can be affected with many cases reported in the spring. Clinical signs include corneal granulation tissue, Multiple foals in a herd may be affected. Topically administered blepharospasm, chemosis, conjunctival hyperemia, mucoid cidofovir (TID) can been used with topical NSAIDs for treatment discharge and corneal ulcers covered by raised, white necrotic of equine herpes ulcers but recurrence is common. plaques. Eosinophilic keratoconjunctivitis resembles a corneal tumor in appearance. KCS may develop in EK-affected horses due to lacrimal gland inflammation. The lacrimal gland should be Calcific band keratopathy palpated to detect swelling. Calcific band keratopathy (CBK) (Figure 8) is a complication of chronic uveitis and consists of deposition of dystrophic calcium in Corneal cytology typically contains numerous eosinophils and the superficial corneal epithelium and stroma. Dense white bands a few mast cells to rule out similar appearing infectious and of calcium are noted in the interpalpebral region of the central neoplastic causes. cornea. Scattered areas of fluorescein retention are present as the Topical corticosteroids (1% prednisolone acetate or 0.1% calcium disrupts the epithelium to result in painful superficial dexamethasone) four to six times a day in early stages (in spite ulcers. Deep ulcers can develop. A gritty sensation is found during of corneal ulcerations), antibiotics (e.g. bacitracin-neomycin- scraping for corneal cytology. It appears to develop in the eyes polymyxin or chloramphenicol), 1% atropine, and 0.03% of horses most aggressively treated with topical corticosteroids phospholine iodide (BID) in combination with systemic for ERU. CBK is rare in ERU horses that have not been treated nonsteroidal antiinflammatory drugs are indicated. Topical medically. cromolyn sodium (4.0% TID) or lodoxamide (0.1% TID), mast Treatment is topically administered calcium chelaters (dipotassium cell stabilizers, can also aid healing. Systemic corticosteroids may ethylene diamine tetraacetate 1.0%) to decrease tear calcium levels be necessary. Superficial lamellar keratectomy to remove plaques and aid healing. Topical antibiotics, atropine and systemic nonspeeds corneal healing. These lesions are typically slow to heal. steroidal anti-inflammatory drugs are also beneficial for the ulcers. Scarring of the cornea occurs frequently. Horses with EK should be dewormed twice with ivermectin 10 days a part, and alternative dewormers should also be considered.

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Figure 9: Diamond burring device used to remove calcium.

Superficial keratectomy and diamond burring (Figure 9) may be necessary to remove the painful calcium deposits. Healing of keratectomy sites can occur with severe scarring. Recurrence of CBK is possible with continued episodes of uveitis. The prognosis for vision is guarded because of subsequent corneal scarring and further uveitis episodes..

Linear keratopathy (LK)

Single linear opacities (Figure 10) at the level of Descemet’s membrane resemble the multiple branching stria in glaucoma (Figure 11). LK lesions are single lesions. They appear related to blunt corneal trauma, causing acute and transient IOP spikes and manifest as corneal edema in the early stages. They are nonprogressive but cause difficulties of interpretation in prepurchase examinations.

Figure 10: Single stria found in linear keratopathy.

WWW.FAEP.NET |

Figure 11: Multiple stria can occur in glaucoma.

Dennis E. Brooks DVM, Ph.D., DACVO is a 1980

graduate of the University of Illinois College of Veterinary Medicine. He passed the certifying examination of the American College of Veterinary Ophthalmologists (ACVO) in 1984. Dr. Brooks received a Ph.D. in 1987 from the University Of Florida College Of Medicine.

Dr. Brooks has written more than 170 academic scientific publications, 76 book chapters, received $2.3 million in research grants, and has given more than 300 lectures both nationally and internationally in comparative ophthalmology. His book, Equine Ophthalmology, was published in 2002 and again in 2008. He published another book, Small Animal Ophthalmology, in 2011. He received the British Equine Veterinary Association’s Sir Frederick Smith Memorial Lecture and Medal Recipient in 2007, and he also received the Frank J. Milne State of the Art Award from the American Association of Equine Practitioners (AAEP) in 2010. AAEP also gave him its Distinguished Educator Award in 2016. He has been a scientist and clinician in academia at the University of Tennessee and the University of Florida, and he is a professor emeritus of ophthalmology at the university of Florida. Dr. Brooks was the president of the American College of Veterinary Ophthalmologists from 1997-1998. He operates an equine ophthalmology consulting service BrooksEyes LLC at present. Dr Brooks has extensive experience in corneal amnion grafting, and he pioneered corneal transplantation and cataract surgery of the horse.

FLORIDAAEP |

@FLORIDA_VMA | The Practitioner  7


THE CHANGING FACE OF EQUINE DENTISTRY JACK EASLEY | DVM, MS, DABVP/Eq, DAVDC/Eq Introduction

Horsemen have always been aware of the benefits of good dental care in improving the performance of the equine athlete as well as extending the useful life span of the horse. Equine dentistry is one of the most common tasks performed by large animal practitioners (Traubdargatz 1991). Dental publications exist from circa 600 BC. Equine dentistry was a pillar of veterinary practices at the turn of the 20th century. By 1906, three complete text books dedicated to equine dentistry were in print (Clarke 1886, Hinebauch 1889, Merillat 1906). Merillat stated “the principal objective of dentistry is to promote the general health (of the horse) by improving mastication and by relieving pain.” Equine clinicians today agree that the goal of dentistry remains the same. Merillat’s text described how to float enamel points, manage deciduous teeth and extract terminally diseased teeth. With the exception of the outstanding clinical work of Becker and colleagues some 50 years later (Becker 1962), the standard of equine dental care saw minimal change through most of the 20th century. Many of the procedures described in the late 17th century, such as floating sharp enamel points, wolf tooth extractions, canine teeth reductions, incisor reductions, cutting tall teeth and dramatic bit seat applications, are commonly practiced today. These procedures cause harm to some horses and without scientific validation of their merit.

In the early 1990s, Floyd introduced veterinarians to the Triadan dental numbering system, which has made communication and record keeping for the dental practitioner more efficient (Floyd 1991). The American Veterinary Dental College Nomenclature and Classification Committee has endorsed the use of the Triadan tooth numbering system. Numbering is based on a fully phenotypic dentition made up of 44 teeth. This three-digit system uses the first digit to designate the quadrant and arch location, and whether the dentition is deciduous (primary) or permanent (adult). The quadrant implies the right or left side of the individual. The arch denotes maxillary or mandibular. The numbering sequence is: upper right, upper left, lower left and lower right. The permanent (adult) dentition utilizes numbers 1 to 4, and the deciduous (primary) dentition uses numbers 5 to 8. In each quadrant, the first or central incisor is always 01 with incisors numbered 01 to 03. The canines, whether present or not, takes up the 04 position in the formula. The premolars are numbered 05 to 08, and the molars are numbered 09 to 11. The last 20 years has brought equine dentistry out of the dark ages and has shed new light on the way veterinarians practice. No longer is a bucket and several floats considered a set of dental instruments. All things have changed starting with the oral/ dental examination and continuing with the way we diagnose and treat dental disease.

Figures 1a and 1b: Oral endoscopic images of the buccal and lingual aspects of a valve diastema with forage trapped between 409 and 410 predisposing to gingival inflammation, recession and progressive periodontal disease.

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Figures 2a and 2b: Images of intraoral mirror examination of an open diastema between 409-410 after forage had been removed.

Ageing Horses by Their Teeth. One of the more important of the “dental anatomy-related balloons” to have been deflated in the last 20 years is Galvayne’s criteria for aging horses of all ages by their dentition. Galvayne stated: “Not one of my students need be at fault with the age of any horse if he makes himself thoroughly conversant with my system for reading teeth. It has never been known to be incorrect” (Galvayne S. Horse Dentition, Thomas Murray, Glasgow, 1885). Many recent objective studies — including those by John Walmsley (1993) and Jill Richardson (1995) in the UK, and Sophie Muylle (1998) in Belgium — have clearly shown Galvayne’s “facts” to be wrong. Lszcynski et al. (2011) reported using the incisors for ageing Hucul horses and unsurprisingly found that their use, when compared to actual breeding documentation, was not accurate enough alone. The accuracy fell substantially after ages 6 and 11. Work by Carmalt and Allen (2008) has demonstrated that the occlusal surfaces of the cheek teeth can also be used as an indicator of age. Periodontal Disease (PD) is an altered state of the periodontium. The periodontium is the attachment apparatus of the tooth consisting of the gingiva, alveolar bone, periodontal ligament (PDL) and the cementum. It is responsible for hypsodontic tooth eruption and for the distribution of masticatory forces from the teeth into the supporting bone. PD is an inflammatory process consisting of cyclic intervals of active destruction (periodontitis) and inactive quiescence. These repetitive cycles of disease cause progressive attachment loss, resulting in increased tooth mobility and eventually premature exfoliation of the tooth. The predisposing feature to periodontitis in horses is food sequestration in the gingival sulcus, which is usually predisposed by inappropriate interproximal spaces between teeth (diastemata). Periodontal disease is the primary cause of tooth loss in mammals and was found to be the reason for extraction of 70 percent of equine cheek teeth in primary practice.

WWW.FAEP.NET |

Periodontal disease is a syndrome, which is comprised of gingivitis, periodontitis, reduced peripheral cementum production, alveolar bone recession and peripheral subgingival caries. It is frequently accompanied by moderate to severe oral pain, which can result in the inability to masticate food effectively and cause significant loss of body condition. The extraoral clinical signs associated with PD are similar to those of other dental diseases and are usually indicative of advanced disease. Weight loss, dysmastication, oral dysphagia (quidding), selective appetite, halitosis, hypersalivation, facial enlargements in the buccal area, purulent nasal discharge, biting problems and behavioral changes have been reported. Since all tissues of the periodontium are innervated, PD is associated with pain. Horses may object to manipulation of the head, mouth or teeth. Oral signs of PD include: • feed trapped in diastema between teeth (Figures 1a and 1b) • accumulation of plaque, calculus, debris or exudate around the tooth • gingival inflammation, edema, recession or hypertrophy • sulcular hemorrhage during examination or odontoplasty • periodontal pocket or diastema formation • tooth mobility, migration or extrusion, and eventual tooth loss The condition of each tissue of the periodontium visualized should be characterized. Standardized periodontal indices — plaque, calculus, sulcular bleeding and gingival indices — are widely accepted in both human and veterinary dentistry and can be used to simplify the documentation of the visual examination (Dixon 2017). Observation of the extent of pathology can be greatly enhanced using a dental mirror or oral endoscopy, which facilitates measurement of the depth of the periodontal pocket with a calibrated periodontal probe (Figures 2a and 2b). Radiography is helpful in confirming the depth and width of attachment loss and associated pathology (Figure 3). FLORIDAAEP |

@FLORIDA_VMA | The Practitioner  9


especially when no obvious oral signs or symptoms are present. Oral signs would present as an obvious deep crown fracture, occlusal secondary dentine discoloration or open occlusal pulp horns, and/or discharging tracts through the periodontal space or gingiva (Figures 4a and 4b). Oral endoscopy has been shown to greatly improve identification of subtle dental changes, such as small periodontal pockets, gingival recession, occlusal fissures and changes to the occlusal secondary dental (Simhofer 2008a).

Figure 3: Dental radiograph (Left-200D to Rt-V open mouth oblique centered in the oral cavity) demonstrates a diastema between the 409 and 410 with horizontal and vertical bone loose between these two teeth (refer to arrow).

Tooth mobility is a reliable and positive predictive, diagnostic and prognostic indicator. Increased mobility is proportionally associated with advancing PD and chances of tooth loss; however, lack of mobility does not always correlate with the lack of or early stage PD. Affected teeth should be manipulated to determine mobility. Tooth movement of 1 to 2 mm is considered normal in geriatric patients, but movement greater than 3 mm almost always indicates advanced, untreatable PD. Endodontic Disease is defined as an infection involving the pulp, usually associated with the dental apex or root and surrounding bone. In the horse, this type of disease has several synonyms: apical osteitis, apical periodontitis, periapical abscess or dento-alveolar infection. This type of dental disease is typically seen in young horses with a median age of 5-7 years old. Early and accurate identification of endodontic disease prior to osseous fistula and secondary effects on the surrounding tissues seldom occurs, but this should be the diagnostic goal. The most common clinical presentation associated with infection of the rostral two or three maxillary cheek teeth (06s-07s-08s) is a rostral maxillary swelling with a cutaneous sinus tract or, less commonly, ipsilateral nasal discharging tract. Infection involving the upper 06s and 07s has been associated with purulent discharge from the ipsilateral nasolacrimal duct. A foul smelling, unilateral nasal discharge associated with sinusitis can be seen with apical infection of the caudal three or four maxillary cheek teeth (08s-09s-10s-11s). Involvement of the infraorbital canal has been associated with apical infection of the upper 08s and 09s. Mandibular enlargement with a sinus tract is seen with apical infections involving the first four lower cheek teeth. The caudal two lower molars (10s-11s) usually cause enlargement and drainage under the muscles of mastication. The proper tooth must be identified, and this can be confusing at times,

Figures 4a: Oral endoscopic image of an endodontically infected 110 with a fractured crown and missing buccal fragment associated with pulp horn No. 1. The remaining four pulp horns are discolored and packed with decayed forage. The two infundibulae appeared to be normal.

Figures 4b: Oral endoscopic image of an endodontically infected 409 with open pulp horns and occlusal crown fracture.

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Figures 5a and 5b: Radiograph and CT image of a pony with bilateral infundibular cement hypoplasia of multiple upper cheek teeth. Notice that the more apical aspect of the infundibulae are affected. On a clinical oral examination, these teeth appeared normal with no infundibular defects on the occlusal surface.

In most cases, radiographs will aid in the diagnosis of apical disease. The sensitivity and specificity of radiography in the diagnosis of equine dental disorders are only 52 to 69 percent and 70 to 95 percent, respectively, with periapical lucency, periapical sclerosis and tooth root clubbing being the most reliable (Barakzai 2010). All of these radiographic changes are associated with chronic disease. Teeth showing occlusal secondary dentine defects often have deep carious lesions involving the crown and are prone to fracture. Exodontia has been the treatment of choice for most chronic apically infected teeth. Oral extraction has been the preferred method of exodontia with the highest success rate and lowest rate of complications (Dixon 2008). Oral extraction can be challenging when attempting to remove a periodontal-intact, long-crowned hypsodont tooth in a young horse. There is potential to cause iatrogenic damage that can have long-term welfare ramifications from attempted extraction. Such potential complications have led to the development of extraoral approaches to extraction via alveolar plate removal, improved methods of retrograde repulsion, minimally invasive buccal procedures and tooth sectioning (O’Neil 2011, Coomer 2011, Menzies 2014). After tooth removal, the secondary infection in the surrounding bone, soft tissues or sinuses must be addressed. Management of these secondary problems can at times be challenging. Infundibular disease has been described as infundibular cement hypoplasia, infundibular caries or patent infundibulum, and it is beginning to be considered a developmental condition. This accounts for the fact that many of these problems are bilateral and affect multiple teeth in the same animal. Infundibular (infundibulum/-a: Latin, funnel) anatomy and development of the upper cheek teeth is complex. The infundibular invaginations of enamel develop as the crown enamel organ forms with the apical aspect of the infundibulum closing at about the time of tooth eruption. The cement lake that fills in this infolded enamel receives its blood supply from the coronal aspect of the tooth while it develops in the alveolar sac prior to eruption. Cement deposition within the infundibulum progresses from the occlusal surface apically. This process may be incomplete at the time of tooth eruption when the occlusal blood supply is disrupted. This disruption usually involves the rostral area of the tooth first with WWW.FAEP.NET |

mucosal communications with the distal infundibular blood supply observed using oral endoscopy for up to six month after tooth eruption. After eruption, maxillary cheek tooth infundibulae display one or more small orifices in the center of the occlusal infundibular cementum. These canals extend through the infundibular cementum to the apical end of each infundibulum and represent the former location of blood vessels during dental development. The differentiation of mesenchymal cells into cementoblasts and subsequent cementum formation depends on adequate blood supply, which is provided by these blood vessels derived from the dental sac (Suske et al. 2016). Oral examination only allows visualization of the coronal surface of the infundibulum — not the more apical aspect. Digital radiology gives limited viewing of severely defective infundibula. Computed tomography allows improved imaging of the internal architecture of the teeth (Figures 5a and 5b). Research conducted by Fitzgibbons et al. on the anatomy of maxillary cheek teeth infundibula in clinically normal horses has helped to better understand infundibular anatomy, hypoplasia and caries. Techniques to fill or restore hypoplastic or carious infundibulae have been described since the 1940s. In the 1990s, the availability of instruments to reach the cheek teeth and air abrasion encouraged practitioners to begin attempting to diagnose and treat these deformed teeth without a good understanding of the disease process. Pearce has reported on 10 years of work with this technique in a clinical setting and has shown the process to be safe for the animal. More recent work by Horbal and Dixon has shown this technique to be of questionable value and lacking in cleaning and filling infundibulae deeper than 10 mm.

References 1.

Kopke et al. (2012) The dental cavities of equine cheek teeth: three-dimensional reconstructions based on high resolution micro-computed tomography, BMC Veterinary Research, 8:173

2. Casey M (2013) A new understanding of oral and dental pathology of the equine cheek teeth. In Vet Clin Equine, 29, 301-324 FLORIDAAEP |

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3. Fitzgibbon CM, du Toit N, Dixon PM. Anatomical studies of maxillary cheek teeth infundibula in clinically normal horses. Equine Vet J 2010; 42:37-43. 4.

Suske A, Poschke A, Schrock P, Kirschner S, Brockmann M, Staszyk C. (2016) Infundibula of equine maxillary cheek teeth. Part 1: Development,blood supply and infundibular cementogenesis. The Veterinary Jour 209, 57-65

5. Easley J and Hatzel J (2010) The History of Equine Dentistry, in Equine Dentistry, 3rd ed, Ed, Easley J, Dixon PM, Schumacher J, Elsevier, Edinburg, 11-25 6. Dixon PM, duTuit N (2010) Equine Pathology, in Equine Dentistry, 3rd ed, Ed, Easley J, Dixon PM, Schumacher J, Elsevier, Edinburg, 13. 7. Dixon PM. (2017) The Evolution of Horses and the Evolution of Equine Dentistry. In: AAEP Proceedings/ Vol 63/ 79-115 8. Suske, A., Poschke, A., Muller, P., Wober, S., Staszyk, C. (2016) Infundibula of equine maxillary cheek teeth. Part 2: Morphological variations and pathological changes. The Veterinary Journal 209, 66–73. 9. Marshall R, Shaw DJ, Dixon PM. (2012) A study of subocclusal secondary dentine thickness in overgrown equine cheek teeth. Vet J. 193:53-57.

Jack Easley, DVM, MS, DABVP/Eq, DAVDC/Eq Jack Easley received a DVM degree from Tuskegee University in 1976. After completing a large animal internship at Oklahoma State University, he served as an associate professor of surgery at Kansas State University from 1978-1980 where he completed an equine surgical residency and received a master's degree in surgery. He was an associate professor of surgery at the Virginia Polytechnic Institute, Virginia-Maryland College of Veterinary Medicine from 1980-1982. In 1982, he was certified as a Diplomate for the American Board of Veterinary Practitioners (Equine) and recertified in 1992, 2002 and 2012. Since 1982, he has been in private practice in Shelbyville, Kentucky where he has an exclusive equineonly practice with an emphasis on dentistry. In 2014, he became board certified by the American Veterinary Dental College as an equine dental specialist. For more than 40 years, Dr. Easley has lectured extensively on and promoted equine veterinary dentistry throughout the world. He has written hundreds of articles for publication in professional as well as lay equine journals, textbooks and periodicals. He serves on the editorial review boards for Equine Veterinary Education, Equine Veterinary Journal and the Veterinary Dental Journal. Dr. Easley is the co-editor and a major contributor of Equine Dentistry, first published in 1999 by Harcourt-Brace Publishing (Saunders) as being the first equine dental textbook in recent times. This textbook was ultimately printed in Spanish and German. The second edition published in October 2004, and the third edition co-authored with Drs. Paddy Dixon and Jim Schumacher released in 2010.

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OPTIONS FOR NECK IMAGING:

RADIOGRAPHS TO ROBOTIC CT – WHAT CAN WE LEARN? AMY L. JOHNSON | DVM, DACVIM (LAIM & NEUROLOGY)

Introduction

often in the absence of overt neurologic disease. These signs usually result in poor performance and can include difficulty with Neck problems, such as cervical osteoarthritis and cervical bending or lateral work (often worse in one direction), behavior vertebral stenotic myelopathy (CVSM), are common in many types change (bucking, bolting, rearing, stopping at fences, reluctance of horses. Cervical radiographs are commonly obtained in horses to bring head and neck up into a frame, or the reluctance to go with performance problems to look for evidence of malformation, forward), or thoracic limb lameness. Recently, the investigation malarticulation or degenerative changes in the articular process of a hopping-like forelimb lameness syndrome in ridden horses joints. Some practitioners will also perform radiographs as part suggested that cervical abnormalities might sometimes be of a pre-purchase evaluation. Interpretation of these radiographs 1 responsible for the unusual gait deficit. Obviously, many other is complicated by the fact that many horses develop degenerative orthopedic or even systemic problems can cause similar signs changes that do not significantly affect performance. and poor performance; however, if a horse is not performing well and has behavior changes without obvious lameness or other explanation, consideration of a cervical problem is warranted. Cervical radiographs are clearly indicated when neurologic disease localized to the cervical spinal cord is present, particularly if signs Cervical radiographs are sometimes performed as part of a preare relatively symmetrical and compatible with a focal compressive purchase evaluation. In the absence of any clinical signs of spinal lesion. Most commonly, horses with cervical spinal cord disease cord disease or neck pain, the horse’s utility could be argued; due to CVSM have general proprioceptive deficits in all four limbs however, for certain populations of horses, the author has become with the pelvic limbs more obviously affected. A long-strided increasingly convinced that they are money well spent for the spastic gait characteristic of upper motor neuron disease is potential purchaser. For example, Warmblood sport horses are generally seen in all four limbs; however, caudal cervical disease frequently purchased and/or imported prior to undergoing much can cause lower motor neuron signs in the thoracic limbs. These training or competition. CVSM is a common neurologic problem signs include a choppy, short-strided, forelimb gait, limb buckling in Warmbloods, but the signs frequently do not manifest until 4-8 at rest or during movement, and muscle atrophy. years of age when workload increases. In these cases, vertebral problems might be radiographically evident prior to development Another obvious indication for cervical radiography is overt neck of overt neurologic disease. pain, evidenced by abnormal posture or movement of the neck at rest or during exercise. Occasionally, horses with neck pain will show dramatic abnormalities such as a “root signature” (standing with one thoracic limb held off the ground) or become “stuck” with First, the quality of the radiographs should be assessed, and the the head and neck held in an abnormal position, often lowered. examiner should ensure that the series is complete (diagnostic Horses with less severe neck pain might show more subtle signs, views from the AO joint through C7-T1). Radiographs with mild obliquity can be assessed but true lateral projections are necessary to obtain accurate and repeatable minimum sagittal diameter ratio measurements. The examiner should systematically assess the alignment and shape of the vertebrae, the size of the vertebral canal, the articular process joints, the intervertebral foramina, and the intervertebral disk spaces (Figure 1).

Indications for cervical radiography

Interpretation of cervical radiographs

After subjective assessment of the vertebral column, more objective assessment should be undertaken using measurement

Figure 1: Radiograph of the caudal cervical region of an 8-year-old Warmblood horse without signs of neck pain or neurologic disease. Note the smooth ventral and dorsal margins of the superimposed articular process joints at each articulation, as well as the prominent, unobscured intervertebral foramina (#). This horse had an anomalous C6 vertebra with asymmetric partial absence of the ventral lamina of the C6 transverse process (*). Also note the normal C7 spinous process ($), which should not be mistaken for an osteophyte.

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Figure 2: Intervertebral sagittal diameter ratio measurement from a 4-year-old Warmblood horse. The C6-7 ratio is abnormal (46 percent). Also note the marked ventral proliferation of the C6-7 articular process joints, extending below the ventral aspect of the vertebral canal and obscuring the normal appearance of the intervertebral foramina (#). A cyst-like lesion is also present (*).

software. The minimum intravertebral sagittal diameter ratio is obtained by dividing the smallest height of the vertebral canal by the largest height of the corresponding vertebral body at its cranial aspect. The minimum intervertebral sagittal ratio is obtained by dividing the smallest dorsoventral measurement between two adjacent vertebrae —from the caudodorsal arch of the cranial vertebra to the craniodorsal aspect of the caudal vertebral body, or from the caudodorsal aspect of the epiphysis of the cranial vertebral body to the craniodorsal aspect of the arch of the caudal vertebra — by the largest height of the caudal vertebral body at its cranial aspect (Figure 2). Myelography is often considered the most accurate antemortem test for CVSM, but it might be supplanted by CT myelography or MRI in the future. Somewhat surprisingly, the diagnostic criteria for myelography have not been definitively established. The most commonly used criteria include ≥ 50 percent reduction of the dorsal myelographic column and ≥ 20 percent reduction of the total height of the dural sac, though subjective evaluation by an experienced observer might be more accurate than either of those methods.

Most common abnormalities

The most common diseases diagnosed radiographically include cervical osteoarthropathy (cervical arthritis or degenerative joint disease) and CVSM. Cervical osteoarthopathy is common in horses. Many clinicians feel comfortable making this diagnosis with radiography or even sonography (Figure 3); however, determining the clinical relevance of the bony changes can be

difficult. Age-related remodeling of the articular process joints is very common in horses and not necessarily indicative of an abnormality. A grading system for bony enlargement of the APJs has been described2 but is not widely utilized. When interpreting the significance of osteoarthritic changes, the author takes several factors into consideration: 1. Age of the horse: Teenage horses often have arthritic changes or enlarged APJs, often in the absence of clinical signs; however, moderate to marked arthritic changes in a young horse probably indicate instability or malarticulation at the affected sites. The vertebral canal should be assessed very critically for evidence of CVSM. 2. Uniformity of the changes: Horses can have differently shaped APJs with some horses having more “slender” APJs and others more bulbous. Normally, all APJs for any given horse look similar with only mild enlargement in the caudal neck; however, if one or two joints are obviously different than the rest, those joints are probably abnormal. 3. Nature of the changes: Bilateral, smooth enlargement of the APJs at an articulation is likely to be less significant than asymmetric enlargement, bony fragmentation (as might occur with osteochondritis dissecans or fractured osteophytes), or very irregular proliferation (with areas of sclerosis, resorption or even cysts). Although the author uses only a subjective grading scheme (mild/moderate/severe), APJs that extend ventrally below the bottom of the vertebral canal and obscure the normal intervertebral foramina are generally considered to have severe changes.

Figure 3: Caudal cervical radiograph from a 13-year-old Thoroughbred. Severe osteoarthritic changes are present at all visible articulations with multiple osteophytes and bony fragmentation (#). All intervertebral foramina are obscured by the bony proliferation (*).

18  The Practitioner  Issue 3 • 2018


4. Clinical signs and other diagnostic testing: If the horse shows clinical signs of neck stiffness and has moderate to severe osteoarthritic changes, the two are probably linked. If the horse shows only mild ataxia AND is positive for EPM on a serum:CSF titer ratio, it is more likely that EPM is to blame for the ataxia, and the radiographic changes are clinically insignificant. In some cases, it is difficult to assess whether the radiographic changes are contributing to the clinical picture. Treatment for other disease conditions, such as EPM is pursued first in an effort to determine the significance. Radiographic diagnosis of CVSM is usually achieved by looking for morphologic indicators as well as performing more objective minimum sagittal ratio measurements. Radiographic indicators include subluxation (dorsal angulation of the more caudal vertebra), physeal enlargement with dorsal projection of the caudal physis (“ski-slope” appearance), osteoarthritis and bony proliferation of the articular processes, osteochondrotic changes at the articular processes, and caudal extension of the dorsocaudal vertebral arch over the cranial physis of the adjacent vertebra.3 Both intra- and intervertebral minimum sagittal ratios have been described.4,5 Published cutoffs for intravertebral ratios are 0.52 for C3-4, C4-5 and C5-6, and 0.56 for C6-7.4 Ratios below the cutoffs indicate an increased risk of having CVSM but do not confirm the diagnosis, nor do they accurately indicate the site of compression. In a more recent study of 26 horses5, intravertebral measurements ≤ 0.485 identified all eight cases of CVSM (Figure 2). Vertebral anomalies are less frequently discussed by clinicians, but they should not be overlooked. Anomalous C6 vertebrae appear to be common, particularly in Warmblood breeds.6 In a population of 100 horses, 24 percent had anomalous C6 with either asymmetric or symmetric absence of the ventral lamina of the transverse process (Figure 1). Preliminary research suggests that anomalous C6 might be associated with increased perceived cervical pain as well as decreased size of the vertebral canal as assessed by minimum intravertebral sagittal ratio.6 Other cervical vertebral anomalies are uncommon but often significant when present. Examples include block vertebrae and anomalous or transitional vertebrae.

Moving beyond traditional radiography: Robotic CT

One of the primary limitations in evaluating the equine cervical vertebral column and spinal cord has been our inability to obtain cross-sectional imaging in the living horse. For decades, CT and MRI size limitations precluded imaging the caudal equine neck; however, the availability of large-bore and robotic CTs for clinical use is going to revolutionize our understanding of the equine cervical vertebral column and its pathology. Major advantages of these systems include the ability to image the neck in multiple planes, detection of lateral or dorsolateral spinal cord compression, and, with some systems, the ability to perform studies in the standing horse. Although these systems will likely

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improve sensitivity and specificity of diagnosis, we still have much to learn, and the agreement between traditional myelography and CT myelography is unknown. Many people prefer to avoid anesthesia when possible, but there are safety concerns with performing myelographic studies in non-anesthetized horses using standing systems. Additionally, dynamic views (flexion and extension) are more difficult to obtain in the standing horse.

References 1. Dyson S, Rasotto R. Idiopathic hopping-like forelimb lameness syndrome in ridden horses: 46 horses (2002-2014). Equine Vet Educ 2016;28:30-39. 2. Down SS and Henson FMD. Radiographic retrospective study of the caudal cervical articular process joints in the horse. Equine Vet J 2009;41:518-524. 3. Mayhew IG, Donawick WJ, Green SL, et al. Diagnosis and prediction of cervical vertebral malformation in Thoroughbred foals based on semi-quantitative radiographic indicators. Equine Vet J 1993;25:435-40. 4. Moore BR, Reed SM, Biller DS, et al. Assessment of vertebral canal diameter and bony malformations of the cervical part of the spine in horses with cervical stenotic myelopathy. Am J Vet Res 1994;55:5-13. 5. Hahn CN, Handel I, Green SL, et al. Assessment of the utility of using intra- and intervertebral minimum sagittal diameter ratios in the diagnosis of cervical vertebral malformation in horses. Vet Radiol Ultrasound 2008;49:1-6. 6. DeRouen A, Spriet M, Aleman M. Prevalence of anatomical variation of the sixth cervical vertebra and association with vertebral canal stenosis and articular process osteoarthritis in the horse. Vet Radiol Ultrasound 2016;57:253-8.

Amy L. Johnson, DVM, DACVIM (LAIM & Neurology) Dr. Johnson received her DVM from Cornell University in 2003. Following an internship at B.W. Furlong and Associates, Dr. Johnson went back to Cornell for a residency in large animal internal medicine. In 2007, she began working as a clinician at New Bolton Center while concurrently completing a residency in neurology at the University of Pennsylvania. In 2011, Dr. Johnson became the third veterinarian in the world to obtain board certification in neurology as well as large animal internal medicine. She currently works at New Bolton Center as assistant professor of large animal medicine and neurology. Her research efforts focus on improving diagnosis of neurologic disease in the living horse, and she has special interests in equine protozoal myeloencephalitis (EPM), Lyme neuroborreliosis and botulism.

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@FLORIDA_VMA | The Practitioner  19


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THE ELITE ATHLETE REHABILITATION:

Rehabilitation Techniques When Preparing for Competition Versus Rehabilitation Techniques During Competition R. D. MITCHELL | DVM, MRCVS, DACVSMR, Cert. ISELP Photos courtesy of Drs. R. D. Mitchell and Anne Moretta Rehabilitation is specialized health care dedicated to improving, maintaining or restoring physical strength and mobility. Such therapy can often be as appropriate in the training of the equine athlete as it is for the injured athlete recovering to fitness and competition. Special exercise regimens that aid in the conditioning of both axial and appendicular skeleton and associated muscles, tendons and ligaments may also be employed in preparation and warm-up prior to competition. Various physical therapy modalities are employed while training which may also be applicable during competitive events. It should be recognized that many therapies used for support of the equine athlete may appear effective but have little or no scientific validation in the horse. The USEF and FEI place restrictions on the use of some external modalities just before and during events, and these will be specifically discussed later. Other modalities are permitted and may provide excellent support for the equine athlete during events.

convalescing from injury/surgery as well as for early warm-up in preparation for exercise. 2. Thermal therapy a. This therapy is the application of cold or heat so as to affect inflammation and circulatory/lymph flow. b. It can be used in conjunction with other therapies, such as massage and stretching to enhance mobility and comfort. c. It is beneficial in acute and chronic conditions. d. Cold therapy is useful for post-exercise maintenance (Figure 1).

In order for any rehabilitation program to be successful, a careful assessment of the patient must be made and a diagnosis established. Some patients may be without pathology initially, but they become sore or injured through intensive or abusive training practices. Periodic veterinary inspection of the horse may detect early problems and possibly prevent injury. It has been documented that lameness is often present when the rider or trainer perceives that everything is OK.1 A myriad of physical therapy techniques and devices are available to the equine practitioner. There are many “black boxes” for which there are some outlandish claims, and it’s up to the practitioner to investigate and learn the true value of various devices. Likewise, some “physical therapy” techniques may prove to be nothing more than placebo and can be a waste of the practitioner’s time. An outline of physical therapy techniques and devices perceived as effective by this author and frequently used for support of the equine athlete follows.

Physical therapy techniques

1. Therapeutic stretching/massage a. An experienced therapist may give the owner/trainer/ veterinarian insight relative to areas of discomfort, joint pathology or muscle spasm. b. Stretching and massage can be of benefit in managing muscle inflammation and spasms, as well as some chronic joint issues. c. Passive manipulation of joints can be of benefit in

Figure 1: Stifle ice

3. Chiropractic manipulation a. This is a popular therapy with little scientific validation; however, there is some recent evidence of its measurable effects.2 b. Therapists usually follow a series of treatments for an “extended” relationship. Perhaps no discernible cure, but it’s good for effective pain management. 4. Acupuncture a. It often identifies repeatable myofascial relationships that are consistently observed in specific musculoskeletal conditions that may aid in accurate diagnosis. b. Various techniques: dry needle, aqua-puncture, electroacupuncture, cold laser and implants.

22  The Practitioner  Issue 3 • 2018


c. It is useful for pre-competition preparation. 5. Kinesiotaping a. The application of elastic tape that augments postural function of muscles. b. It may improve blood and lymphatic flow. c. It’s popular in human athletics. 6. Saddle Fit a. While not so much a physical therapy technique, this concept is very important to the overall comfort and performance of the horse.

3. Therapeutic ultrasound produces a clinical effect on tissue by two means: thermal and non-thermal effects. Thermal effects are due to the absorption of the sound waves. Non- thermal effects are from cavitation, microstreaming and acoustic streaming.6 These effects are useful for controlling the side effects of inflammation and encouraging tissue repair. 4. Transcutaneous electrical nerve stimulation (TENS) can be effective for local pain relief, especially if related to muscle spasm and joint pain. These devices may work by simply “overloading” the sensory nerves. 5. Laser therapy a. Low Level Laser Therapy (LLLT)-Class 1-3b

b. An experienced saddle fitter with good working knowledge of equine anatomy is essential. Horses change shape as they train and develop. It is not “one size fits all.”

i. Cold Laser Therapy-Various units available that claim physiological effects but do not generate heat have a “photochemical effect.” ii. It may be used as an alternative to acupuncture needles on specific points.

Physical therapy devices

Many therapeutic devices have been developed that claim restorative and medical value. It is incumbent upon the professional practitioner to investigate and educate him- or herself on the relative value and potential benefit of a particular device to the patient for a specific condition. A number of devices have had extensive scientific investigation while others have little science behind their use. Studies of many devices used in humans are lacking in equine medicine. A list of more commonly used devices follows: 1.

iii. It may treat regions to manage myofascial pain. iv. It’s reported as useful for wound management. b. Class IV- May produce a thermal effect and can burn skin and cause eye damage (Figure 3). i. It has a “photochemical” and thermal effect. ii. There’s limited research suggesting a regenerative effect.

Pulsating electromagnetic field therapy (PEMF): It has been recognized in benefitting fracture repair for many years.3 Further beneficial effects have been recognized for soft tissue repair.4 Pulsating magnetic fields affect nitric oxide levels in tissue and vasodilation/constriction.

iii. Practical experience suggests a very useful response to therapy.

2. Extracorporeal shock wave therapy (ESWT) a. The shockwave alters cell membrane permeability (Figure 2). b. It stimulates osteoblasts and fibroblasts. c. It downregulates nociceptors, thereby reducing pain. d. There is evidence that ESWT stimulates nerve regeneration.5

Figure 3: Class IV laser

6.

Figure 2: Shockwave therapy

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A form of neuromuscular electrical stimulation, functional electrical stimulation (FES) has been used extensively in humans to facilitate recovery from neuromuscular trauma (Figure 4). Recent studies would indicate that there is an effect of increasing mitochondrial concentration in muscle cells which may enhance function in exercising horses.7 The device can stimulate deeper tissues, and the attainment of stronger muscular

FLORIDAAEP |

@FLORIDA_VMA | The Practitioner  23


contractions is possible.8 It appears to be well tolerated and effective in horses for maintaining normal muscle tone and function, and reducing spasm during convalescence as well as during training.

3. Tack walking: These are more simple exercises that may be augmented by lateral exercises such as shoulder-in, haunches-in or walking over poles, also up and down hill to aid in development of core strength. 4. Walk/Trot/Canter is useful to help increase bone density along with muscular and ligament strength. This is a good alternative to repetitive training in the discipline, i.e., “don’t jump every day.” Trail riding is often good for the horse’s brain and attention span by getting out of the usual work arena. 5.

Walker, treadmill, water treadmill (Figure 5) and long line work are all alternative forms of exercise to riding which may be performed at different times of the day in conjunction with work under saddle.

Figure 4: Functional electrial stimulus (FES)

7. Vibration plate therapy (example: TheraPlate) a. It has been shown to be as effective as some exercise programs in elderly humans.9 b. It may provide some motion effect for convalescing horses that aids in maintaining bone density and muscle tone. 8. SQUID Therapy Signals (example: Cytowave): This device produces an electromagnetic wave, but it is not the same as older PEMF. The claim is that the device provides a signal mimicking natural body electromagnetic signals, maximizing electrochemical reactions for optimum repair. There is little scientific evidence of its efficacy but anecdotal reports, including this author’s personal experience, have been impressive. 9. Massage blankets and thermal blankets: These are widely used to stimulate the back and torso prior to exercise. There is not much in the way of scientific documentation, but horses seem accepting.

Exercise programs

1. Manipulative and stretching exercise a. Stretching: Passive manipulation by a handler to improve mobilization and comfort pre-exercise and tacking up.

Figure 5: Water treadmill

b. Active stretching, i.e. “carrot stretches,”10 when performed on a daily basis at least five days per week can help maintain abdominal and top line muscle tone as well as cervical flexibility.

When to use therapy devices

2. Hand walking or an alternative, such as a treadmill or a walker. is advised in the working horse at least once if not twice daily in addition to working exercise. This mimics normal activity by which the horse evolved.

Many of the physical therapy techniques and devices are as applicable to the working horse as the convalescent horse; however, optimal use can improve results. Certainly, stretching and flexibility exercises are appropriate for both the training horse and the horse warming up for competition. Devices such as the PEMF and thermal blankets and therapeutic ultrasound may be more beneficial pre-exercise to benefit for “warm-up.” Likewise, FES, TENS and cold laser devices may improve comfort and muscle

24  The Practitioner  Issue 3 • 2018


function if used pre-exercise. Care should be taken in the use of ESWT and subsequently exercising the horse as these devices may reduce some sensation that could lead to further injury in this author’s opinion. The application of cold therapy immediately following exercise may reduce potential hemorrhage and lymph edema, as well as reducing cellular responses to micro-trauma. Some devices are restricted for use in the elite sport horse entering competition. The FEI restricts the use of ESWT to five days prior to the event, and similarly the USEF limits its use to three days prior except for back therapies which may be performed by a veterinarian up to 24 hours prior to an event. Restriction is due to the perception that ESWT blocks pain and may allow an injured horse to perform putting them at risk for further injury. The use of electro-acupuncture is forbidden at FEI events but not restricted at USEF competitions. Solid needle acupuncture is allowed at FEI events; however, an authorized treating veterinarian must “supervise” acupuncture therapy, if not personally doing it, and the therapists must identify themselves to the veterinary delegate and present appropriate qualifications. Chiropractic therapy is allowed in both jurisdictions, but, again, in FEI the therapist must identify him- or herself to officials. Such therapies may not be performed when the stables are officially closed. The application of kinesiotape is only allowed while the horse is in the stall at FEI and USEF events. Presumably this is because of a public image that the horse might be working and competing with a problem if the tape was allowed while exercising. Cooling devices are restricted per FEI rules to not cool below 0°C; however; USEF does not have a rule in place restricting how cold cooling devices may be. The use of laser devices are allowed in USEF and FEI competitions, but FEI has historically not allowed Class IV devices to be used in the enclosure. FES devices, because they produce muscular contractions, may be restricted similarly to electroacupuncture. Currently, it’s up to the decision of the individual FEI veterinary delegate. There is no restriction per USEF. TENS devices can be used in both jurisdictions. Ultrasound therapy may be used prior to and during completion in USEF and FEI competitions. Mentioned previously, electromagnetic devices for the most part are permitted; however, very powerful devices that produce muscle contractions have been a concern because of a potential analgesic effect as claimed by the manufacturer (MagnaWave). Some veterinary delegates have prohibited their use. Similarly, the Cytowave device has been restricted by some veterinary delegates because of lack of understanding of its effects and function. It would seem logical that if PEMF devices are allowed, this device would be as well. These inconsistencies are a major concern to the International Sport Horse Veterinarians Association (ISHVA), and there efforts are being made to develop more consistent rules with regard to therapeutic devices. Discussing the use of therapeutic devices with the veterinary delegate prior to an event is advisable.

References 1. Dyson S, Greve L, Subjective gait assessment of 57 sports horses in normal work: a comparison of the response to flexion tests, movement in hand, on the lunge and ridden; JEVS 38 (2016) 1-7 2. Gomez Alvarez CB, L’Ami JJ, Moffatt D, Back W, van Weeren PR, Effect of chiropractic manipulations on the kinematics of

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back and limbs in horses with clinically diagnosed back problems; Equine vet. J. (2008) 40(2) 153-159 3. Bassett CA, Pawluk RJ, Pilla AA; Acceleration of fracture repair by electromagnetic fields. A surgically noninvasive method. Ann N Y Acad Sci.1974; 238: 242–62. 4. Aaron RK, Ciombor DM, Therapeutic effects of electromagnetic fileds in the stimulation of connective tissue repair, J Cell Biochem, 1993 May; 52(1) 42-6. 5. Jung-Ho Lee, Sung-Hyoun Cho, Effect of extracorporeal shock wave therapy on denervation atrophy and function caused by sciatic nerve injury. J Phys Ther Sci, 2013 Sep; 25(9): 1067-69 6 Steven Mo; Constantin-C Coussios; Len Seymour; Robert Carlisle (2012). "Ultrasound-Enhanced Drug Delivery for Cancer". Expert Opinion on Drug Delivery. 9(12): 1525. 7. Schils S, Carraqro U, Turner T, Ravara B, Gobbo V, Kern H, Glebmann L, Pribyl J, Funtional electrical stimulation for equine muscle hypertonicity: histological changes in mitochondrial density and distribution. JEVS, 2015 Nov-Dec, 35(11-12) 907-915 8. Schils S, Review of electrotherapy devices for use in veterinary medicine, in Proceedings. Am Assoc Equine Pract 2009;58;68-73. 9. Bogaerts A, et al, Impact of whole-body vibration training versus fitness training on muscle strength and muscle mass in older men: a 1 year randomized controlled trial. J Gerontol A Biol Sci Med Sci. 2007 Jun;62(6):630-5 10. Stubbs NC, Kaiser LJ, Hauptman J, Clayton HM, Dynamic mobilization exercises increase cross sectional area of musculus multifidus. Equine vet J (2011)43 (5) 522-529

R. D. Mitchell, DVM, MRCVS, DACVSMR, Cert. ISELP Dr. Mitchell is originally from North Carolina where he participated in foxhunting and hunter/jumper competitions from childhood to an adult. He is currently president of Fairfield Equine Associates in Newtown, Connecticut, practicing equine veterinary medicine and surgery with an emphasis on lameness and imaging. Dr. Mitchell has served as an official veterinarian for the U.S. Equestrian Team at six Olympic Games, as well as multiple Pan American and World Games. He has been internationally certified in veterinary acupuncture and equine locomotor pathology and is a Diplomate of the American College of Veterinary Sports Medicine and Rehabilitation. Dr. Mitchell has authored many nationally and internationally published articles and textbook chapters on equine health care and welfare. He has served on multiple boards of directors including USEF, Connecticut Veterinary Medical Association, the American Association of Equine Practitioners and the EQUUS Foundation, as well as serving currently as a trustee for the American Horse Council. He is the current chair of the AAEP Foundation Advisory Council. He was a founding board member of the International Society of Equine Locomotor Pathology (ISELP).

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Practitioner Issue 3, 2018  

A publication by the Florida Association of Equine Practitioners, an equine-exclusive division of the FVMA. Your Invitation to Attend the 14...

Practitioner Issue 3, 2018  

A publication by the Florida Association of Equine Practitioners, an equine-exclusive division of the FVMA. Your Invitation to Attend the 14...

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