
Andrew Jonathan DartThe University of Sydney · Faculty of Veterinary Science
Andrew Jonathan Dart
BVSc, PhD, Dip ACVS, Dip ECVS
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Introduction
Skills and Expertise
Publications
Publications (130)
This chapter focuses on some of the more promising adjunctive and novel therapies developed for or adapted to the horse, based on the specific underlying characteristics that govern wound repair in this species. The choice of topics covered in this chapter is based on the volume and quality of data published in the veterinary medical literature per...
Recurrent laryngeal neuropathy (RLN) has been recognised for two centuries in horses. Surveys undertaken in Europe and the United States have reported that prosthetic laryngoplasty is the most common treatment for RLN, particularly for advanced cases. Despite widespread adoption of this surgical technique for treatment of RLN, reported success rate...
Objective
To investigate the effect of activated protein C (APC) on second intention healing of distal limb wounds in horses.Methods
In this experimental study of eight Standardbred geldings, six full-thickness skin wounds (2 × 1.5 cm) were created on one metacarpus (biopsy limb) and five similar wounds were created on the contralateral metacarpus...
In addition to the generic properties of honey, manuka honey has a nonperoxide antimicrobial activity largely attributed to methylglyoxal. Commercially, manuka honey is graded against a standard antiseptic, phenol, to provide a measure of antimicrobial activity referred to as the unique manuka factor (UMF). The higher the UMF, the greater the antim...
Cet article décrit la suture de la ligne blanche lors de relaparotomie à la suite de complications incisionnelles par infection et éventration chez 3 chevaux. La mise en place de points de soutien en matelassier horizontaux avec un fil de suture en acier inoxydable à 10 cm de l’incision a permis d’éviter la déhiscence de la plaie et une hernie inci...
To survey veterinary practitioners in Australia on how they administer pentosan polysulfate (PPS) to horses and their perceptions of the efficacy of PPS for: the prevention and treatment of osteoarthritis (OA), the treatment of OA when PPS is combined with other drugs, and the efficacy of PPS compared with other disease-modifying osteoarthritic dru...
Introduction
Intervertebral disc degeneration (IVDD) is implicated in 40% of low back pain (LBP) cases. A total of 80% of people will be affected by LBP some time in their lifetime. LBP has a considerable socioeconomic impact, costed at $100 billion in the United States in 2006 and $9.17 billion in Australia in 2001. LBP was designated a National H...
Tendon tears are common in both the ageing and sporting communities. Treatments that restore normal structure and function are lacking despite increasing knowledge of the inflammatory and matrix changes that occur in the tissue after a stress-induced injury. Increased cellularity, disruption of collagen fibre alignment and excessive accumulation of...
One of the hallmarks of developing tendinopathy after injury is the accumulation of toluidine-blue-positive sulfated glycosaminoglycan, attributed to increased expression and synthesis of the large proteoglycans (PGs) aggrecan and versican. Indeed, there is evidence that, in many instances, these molecules are already chronically present in the ten...
OBJECTIVE: To determine the effect of horse age and laryngeal prosthesis location on rima glottidis area in cadaveric larynges.
STUDY DESIGN: Experimental study.
ANIMALS: Cadaveric equine larynges (n = 40).
METHODS: Specimens were grouped by age: group 1, ≤5 years (n = 18); group 2, >5 to ≤10 years (n = 12); group 3, >10 years (n = 10). A cranial p...
OBJECTIVES: To evaluate the effect of 3 laryngeal prostheses alone or in combination on rima glottidis area in horses.
STUDY DESIGN: Experimental randomized design.
SAMPLE POPULATION: Cadaveric equine larynges (n = 22).
METHODS: Three prostheses were preplaced in each of 14 larynges. Rima glottidis area was measured after loading each suture in 5 N...
Perlecan is a widely distributed, heparan sulphate proteoglycan with roles in the sequestration of FGFs, PDGF, VEGF through which it promotes cell proliferation and matrix production. Perlecan also stabilises extracellular matrices through interaction with a diverse range of matrix components. This study examined the distribution of perlecan in an...
Objectives:
To compare the effects of manuka honey and manuka honey gel on second intention healing of noncontaminated distal limb wounds and those contaminated with feces.
Study design:
Experimental study.
Animals:
Standardbred horses (n = 10).
Methods:
Five full-thickness wounds (2 × 2 cm) were created on both metacarpi. Wounds on 1 foreli...
Evaluate synovial fluid cytology, total protein concentration and viscosity after intra-articular administration of combined pentosan polysulfate and glucosamine in horses.
Ten adult Standardbred horses had each carpal joint (n = 20) randomly assigned to one of two treatments: control (5 mL saline) or treated (pentosan polysulfate and glucosamine)....
To evaluate the effect of collecting serial tracheal aspirate (TA) and bronchoalveolar lavage (BAL) samples on the cytological findings of subsequent fluid samples obtained from horses without clinical signs of respiratory disease.
Experimental.
Six healthy Standardbred horses.
Endoscopically-guided TA samples, and BAL samples collected using the b...
Review 103 cases of presumed tick envenomation in horses.
Retrospective study.
Variables, including date of presentation, age, breed, weight, presence of ticks, gait and respiration scores, duration of recumbency, treatment, outcome and complications were recorded. A series of univariable screening tests were performed and used in a multivari...
To determine the effect of manuka honey on second-intention healing of contaminated, full-thickness skin wounds in horses.
Experimental.
Adult Standardbred horses (n = 8).
One wound was created on the dorsomedial aspect of the third metacarpus in both forelimbs, contaminated with feces, and bandaged for 24 hours. Bandages were removed and wounds ri...
Suture materials and staples play an important role in wound repair by providing support to healing tissues. There is no ideal suture material. Important properties to consider when selecting a suture material are tensile strength, diameter, tissue absorption, coefficient of friction, knot security and strength, elasticity and plasticity, memory, h...
An 8-week-old, 16-kg alpaca cria was presented with a 2-week history of acute onset of left forelimb lameness.
The cria was weight-bearing but lame at the walk in the left forelimb. There was swelling, heat and pain on palpation of the soft tissues, extending from the mid-shaft of the humerus to the elbow. There was no evidence of a traumatic injur...
Objective: To evaluate whether wound type or site influence the production of cartilage oligomeric matrix protein (COMP) and transforming growth factor β1 (TGF-β1), and determine if there is a correlation between TGF-β1and COMP during healing.
Study Design: Experimental.
Animals: Standardbred horses (n=6), 4–8 years old.
Methods: Six, standardized,...
Two horses presented with a history of severe lameness that was localised to the area around the second phalanx (P2) of one forelimb. Radiographs of the second phalanx of both horses were unremarkable, apart from some smooth periosteal new bone production on the dorsum of P2. Magnetic resonance imaging revealed a non-displaced fracture of P2 in bot...
A 12-week-old female alpaca cria weighing 10 kg presented with a 2-month history of left hindlimb lameness associated with osteomyelitis and sequestration of the shaft and wing of the left ilium. The affected segment of the ilium was surgically removed. Bacteriological culture revealed a small number of mixed aerobic and anaerobic bacteria. The cri...
To evaluate the effect of a non-occlusive dressing incorporated in a 3-layer bandage on second intention healing of wounds of the distal portion of the limb.
Untreated wounds in 33 adult horses used in four studies using the same wound-healing model conducted over 5 years.
Standardised, full-thickness wounds were made in the skin overlying the dors...
To assess the effect of 1 or 2 laryngeal prosthetic sutures on rima glottidis areas in equine laryngeal specimens.
Experimental, randomized design.
Cadaveric equine larynges (n=16).
Larynges were collected from 10 horses; 2 sutures each were preplaced in the right and left sides of each larynx. A dorsal suture (DS) was placed through the caudal rim...
A mare was referred for further evaluation of a mass found in the left caudal abdomen during a routine postpartum reproductive palpation. The mare was clinically normal with no history of health problems. Ultrasonographic examination of the mass confirmed its presence, but the origin of the mass could not be accurately determined. Routine haematolo...
To evaluate histologic, immunohistochemical, and molecular changes in tendon induced by altered strain in a large-animal model.
A full-thickness partial-width laceration of the infraspinatus tendon was created in 5 sheep, while 5 sham-operated sheep were used as controls. Sheep were killed after 4 weeks, and 4 differentially stressed tendon regions...
Ingestion of foreign bodies is uncommon in horses when compared with indiscriminate grazers such as cattle. This case report describes the diagnosis and treatment of a cervical abscess in a Thoroughbred racehorse thought to be associated with ingestion of wire. Radiographic and ultrasonographic examination provided a diagnosis, and conservative tre...
A 1-month-old alpaca cria presented with a 13 degree valgus deformity of the left metacarpophalangeal joint. The angular limb deformity was centered on the distal metacarpal physes. Transphyseal bridging of the physes was recommended. Two 2.7 mm cortical bone screws were placed either side of the distal metacarpal physes and a figure of eight wire...
A 4-day-old alpaca cria presented for inappetence that responded to symptomatic treatment. The cria re-presented with acute signs of inappetence and azotaemia. The azotaemia persisted despite intravenous fluid therapy. There was no right kidney on ultrasound and there appeared to be perirenal oedema around the left kidney. A diagnosis of right rena...
Enteral fluids administered alone, or in conjunction with intravenous fluids, are reported to be useful for the treatment of dehydration and electrolyte loss associated with diarrhoea in a number of species, following exercise in horses and for feed impaction of the large intestine of horses. Enteral fluids are suitable for treatment of mild to mod...
To report dynamic collapse of the apex of the left corniculate process under the right corniculate process into the airway at the dorsal apposition of the paired arytenoid cartilages during exercise as a cause of upper airway dysfunction in horses.
Retrospective study.
Fifteen horses with a history of poor performance and/or upper respiratory tract...
The in vitro and in vivo mechanical properties of the superficial digital flexor tendon have been described. To date the focus has been on single load to failure testing, however refined in vivo methods may prove useful to evaluate the effects of treatment and exercise on tendons. During maximal exercise, the adult superficial digital flexor tendon...
The purpose of the study was to describe the prevalence of upper airway abnormalities and establish if any significant associations existed between study variables and the two most frequently identified disorders; axial deviation of the aryepiglottic folds and dorsal displacement of the soft palate. The clinical records and video-recordings of all...
An adult llama and four alpacas were referred with long bone fractures. The llama presented with a closed, comminuted fracture of the right metatarsal bones. Two of the alpacas presented with comminuted fractures of the proximal radius. One fracture was closed and one was open. One alpaca had a closed, comminuted fracture of the distal radius, and...
Laparoscopy is a minimally invasive procedure that has applications as a diagnostic, therapeutic and prognostic technique. Specialized equipment is necessary to perform equine laparoscopy, and there is a large range of instruments, both disposable and non-disposable available. Laparoscopic procedures described include ovariectomy, cryptorchidectomy...
Wound repair is a complex series of coordinated events regulated by a delicately orchestrated cascade of cytokines and growth factors that restore the structural integrity of damaged tissue. Manipulation of the growth factor profile or wound environment through topical application of therapeutic agents could positively influence the rate and qualit...
A 26-day-old entire male alpaca was referred for surgical treatment of a cleft soft palate. Mandibular symphysiotomy and three-layer closure of the palatal defect resulted in primary intention healing. Despite complications related to anaesthesia the alpaca made a full recovery.
A 2-day-old Warmblood colt foal was referred for evaluation of progressive abdominal distension and lethargy. Haemoperitoneum was diagnosed and a ventral midline laparotomy revealed capsular rupture, sub capsular haematoma and haemorrhage of the left kidney. Unilateral nephrectomy was performed and the foal recovered uneventfully, with no reported...
To evaluate chemical arthrodesis using sodium monoiodoacetate for treatment of degenerative joint disease of the tarsometatarsal and distal intertarsal joints.
Retrospective clinical study.
Horses were diagnosed with degenerative joint disease of one or more of the tarsometatarsal or distal intertarsal joints based on history, lameness examination,...
To determine the effectiveness and incidence of complications of palmar digital neurectomy using the guillotine technique in horses presented for lameness originating from sites innervated by these nerves.
Retrospective study of 24 clinical cases.
Twenty-four horses undergoing a palmar digital nerve neurectomy between June 1997 and June 2001.
The r...
Recombinant equine growth hormone (reGH) has recently been evaluated for effects on body condition and wound healing. It has the potential to influence articular cartilage via stimulation of IGF-1.
To investigate effects of administration on synovial joint metabolism.
Six mature horses were given 20 microg/kg bwt reGH daily for 8 weeks by i.m. inje...
To report on the outcome of surgical treatment of acute abdominal crises in miniature breed horses.
Retrospective case series of miniature horses presented to the University Veterinary Centre, Camden with an acute abdominal crisis.
Hospital records of all miniature horses that underwent ventral midline laparotomy for acute abdominal crisis between...
A female breeding alpaca with acute lameness of the left hindleg was diagnosed with a craniodorsal coxofemoral luxation. Repair was achieved using extracapsular stabilisation. Two nylon sutures were passed through a hole drilled in the femoral neck and anchored to the dorsal acetabulum using two screws and two spiked washers. A metal crimp was used...
Intravenous catheters are used for the administration of medications and fluids and are an integral part of veterinary practice. The aim of catheter use is to optimise administration of medication and minimise complications such as thrombus formation, thrombophlebitis and sepsis. Catheters made from teflon are less flexible, less durable and stimul...
Suture materials play an important role in veterinary surgery by providing support for healing tissues during wound repair. As there is no single ideal suture material, clinicians must compromise on some properties when selecting a material for a specific purpose. By reviewing the characteristics of absorbable and non-absorbable materials, general...
Suture materials play an important role in veterinary surgery by providing support for healing tissues during wound repair. As there is no single ideal suture material, clinicians must compromise on some properties when selecting a material for a specific purpose. By reviewing the characteristics of absorbable and non-absorbable materials, general...
Over-strain injury of the superficial digital flexor tendon (SDFT) is a common injury in the horse. Tendon appears to adapt to loads placed on it during development, but fatigue damage accumulates after skeletal maturity, which is inadequately repaired and predisposes to clinical tendinitis. In any population of horses, there is a wide variation in...
To evaluate the effect of a commercially available 25% propylene glycol hydrogel preparation (Solugel; Johnson and Johnson Medical, North Ryde, Australia) on healing of full-thickness skin wounds on the distal aspect of the limb in horses.
Experimental.
Eight Standardbred horses.
Standardized (2.5 x 2.5 cm) full-thickness skin wounds were created o...
To evaluate the effect of intramuscular administration of recombinant equine growth hormone on healing of full thickness skin wounds on equine limbs.
Experimental.
Nine Standardbred horses.
In study 1, standardized full thickness skin wounds (2.5 x 2.5 cm) were made over the dorsomedial aspect of the mid-cannon bone of 1 forelimb and 1 hindlimb in...
To evaluate the effect of recombinant equine growth hormone (rEGH) on the in vitro biomechanical properties of normal adult equine superficial digital flexor tendon (SDFT).
Completely randomized design.
Nine Standardbred horses, 6 to 9 years of age with ultrasonographically normal forelimb SDFT.
Six horses were administered intramuscular (IM) rEGH...
To evaluate the effect of recombinant equine growth hormone (rEGH) on the in vitro biomechanical properties of healing superficial digital flexor tendon (SDFT) in horses.
Completely randomized design.
Twelve Standardbred horses, 3 to 7 years of age, with ultrasonographically normal forelimb SDFT.
One week after induction of collagenase (2,000 U) in...
Objective To determine the predictive values, sensitivity and specificity of abdominal fluid variables associated with the need for surgery in horses with an acute abdominal crisis.DesignRetrospective study.AnimalsTwo-hundred and thirty-six horses examined for signs of abdominal pain between January 1993 and June 1999.Methods
Breed, age and gender...
Minimally displaced, spiral, radial fractures were diagnosed in three adult horses. Two horses had open fractures and in one horse the fracture was closed. A diagnosis was made on radiographs taken 24 h, 5, and 9 days after the fracture. There was minimal displacement of the fracture fragments despite the considerable time which had elapsed between...
Two alpaca crias and one 14-month-old alpaca were referred for treatment of bilateral carpal valgus. In one cria, hemi-circumferential periosteal transection and elevation combined with an ulna osteotomy was performed initially without success, however transphyseal bridging with screws and wires was used successfully in both crias to straighten the...
To evaluate the effects of three different doses of sodium pentosan polysulphate (PPS) on haematological and haemostatic variables in adult horses.
Eight adult standardbred horses were used. All horses received a single injection of 0, 3, 6, and 10 mg/kg of PPS at the beginning of each treatment week for 4 weeks so that by the end of the study all...
To review the clinical findings, diagnosis and treatment of 51 horses with peritonitis attributed to Actinobacillus equuli.
Retrospective study of clinical cases.
Breed, age and gender of horse, history, physical examination findings, treatment and outcome were determined from the hospital records of 51 horses in which a diagnosis of peritonitis at...
To determine whether quantitative analysis of sonographic brightness could be used to detect healing of an induced injury of the superficial digital flexor tendon in horses and whether rate of healing was influenced by equine recombinant growth hormone.
8 clinically normal Standardbreds.
A localized injury was created in the left and right superfic...
Three horses with severely comminuted, open facial bone fractures and one horse with a comminuted, open orbital rim fracture were referred for treatment. Severe facial bone asymmetry and epistaxis were apparent in all cases and subcutaneous emphysema was present in two, however physical and neurological examinations were otherwise normal. Radiograp...
To evaluate high-speed treadmill videoendoscopy as a diagnostic technique and document the abnormalities found in Australian horses referred for poor performance associated with abnormal upper respiratory tract noise but where a definitive diagnosis could not be made at rest.
A retrospective clinical study using client-owned horses.
The clinical re...
A 2-week-old Miniature Horse foal was referred for evaluation and treatment of a luxated right tarsometatarsal joint. Treatment consisted of closed reduction and internal fixation using two partially threaded Steinmann pins placed in normograde fashion through the tuber calcis into the proximal third metatarsus.
Traumatic luxation has been reported...
The superficial digital flexor tendon (SDFT) is an elastic structure that during maximal exercise appears to operate close to its functional limits. The biomechanical and biochemical responses to exercise, injury, and healing are still poorly understood but ongoing research is providing valuable new information which is addressed in this review. It...
Three alpacas that presented with dystocia characterised by failure of the cervix to dilate, underwent caesarean section. Surgery on each animal was performed through a ventral midline incision under general anaesthesia. Two live crias were delivered and one cria was dead at delivery. All three alpacas had retained foetal membranes for a period of...
A mature male alpaca with acute lameness of the left handlimb was diagnosed as having a rupture of the cranial cruciate ligament. Repair was achieved using a combination of surgical techniques. A patellar ligament autograft was passed under the cranial meniscal ligament, through the joint and over the femoral condyle, and anchored using a screw and...
To evaluate nonsurgical management of type II fractures of the distal phalanx in Standardbred horses.
Retrospective study of 48 affected horses.
Most fractures occurred on the lateral palmar process of the left forelimb or the medial palmar process of the right forelimb; 81% of horses were considered sound enough to return to training and 63% raced...
Three neonatal alpacas were treated for MCP flexural deformities. Two crias responded well to conservative therapy using splints made from fibreglass cast material. One cria with severe deformity failed to respond to conservative treatment but recovered satisfactorily after transection of the suspensory ligament in both legs. It seems that mild cas...
Complications associated with equine castration are the most common cause of malpractice claims against equine practitioners in North America. An understanding of the embryological development and surgical anatomy is essential to differentiate abnormal from normal structures and to minimise complications. Castration of the normal horse can be perfo...
Three Thoroughbred horses with unilateral progressive ethmoid haematomas were treated using intralesional injections of 10% formalin (4% formaldehyde solution). Injections were performed in the standing sedated horse through the nasal passages under endoscopic guidance and, when the ethmoid haematoma involved the paranasal sinuses, through holes tr...
A captive Malayan tapir was observed to have inappetence, weight loss, signs of depression, mild dehydration and diarrhoea. Haematological and serum biochemical tests showed anaemia, hypoproteinaemia, hyperfibrinogenaemia and neutrophilia with a left shift. Ultrasonic examination of the abdomen under anaesthesia revealed a well-encapsulated abscess...
To evaluate the clinical, haematological, and serum biochemical effects of two large doses of recombinant equine growth hormone.
Duplicated Latin square.
Three Thoroughbred and three Standardbred mares aged between 12 and 17 years.
Two horses were randomly assigned into one of three groups. On each of three successive days, each horse pair received...
All horses undergoing coeliotomy for an acute abdominal crisis are at risk of developing ileus and should receive therapy aimed at promoting gastrointestinal function by restoring fluid and electrolyte balance. Adequate analgesia and prevention against peritonitis, bacteraemia and endotoxaemia should be provided. Horses that at the time of surgery...
To review the breed, age, gender, clinical and laboratory findings, treatment and outcome of horses with caecal disease presented to a referral centre.
Retrospective study of 96 cases.
The breed, age, and gender of the study population were compared with the corresponding hospital population for the same period. The means (+/- SD) for clinical and...