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Biomedical subjects

A J Dart

Publications and source records attributed to A J Dart.

At least 37 records · Page 2Linked to original sources
PubMed2001

Evaluation of high-speed treadmill videoendoscopy for diagnosis of upper respiratory tract dysfunction in horses.

OBJECTIVE: 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. DESIGN: A retrospective clinical study using client-owned horses. PROCEDURE: The clinical records and videorecordings of all horses referred to the University of Sydney for poor performance associated with abnormal upper respiratory tract noise during a 13-month period were examined. Only horses with a normal physical examination including absence of lameness, and where a definitive diagnosis of the cause of the abnormal upper respiratory tract noise could not be made from the resting videoendoscopic examination were included in the study. The age, gender, breed of horse and the purpose for which the horse was used were ascertained from the record and videorecordings were reviewed by the authors and any abnormalities noted. RESULTS: There were 37 horses included in the study. An upper airway abnormality was identified during high-speed treadmill videoendoscopy in 73% of horses. One abnormality was identified in 22 horses, 2 abnormalities in 4 horses and 3 abnormalities in 1 horse. Abnormalities identified included laryngeal hemiparesis (n = 15), axial deviation of the aryepiglottic folds (n = 10), pharyngeal collapse (n = 3), dorsal displacement of the soft palate (n = 2), epiglottic collapse (n = 1), axial deviation of the vocal cord (n = 1) and laryngeal collapse (n = 1). CONCLUSIONS: The results of this study are similar to reports from overseas and suggest high-speed treadmill videoendoscopy appears to be a useful technique to diagnose the cause of upper airway dysfunction in Australian horses referred specifically for poor performance associated with abnormal upper respiratory noise. However, a diagnosis will not be made in all horses undergoing this procedure. There were five horses with two or three abnormalities none of which were apparent at rest. This would suggest that in all horses making abnormal upper respiratory noise associated with poor performance, even where an abnormality is identified at rest, high-speed treadmill videoendoscopy should be performed for a complete diagnosis.

Animals↗
PubMed2001

Peritonitis associated with Actinobacillus equuli in horses: 51 cases.

OBJECTIVE: To review the clinical findings, diagnosis and treatment of 51 horses with peritonitis attributed to Actinobacillus equuli. DESIGN: Retrospective study of clinical cases. METHODS: 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 attributed to A. equuli was made between January 1993 and June 1999. Results of abdominal fluid cytology and bacteriology, antimicrobial sensitivity patterns, haematology and faecal egg counts, when performed, were also retrieved. RESULTS: There was a variety of breeds of horses affected. There were 35 male and 17 female horses, aged from 9 months to 22 years, presented. Lethargy, signs of depression with mild to moderate signs of abdominal pain and inappetence were the most common reasons for presentation. Most horses had elevated heart and respiratory rates, an elevated rectal temperature and reduced intestinal borborygmi heard on auscultation of the abdomen. Abnormal colour with an elevated protein were features of an abdominal fluid sample in 98% of horses and a marked elevation in nucleated cell count was present in all samples. Pleomorphic gram-negative rods were seen on cytology in 53% of samples and a positive culture of A. equuli was returned in 72% of samples. Other laboratory findings in some horses included mild haemoconcentration, hypoproteinaemia, an elevated circulating nucleated cell count with a left shift, an elevation in fibrinogen concentration and an elevated faecal egg count. All horses demonstrated a rapid response to treatment with procaine penicillin alone, or a combination of procaine penicillin and gentamicin sulphate. Where antimicrobial sensitivity tests were performed, all but two isolates were sensitive to procaine penicillin. All horses responded to antimicrobial and supportive therapy and were discharged from hospital. CONCLUSION: Horses with A. equuli peritonitis present with similar clinical signs as horses with other causes of abdominal pain. However, these signs, when evaluated in conjunction with the results of abdominal fluid analysis and response to treatment, are characteristic of A. equuli peritonitis. Pleomorphic gram-negative bacteria may be seen on a cytological preparation of the abdominal fluid sample, and a positive bacterial culture may be obtained in some, but not all, cases. Most isolates are sensitive to procaine penicillin, so treatment with procaine penicillin and gentamicin sulphate is recommended until antimicrobial sensitivity is known.

Actinobacillus↗
PubMed2001

Surgical correction of carpal valgus deformity in three alpacas.

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 limbs. As the distal radial and ulna growth plates had closed in the 14-month-old alpaca, bilateral wedge ostectomies of the distal radius and transfixation casts were used to straighten and stabilise the limbs. The ostectomy sites healed and the alpaca is ambulatory, although carpal flexion is significantly reduced. Until the relationship between the growth rate of crias and the success of hemicircumferential periosteal transection and elevation and ulna osteotomy is established, transphyseal bridging may provide a more reliable result in crias with carpal valgus deformity and open physes. Wedge ostectomy and application of a transfixation cast can be used to correct severe carpal valgus deformities in alpacas with closed physes.

Animals↗
PubMed2001

Surgical repair of skull fractures in four horses using cuttable bone plates.

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. Radiography and endoscopy were of some use in assessing the degree of damage, although the true extent of the damage was more apparent at surgery. Surgical reduction of the fractures was recommended to maximise cosmetic and functional outcome. After surgical debridement and reduction of the fractures the bone fragments remained unstable and were not amenable to stabilisation with interfragmentary wires alone, so 2 mm cuttable bone plates were used to maintain fracture alignment. Screw migration occurred in three horses and in one of these horses the plate had to be removed. Other complications were minor and in all horses the fractures healed with good cosmetic and functional outcome. The use of cuttable bone plates should be considered as a reasonable alternative to inter-fragmentary wiring for unstable, comminuted fractures of the facial bones, even where fractures are open.

Animals↗
PubMed2001

Use of quantitative analysis of sonographic brightness for detection of early healing of tendon injury in horses.

OBJECTIVES: 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. ANIMALS: 8 clinically normal Standardbreds. PROCEDURES: A localized injury was created in the left and right superficial digital flexor tendons of each horse by injection of 2,000 units of collagenase. After injury, 4 horses received equine recombinant growth hormone, a possible promoter of tendon healing. Sonographic images (7.5 MHz) of the flexor tendons and ligaments of the metacarpal region were recorded on videotape prior to injury and weekly for 7 weeks after injury. Images were digitized, and sonographic brightness of tendons and ligaments was calculated. RESULTS: Collagenase-induced injury was sonographically similar to naturally occurring injury. After injury, sonographic brightness of the tendon decreased; after 3 weeks, brightness progressively increased, although by 7 weeks brightness had not returned to preinjury value. Equine recombinant growth hormone had no significant effect on the rate of tendon healing, as evaluated sonographically or at necropsy. CONCLUSIONS AND CLINICAL RELEVANCE: As healing developed, alterations in sonographic brightness of injured tendons coincided with real changes in tendon structure. Quantitative sonographic brightness could be used to accurately monitor healing of equine tendon and ligament injuries and investigate the efficacy of various treatment regimens.

Animals↗
PubMed2000

Surgical treatment of tarsometatarsal joint luxation in a miniature horse foal.

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 to occur in the tarsocrural, proximal intertarsal and tarsometatarsal joints within the equine tarsus. Treatment for luxation of the distal intertarsal joint has not been documented. The treatment method most commonly suggested for tarsal luxation is closed reduction and cast immobilisation. Internal fixation using lag screws and plating has also been described. A combination of internal fixation and external coaptation is thought to achieve maximal stability and allow faster convalescence in cases of tarsal luxation. This case report describes for the first time a technique using two Steinmann pins to achieve successful internal fixation of a traumatic tarsometatarsal joint luxation in a 2-week-old Miniature Horse foal.

Animals↗
PubMed2000

Ventral midline caesarean section for dystocia secondary to failure to dilate the cervix in three alpacas.

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 12 h to 4 d and one developed uterine prolapse, which was replaced using sedation and epidural anaesthesia. There were no complications associated with the surgical procedure and all three alpacas went on to have confirmed pregnancies. Caesarean section through a ventral midline incision should be considered an alternative for treatment of difficult dystocias in alpacas.

Animals↗
PubMed2000

Superficial digital flexor tendonitis in the horse.

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 appears that the SDFT matures early, after which time it has limited ability to adapt to stress and undergoes progressive degeneration. Focal hypocellularity, collagen fibril degeneration, selective fibril loading and alterations in the noncollagenous matrix occur primarily within the central core region of the midmetacarpal segment. Current treatment strategies have had equivocal results in returning animals to optimal athletic activity. To date it would seem that progressive rehabilitation programmes coupled with regular ultrasonographic evaluations are a cost-effective and comparable strategy when compared to surgical treatment methods. Recent interest in pharmacological modulation of intrinsic healing of collagenous structures has led to the investigation of various growth factors as potential therapeutic aids in the healing of tendon injuries. However, one of the major goals in tendon research, and one which holds the most optimism for success in the immediate future, is the prevention of tendon injuries.

Animals↗
PubMed1999

Treatment of progressive ethmoidal haematoma using intralesional injections of formalin in three horses.

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 trephined into the affected sinus. Regression of the lesions occurred in all cases after repeated injections. This technique appears to be a safe and effective treatment for progressive ethmoid haematomas in the horse.

Animals↗
PubMed1999

Equine castration: review of anatomy, approaches, techniques and complications in normal, cryptorchid and monorchid horses.

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 performed using sedation and regional anaesthesia while the horse is standing, or under general anaesthesia when it is recumbent. Castration of cryptorchid horses is best performed under general anaesthesia at a surgical facility. Techniques for castration include open, closed and half-closed techniques. Failure of left and right testicles to descend occurs with nearly equal frequency, however, the left testicle is found in the abdomen in 75% of cryptorchid horses compared to 42% of right testicles. Bilateral cryptorchid and monorchid horses are uncommon. Surgical approaches described for the castration of cryptorchid horses include an inguinal approach with or without retrieval of the scrotal ligament, a parainguinal approach, or less commonly a suprapubic paramedian or flank approach. Laparoscopic castration of cryptorchid horses has recently been described but the technique has limited application in practice at this time. A definitive diagnosis of monorchidism can only be made after surgical exploration of the abdomen, removal of the normal testis and hormonal testing. Hormonal assays reported to be useful include analysis of basal plasma or serum testosterone or oestrone sulphate concentrations, testosterone concentrations following hCG stimulation, and faecal oestrone sulphate concentrations. Reported complications of castration include postoperative swelling, excessive haemorrhage, eventration, funiculitis, peritonitis, hydrocele, penile damage and continued stallion-like behaviour.

Animals↗
PubMed1999

Nonsurgical management of type II fractures of the distal phalanx in 48 standardbred horses.

OBJECTIVE: To evaluate nonsurgical management of type II fractures of the distal phalanx in Standardbred horses. DESIGN: Retrospective study of 48 affected horses. RESULTS: 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. Of those returning to racing, 41% competed in > 10 races, 37% in 2 to 10 races and 22% in only 1 race. There was no difference in performance before and after fracture. Twenty-four of 25 horses had a bar shoe fitted for > 50% of the treatment phase. Of those horses returning to training without a bar shoe, 89% refractured at the same site. Sixty percent of horses returning to training with a bar shoe raced successfully. The total convalescent time, the time rested in a box and the time spelled in a paddock were similar for horses returning to racing and those that did not. The age of the horse had no effect on the ability to return to racing. CONCLUSION: The prognosis for type II fractures of the distal phalanx is guarded. It is advisable to fit a bar shoe on the horse during convalescence. Horses returning to training and racing with a bar shoe appear less likely to refracture the distal phalanx. Those horses that return to racing can perform at a level similar to that prior to fracture.

Animals↗
PubMed1999

Management of bilateral flexural deformity of the metacarpophalangeal joints in three alpaca crias.

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 cases of flexural deformity of the MCP joint in alpaca crias respond well to conservative therapy but that surgical correction may be required in more severe cases. Sequential transection of the structures limiting extension of the MCP joint may result in fewer complications than previously reported techniques.

Animals↗
PubMed1999

Repair of cranial cruciate ligament rupture in an alpaca.

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 washer. Two nylon sutures were passed through a hole made in the tibial crest, and secured under the screw. The alpaca was confined in a stall for 3 months. Exercise was then increased progressively for 3 months. One year after surgery the alpaca is sound and has resumed breeding activity.

Animals↗
PubMed1998

Surgical management of an abdominal abscess in a Malayan tapir.

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. The abscess was marsupialised to the ventral body wall. Culture of the pus produced a mixed bacterial growth. Antimicrobial therapy was based on bacterial sensitivity results. Follow-up ultrasonic examinations showed resolution of the abscess. Ninety-one days after surgery the tapir began regurgitating food and water. An abscess originating from the stomach and occluding the lumen of the duodenum was identified at surgery. The abscess ruptured during surgical manipulations and the tapir was euthanased.

Abdominal Abscess↗