Urinothorax in a Quarter Horse filly

An 18 h old Quarter Horse filly, while being treated for diarrhoea, was evaluated for a distended abdomen and electrolyte abnormalities. Peritoneal and pleural fluid was detected by ultrasound and a presumptive diagnosis of a ruptured bladder was made. Intravenous fluid therapy was instituted to correct the electrolyte abnormalities prior to surgical repair of the bladder tear. Anaesthetic complications included hypoxaemia and decreased compliance secondary to the pleural effusion; therefore, a thoracocentesis was performed. Analysis of the pleural fluid revealed a pleural fluid to serum creatinine ratio of >1.0, indicative of urinothorax. The filly recovered from anaesthesia and was discharged on systemic antimicrobials. Urinothorax should be considered in cases of uroperitoneum with concurrent pleural effusion. Early detection may decrease patient morbidity and anaesthetic complications.     

The use of computed tomography to assist orthopaedic surgery in 86 horses (2002–2010)

Imaging‐assisted orthopaedic surgery is becoming part of routine orthopaedic practice in horses and several techniques have been reported. However, there are no published reports describing the use of intraoperative computed tomography (CT) for surgical guidance and immediate post operative control in the horse. This use of CT in equine orthopaedics is currently limited because of the logistic problems associated with availability of CT scans in surgical theatres as well as concerns over radiation safety. The aim of this report was retrospectively to report CT assisted orthopaedic surgical cases in our practice through identifying the types of surgery where it was used, to list the technical problems that were encountered, to describe solutions to these, and to discuss the applications of the technique. All surgical procedures were performed with the assistance of a peripheral quantitative computed tomography (pQCT) scanner. CT assisted orthopaedic surgery in 86 patients during the study period. Reasons for CT included: 1) use of CT at the beginning of the surgical procedure to document the lesion and identify surgical landmarks (n = 75); 2) pre, intra‐ and post operative use of CT in comminuted fractures of the middle or proximal phalanx to guide and control internal fixation (n = 7); and 3) post operative use of CT to monitor the results of the surgical procedure (n = 4). Proper planning in both the draping steps and the use of polyvinyl splints to stabilise the limb allowed for movements of the gantry around the limb. The time required to obtain one slice was not dissimilar to the time that is necessary to take and process a single digital radiograph. The radiation dose with the pQCT described here is <0.5 µSv and its acquisition time should be balanced against radiation risks of conventional CT systems.     

Bilateral ureterocystostomy to correct left ureteral atresia and right ureteral ectopia in an 8-month-old standardbred filly

OBJECTIVES: To report the diagnosis and outcome after surgical correction of bilateral distal ureteral anomalies in a Standardbred filly. STUDY DESIGN: Clinical case report. ANIMAL: An 8-month-old, 310 kg Standardbred filly with left ureteral atresia and right ureteral ectopia. METHODS: The filly was admitted for evaluation of incontinence since birth and severe urine scalding of the hindquarters. Diagnosis was made by both direct (cystoscopy and vaginoscopy) and indirect (intravenous pyelography, ultrasonography, and scintigraphy) evaluation of the ureters and bladder. The filly had left ureteral atresia, hydronephrosis, and decreased left-sided renal function and right ureteral ectopia before surgery. Surgical correction was performed on the left by an end-to-side stapled anastomosis technique and on the right by a side-to-side hand-sewn anastomosis technique. RESULTS: Surgical correction was successful. The filly had no postoperative complications and remained continent 18 months after surgery. Left renal function improved. CONCLUSION: Ureteral anomalies can be successfully repaired in larger (>300 kg) foals and some renal function may be restored after surgical correction. CLINICAL RELEVANCE: Scintigraphy should be considered in diagnosis of ureteral anomalies, assessing renal function, and determining prognosis for horses with hydronephrosis caused by ureteral ectopia and atresia.     

Endoscopic diagnosis of unilateral ectopic ureter in a yearling filly

Unilateral ectopic ureter was diagnosed by endoscopic examination in an 18-month-old filly examined because of chronic urine dribbling. Intramuscular administration of azosulfamide discolored the urine and enhanced visualization of the ectopic ureter. Endoscopy proved valuable in determining that only one ureter entered the urinary bladder and in locating the ectopic ureter in the ventral portion of the vagina.     

Comminuted basilar skull fracture in a colt: Use of computed tomography to aid the diagnosis

The case of a one‐year‐old colt with acute onset of neurological dysfunction and epistaxis after a traumatic event is presented. After initiating emergency treatment, the colt was anaesthetised for diagnostic imaging. Radiographic examination of the head was suggestive of soft tissue opacity in the area of the guttural pouches, but was inconclusive about osseous involvement. A computed tomography (CT) scan, used to obtain further details, showed a comminuted basilar skull fracture with 2 displaced fragments that were not detected by radiography. Because of the poor prognosis for survival and return to athletic function, the horse was subjected to euthanasia. CT imaging provided the most useful diagnostic information about type, localisation, extension and severity of the basilar skull fracture.     

Congenital hypoplasia of the dorsal colon in a Quarter Horse filly with chronic,intermittent colic

Congenital colonic anomalies are rare in the horse and, to the authors' knowledge, no cases have been reported that include measurements of each segment of the large colon to confirm which section is abnormal. This case report describes chronic, intermittent colic in a Quarter Horse filly that had been attributed to chronic idiopathic hepatitis prior to an exploratory laparotomy. A colonic anomaly discovered at surgery became the primary differential for aetiology of the intermittent colic. Euthanasia of the filly and necropsy allowed further examination of the anomaly, where it was determined that the dorsal colon was short compared to the ventral large colon. In addition, the diagnosis of chronic idiopathic hepatitis was confirmed.     

Developmental orthopaedic disease and early osteoarthritis of the temporomandibular joint in a 15-month-old Quarter Horse filly

A 15-month-old Quarter Horse filly presented for evaluation of hard swellings over the left temporomandibular joint (TMJ) and the right metatarsophalangeal joint (MTPJ). The TMJ swelling had been noted since she was weaned at 4 months of age and had slowly enlarged since then. Radiographs of both TMJs and the right MTPJ were performed, which revealed severe osteoarthrosis associated with osteochondrosis-like lesions. The filly was subjected to euthanasia due to the poor prognosis for performance. Computed tomography and post-mortem examination, including histopathology of the left TMJ, revealed early osteoarthritis (OA) associated with osteochondrosis-like lesions of the left TMJ and the right MTPJ, while the right hind proximal interphalangeal joint (PIPJ) was diagnosed with early OA.     

The use of computed tomography to diagnose bilateral forelimb tendon pathology in a horse with unilateral lameness

A horse with unilateral forefoot lameness had bilateral deep digital flexor tendon (DDFT) lesions on computed tomography (CT). Venous contrast enhanced CT revealed distal sesamoidean impar desmitis in the lame forelimb. Computed tomography is useful for diagnosis of soft tissue lesions within the hoof capsule and contrast enhancement improves lesion conspicuity.     

Surgical management of an enterocutaneous umbilical fistula caused by an incarcerated Richter's hernia in a one-year-old Quarter Horse filly

This article reports a case of a one-year-old Quarter Horse filly with an enterocutaneous fistula resulting from an umbilical hernia since birth, treated successfully by en bloc resection of the hernial sac with the fistula and closure of the ileum with a modified Heineke-Mikulicz technique. This consisted of closing the intestinal wound transversely to the long axis after excision of the fistula to help preserve a sufficient intestinal lumen and prevent potential stricture formation after longitudinal closure. Umbilical hernias are reported to have an incidence of 0.5–2.0% usually resolve spontaneously. Reducible hernias do not represent a surgical emergency whereas incarcerations should always undergo surgery as soon as possible. Enterocutaneous fistulae occur uncommonly as a result of congenital umbilical herniae that developed spontaneously into Richter's herniae or Littré herniae or they are induced traumatically or iatrogenically after therapeutic attempts. In most cases, enterocutaneous fistulae do not require immediate surgery. However, the excision of the fistula should be scheduled within a few days after diagnosis. In the current case, the owner reported a healthy development of the filly after 1 year without any functional problems. This case represents an example of successful use of the Heineke-Mikulicz technique to establish an alternative to standard end-to-end anastomosis.     

Comparison between radiography and computed tomography for diagnosis of equine skull fractures

The equine head is a complex structure prone to traumatic injuries. To determine the value and limitations of radiography and (CT) for the diagnosis of skull fracture, the differences between the two modalities were described. Two observers retrospectively reviewed the radiographic and CT images of 18 horses with a skull fracture. To allow direct comparison between the two modalities, a simplified fracture classification system was used. In 3/18 cases the evaluation of the radiographic examination concluded no injuries visible. In 2/15 cases soft tissue involvement was not detected and in 7/15 cases the extension of the fracture was underestimated with radiography. Radiography classified 4/10 multiple fractures incorrectly as single fracture and 5/15 comminuted fractures on CT were diagnosed as simple fracture with radiography. The number of fragments was underestimated with radiography in 14/15 cases. In conclusion, radiography is able to diagnose a skull fracture in most cases. Skull fractures however are not similarly classified after radiographic and CT evaluation, which causes a difference in interpretation and perception of the fractures. Therefore, CT should be the modality of choice for surgical planning and prognosis.     

A technique for computed tomography (CT) of the foot in the standing horse

Computed tomography (CT) in equine orthopaedics is currently limited because of the price, availability, impossibility to transport the scanner into surgical theatre, and the contraindications of general anaesthesia in some patients. A pQCT (peripheral quantitative computerised tomography) scanner was designed by the authors to image the limbs of the horse, both in standing or recumbent position. Standing computed tomography of the foot with a pQCT scanner is feasible and well tolerated by the horse. It enables good visualisation of bony structures but is not suitable to evaluate soft tissues. The technique can also assist surgery by assessing the 3D configuration of bone lesions.     

Analysis of conformational variations of the cricoid cartilages in Thoroughbred horses using computed tomography

Reasons for performing study: Loss of arytenoid abduction is a common post operative complication of laryngoplasty without a definitive cause. It has been a clinical impression during laryngoplasty surgery that there is great conformational variability along the caudal edge of the Thoroughbred cricoid cartilage that could impact post operative retention of suture position. A change in suture position would probably lead to some loss of abduction. Defining any structural variability of the cricoid would be an initial step in determining whether this variability could impact on the retention of suture position. Hypothesis: Anatomical variations in the larynx of Thoroughbred horses may be detected and measured using objective analysis and computed tomography. Methods: Larynges were harvested from 15 mature Thoroughbred horses. Helical CT scans were performed on each specimen. Three independent observers performed a series of measurements on 2D and 3D reconstruction images using digital software. Measurements included the lateral cricoid angle, the caudal cricoid prominences, the distance to the cricoid slope, the angle of the cricoarytenoid joints (CAJ), the cricoid thickness and the suture angle. Mean, standard deviation, coefficient of variation and linear regression analysis were performed among all observers and all measurements. Results: Notable conformational differences were evident on the 3D reconstructions. The highest degree of variability was found in 3 measurements: the distance to the lateral cricoid slope, the lateral cricoid angle and the cricoid thickness. A larger left CAJ angle directly and significantly correlated with a larger suture angle. Conclusions: There are notable conformational differences among cricoid specimens in the Thoroughbred larynx. Potential relevance: The morphometric differences identified may impact on optimal prosthesis placement and long‐term retention. Since a larger lateral cricoid angle may facilitate abduction loss secondary to a displaced and loosened suture, alternative techniques for suture placement may be of value to prevent arytenoid abduction loss.     

Use of serial standing computed tomography for diagnosis,treatment and monitoring of a horse with acute myonecrosis of the head

An 11-year-old American Quarter Horse gelding was referred to the JT Vaughan Large Animal Teaching Hospital at Auburn University, College of Veterinary Medicine, for investigation of acute and severe right-sided facial swelling and nasal discharge. Standing computed tomographic (CT) examination of the head identified severe soft tissue swelling surrounding the right mandible, emphysema within the soft tissues tracking along fascial planes and right-sided caudal and rostral maxillary sinusitis. Using CT identification and ultrasound guidance, several targeted fasciotomies were created into the right masseter, cranial cervical musculature, supraorbital space and caudo-medial aspect of the mandible. The right-sided sinusitis was treated by right conchofrontal sinus trephination and lavage. Aerobic and anaerobic cultures obtained from the fasciotomy sites and conchofrontal sinus both yielded Prevotella intermedia and Peptostreptococcus asaccharolyticus. During hospitalisation, serial, standing CT examinations were performed for monitoring case progression and guiding further fasciotomies in the face of continued myonecrosis. Follow-up CT performed at 1 month showed resolution of the emphysema and presence of chronic right ventral conchal sinusitis. The sinusitis was treated by fenestration of the right ventral concha with a diode laser via the nasal passage.     

Technical set‐up and radiation exposure for standing computed tomography of the equine head

The recent adaptation of human computed tomography (CT) machines to enable scanning of the equine head via standing sedation has revolutionised our ability to acquire images of this complex anatomical region. There are a small number of CT systems installed worldwide and it is to be expected that this will increase in the next few years; however, currently, there is no publication that describes the technical set‐up required to permit CT scanning of the equine head. This paper describes the technical set‐up, technique and exposures necessary to accomplish CT scanning of the horse under standing sedation to diagnose disorders of the equine head.     

Congenital hypodontia in three horses diagnosed by computed tomography

Dental agenesis is a congenital disease defined as failure of formation of one or more teeth, which has been extensively described in human literature and that has been documented in several other species including cats, dogs, seals and sea lions, mice, and ungulates. The aim of this study was to review the clinical and computed tomographic (CT) features of tooth agenesis in a population of horses. Retrospective review of the imaging records from the Langford Equine Hospital was performed, including all horses that underwent head CT between January 2015 and June 2017. Of a total number of 167 CT scans, three horses with hypodontia were found. All three cases had agenesis of the maxillary 08s and one case had additional agenesis of the 307 and 308 teeth. Delayed resorption of the corresponding deciduous teeth was reported in all cases. The empty space left by the absent teeth was filled either by heterogeneous bone tissue alone (two cases) or by a combination of bone and soft tissue (one case). Alignment between teeth was preserved, and there was no displacement of the neighbouring teeth adjacent to the agenesis site. All three horses presented a symmetric pattern of dental agenesis within the maxillary arcades. The maxillary 08s, which are the latest to erupt, were the most affected teeth. This was similar to that reported in human literature, where the teeth that form later during development are the most vulnerable to dental agenesis.     

Histopathology and computed tomography of age‐associated degeneration of the equine temporohyoid joint

Reasons for performing study: The aetiology of temporohyoid osteoarthropathy (THO) is unknown; both primary infectious and degenerative causes have been suggested. Hypothesis: There is a significant association between increasing age and severity of temporohyoid joint degeneration. To examine the histopathology of the temporohyoid articulation in aged horses and to compare the appearance of the joint with computed tomography (CT) and peripheral quantitative CT (pQCT). Methods: pQCT scans of the temporohyoid articulations were obtained bilaterally from 31 horses (range age 1–44 years) post mortem and images were graded by 2 blinded observers on 2 occasions for the presence of osteophytes, irregularity of the joint surface and mineralisation. Eight heads had been examined previously by CT, with the images similarly graded for the shape and density of the proximal stylohyoid bones, bone proliferation surrounding the joint, mineralisation of the tympanohyoid cartilage and the relationship of the petrous temporal bone to the stylohyoid bone. Sixteen temporohyoid joints were then evaluated histologically. Results: There was significant association between the mean pQCT degeneration score and age (rho = 0.75; P<0.0001), between the pQCT and CT score (rho = 0.63; P = 0.01) and between the degenerative changes identified within each temporohyoid joint within each horse (rho = 0.81; P<0.0001). Age‐associated changes included the development of a club shape by the proximal stylohyoid bone, rounding of the synostosis with the petrous temporal bone and extension of osteophytes from the petrous temporal bone to envelope the stylohyoid head and bridge the joint. In no horse was there any evidence of osteomyelitis within the petrous temporal bone, stylohyoid bone or tympanohyoid cartilage. Conclusions: This study provides evidence that age is associated with increasing severity of degenerative changes in the equine temporohyoid joint and that similar changes are commonly found bilaterally. Potential relevance: The changes identified appear similar, albeit milder to the changes reported in horses with THO, suggesting that degenerative, rather than infectious causes may underlie the aetiology of THO. Future work should be directed at examining the histopathology of clinical THO cases.     

Use of computed tomography to evaluate a fracture associated with a subchondral pedal bone cyst in a horse

The radiological examination of bone lesions can be challenging, considering the complex superimposition of the 3D anatomy of a region on to a 2D image. This report describes the findings achievable with different diagnostic imaging modalities (radiography, arthrography, spiral computed tomography) and the correlation with the post mortem and histopathological findings in a horse with a fracture associated with an osseous cyst‐like lesion in the third phalanx. CT was highly superior to radiography to evaluate the spatial configuration and completeness of the fracture, relationship between the fracture and osseous cyst‐like lesion, architecture of the cyst, presence of its communication with the joint and secondary degenerative joint disease. In conclusion, CT represents an asset in these cases for an accurate prognosis and therapy.     

Reoccurrence of a paranasal osteoma following surgical removal in a 6-month-old Warmblood filly

A 6-month-old Warmblood filly presented for evaluation of a left sided unilateral mucopurulent discharge of 5 weeks' duration. Upper airway endoscopy revealed a large, smooth mass in the region of the ethmoturbinates. Dorso-ventral and lateral radiographs of the head revealed a large osseous mass in the left paranasal area. A biopsy was performed under general anaesthesia and an osteoma was diagnosed. A computed tomography (CT) examination was performed to guide surgical removal. Surgery was performed under general anaesthesia and a large mass was removed ~15 × 9 cm. A CT examination 3 months following surgery revealed three small areas of mineralisation. It was difficult to differentiate if these were areas of regrowth or portions of the original mass that were not entirely removed. A CT examination 8 months later revealed one of the areas had increased moderately in size. A second surgery was performed standing to remove the growth. A final CT 8 months later revealed no further evidence of a bone growth. This report describes the successful removal of an osteoma regrowth following initial surgical removal and, to the best of the authors’ knowledge, is the first to describe the reoccurrence of an osteoma after surgical intervention. It also describes a successful rhinotomy in the standing equine patient. This case highlights the importance of serial follow-up imaging after surgical removal as osteoma regrowth occurred in this case.