Complex vertebral malformation in a holstein calf: report of a case in the USA.

Complex vertebral malformation (CVM), a familial syndrome of Holstein calves, has been reported in aborted fetuses and in prematurely born, stillborn, and neonatal calves. Affected calves have anomalies in the vertebral column, including hemivertebrae, fused and misshapen vertebrae and ribs, scoliosis, and vertebral synostosis. Concurrent low body weight, symmetrical arthrogryposis, and cardiac anomalies have been documented in affected calves. The syndrome was identified and characterized in Holstein cattle in Denmark; however, a global distribution of this genetic disorder is likely based on identification of common ancestral sires widely used for artificial insemination. This is the first documented case of CVM in a Holstein calf in the USA.

Anatomic models and phantoms for diagnostic ultrasound instruction.

The preparation and application of anatomic models and phantoms to facilitate learning diagnostic ultrasound is described. Imaging with diagnostic ultrasound requires mastery of many skills, along with knowledge of sound-tissue interactions which contribute to the formation of diagnostic images and artifacts. Understanding the genesis of artifacts encountered during ultrasound scanning can avoid misinterpretation and aid diagnosis. In addition, development of machine related knowledge and skills, including manipulation of the transducer and the selection of correct settings for variables such as gain, power, time-gain compensation, and transducer type, is dependent on an understanding of how these factors affect the image. The normal appearance of an organ relates to both its echogenicity and morphologic characteristics, and confirmation of the nature of an abnormality often requires ultrasound guided biopsy. The use of anatomic models and phantoms in ultrasound instruction allows principles to be demonstrated, knowledge acquired, and biopsy procedures practiced and mastered in a controlled setting. This can minimize live animal use, and enhance the knowledge base and skills of the clinician prior to applying this diagnostic technique to the clinical patient.

Evaluation of a method for experimental induction of osteoarthritis of the hip joints in dogs.

OBJECTIVE: To evaluate a method for experimental induction of osteoarthritis in the hip joints of dogs. ANIMALS: 12 mixed-breed dogs. PROCEDURE: A unilateral triple pelvic osteotomy was performed. In 6 dogs, the iliac osteotomy was repaired with 45 degrees of internal rotation, reducing coverage of the femoral head by the acetabulum. In the other 6 dogs, the fragments were repaired in anatomic alignment. Radiography, force plate evaluations, and subjective lameness evaluations were performed before and after surgery. Dogs were euthanatized 7 months after surgery, and samples of cartilage and joint capsule were examined histologically. RESULTS: Subjective lameness scores, radiographic appearance of the hip joints, and Norberg angles were not significantly different between groups; however, force plate evaluations did reveal significant differences in vertical ground reaction forces. Femoral head coverage was significantly decreased with rotation of the acetabulum. Mild inflammatory changes were discernible in the joint capsule and articular cartilage of some dogs in both groups. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that 45 degrees internal rotation of the acetabulum does not consistently induce biologically important osteoarthritic changes in the hip joints of dogs.

Evaluation of a technique to occlude the internal carotid artery of horses.

OBJECTIVE: To evaluate an occlusion technique for the internal carotid artery of horses using an intravascular, detachable, self-sealing, latex balloon distally and ligatures proximally. STUDY DESIGN: Experimental study. ANIMALS: Six healthy adult horses. METHODS: In each horse, the left internal carotid artery was occluded by placement of an intravascular, detachable, self-sealing, latex balloon distally and two ligatures proximally. Radiographs were taken on days 2, 5, 10, and 30 after surgery to evaluate balloon inflation and position. Endoscopic examination of the left guttural pouch was performed 10 days after surgery to evaluate the integrity of the internal carotid artery and surrounding tissues. At 30 days, the left and right, common, internal, and external carotid arteries were examined grossly and then processed for histologic evaluation. RESULTS: Immediate and long-term occlusion of the left internal carotid artery was achieved in all horses. The surgical procedure was technically straightforward and no intraoperative or postoperative complications were encountered. The balloons remained inflated and in their original position throughout the study. Maturing to mature, organized thrombi were present in the left internal carotid artery in all horses at 30 days. The cerebral arterial circle and common carotid artery were patent at their junctions with the internal carotid artery in all horses. CONCLUSIONS: Use of an intravascular, detachable, self-sealing, latex balloon distally and ligatures proximally is an effective technique for occluding the internal carotid artery of horses. CLINICAL RELEVANCE: This technique may be useful for prevention of fatal hemorrhage in horses with lesions of the internal carotid artery.

Diagnostic imaging of osteoarthritis.

Osteoarthritis is a common orthopedic problem in the small animal patient. In most cases, the degenerative changes in the joint are secondary to some predisposing cause. The objective of diagnostic imaging is to define the extent and nature of the degenerative changes and to identify the responsible underlying abnormality. To achieve this, appropriate imaging procedures should be used. Although conventional radiography is the most common method used to evaluate osteoarthritis, there has been an increase in the application of other imaging technologies during the past several years. These modalities can provide the clinician with additional information that can improve case management. The radiographic changes that accompany osteoarthritis are reviewed, and indications for the various imaging modalities are outlined. The causes and presentation of osteoarthritis of the major diarthrodial joints of the appendicular skeleton are described.

Radiologic evaluation of the liver and gastrointestinal tract in rats infected with Taenia taeniaeformis.

In rats infected with the cestode Taenia taeniaeformis, hepatomegaly results from development of parasitic cysts in the liver. Diffuse nodular mucosal hyperplasia in the glandular region (corpus and antrum) of the stomach, and gross thickening of the intestinal mucosa also result. Between postinfection days (PID) 21 and 84, radiologic observations were made after oral administration of a barium sulfate suspension in T taeniaeformis-infected rats and in age/sex-matched controls. There was radiographic evidence of hepatic enlargement at PID 21. Enlargement of the gastric folds was first observed along the greater curvature of the stomach at PID 35. Fimbriation of small intestinal mucosal surfaces resulted from thickening of the intestinal villi and was observed in the duodenum at PID 21. Intestinal motility was assessed, and contractions were counted, using image intensification fluoroscopy, then were recorded on videotape. There were no significant differences between control and infected rats for gastric emptying time, intestinal transit time, and number of intestinal contractions per minute. Barium contrast radiography clearly indicated large gastric folds, thickening of the small intestinal villi, and hepatic enlargement, and was useful for assessing gastrointestinal motility.

Anatomic features and radiographic observations of gastric emptying and small intestinal motility in the rat.

This study presents the first report of the identification of anatomic structures on survey radiographs of the abdomen of the rat, along with detailed barium contrast studies of the gastrointestinal tract in normal rats. The rats (49 to 112 days old) were chemically restrained with a combination of 0.71 mg ketamine hydrochloride/g of body weight and 0.5 mg of acetylpromazine maleate injected intramuscularly. Following sedation, a 36% (wt/vol) micropulverized barium sulfate suspension was administered via a stomach tube at a dose of 0.02 ml/g of body weight. The radiographic features of the gastrointestinal tract were enhanced after coating of the mucosal surfaces with the high-density barium suspension. Internal structures of the stomach and mucosal surfaces of the intestine were clearly identified. The barium contrast study was used to establish gastrointestinal transit times. The mean gastric emptying time was 11 +/- 4.27 (SEM) min and mean intestinal transit time was 5 +/- 0.75 (SEM) h. Image intensification fluoroscopy was used to observe patterns of small intestinal motility and to establish small intestinal contraction rates. Prominent cluster of circular contractions were primarily observed in the jejunum, and wave-type peristalsis was primarily observed in the duodenum. Isolated circular contractions and weak segmentation patterns were observed in the ileum. The mean contraction rate per minute was observed to be 14 +/- 2.12 (SEM) in the jejunum. We propose that under the conditions of the current study, radiographic investigation of gastrointestinal function in rats is a feasible and inexpensive procedure.

Evaluation of the proximal portion of the femur as an autogenous cancellous bone donor site in dogs.

The proximal portion of the femur was evaluated as a source of autogenous cancellous bone in dogs. Bilateral oval cortical defects were created in the lateral subtrochanteric area of the femur in 16 dogs. Cancellous bone was removed and the weight recorded. Cancellous bone was similarly harvested from the proximal portion of the humerus in 7 of these dogs. Subtrochanteric femoral defects in 11 dogs were randomly assigned to receive cancellous bone graft obtained from the femur (n = 4) or the humerus (n = 7). Subtrochanteric defects in 5 dogs were not grafted. Radiographic assessment of subtrochanteric defects was performed at 4-week intervals, and histologic assessment at 4, 8, 16, and 24 weeks after surgery. Nongrafted donor sites healed by ingrowth of trabecular bone during the first 12 weeks after surgery. By week 24, the lateral cortical wall had reformed, but remodeling was incomplete. Donor sites grafted with cancellous bone healed similarly, but with more rapid healing and more complete remodeling evident by week 24. Although the mean weight of cancellous bone harvested from the proximal portion of the femur (0.82 +/- 0.22 g) was significantly (P less than 0.05) less than that harvested from the proximal portion of the humerus (1.38 +/- 0.29 g), there was no qualitative histologic or radiographic difference in bony healing of grafted defects. We determined that the proximal portion of the femur can be safely used to provide moderate amounts of cancellous bone, and that a second bone graft can be collected from the same subtrochanteric donor site after 12 weeks.

Canine bone shape analysis by use of a radiographic image-classification system.

A radiographic image-classification system was developed to analyze and compare the shape of the humerus of neonatal Labrador Retriever and Labrador Retriever x Beagle pups that were either phenotypically normal or affected with an ocular-skeletal dysplasia syndrome. The system consistently defined the shape of the humerus within the groups of pups studied and indicated a difference in the shape of the humerus between normal and affected pups. Results indicated that the radiographic image-classification system may be able to identify Labrador Retriever pups affected by the ocular-skeletal dysplasia syndrome at or shortly after birth.

Evaluation of biocompatible osteoconductive polymer as an orthopedic implant in dogs.

The biocompatibility and osteoconductive properties of biocompatible osteoconductive polymer (BOP), a synthetic implant, were evaluated. Bilateral oval cortical defects (1 x 2 cm) were made in the lateral subtrochanteric area of the proximal portion of the femur in 16 dogs that later were treated with BOP fiber (n = 16) or autogenous cancellous bone (n = 11), or were not treated (n = 5). The BOP block was attached extraperiosteally to the proximal portion of the humerus in 6 dogs. Radiographic assessment of surgery sites was performed at 4-week intervals, and histologic evaluation was performed at 4, 8, 16, and 24 weeks after surgery. Radiographic signs of bone healing were not observed in defects treated with BOP fiber. Defects treated with cancellous bone or not treated had radiographic signs of progressive bone ingrowth. Radiographic evidence of periosteal new bone formation near control and BOP-treated defects was observed 4 weeks after surgery; increased periosteal reaction was associated with BOP fiber. This new bone had resorbed by week 24, except bone adjacent to BOP fiber, where continued periosteal reaction was apparent. Histologic evidence of bone formation was observed extending to, but not incorporating, BOP fibers. The BOP fibers became surrounded by a fibrous capsule, and fibrovascular connective tissue infiltrated between and into BOP fibers, but minimal bone formation incorporated the BOP material during the follow-up period. During that time, active periosteal new bone formation was evident adjacent to the BOP fibers. Defects treated with cancellous bone or not treated healed by ingrowth of cancellous bone during the first 12 weeks after surgery and by reformation of the lateral cortical wall by week 24. The BOP blocks became surrounded by a fibrous capsule, but connective tissue or bone ingrowth into BOP blocks was not observed. Results indicate that BOP is not osteoconductive within a 6-month time frame when used in subtrochanteric femoral defects or when placed extraperiosteally on the proximal portion of the humerus of clinically normal dogs.

Direct cutaneous arterial supply to the tail in dogs.

Cutaneous arterial blood supply to the tail was evaluated in 12 dogs. Subtraction radiography of internal iliac artery and distal aorta angiography in 3 of these dogs was used to determine arterial blood supply to the tail from the median sacral and lateral caudal arteries. Dissection of the tail in 8 canine cadavers revealed bilateral subcutaneous location of lateral caudal arteries following tail amputation. An axial pattern flap based on the lateral caudal arteries contributed to the reconstruction of a large caudodorsal cutaneous defect in a dog. An axial pattern flap based on the lateral caudal arteries following tail amputation may be indicated to aid reconstruction of large caudodorsal cutaneous defects of the trunk in dogs.

An ectopic wing in a wild black vulture (Coragyps atratus).

An approximately 5-month-old black vulture (Coragyps atratus) was presented with the chief complaint of cervicomelia. A full-sized ectopic wing, with its own pectoral girdle, was found attached to the dorsal surface of the last few cervical vertebrae. There was deformation (right dorsolateral narrowing) of the spinal canal at the point of attachment with a corresponding compression of the spinal cord.

Vertebral lymphosarcoma in a cat.

Lymphosarcoma of the cauda equina in a domestic shorthair cat invaded the body of L7 and cranial portion of the sacrum. Clinical signs consisted of acute ambulatory paraparesis, tail paralysis, and dyschezia. Radiographically, there was evidence of bone lysis. Surgical exploration yielded a diagnosis, but did not induce improvement in the cat, which was subsequently euthanatized. Neurologic signs were similar to those associated with sacral nerve root avulsion injuries in cats.

Inheritance of associated ocular and skeletal dysplasia in Labrador retrievers.

A breeding colony was established to investigate the inheritance of associated ocular and skeletal dysplasia in Labrador Retrievers; 124 pups were produced. These pups were evaluated for the presence of ocular lesions, including cataracts, vitreous strands, persistent hyaloid remnants, retinal folds, retinal dysplasia, peripapillary hyperreflectivity, and rhegmatogenous retinal detachments, and skeletal abnormality, which was recognized by shorter than normal forelimbs and an abnormal morphologic appearance of the radius and ulna. Analysis of the distribution of lesions in pups indicated that the syndrome is caused by one abnormal gene, which has recessive effects on the skeleton and incompletely dominant effects on the eye. This would suggest that suspect carrier dogs could be identified by test matings with a known homozygote.

Thoracic radiographic appearance during lung inflation in neonatal calves.

The effect of lung inflation on thoracic radiographic anatomy was determined in seven anesthetized calves less than one week of age. Radiographs were taken with the calves in dorsoventral (DV), ventrodorsal (VD), left and right lateral recumbency at functional residual capacity (FRC), at half inflation of the lung and at total lung capacity (TLC). Lung volumes were maintained by positive pressure ventilation. Increases in areas and linear dimensions during lung inflation were not uniform, being greatest in the caudal and especially the caudal ventral regions of the thorax. With inflation, heart size decreased and the heart shadow moved caudad as the diaphragm flattened. When the calf was shifted from the DV to the VD position, the heart displaced toward the left thoracic wall. Lung areas were larger on VD than on DV projections with the right lung being larger than the left. On lateral radiographs the most reliable, easily observed indication of the stage of lung inflation was the area bounded by the vena cava, the caudal heart border and the diaphragm. On the DV or VD radiographs the transthoracic width at the diaphragm was the best indicator of the degree of lung inflation.