MRI characteristics of ventral vertebral venous plexus occlusion due to lymphoma in a large breed dog

Intravascular lymphoma is a rare presentation of lymphoma with a predilection to the central nervous system (CNS). A 9-year-old male-neutered Collie presented with a 3-month history of lymphadenopathy and a 6-day history of an acute onset, progressive, painful, symmetrical L4-S3 myelopathy. Magnetic resonance imaging revealed multifocal extradural spinal cord compressions from L3 to L6 secondary to a bilaterally enlarged and occluded ventral vertebral venous plexus (VVVP). Histopathology revealed low-grade lymphoma within the venous plexus in the lumbar vertebral column, tracheobronchial lymph nodes, and tonsils. Intravascular lymphoma should be considered a differential diagnosis for enlarged VVVP causing compression of the spinal cord.     

Biomechanical and Histological Evaluation of a Laparoscopic Stapled Gastropexy Technique in Dogs

The biomechanical holding strength and histological characteristics of a laparoscopic stapled gastropexy (LG) adhesion were compared with that of an incisional gastropexy (IG) adhesion. An LG was performed in 14 dogs and an IG was performed in six dogs. During the LG procedure, the abdomen was insufflated with carbon dioxide and three cannulae were placed in the caudal aspect of the right side of the abdomen. A 35 mm laparoscopic stapler was used to staple the gastric antrum to the adjacent right lateral abdominal wall. The IG procedure was performed through a ventral midline celiotomy. A 35 mm IG was made by apposing the gastric antrum to the adjacent right lateral abdominal wall with two continuous rows of suture. Half of each group of dogs was euthanatized at 7 and 30 days after surgery. The mean tensile load to failure at 7 days was 44.86 ± 18.54 N for the LG group and 85.33 ± 23.59 N for the IG group ( P <.05). At 30 days the values were 72.93 ± 18.01 N for the LG group and 71.17 ± 12.11 N for the IG group ( P =.41). The gastropexy adhesions in the 7-day postoperative group contained variable amounts of fibrin, hemorrhage, mononuclear cell inflammation, loose fibrovascular tissue, and mature collagenous connective tissue. Adhesions in the 7-day postoperative group were divided subjectively into three histological subgroups based on the relative amounts of mature connective tissue within the adhesion. The LG and IG adhesions were randomly distributed among these subgroups ( P = 1.0). Adhesions in the 30-day postoperative group contained well-organized fibrous connective tissue. No difference in the amount of connective tissue could be detected histologically in the LG or IG adhesions. Complications with the LG procedure included stomach perforation (2 cases), splenic puncture (2 cases), and subcutaneous emphysema (4 cases).     

Cardiorespiratory Effects of the Intravenous Administration of Tiletamine-zolazepam to Cats

The hemodynamic and respiratory effects of three doses (9.7, 15.8, and 23.7 mg/kg intravenous [IV]) of a 1:1 combination of tiletamine and zolazepam were studied after isoflurane anesthesia in cats instrumented for the recording of hemodynamic data. Systolic, mean, and diastolic arterial blood pressures were decreased 1 minute after drug administration but then increased above baseline with all three doses. Cardiac output was decreased briefly at 1 minute with the 15.8 and 23.7 mg/kg doses. The rate of development of left ventricular pressure and peripheral vascular resistance decreased at 1 minute but returned to baseline or above by 10 minutes. There were no significant changes in heart rate, central venous pressure, or left ventricular end diastolic pressure. The arterial pH and blood gas measurements reflected the development of respiratory acidosis after administration of 23.7 mg/kg. These results support the conclusions that tiletamine-zolazepam administered intravenously is a useful and comparatively safe anesthetic agent in the cat.     

Resection of Subvalvular Aortic Stenosis Surgical and Perioperative Management in Seven Dogs

Open heart surgery was performed during cardiopulmonary bypass (CPB) to surgically correct subvalvular aortic stenosis in seven dogs. After initiation of total CPB, cardiac arrest was induced by antegrade and retrograde administration of blood cardioplegia. The subvalvular fibrous stenosis was resected through a transverse aortotomy. Intraoperatively and postop-eratively, dobutamine, nitroprusside, lidocaine, blood(-products), and crystalloid solutions were used to manage hypotension and optimize cardiac index.
Aortic cross-clamp time varied from 73 to 166 minutes, and duration of CPB varied from 130 to 210 minutes, latrogenic incision into the mitral valve in two dogs was the most significant introperative complication. Postoperative complications included: hypoproteinemia (n = 7), premature ventricular depolarization (n = 6), increased systemic vascular resistance index (n = 5), increased O₂ extraction (n = 3), pulmonary edema (n = 2), and decreased cardiac index (n = 1). All seven dogs were discharged alive and in stable condition. Six dogs are alive and in stable condition after a mean follow up of 15.8 months.
This is the first detailed report of CPB in a series of clinical veterinary patients. Using the techniques described in this paper, open heart surgery of considerable duration can be performed successfully in dogs with significant myocardial hypertrophy and endomyocardial fibrosis secondary to subvalvular aortic stenosis.     

PERCUTANEOUS CHOLECYSTOGRAPHY IN NORMAL DOGS

A technique for fluoroscopically guided percutaneous cholecystography, using a 23-gauge Chiba needle, is described. Successful percutaneous cholecystograms were obtained in 20 normal dogs, with minimal short-term and no long-term clinical side effects.     

SCINTIGRAPHIC EVALUATION OF THE THORACIC SPINE IN THE ASYMPTOMATIC RIDING HORSE

Scintigraphic evaluation of the spinous processes of the equine spine has been done by subjective evaluation of radiotracer uptake in clinically abnormal horses. To determine the range of variation in asymptomatic riding horses, 33 normal horses were examined. Two 60 degrees oblique views of the thoracic and lumbar spine were evaluated subjectively, and a semi quantitative method based on standardized regions of interest in each spinous process in T10-L3 was also applied. A ratio between each spinous process and a reference area (Rib 15 or 16) was calculated. The effects of two different color displays and a smoothing filter were assessed. The results of the subjective evaluation was compared to the calculated ratios, and the associations between age, gender, weight, height, use and increased radiotracer uptake, and ratios were analyzed. No significant association was found between age, gender, weight, height, use and increased radiotracer uptake, or ratio. One or more areas of increased radiotracer uptake between T13 and T18 were common in the asymptomatic riding horse, which may have implications for the interpretation of clinical patients. The blue, green and red color display had a higher sensitivity for detecting increased radiotracer uptake compared to the continuous grayscale. The smoothing filter used in this study had no effect on the detection of areas with increased radiotracer uptake. The association between the results of the subjective evaluation and the semi quantitative method was apparent when analyzed in T13-17. To evaluate if the semi quantitative method can replace the subjective evaluation, studies on clinically affected horses are necessary.