Cinematographic analysis of the gait of lame horses V: Fibrotic myopathy

A horse with fibrotic myopathy of the semitendinosus muscle of the right hind limb was studied. Observation of the horse in movement showed that protraction of the affected limb terminated abruptly and the hoof was slapped down on the ground. High speed cinematography with computer-aided analysis of the film was used to analyze the gait in greater detail. The results showed that the right hind limb approached the ground almost vertically making impact toe-first, whereas the left hind limb was moving forward relative to the ground when it made heel-first impact. Significant differences were recorded in the sequence and placement of the limbs on the 2 diagonals. The hind limb preceded the forelimb at impact on both diagonals, but at lift-off the lame right hind limb preceded the left forelimb, whereas the sound left hind limb lifted off later than the right forelimb. The distance between the diagonal limb pair during the stance phase was shorter for the left diagonal (left fore-right hind limb pair) than for the right diagonal (right fore-left hind limb pair) (P<0.01). The suspension following the left diagonal was longer than that following the right diagonal (P<0.01).     

The effect of fence height and width on the limb placements of show jumping horses

The purpose of the study was to investigate the effect of fence type (vertical, square oxer) and fence height (1.10 m, 1.25 m, 1.40 m) on the limb displacements from the base of the fence during the approach, take off, landing and move off. Four experienced Grand Prix jumpers were filmed using 2 high speed 16 mm cine cameras set up in series, perpendicular to the path of jumping motion. A minimum of 8 limb impacts on each side of the fence were recorded during a total of 96 jumping efforts. The variables measured were fence type, fence height, total distance jumped, and the limb displacements from the fence. The limb displacements were measured from the base of the first element on the take- off side and from the base of the last element on the landing side. A repeated-measures desing, multivariate analysis of variance was used to determine the effect of fence type and fence height on the displacement of the limbs from the fence and on the total jump distance. A conservative value of 0.01 alpha was used to minimize the likelihood of falsely classifying an effect as significant.There was no interaction between the effects of fence type and fence height for any of the variables. The positions of the limb placements on the take-off side of the fence were independent of both type and height. On the landing side the placements of the lead forelimb at landing and the lead hind limb in the first stride after landing were closer to the last element of the oxer than the vertical at all heights (P<.01). Fence height had a significant effect on the displacement from the base of the last element for both forelimbs at landing, and for the trailing hind limb and both forelimbs in the subsequent stride (P<.01). Duncan's multiple comparison test indicated that there was a progressive increase in the displacement of these 5 limbs from the last element as the height of the fence increased. The jump distance was independent of fence type, but was shown to increase significantly with fence height (P<.01). The results have implications for course designers in setting the distances between fences and for riders in anticipating the effects of these distances.     

Osteosarcoma Eight Years After Total Hip Arthroplasty

This report presents a case of osteosarcoma of the femoral diaphysis associated with chronic stimulation of the area by an unstable femoral prosthesis after total hip arthroplasty performed 8 years previously. The pathogenesis of this transformation may be similar to that proposed for fracture-associated sarcoma. Neoplasia should be considered as a possible late complication of total hip arthroplasty.     

COMPARISON OF THE RESISTIVE INDEX TO CLINICAL PARAMETERS IN DOGS WITH RENAL DISEASE

The resistive index (RI) is a measurement of arteriole vascular resistance and is obtained by pulsed-wave Doppler interrogation. The diagnostic potential of the renal resistive index (RI) was retrospectively investigated in 142 kidneys from 81 dogs. The resistive index of each kidney was compared to clinical laboratory parameters, clinical diagnoses, and sonographic findings. The mean renal resistive index (RI) for 22 normal kidneys was 0.61 (standard deviation = 0.06). An elevation in the mean renal RI (>0.70) was found for the clinical diagnoses of acute renal failure and congenital dysplasia. When a RI of greater than 0.70 was considered abnormal, the sensitivity and specificity of the RI in determining normal vs, abnormal kidneys were 38% and 96% respectively.     

Incarceration of Small Intestine Through Rents in the Gastrosplenic Ligament in the Horse

Incarceration of the small intestine through a rent in the gastrosplenic ligament was diagnosed in five horses. Three affected horses were mature males and two were mature females. Persistent moderate to severe abdominal pain, elevated heart rate, congested mucous membranes, serosanguineous peritoneal fluid, and distended small intestine on rectal examination were consistent findings.
Exploratory celiotomy or gross necropsy examination showed the incarcerated intestine to be distal jejunum or ileum. In all horses, the intestine had herniated cranially through the rent in the gastrosplenic ligament. The incarcerated intestine was situated lateral to the stomach and craniolateral to the spleen. Three horses underwent exploratory celiotomy, and the incarcerated small intestine was reduced by gentle traction and then resected. Two of these horses were alive more than 2 years postoperatively without recurrence of signs of abdominal pain, and one was euthanized because of dehiscence of the abdominal incision. Two horses were euthanized without surgical intervention, and necropsy examination revealed a recent rent in the gastrosplenic ligament. This condition should be considered in the differential diagnosis of causes of small intestinal strangulation and obstruction in the horse.     

Reverse tolerance to the stimulant effects of morphine in horses

Horses were given 4 intravenous injections of morphine sulfate, 0.5 mg per kg, spaced two days apart. The motor response to morphine was measured by counting the number of steps taken with the left foreleg during a 4 minute interval at various times after the injection. By the third injection of morphine there was a significant increase in motor response. This sensitization or reverse tolerance persisted for several weeks after the last injection. Cross-sensitization also developed to the stimulant effects of apomorphine. This finding suggests that sensitization to the stimulant effects of morphine may involve dopamine receptors in the central nervous system.     

Computed Tomographic Lymphography of the Thoracic Duct by Mesenteric Lymph Node Injection

Objective— To document a novel technique to image the thoracic duct and its tributaries by contrast enhanced computed tomography (CT) lymphography.
Study Design— Clinical report.
Animals— Dogs (n=6) idiopathic chylothorax.
Methods— Ultrasonography was used to guide percutaneous injection of intestinal lymph nodes with nonionic iodinated contrast medium for preoperative CT lymphography of the thoracic duct in 6 dogs with chylothorax. Thoracic CT images were acquired immediately after contrast medium injection. All dogs had subtotal pericardectomy and thoracic duct ligation. Postoperative thoracic duct lymphography was performed in 3 dogs. Superficial cervical lymph node lymphography was performed in 2 dogs to determine cervical lymphatic contribution to thoracic effusions.
Results— Preoperative thoracic duct lymphography using this technique was successful in delineating the cisterna chyli, thoracic duct, and associated lymphatic vessels in all dogs. Immediate postoperative lymphography performed in 2 dogs revealed successful duct ligation in 1 dog and persistent lymphatic leakage in the other. A 1-month postoperative thoracic duct lymphogram performed in 1 dog revealed unsuccessful ligation or recannulation of 1 of 3 redundant vessels seen preoperatively.
Conclusion— Percutaneous CT lymphography results in excellent detection of the thoracic duct and abnormal thoracic duct drainage patterns both pre- and postoperatively. The contribution of superficial cervical lymph node drainage to reoccurrence of effusions can be evaluated.
Clinical Relevance— Percutaneous CT lymphography using ultrasound-guided contrast medium injection should be considered as an alternative to conventional open abdominal approaches to radiographic or CT lymphography.     

Ex Vivo Evaluation of the Effect of Tibial Plateau Osteotomy on the Proximal Tibial Soft Tissue Envelope With and Without the Use of Protective Gauze Sponges

Objective— To investigate the effect of tibial plateau leveling osteotomy (TPLO) on the proximal tibial soft tissue envelope with and without use of protective gauze sponges, and to determine whether the action of an oscillating saw blade on the gauze sponges would result in retention of particulate cotton debris. Study Design— Cadaveric study. Animals— Medium to large breed dog cadavers (n=10; 20 pelvic limbs). Methods— TPLO was performed using the currently recommended technique involving dissection of the proximal tibial soft tissue envelope and its protection using cotton gauze sponges. In paired limbs, the procedure was repeated but no attempt was made to retract and protect the proximal tibial soft tissue envelope. Damage to the soft tissue envelope and presence of gross particulate cotton debris were investigated by direct observation and photographic analysis. Presence of microscopic cotton debris was investigated using light microscopic analysis of wound lavage fluid. Results— No soft‐tissue trauma was found in gauze sponge‐protected specimens. When protective gauze sponges were not used, full‐thickness (sagittal plane) lacerations to the caudoproximal tibial muscle group occurred in all specimens with a mean craniocaudal width of 9.5 mm (range 2–12 mm). The cranial tibial muscle was traumatized in only 1 specimen without protective gauze sponges. Trauma to the popliteal vessels was not identified in any specimen. No gross cotton debris was identified, but microscopic cotton fibers (diameter, 7–35 μm) were identified in lavage fluid from all gauze sponge‐protected specimens. Conclusions— Use of protective gauze sponges is effective in protecting the proximal tibial soft tissue envelope from an oscillating TPLO saw blade, but results in retention of microscopic cotton particulate debris within the operative site. Significant soft tissue trauma is seen only in the caudoproximal tibial muscle group if protective gauze sponges are not used. Clinical Relevance— Retraction and protection of the caudoproximal tibial soft tissue envelope is recommended during TPLO; however, to prevent retention of microscopic particulate cotton debris, alternatives to cotton gauze sponges should be considered as protective devices.