Stress Fractures of the Acetabulum in 26 Racing Greyhounds

Acetabular fractures in 26 racing Greyhounds were reviewed. All fractures occurred during racing or training and were unrelated to any external trauma. All fractures had similar configurations, were minimally displaced, and involved only the acetabulum. Affected dogs were young (16-36 months). Fractures occurred unilaterally (22 dogs) and bilaterally (4 dogs). There was no sex predilection, and both right and left sides were equally represented. Bilateral fractures were associated with retraining between the occurrence of the first and second fractures. Radiographically, a fracture line was consistently visible in the caudal third of the acetabulum. Fractures in gross specimens resembled an inverted "Y." Results of histologic evaluation of two fractured acetabula showed changes characteristic of a nonunion fracture. Microfractures were evident in the grossly normal acetabulum opposite the fractured side. Evidence obtained from this study suggests a common pathogenesis of the fractures related to tremendous repetitive stresses produced during running. Greyhounds with unilateral acetabular fractures may provide a reproducible model for future studies of stress fractures in animals and humans because of the high incidence of bilateral fractures that develop during retraining. Surgical repair of the acetabular stress fracture was more successful than conservative management in returning the dogs to competitive racing.     

Evaluation of Experimental Transection and Partial Excision of the Caudal Cruciate Ligament in Dogs

The caudal cruciate ligament (CaCL) of one stifle joint in seven dogs was transected and a 2 to 4 mm section was removed. Six months after surgery, none of the dogs were lame. Thigh muscle circumference, stifle range of motion, and internal tibial rotation in the operated limb were not significantly different from the preoperative measurements or the contralateral, unoperated limb. A caudal drawer motion was consistently present in the stifle joints with a transected CaCL. A radiographic evaluation of the operated stifle joints did not reveal osteoarthritic changes; four of seven stifle joints had an irregular fat pad 6 months after surgery. Results of a joint fluid analysis revealed a slight increase in synovial cells within treated stifle joints; inflammatory cells were not observed. The only gross morphologic change in stifle joints with a severed ligament was enlarged knobby remnants of the CaCL. Articular cartilage defects or osteophytes were not observed. Results of a histologic examination of the CaCL remnants revealed synovial cellular capping and intraligamentous fibroplasia. Based on a limited number of dogs, it was concluded that isolated transection of the CaCL produced minimal clinical and pathologic changes in the stifle joint during a 6 month period.     

Spinal Fixation in Dogs Using Steinmann Pins and Methylmethacrylate

Steinmann pins and methylmethacrylate were used to stabilize 17 vertebral fractures or luxations and one unstable congenital spinal deformity in 18 dogs of a wide range of ages and body weights. Of 12 dogs available for follow-up examination (4–43 months), 10 were normal or only mildly ataxic, and two were ambulatory but severely ataxic. Five dogs died or were euthanized in the early postoperative period, but none of the deaths could be attributed to the technique. Uncommon complications associated with this fixation technique were pin migration and wound infection.     

Use of a Vascular Skeletal Muscle Graft for Canine Esophageal Reconstruction

A technique for reconstruction of the thoracic esophagus was evaluated in 13 dogs. A 9 x 10 cm section of transversus abdominis muscle was harvested, fashioned into a tubular graft, and vascularized via the greater omentum. The vascularized tube was advanced into the caudal thorax through the diaphragm at a second surgery 20 to 44 days after harvesting the section of the transversus abdominis muscle. A 5 cm section of caudal thoracic esophagus was replaced with the vascular tubular graft. One dog died because of incarceration of the intestine within the tube and two dogs were euthanized because of infected tubes. One dog died due to an anesthetic complication, one dog had a diaphragmatic hernia and died, and one dog died from pyothorax. Leakage of luminal contents at the anastomoses did not occur in any dog. Seven dogs survived both surgeries but showed deglutitory difficulty 6 days postoperatively due to the grafted esophageal segments becoming severely strictured in each case. Angiography demonstrated vascularization of the full thickness of the graft in each of the seven dogs. An unacceptably high incidence of infection and stricture formation made this technique unsuitable for clinical use.     

Ureterocolonlc Anastomosis in Ten Dogs with Transitional Cell Carcinoma

Ureterocolonic anastomosis (UCA) was performed in 10 dogs with transitional cell carcinoma of the urinary bladder trigone or the urethra, or both. All grossly visible tumor was excised. All of the dogs recovered from anesthesia and surgery and had anal continence with no urine leakage. One dog died of undetermined causes 7 days after surgery. Nine dogs survived 1 to 5 months. The owners of eight of the dogs considered their dog's quality of life to be acceptable. Four dogs were euthanatized because of neurologic disease, three of which also had nausea and vomiting. The neurologic and gastrointestinal signs may have been caused by hyperammonemia, metabolic acidosis, and uremia. Blood ammonia levels were elevated in two dogs with neurologic signs. Hyperchloremic metabolic acidosis that was reversible with bicarbonate therapy was diagnosed in five dogs. All of the dogs were azotemic because of intestinal recycling of urea. Serum creatinine concentrations increased in four dogs after surgery. Drug-induced renal disease may have developed in two dogs. Pyelonephritis developed in five kidneys, two of which had outflow obstruction and two had bilateral hydroureteronephrosis before the UCA. In this small number of dogs, surgical excision of transitional cell carcinoma was not curative with six dogs having confirmed metastatic lesions at the time of death.     

Open Peritoneal Drainage in Experimental Peritonitis in Dogs

Peritonitis was induced In 12 dogs by creation of an avascular jejunal loop. After 24 hours, the avascular jejunal loop was removed, and purulent material was removed by aspiration. The abdominal incision in six experimental dogs was left open under a bandage, while the incision was closed in six control dogs. All six open abdomen, and four control, dogs survived the 8 days of the study. The number of bacteria in the peritoneal exudate in experimental animals was less than in control animals. At the end of the 8 day study, experimental animals were more active, had better appetites, and were less likely to have fever, vomition, diarrhea, and dehydration. Experimental animals weighed significantly less than control animals. There were no differences between groups with respect to biochemical and hematologic parameters. At necropsy, experimental animals had fewer adhesions and less peritoneal fluid accumulation than control animals. Complications of open peritoneal drainage included persistent fluid loss, weight loss, adhesions of abdominal viscera to the bandage, and contamination of the peritoneal cavity with cutaneous organisms.     

Proximal Urethral Reconstruction Using a Distally Based Ventral Bladder Tube Flap An Experimental Study

Reconstruction of the proximal urethra using a distally based tube flap mobilized from the ventral bladder wall was performed on 12 clinically normal dogs after total prostatectomy and resection of 2 cm of membranous urethra. One dog was euthanized at 6 hours and one at 36 hours after surgery because of surgical complications. Five dogs were euthanized at 10 days, two dogs at 6 weeks and three dogs at 12 weeks. Advancement of the tube flap allowed for tension-free anastomosis to the membranous urethra. Vascular integrity was maintained in all flaps. Intermittent to continuous postoperative urinary incontinence occurred in 7 of 10 dogs. The incontinence was transient in all 6 and 12 week dogs except one in which a persistent stress incontinence developed. Mild to severe dysuria was noted in 8 of 10 dogs, but was also transient in all of the 6 and 12 week dogs, with the exception of one dog. Postoperative urethral closure pressure profilometry revealed decreased tone in the membranous urethra in all 6 and 12 week dogs. It was concluded that proximal urethral reconstruction, using a ventral bladder tube flap, is a viable technique that may permit functional urodynamic recovery in dogs with significant proximal urethral loss.     

A Muscle Separating Approach to the Equine Shoulder Joint for the Treatment of Osteochondritis Dissecans

A muscle separating approach with tenotomy of the teres minor was used to expose osteochondritis dissecans lesions in the shoulder joints of five horses. Horses selected for surgery were severely lame or had a long history of lameness. Adequate surgical access allowed removal of cartilage flaps, curettage of the subchondral bone, and in one horse, the removal of an osteocartilaginous free body. Surgical wounds healed by primary intention; one horse developed a seroma that was drained. Three of the five horses were clinically sound 3 months following surgery. Two other horses were pasture sound but lame after extensive athletic activity.