In vitro comparison of proximal ulnar osteotomy and distal ulnar osteotomy with release of the interosseous ligament in a canine model.

OBJECTIVE: To determine the effect of proximal ulnar osteotomy (PUO), distal ulnar osteotomy (DUO), and DUO with release of the interosseous ligament (DOLR) on displacement of the proximal ulna at the radioulnar joint. STUDY DESIGN: Experimental mechanical study. SAMPLE POPULATION: Cadaveric, skeletally mature canine thoracic limb pairs (n=11). METHODS: Thoracic limbs disarticulated at the elbow were randomly assigned to 1 of 2 groups: (A) limbs were tested with no treatment (NOTX), then with PUO; (B) limbs were tested with DUO followed by DOLR. A distraction force was applied to the proximal ulna with the distal limb secured in a frame, and displacement of the proximal ulnar segment at the radioulnar joint was recorded. RESULTS: Mean displacement was 0.36 mm (95% confidence interval [CI]: 0-1.12 mm) in the NOTX group, 4.68 mm (95% CI: 3.82-5.55 mm) for PUO limbs, 0.95 mm (95% CI: 0.52-1.39 mm) for the DUO group, and 4.36 mm (95% CI: 3.71-5.02 mm) for the DOLR group. Mean ulnar displacement of the DOLR group was significantly different compared with the DUO group, but there was no significant difference between the PUO and DOLR groups. CONCLUSIONS: No significant difference was observed in displacement of the proximal ulnar segment after DOLR compared with PUO.

Thoracoscopic subtotal pericardiectomy and right atrial mass resection in a dog.

CASE DESCRIPTION: A 10-year-old spayed female Corgi mix was examined for a 3-week history of lethargy and weight gain. CLINICAL FINDINGS: Physical examination findings included muffled heart sounds and a distended abdomen with a fluid wave on ballottement. Thoracic radiography revealed a globoid cardiac silhouette, and thoracic ultrasonography indicated pericardial effusion and a pedunculated mass originating from the right auricle. TREATMENT AND OUTCOME: Initial treatment consisted of pericardiocentesis. One week later, thoracoscopic right atrial mass resection was performed. No surgical complications were noted, and the dog was discharged approximately 28 hours after surgery. Results of histologic examination of the mass indicated a grade 2 hemangiosarcoma with incomplete margins. Treatment with doxorubicin was initiated 35 days after surgery. The dog survived for 177 days after mass resection, when it was euthanized because of complications related to metastatic disease. CLINICAL RELEVANCE: Findings suggested that thoracoscopic right atrial mass removal combined with adjunct doxorubicin treatment may be a viable alternative to thoracotomy in dogs with right atrial masses.

Proximal duodenal perforation in three dogs following deracoxib administration.

The purpose of this study was to describe the clinical and gross pathological findings, treatment, and outcome in three dogs receiving deracoxib that developed proximal duodenal perforation and subsequent septic peritonitis. Clinical findings were acute vomiting and anorexia following initiation of deracoxib therapy. Deracoxib dosages ranged from 2 to 3 mg/kg per os q 24 hours. In each dog, exploratory laparotomy revealed duodenal perforations approximately 1 cm orad to the major duodenal papilla. Two out of three dogs survived following exploratory laparotomy. Two of three dogs in the present case series received the approved deracoxib dosage. Dogs receiving deracoxib, even at labeled dosages, should be monitored judiciously for signs of gastrointestinal disease.

In vitro biomechanical comparison of polypropylene mesh, modified three-loop pulley suture pattern, and a combination for repair of distal canine achilles' tendon injuries.

OBJECTIVE: To compare mechanical stability between a novel polypropylene mesh repair (Mesh), a modified 3-loop pulley suture (Suture), and a combination of the techniques (Suture+Mesh) for the repair of distal canine Achilles' tendon ruptures. STUDY DESIGN: In vitro mechanical evaluation. SAMPLE POPULATION: Cadaveric canine Achilles' tendon/calcaneus units (n=34). METHODS: Constructs were loaded under tension to failure in a materials testing machine with synchronized kinematic analysis. Ultimate load to failure, global construct stiffness, and force required to reach 1 and 3 mm gap formation was recorded. RESULTS: Ultimate load to failure was greatest for the Suture+Mesh group and lowest for the Suture group. The Suture+Mesh technique afforded a significantly greater global stiffness than the Suture or Mesh treatments. Force to generate 1 and 3 mm gap formation was greatest with the Suture group. CONCLUSIONS: The Suture+Mesh group had the highest ultimate load to failure and afforded the greatest global stiffness though it had no added benefit to resist local gap formation at the repair. CLINICAL RELEVANCE: Achilles' ruptures repaired with suture can be augmented with mesh to increase the ultimate load to failure, but as currently tested, there was a decrease in resistance to gap formation At this time we cannot recommend Mesh or the Suture+Mesh techniques without further testing.

Retroperitoneal sarcomas in dogs: 14 cases (1992-2002).

OBJECTIVE: To describe the clinical features, surgical and histologic findings, biological behavior, and outcome of dogs with retroperitoneal sarcomas. DESIGN: Retrospective study. ANIMALS: 14 dogs. PROCEDURES: Medical and pathology records from 1992 to 2002 of dogs with tumors originating in the retroperitoneal space were reviewed. Dogs with retroperitoneal tumors originating from the adrenal glands, kidneys, or ureters were excluded. Inclusion criteria included observation of a tumor arising from the retroperitoneal space during exploratory surgery or necropsy and histologic confirmation of tumor type. Details of clinical signs, diagnostic findings, surgical management, and outcome were determined from medical records and telephone interviews with veterinarians and owners. RESULTS: Retroperitoneal sarcoma was diagnosed in 14 dogs, 2 at necropsy and 12 during exploratory surgery. Hemangiosarcoma was the most common histologic diagnosis. Seven dogs had regional extension of the sarcoma into adjacent organs, and 4 dogs had metastatic disease. Grossly complete resection was possible in 6 dogs. Cytoreductive surgery or incisional biopsy was performed in the remaining dogs. Two dogs were treated with palliative radiation therapy (1 intraoperatively and 1 postoperatively). Three dogs received adjunctive chemotherapy, although none completed the targeted course because of development of local recurrence or metastatic disease. Local recurrence was reported in 2 of 12 dogs and metastasis in 10 of 14 dogs. Thirteen dogs died or were euthanatized as a result of the retroperitoneal sarcoma; 1 dog was alive and disease-free 410 days after surgery. Median survival time was 37.5 days. CONCLUSIONS AND CLINICAL RELEVANCE: In dogs, retroperitoneal sarcomas are aggressive tumors with a high rate of local recurrence and metastasis, and a poor survival time.

Intercostal thoracotomy closure: transcostal sutures as a less painful alternative to circumcostal suture placement.

OBJECTIVE: To determine if transcostal thoracotomy closure resulted in less pain than circumcostal closure. STUDY DESIGN: Experimental cadaver and prospective clinical study. ANIMALS: Two canine cadavers and 13 adult, 22-29 kg dogs. METHODS: Phase 1: In 2 cadavers, 4 suture passage techniques were evaluated to determine the incidence of nerve entrapment in circumcostal intercostal thoracotomy closure. Phase 2: Pain after circumcostal closure (7 dogs) or transcostal closure (6 dogs) of a 4th intercostal space thoracotomy was evaluated by use of pain threshold scores, fentanyl administration rates, heart and respiratory rates, and numerical ratings for behavior. Arterial blood gas analyses were obtained 4 hours postoperatively. Transcostal closure was accomplished by drilling 5-6 small holes in the 5th rib and passing sutures through the holes and around the 4th rib to achieve closure. Pain threshold scores (PTS) were measured by an observer unaware of closure assignment, at 2, 4, 12, and 24 hours after closure by applying slowly increasing pressure to the incision line using a load cell. Rates of fentanyl administration were adjusted based on subjective impressions of dog comfort by a second observer unaware of closure assignment. RESULTS: A 70-100% incidence of nerve entrapment was found for all circumcostal techniques. PTS was higher (P=.045) and fentanyl infusion rates were lower (P=.001) for the transcostal group at 2, 4, 12, and 24 hour postoperatively compared with the circumcostal group. CONCLUSION: There is a high incidence of nerve entrapment using circumcostal closure techniques. A transcostal technique appears to be associated with less pain during the first 24 hours postoperatively. CLINICAL RELEVANCE: Based on lower pain scores, transcostal thoracotomy closure may be preferable to circumcostal closure techniques.

In vitro evaluation of the distribution of blood flow within a canine bipedicled latissimus dorsi muscle flap.

OBJECTIVE: To identify the predominant perforating artery in the canine latissimus dorsi muscle and demonstrate that perfusion of the predominant perforating artery improves blood flow in segments of the latissimus dorsi muscle that are located distally from the thoracodorsal artery. SAMPLE POPULATION: Latissimus dorsi muscles dissected from 7 dogs. PROCEDURES: Colored microspheres were used to determine the degree of perfusion of the latissimus dorsi muscle via the thoracodorsal artery, predominant perforating artery, or the thoracodorsal artery and predominant perforating artery together. The latissimus dorsi muscle was divided into 4 proximal to distal segments relative to the thoracodorsal artery (segments A, B, C, and D, respectively). RESULTS: The perforating artery, located at the level of the fifth intercostal space, predominantly supplied perfusion to segments B, C, and D. The number of microspheres received by segment C was significantly higher when the thoracodorsal artery and perforating artery were used for muscle perfusion (181.40 +/- 44.90 microspheres/300 g of tissue for every 3,000 spheres injected), compared with use of the thoracodorsal artery alone (60.00 +/- 13.70 microspheres/300 g of tissue for every 3,000 spheres injected). CONCLUSIONS AND CLINICAL RELEVANCE: Blood flow via the predominant perforating artery improves perfusion to the middle part of the latissimus dorsi muscle in dogs. A bipedicled latissimus dorsi muscle flap would provide a healthier muscle for cardiac assist in the treatment of dilated cardiomyopathy in dogs.

Medical and surgical treatment of pyothorax in dogs: 26 cases (1991-2001).

OBJECTIVE: To compare outcomes of dogs with pyothorax treated medically versus surgically and to identify prognostic indicators for dogs with pyothorax. DESIGN: Retrospective study. ANIMALS: 26 dogs. PROCEDURE: Medical records were reviewed to obtain information regarding signalment, results of physical and laboratory evaluations at the time of initial examination, results of bacterial culture of pleural fluid, radiographic abnormalities, treatment (surgical vs medical), complications, whether the disease recurred, disease-free interval, survival time, and cause of death. RESULTS: Calculated proportions of dogs free from disease 1 year after treatment were 25 and 78%, respectively, for dogs treated medically and surgically. Treatment was 5.4 times as likely to fail in dogs treated medically as in dogs treated surgically. Two regression models relating treatment group (medical vs surgical) to disease-free interval were found to be significant. The first contained terms for medical treatment and isolation of Actinomyces spp from pleural fluid; the second contained terms for medical treatment and radiographic detection of mediastinal or pulmonary lesions at the time of initial examination. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that surgical treatment is associated with a better outcome than medical treatment in dogs with pyothorax. In addition, surgery should be considered if radiographic evidence of mediastinal or pulmonary lesions is detected or if Actinomyces spp is isolated from the pleural fluid.