Clinical outcomes of patient-specific porous titanium endoprostheses in dogs with tumors of the mandible, radius, or tibia: 12 cases (2013-2016).

OBJECTIVE To characterize the processes involved in and outcomes achieved with custom-designed patient-specific implants to provide functional replacement of skeletal structures in dogs with tumors of the mandible, radius, or tibia. DESIGN Prospective case series. ANIMALS 6 dogs with mandibular tumors, 5 with tumors of the distal aspect of the radius, and 1 with a tumor in the distal aspect of the tibia treated from June 2013 to September 2016 at 3 referral centers. PROCEDURES After tumor staging, implants were designed from patients' CT scans by means of various computer-aided design applications and printed by means of selective laser melting in titanium-6 aluminum-4 vanadium alloy. A cutting jig was created in thermoplastic to ensure each osteotomy was performed as planned. Following ostectomy, the implant was secured into the defect with screws of appropriate size and length. RESULTS Initial return to normal clinical function was good to excellent for 11 of the 12 dogs. However, major complications resulted in revision of the implant or amputation of the limb in 5 dogs, and at least 3 of these complications were considered a consequence of faulty implant design or manufacturing. Infection developed in 2 dogs and was successfully treated in 1 dog. The longest-surviving dog maintained good limb function for 2 years. CONCLUSIONS AND CLINICAL RELEVANCE This is the largest reported series of dogs managed with customized 3-D-printed titanium implants. The 3-D printing allowed complex and patient-specific 3-D geometries to be fabricated, enabling function-sparing treatment of bone cancer affecting multiple anatomic sites.

Effect of bevacizumab on angiogenesis and growth of canine osteosarcoma cells xenografted in athymic mice.

Objective-To investigate the effects of bevacizumab, a human monoclonal antibody against vascular endothelial growth factor, on the angiogenesis and growth of canine osteosarcoma cells xenografted in mice. Animals-27 athymic nude mice. Procedures-To each mouse, highly metastasizing parent osteosarcoma cells of canine origin were injected into the left gastrocnemius muscle. Each mouse was then randomly allocated to 1 of 3 treatment groups: high-dose bevacizumab (4 mg/kg, IP), low-dose bevacizumab (2 mg/kg, IP), or control (no treatment). Tumor growth (the number of days required for the tumor to grow from 8 to 13 mm), vasculature, histomorphology, necrosis, and pulmonary metastasis were evaluated. Results-Mice in the high-dose bevacizumab group had significantly delayed tumor growth (mean ± SD, 13.4 ± 3.8 days; range, 9 to 21 days), compared with that for mice in the low-dose bevacizumab group (mean ± SD, 9.4 ± 1.5 days; range, 7 to 11 days) or control group (mean ± SD, 7. 2 ± 1.5 days; range, 4 to 9 days). Mice in the low-dose bevacizumab group also had significantly delayed tumor growth, compared with that for mice in the control group. Conclusions and Clinical Relevance-Results indicated that bevacizumab inhibited growth of canine osteosarcoma cells xenografted in mice, which suggested that vascular endothelial growth factor inhibitors may be clinically useful for the treatment of osteosarcoma in dogs. Impact for Human Medicine-Canine osteosarcoma is used as a research model for human osteosarcoma; therefore, bevacizumab may be clinically beneficial for the treatment of osteosarcoma in humans.

Stabilization of juxta-physeal distal tibial and fibular fractures in a juvenile tiger using a hybrid circular-linear external fixator.

OBJECTIVE: To report stabilization of closed, comminuted distal metaphyseal transverse fractures of the left tibia and fibula in a tiger using a hybrid circular-linear external skeletal fixator. STUDY DESIGN: Clinical report. ANIMAL: Juvenile tiger (15 months, 90 kg). METHODS: From imaging studies, the tiger had comminuted distal metaphyseal transverse fractures of the left tibia and fibula, with mild caudolateral displacement and moderate compression. Multiple fissures extended from the fractures through the distal metaphyses, extending toward, but not involving the distal tibial and fibular physes. A hybrid circular-linear external skeletal fixator was applied by closed reduction, to stabilize the fractures. RESULTS: The fractures healed and the fixator was removed 5 weeks after stabilization. Limb length and alignment were similar to the normal contralateral limb at hospital discharge, 8 weeks after surgery. Two weeks later, the tiger had fractures of the right tibia and fibula and was euthanatized. Necropsy confirmed pathologic fractures ascribed to copper deficiency. CONCLUSION: Closed application of the hybrid construct provided sufficient stability to allow this 90 kg tiger's juxta-articular fractures to heal with minimal complications and without disrupting growth from the adjacent physes.

Fusion podoplasty for the management of chronic pedal conditions in seven dogs and one cat.

Eight animals underwent fusion podoplasties for the treatment of chronic interdigital furunculosis (n=3), ectrodactyly (n=1), digit abnormalities associated with tendonectomy (n=1), redundant indertigital skin (n=1), conformational deformity (n=1), and necrotizing fasciitis of the paw (n=1). Median duration of bandaging was 14 days, and median duration of hospitalization was 5 days. Four dogs had dehiscence, which occurred at a mean time of 11 days after surgery. Clinical abnormalities necessitating podoplasty resolved in six animals and improved in two. Six animals had normal ambulation and two dogs had slight weight-bearing lameness after a median follow-up time of 29 mo. Fusion podoplasty may be recommended as a salvage procedure for the treatment of various chronic pedal diseases in dogs and cats.

Occlusion of the thoracic duct using ultrasonically activated shears in six dogs.

OBJECTIVE: To assess the feasibility of sealing the thoracic duct (TD) in dogs using ultrasonically activated shears via thoracoscopy. STUDY DESIGN: In vivo experimental study. ANIMALS: Mature dogs (n = 6). METHODS: Dogs were anesthetized without pulmonary exclusion and positioned in left lateral recumbency. Lymphangiography was performed to identify TD anatomy. Methylene blue was injected into the lymphatic catheter to identify the TD and its branches. Under thoracoscopic guidance (right dorsal 8-10th intercostal spaces), the TD was sealed with an ultrasonic device and lymphangiography was repeated. If the flow of contrast continued beyond the occlusion site, additional attempts to seal the duct were made. Dogs were euthanatized, the TD was excised and fixed in formalin for histopathology. RESULTS: Thoracoscopic identification of the TD was possible in 5 dogs. Three dogs required conversion to a thoracoscopic-assisted approach and 3 dogs required resealing of the TD closer to the diaphragm. Thoracic duct occlusion (TDO) was ultimately achieved in all 6 dogs based on follow-up lymphangiography. TDO by tissue coagulation was confirmed by histopathology. CONCLUSIONS: Thoracoscopic identification and occlusion of the TD using ultrasonically activated shears with bilateral lung ventilation is technically feasible in normal dogs and provides a less invasive alternative to open thoracotomy procedures.

Excision of a congenital laryngeal cyst in a five-month-old dog via a lateral extraluminal approach.

CASE DESCRIPTION: A 5-month-old neutered male Golden Retriever was evaluated because of moderate stridor, exercise intolerance, and dyspnea. The dog had been neutered 3 weeks previously, and the referring veterinarian identified a large fluid-filled swelling on the left lateral aspect of the larynx during anesthetic intubation for that surgery. The referring veterinarian drained fluid from the mass by use of needle centesis via the oral cavity, which resulted in temporary improvement in clinical signs; however, the clinical signs returned soon thereafter. CLINICAL FINDINGS: A large, soft, spherical mass was located between the left arytenoid and thyroid cartilages and axial to the left ceratohyoid bone, thus causing partial obstruction of the rima glottidis. Laryngoscopic examination, computed tomography (CT), and cytologic evaluation of aspirates performed before surgery; examination during surgery; and histologic evaluation of tissues following surgical excision confirmed the diagnosis of a laryngeal cyst. TREATMENT AND OUTCOME: Complete surgical excision was successfully performed via a lateral extraluminal approach to the larynx. One week after surgery, the dog coughed only occasionally. Twelve months after surgery, the owner reported that the dog was clinically normal with no recurrence of clinical signs, and laryngoscopic examination revealed no recurrence of the cyst or other pathological changes in the laryngeal region. CLINICAL RELEVANCE: Congenital laryngeal cysts are rarely reported in domestic animals. The information provided here described the CT appearance of a laryngeal cyst and the use of CT in diagnosis and surgical planning. Congenital laryngeal cysts can be resected via a lateral submucosal approach.

Postmortem evaluation of surgery site leakage by use of in situ isolated pulsatile perfusion after partial liver lobectomy in dogs.

OBJECTIVE: To evaluate postmortem surgery site leakage by use of in situ isolated pulsatile perfusion after partial liver lobectomies. ANIMALS: 10 healthy mixed-breed male dogs. PROCEDURES: Dogs were anesthetized, and 5 surgical techniques (pretied suture loop, energy-based sealer-divider, harmonic scalpel, suction with clip application, or suction with use of a thoracoabdominal stapler) were used to perform 5 partial liver lobectomies in each dog. Dogs were euthanatized, and the portal vein and hepatic artery were cannulated and perfused with a modified kidney perfusion machine (pulsatile flow for arterial perfusion and nonpulsatile flow for portal perfusion). Lobectomy sites were inspected for leakage of perfusate, and time until detection of leakage was recorded. The techniques in each dog were ranked on the basis of time until leakage. Time until leakage and rankings for each surgical technique were analyzed by use of an ANOVA. RESULTS: Leakage of perfusate was recorded in 44 lobes at supraphysiologic pressures. Of the 6 lobes without leakage, a pretied suture loop procedure was performed in 5 and a harmonic scalpel procedure was performed in 1. Time until leakage and the ranking differed significantly between the pretied suture loop and the other techniques. Time until leakage and ranking did not differ significantly among the other techniques. CONCLUSIONS AND CLINICAL RELEVANCE: Time until leakage of perfusate was greater for the pretied suture loop technique than for the other techniques, and that technique did not fail in 5 of 10 lobes. However, all techniques appeared to be safe for clinical use.

Primary anastomosis of segmental external auditory canal atresia in a cat.

External auditory canal atresia (EACA) may arise as a congenital deformity, or as sequel to external auditory canal trauma. Diagnosis of EACA was made in this 3-year-old cat by video otoscopy and computed tomography. Successful treatment of congenital segmental EACA was achieved, using end-to-end anastomosis. Primary anastomosis should be considered for treatment of both acute and chronic separation of the annular and auricular cartilages, as well as congenital EACA in the cat.

Intracardiac foreign body in a dog.

A dog that was referred to the University of Florida Veterinary Medical Center was discovered to have a bamboo skewer within the right atrium and right ventricle, traversing the tricuspid valve. The skewer was ingested approximately four months prior to referral and was partially removed via gastrotomy. The presenting complaint at the time of referral included coagulopathy, anemia and leukocytosis. A linear, hyperechoic structure was identified in the right heart during an echocardiogram. The foreign body was suspected to be a portion of the skewer that the patient had previously ingested. Cardiopulmonary bypass was performed and the foreign body was removed successfully. Complications following surgery included the development of tricuspid valve and ventricular wall thrombi, atrial flutter and amiodarone toxicity. Many indications have been described in the veterinary literature for cardiopulmonary bypass. However, to the best of the authors' knowledge, successful removal of an intracardiac foreign body with cardiopulmonary bypass has not been reported in a veterinary patient. This represents a new indication for cardiopulmonary bypass in veterinary medicine.

Development of an intramuscular xenograft model of canine osteosarcoma in mice for evaluation of the effects of radiation therapy.

OBJECTIVE: To develop an IM xenograft model of canine osteosarcoma in mice for the purpose of evaluating effects of radiation therapy on tumors. ANIMALS: 27 athymic nude mice. PROCEDURES: Mice were randomly assigned to 1 of 3 groups of 9 mice each: no treatment (control group), radiation at 10 Gy, or radiation at 15 Gy. Each mouse received 5 x 10(5) highly metastasizing parent osteosarcoma cells injected into the left gastrocnemius muscle. Maximum tumor diameter was determined with a metric circles template to generate a tumor growth curve. Conscious mice were restrained in customized plastic jigs allowing local tumor irradiation. The behavior and development of the tumor xenograft were assessed via evaluations of the interval required for tumor-bearing limbs to reach diameters of 8 and 13 mm, extent of tumor vasculature, histomorphology of tumors, degree of tumor necrosis, and existence of pulmonary metastasis and clinical disease in affected mice. RESULTS: Tumor-bearing limbs grew to a diameter of 8 mm (0.2-g tumor mass) in a mean +/- SEM interval of 7.0 +/- 0.2 days in all mice. Interval to grow from 8 to 13 mm was significantly prolonged for both radiation therapy groups, compared with that of the control group. Histologic evaluation revealed the induced tumors were highly vascular and had characteristics consistent with those of osteosarcoma. Pulmonary metastasis was not detected, and there was no significant difference in percentage of tumor necrosis between groups. CONCLUSIONS AND CLINICAL RELEVANCE: A reliable, repeatable, and easily produced IM xenograft model was developed for in vivo assessment of canine osteosarcoma.

Canine histiocytic diseases.

Canine histiocytic diseases are an emerging spectrum of diseases characterized by proliferations of histiocytic cells. Nonneoplastic histiocytic disease (reactive histiocytosis, comprising cutaneous and systemic histiocytosis) is uncommon. Neoplastic histiocytic diseases include cutaneous histiocytoma, which is a benign histiocytic tumor, and localized and disseminated histiocytic sarcoma (previously known as malignant histiocytosis), which are malignant diseases. The differentiation of histiocytic diseases can be challenging. This article outlines the characteristics of each disease entity and details the clinicopathologic, histologic, immunohistochemical, prognostic, and therapeutic differences among them.