Fracture repair using a polyaxial locking plate system (PAX).

OBJECTIVES: To report outcomes and complications of dog and cat fractures treated with the polyaxial locking plate system (PAX). STUDY DESIGN: Case series. ANIMALS: Dogs (n = 60) and 2 cats. METHODS: Medical records (December 2009-March 2011) of dogs and cats with fractures treated with the PAX system were reviewed. Cases with adequate follow-up to document a functional union, had surgery performed by an author, had no prior treatment of the fracture(s), and with complete operative records were included. Signalment, body weight, bone(s) fractured, area of bone fractured, fracture classification, concurrent orthopedic injuries, complications, time to functional union, if minimally invasive plate osteosynthesis (MIPO) techniques were used, plate size, number of plates, bone graft use, and ancillary methods of fixation were recorded. Additionally, fracture segment: plate length, screw, number of plate holes, number of empty screw holes overlying/adjacent to the fractures, number of cortices engaged above/below the fracture was evaluated. Variables were evaluated statistically for effect on complications and functional union. RESULTS: Sixty-two animals were included. Mean time to functional union was 7.1 weeks. Complications occurred in 12 animals (19%) and plate failure occurred in 3 (5%). Statistically significant factors that affected time to functional union were the presence of multiple injuries and age. Those associated with complications were double plates and number of cortices engaged above and below fractures. CONCLUSIONS: The PAX system allows for multidirectional screw insertion with an overall complication rate and time to functional union similar to other fracture repair implant systems.

Clinical validation of a next-generation sequencing-based multi-cancer early detection "liquid biopsy" blood test in over 1,000 dogs using an independent testing set: The CANcer Detection in Dogs (CANDiD) study.

Cancer is the leading cause of death in dogs, yet there are no established screening paradigms for early detection. Liquid biopsy methods that interrogate cancer-derived genomic alterations in cell-free DNA in blood are being adopted for multi-cancer early detection in human medicine and are now available for veterinary use. The CANcer Detection in Dogs (CANDiD) study is an international, multi-center clinical study designed to validate the performance of a novel multi-cancer early detection "liquid biopsy" test developed for noninvasive detection and characterization of cancer in dogs using next-generation sequencing (NGS) of blood-derived DNA; study results are reported here. In total, 1,358 cancer-diagnosed and presumably cancer-free dogs were enrolled in the study, representing the range of breeds, weights, ages, and cancer types seen in routine clinical practice; 1,100 subjects met inclusion criteria for analysis and were used in the validation of the test. Overall, the liquid biopsy test demonstrated a 54.7% (95% CI: 49.3-60.0%) sensitivity and a 98.5% (95% CI: 97.0-99.3%) specificity. For three of the most aggressive canine cancers (lymphoma, hemangiosarcoma, osteosarcoma), the detection rate was 85.4% (95% CI: 78.4-90.9%); and for eight of the most common canine cancers (lymphoma, hemangiosarcoma, osteosarcoma, soft tissue sarcoma, mast cell tumor, mammary gland carcinoma, anal sac adenocarcinoma, malignant melanoma), the detection rate was 61.9% (95% CI: 55.3-68.1%). The test detected cancer signal in patients representing 30 distinct cancer types and provided a Cancer Signal Origin prediction for a subset of patients with hematological malignancies. Furthermore, the test accurately detected cancer signal in four presumably cancer-free subjects before the onset of clinical signs, further supporting the utility of liquid biopsy as an early detection test. Taken together, these findings demonstrate that NGS-based liquid biopsy can offer a novel option for noninvasive multi-cancer detection in dogs.

Influence of carboplatin infusion on osteosarcoma blood flow.

PURPOSE: Herein we report that carboplatin infusion influenced tumor blood flow signal independent of the mechanical decompression induced by the artificial lymphatics system technology that was being evaluated as part of a randomized veterinary clinical trial, treating spontaneously occurring canine appendicular osteosarcoma, a tumor very similar to its human counterpart. METHODS: Blood flow within the central region of the tumor was recorded continuously using laser Doppler flowmetry, a real-time measurement technology. Time-averaged flow values were computed from segments taken from the recordings immediately before starting carboplatin infusion, and during infusion. RESULTS: Carboplatin increased the tumor blood flow signal by an additional 59 +/- 26% (mean +/- SEM; p = 0.06) over the increase induced by the decompression. The increase started within 49 +/- 46 s after the start of infusion, had a response time constant of 19 +/- 21 s and persisted throughout the infusion, ending shortly after infusion ended. CONCLUSION: The rapidity of the flow signal increase suggests that carboplatin may have an autonomic effect on circulation, either local or systemic. The observations identify a new action of this drug and suggest a possible mechanism to exploit therapeutically.

Successful treatment of atlantooccipital luxation in an alpaca (Lama pacos).

A 7-mo-old male alpaca (Lama pacos) presented with an abnormal lowered posture of the head and neck and reluctance to walk. Cervical radiographs demonstrated atlantooccipital luxation. Successful manual closed reduction was achieved while the animal was anesthetized, resulting in complete return to normal gait and posture.

Principles of surgery for the cancer patient.

The appropriate diagnosis and treatment of patients with cancer are most correctly made through the cooperative efforts of a team of specialists, including an oncologist, surgeon, and pathologist. Preoperative determination of the tumor type and histologic grade, extent of the mass, and the patient's health status will result in the most comprehensive course of action. Diagnosis and staging of the tumor are paramount to preparing an optimal treatment plan. To ensure the best possible outcome, the preoperative, surgical, and postoperative plan should be customized to the individual cancer patient and their owner while following given guidelines. This article describes the basic principals for evaluation and operative management of the surgical oncology patient.

Use of an artificial lymphatic system during carboplatin infusion to improve canine osteosarcoma blood flow and clinical response.

BACKGROUND: The artificial lymphatic system (ALS), a mechanical system designed to reduce increased interstitial fluid pressure in solid tumors and enhance the delivery of chemotherapy, was evaluated within a randomized clinical trial treating spontaneously occurring canine appendicular osteosarcoma (OS), a tumor similar to its human OS counterpart. METHODS: An ALS was investigated for its ability to increase OS blood flow and increase uptake of intravenously administered carboplatin. RESULTS: Blood flow increased by 314% in tumors with active ALS drains versus 126% in control tumors (P < .03). Tumor carboplatin uptake increased by 51% after drain activation (P = .07). Microvascular density (MVD) was measured in tumors after surgical amputation and in corresponding bone regions in a cohort of normal dogs. The OS tumors had equivalent MVD as normal bone, and MVD was higher in the humerus than the femur (P < .03) in both tumor and normal bone. Median survival between the ALS-treated and control cohorts was not different despite increased drug uptake or ALS manipulation. Compared with historic controls, ALS drain insertion into tumors to reduce interstitial fluid pressure did not worsen the prognosis. CONCLUSIONS: The findings in canine spontaneously occurring OS indicate that an ALS may be of value as a chemotherapy adjunct for enhancing the delivery of chemotherapy to tumor interstitium.

Dog osteogenic sarcoma microvasculature observed with a Spälteholz technique.

A well-distributed, patent microvascular network is essential for adequate, uniform delivery of chemotherapy into solid tumors. This network has not been evaluated in osteogenic sarcoma. Spälteholz tissue clarification was used to observe the microvasculature of canine humeri bearing osteogenic sarcoma. Freshly amputated limbs, obtained from therapeutic amputation, were infused with a micron-sized carbon particle solution, frozen, and then cut into sagittal and axial 0.5-mm thick sections. They were photographed, then radiographed using high resolution Faxitron xray, chemically treated to clarify the tissue, and then rephotographed. Microvasculature was identified by the localization of carbon particles, which were unaffected by the clarification process, within the clarified sections. Clarified section photographs were digitized to gray scale levels and analyzed using IMAGE software; levels are directly related to capillary density. Faxitron and original images were registered to the clarified images to identify tissue regions. Multiple regions of interest from normal muscle, fat, bone, and tumor regions were selected and averaged. The microvasculature of the tumor was inhomogeneous, whereas its density was considerably lower than normal adjacent muscle and bone (range, 56-72% lower). These findings suggest that insufficient microvascular density and distribution may provide additional explanation for the poor response of solid tumors to chemotherapy and radiation therapy.