Computed Tomographic Evaluation of Safe Corridors for Pin Placement in Rabbit Thoracolumbar Vertebrae and Sacrum.

OBJECTIVE: The aim of this study was to identify safe corridors for pin placement in the terminal thoracic vertebrae, lumbar vertebrae and sacrum of rabbits using computed tomography (CT) in cadaveric models. STUDY DESIGN: Computed tomographic imaging of 25 adult New Zealand white rabbit (Oryctolagus cuniculi) cadavers was evaluated. Safe insertion corridors at the cranial and caudal end cortical sections (ECS) of the vertebrae were determined using a multiplanar reconstruction software. Pins were placed to allow maximal bone purchase within the safe corridors. Post-procedure CT imaging was performed to evaluate the pin position. RESULTS: The median safe corridor height in the thoracic and lumbar cranial ECS (2.54 mm; 1.39-3.97 mm) was significantly lower than that of caudal ECS (3.98 mm; 1.66-5.53 mm; p < 0.001). The mean widths of the left and right sacral safe corridors were not significantly different. Of the 99 pins placed, 70.7% of the pins were appropriately placed without vertebral canal impingement. Errors included partial canal impingement (12.1%), complete canal impingement (5.1%), inadequate bone purchase (7.1%), placement into the intervertebral disc space (1.0%) or in the incorrect ECS than intended (4.0%). The odds ratio of successful pin insertion without canal impingement was 2.77 (95% confidence interval, 1.04-7.43; p < 0.05) times higher in the caudal ECS than in the cranial ECS. CONCLUSION: The corridor identified in this study can be used as a guideline for pin placement in the thoracic and lumbar vertebrae of New Zealand white rabbits. Further biomechanical studies are required.

Ex vivo comparison of pin placement with patient-specific drill guides or freehand technique in canine cadaveric spines.

OBJECTIVE: To compare vertebral implant placement in the canine thoracolumbar spine between 3D-printed patient-specific drill guides (3DPG) and the conventional freehand technique (FH). STUDY DESIGN: Ex vivo study. ANIMALS: Cadaveric canine spines (n = 24). METHODS: Implant trajectories were established for the left and right sides of the T10 through L6 vertebrae based on computed tomography (CT) imaging. Customized drill guides were created for each vertebra of interest. Each cadaver was randomly assigned to one of six veterinarians with varying levels of experience placing vertebral implants. Vertebrae were randomly assigned a surgical order and technique (3DPG or FH) for both sides. Postoperative CT images were acquired. A single, blinded observer assessed pin placement using a modified Zdichavsky classification. RESULTS: A total of 480 implants were placed in 240 vertebrae. Three sites were excluded from the analysis; therefore, a total of 238 implants were evaluated using the FH technique and 239 implants using 3DPG. When evaluating implant placement, 152/239 (63.6%) of 3DPG implants were considered to have an acceptable placement in comparison with 115/248 (48.32%) with FH. Overall, pin placement using 3DPG was more likely to provide acceptable pin placement (p < .001) in comparison with the FH technique for surgeons at all levels of experience. CONCLUSION: The use of 3DPG was shown to be better than the conventional freehand technique regarding acceptable placement of implants in the thoracolumbar spine of canine cadavers. CLINICAL SIGNIFICANCE: Utilizing 3DPG can be considered better than the traditional FH technique when placing implants in the canine thoracolumbar spine.

POSTMORTEM COMPUTED TOMOGRAPHY AND MAGNETIC RESONANCE IMAGING FINDINGS IN A CASE OF COINFECTION OF DOLPHIN MORBILLIVIRUS AND ASPERGILLUS FUMIGATUS IN A JUVENILE BOTTLENOSE DOLPHIN (TURSIOPS TRUNCATUS).

A freshly dead juvenile bottlenose dolphin (Tursiops truncatus), recovered from the waters near Sand Key, Clearwater, FL, was imaged postmortem using computed tomography and magnetic resonance imaging prior to conventional necropsy. The pattern of imaging findings in the brain was compatible with severe multifocal meningoencephalitis with intralesional necrosis and/or hemorrhage, and the pattern of imaging findings in the lungs was compatible with severe multifocal bronchopneumonia. The subsequent investigation included necropsy, histology, culture, and molecular diagnostics and demonstrated disseminated coinfection of dolphin morbillivirus and Aspergillus fumigatus. This is the first report documenting the cross-sectional imaging findings of this important cetacean comorbidity and demonstrates advances in modern, cooperative investigations of marine mammal mortality events.

RENAL NEOPLASIA FROM A SINGLE POPULATION OF PTEROPODID BATS.

Neoplastic diseases have rarely been reported in the family Pteropodidae, and primary malignant renal neoplasms are generally uncommon across animal species. This case series describes four cases of primary renal neoplasia: three renal cell carcinomas and one nephroblastoma in three species of pteropodid bats, specifically large flying foxes (Pteropus vampyrus, n = 2), straw-colored fruit bat (Eidolon helvum, n = 1), and a little golden-mantled flying fox (Pteropus pumilus, n = 1). Two of the cases were diagnosed antemortem using ultrasonography, computed tomography, and cytology; and one of these bats with a renal cell carcinoma was treated successfully with a unilateral nephrectomy. The remaining two cases were diagnosed at necropsy.

Radiographic Differentiation of Cranial Mediastinal Lymphomas from Thymic Epithelial Tumors in Dogs and Cats.

In both dogs and cats, the most common cranial mediastinal masses (CMMs) are lymphoma and thymic epithelial tumors (TETs). Pretreatment differentiation of these tumors using fine needle aspiration or biopsy is essential because lymphomas are treated medically, whereas TETs are treated surgically. The purpose of this retrospective study was to determine whether thoracic radiographic findings can be used to aid clinicians in preliminarily differentiating the two tumor types before cytology or histopathology results become available. Medical records, available cytologic or histologic samples, and thoracic radiographs were evaluated for 62 dogs and 28 cats. Seventeen radiographic criteria were assessed by two examiners, and regression modeling was performed to test for significant predictors of tumor type. In dogs, CMMs with at least two well-defined radiographic margins on a lateral view and CMMs causing a rightward shift of the cardiac silhouette on a ventrodorsal or dorsoventral view were significantly more likely to be TETs than lymphomas (P < .001 and P < .01, respectively). No significant predictive variables were identified in cats. Radiographic findings do not eliminate the need for invasive sampling, but in dogs, they may guide the clinician in providing preliminary information to owners regarding the staging and therapeutic measures that may eventually be recommended.

Evaluation of Two Training Methods for Teaching the Abdominal Focused Assessment with Sonography for Trauma Technique (A-FAST) to First- and Second-Year Veterinary Students.

Ultrasound techniques, including focused assessment with sonography for trauma (FAST) examinations, are commonly used in veterinary practice, making inclusion of ultrasound in veterinary curricula increasingly important. The best approach for teaching ultrasound techniques in veterinary medicine has not been evaluated. This study compared the results of two training techniques, live-animal training and online video instruction, on students' performance during abdominal FAST (A-FAST) examinations. Thirty-eight first- and second-year veterinary students were randomly assigned to learn A-FAST via a live-animal laboratory or an instructional video. The live-animal group received one-on-one instruction in A-FAST techniques during a single laboratory. The video group received a link to an instructional video demonstrating A-FAST techniques, allowing unlimited viewing opportunities over a two-week period. Both groups were also provided written instructional information. All participants were assessed on their ability to find and correctly name the four A-FAST quadrants on a live animal. We found a significant difference between the two groups in the students' ability to identify the diaphragmatic-hepatic (DH) view, but for the other three views (hepatorenal, splenorenal, and cystocolic), training method did not affect performance. Results suggest the potential for using a multi-modal instructional approach to teach ultrasound techniques to veterinary students.

Systemically administered IgG anti-toxin antibodies protect the colonic mucosa during infection with Clostridium difficile in the piglet model.

The use of anti-toxin human monoclonal antibodies (HMab) as treatment for C. difficile infection has been investigated in animal models and human clinical trials as an alternative to or in combination with traditional antibiotic therapy. While HMab therapy appears to be a promising option, how systemically administered IgG antibodies protect the colonic mucosa during Clostridium difficile infection is unknown. Using the gnotobiotic piglet model of Clostridium difficile infection, we administered a mixture of anti-TcdA and anti-TcdB HMabs systemically to piglets infected with either pathogenic or non-pathogenic C. difficile strains. The HMabs were present throughout the small and large intestinal tissue of both groups, but significant HMabs were present in the lumen of the large intestines only in the pathogenic strain-infected group. Similarly, HMabs measured in the large intestine over a period of 2-4 days following antibody administration were not significantly different over time in the gut mucosa among the groups, but concentrations in the lumen of the large intestine were again consistently higher in the pathogenic strain-infected group. These results indicate that systemically administered HMab IgG reaches the gut mucosa during the course of CDI, protecting the host against systemic intoxication, and that leakage through the damaged colon likely protects the mucosa from further damage, allowing initiation of repair and recovery.