SPINAL MAST CELL TUMORS IN DOGS: IMAGING FEATURES AND CLINICAL OUTCOME OF FOUR CASES.

Published information regarding canine vertebral column mast cell tumors (MCTs) is limited. The objectives of this study were to report clinical and advanced imaging findings for a group of dogs with confirmed spinal MCT. Inclusion criteria for this retrospective case series were dogs with spinal magnetic resonance imaging (MRI) or computed tomography (CT) scans and a histological diagnosis of spinal MCT. Clinical, imaging, treatment, and outcome data were recorded. Four dogs met inclusion criteria. One dog had primary spinal MCT and three dogs had metastatic spinal MCT. All four dogs presented for paraspinal hyperesthesia and subacute progressive or acute myelopathy. All CT and MRI lesions were extradural. Two cases exhibited distinct masses in the epidural space. In one case, an epidural tumor invaded from the paravertebral musculature. One case exhibited polyostotic lesions indistinguishable from multiple myeloma by MRI. One dog with a primary epidural low-grade MCT remains clinically normal 4 years postoperatively, following adjunctive lomustine. An epidural high-grade MCT, metastatic from a cutaneous tumor, recurred within 2 months of surgery despite adjunctive vinblastine. Two high-grade cases with concurrent visceral involvement were euthanized immediately after imaging. In dogs, MCT should be considered as a differential diagnosis for a progressive painful myelopathy and CT or MRI evidence of an extradural spinal lesion (epidural, paravertebral, or polyostotic). While more often associated with cutaneous or disseminated disease, MCT may also occur as a primary tumor of the epidural space in dogs.

Effects of negative pressure wound therapy on healing of open wounds in dogs.

OBJECTIVE: To compare the effect of negative pressure wound therapy (NPWT) with standard-of-care management on healing of acute open wounds in dogs. STUDY DESIGN: Prospective, controlled, experimental study. ANIMALS: Adult dogs (n=10). METHODS: Full-thickness 4 m × 2 m wounds were surgically created on each antebrachium and in each dog were randomized to receive either NPWT or standard wound dressings (CON) for 21 days. Dressing changes and wound evaluations were made at 8 time points. First appearance of granulation tissue, smoothness of granulation tissue, exuberance, percent epithelialization, and percent contraction were compared. Biopsies for histopathology were taken, and histologic scores determined, at 5 time points, and aerobic bacterial wound cultures performed at 2 time points. RESULTS: Granulation tissue appeared significantly earlier, and was smoother and less exuberant in NPWT wounds compared with CON wounds. Percent contraction in NPWT wounds was less than CON wounds after Day 7. Percent epithelialization in NPWT wounds was less than CON wounds on Days 11, 16, 18, and 21. Histologic scores for acute inflammation were higher in NPWT on Day 3, and lower on Day 7, than CON wounds. Bacterial load was higher in NPWT on Day 7. CONCLUSION: NPWT accelerated appearance of smooth, nonexuberant granulation tissue; however, prolonged use of NPWT impaired wound contraction and epithelialization.

Clinical characteristics, magnetic resonance imaging features, treatment, and outcome for presumed intracranial coccidioidomycosis in 45 dogs (2009-2019).

BACKGROUND: Knowledge of the clinical and magnetic resonance imaging (MRI) features of intracranial Coccidioides infection in dogs is essential for prompt diagnosis to limit disease-associated morbidity and death. OBJECTIVES: To describe the MRI appearance of intracranial coccidioidomycosis in dogs, identify associated clinical and clinicopathologic findings, and report outcomes of medical treatment. ANIMALS: Forty-five client-owned dogs with presumed intracranial Coccidioides infection. METHODS: Retrospective case series. Medical records and images were reviewed. Clinical history, examination findings, serology, imaging characteristics, treatment, and outcome were recorded. Included cases had an abnormal brain MRI and positive Coccidioides serology by agar-gel-immunodiffusion (AGID). RESULTS: Median age was 7-years. Generalized tonic-clonic seizures were the most common presenting sign (25/45). Two lesion categories were identified: a granulomatous form with 1 or more distinct, intra-axial, contrast-enhancing foci (37/45), and a second variation with diffuse, bilateral, symmetrical lesions of the caudate nuclei and frontal lobes (8/45). Serum IgG titers ranged from 1 : 1 to ≥ 1 : 256; 2 dogs had positive IgM titers at 1 : 2. All dogs with follow-up serology (34/45) had a reduction in titer. Mean duration of follow-up was 22.4 ± 20.5 months (median 16 months). Six dogs were lost to follow-up <1-year after diagnosis (median 9 months). Five dogs were clinically well but had yet to be followed for >1-year. Of the remaining 34 dogs, 28 (82%) were alive ≥ 1-year after diagnosis. Thirteen of these dogs had follow-up times ≥ 2-years. CONCLUSIONS AND CLINICAL IMPORTANCE: The prognosis for intracranial Coccidioides infection is generally more favorable with medical treatment than in earlier reports.

Effects of conventional and slanted ventral slot procedures on the biomechanical behavior of the C5-C6 vertebral motion unit in dogs.

OBJECTIVE To compare the effects of conventional and slanted ventral slot procedures on the biomechanical behavior of the C5-C6 vertebral motion unit (VMU) in dogs. SAMPLE 14 vertebral columns (C4 through C7) from canine cadavers. PROCEDURES Specimens were assigned to a conventional or slanted ventral slot group (n = 7/group). For each specimen, the C5-C6 VMU was tested in ventral and dorsal bending and positive and negative axial torsion before and after surgery. Range of motion (ROM), stiffness, and energy absorption were compared between the 2 groups. RESULTS Both procedures significantly increased the ROM and stiffness and significantly decreased the energy absorption of the C5-C6 VMU in ventral and dorsal bending. Both procedures also increased the ROM in positive and negative axial torsion. In negative torsion, total stiffness and stiffness over the maximum ROM tested decreased less for the slanted slot procedure than for the conventional slot procedure. There were no significant differences between procedures for any of the other biomechanical outcomes examined. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that the biomechanical response of the C5-C6 VMU to the conventional and slanted ventral slot procedures was not significantly different, especially when considering postsurgical instability induced by both procedures. This was most likely due to disruption of the nucleus pulposus and dorsal annulus fibrosus of the disk with both procedures. On the basis of these findings, neither procedure appeared biomechanically superior. Comparative clinical studies are warranted to further evaluate the 2 procedures.