Endoscopic treatment of acute oropharyngeal stick injuries in dogs: 46 cases (2010-2020).

OBJECTIVES: To review long-term outcomes of dogs with acute oropharyngeal stick injuries managed with rigid endoscopy at a UK referral centre. MATERIALS AND METHODS: Retrospective analysis and follow-up with referring veterinary surgeons and owners of patients treated between 2010 and 2020. A medical record search was performed and data regarding signalment, clinical presentation, treatment and long-term outcomes were recorded. RESULTS: Sixty-six dogs with acute oropharyngeal stick injury were identified and 46 (70.0%) of these had endoscopy of the wound. The dogs were of various breeds, ages (median=3 years; range 0.6 to 11 years) and weights (median=20.4 kg; range 7.7 to 38.4 kg) and 58.7% of patients were male. The median time from injury to referral was 1 day (range 2 hours to 7 days). Patients were anaesthetised, and injury tracts were explored using 0° and 30° forward-oblique, 2.7 mm diameter, 18 cm length rigid endoscopes with a corresponding 14.5 French sheath using saline infusion via gravity. All foreign material that could be grasped was removed using forceps. Tracts were flushed with saline and reinspected to confirm removal of all visible foreign material. Out of 40 dogs with long-term follow-up, 38 (95.0%) had no major long-term complications. The remaining two dogs developed cervical abscessation after endoscopy, one of which resolved after repeat endoscopy and the other resolved after open surgery. CLINICAL SIGNIFICANCE: Long-term follow-up of dogs with acute oropharyngeal stick injury managed with rigid endoscopy showed an excellent outcome in 95.0% of cases.

Outcome of superficial brachial axial pattern flaps used to close skin defects in dogs: 16 cases (1996-2019).

OBJECTIVES: To report the complication rate, type of complications and outcome of the superficial brachial axial pattern flap when used for closure of skin defects in dogs. MATERIALS AND METHODS: Medical records of dogs treated with a superficial brachial axial pattern flap for closure of a skin defect were reviewed. Information regarding signalment, reason for axial pattern flap use, skin flap size, flap healing, postoperative complications and need for revision surgery was collected. RESULTS: Sixteen dogs were included in the study. Indications for the superficial brachial axial pattern flap included closure following tumour removal (15/16, 94%) and management of a non-healing wound on the olecranon (1/16, 6%). Postoperative complications occurred in all dogs and included partial dehiscence (7/16, 44%), partial flap necrosis (6/16. 38%), seroma formation (5/16, 31%), flap oedema (3/16, 19%) and complete flap necrosis (2/16, 13%). Eight flaps (50%) healed without open wound management or additional surgery. Five dogs required open wound management without additional surgery, and three dogs (19%) required revision surgery. CLINICAL SIGNIFICANCE: Use of the superficial brachial axial pattern flap was associated with a high rate of complications. Most complications were managed without additional surgery and all wounds eventually healed, in some cases after prolonged open wound management.

Is the caudal auricular axial pattern flap robust? A multi-centre cohort study of 16 dogs and 12 cats (2005 to 2016).

OBJECTIVE: To determine the frequency and type of healing complications arising after the use of the caudal auricular axial pattern flap to close defects on the head in dogs and cats. MATERIAL AND METHODS: Multi-centre retrospective cohort study. Centres were recruited by the Association for Veterinary Soft Tissue Surgery Research Cooperative. Medical records of 11 centres were reviewed, and data from all dogs and cats treated with a caudal auricular axial pattern flap were retrieved. The following data were recorded: signalment, reason for reconstruction, flap dimensions, anatomic landmarks used, histological diagnosis, flap healing and whether revision surgery was required. RESULTS: Twenty-eight cases were included: 16 dogs and 12 cats. Flap length: width ratio was approximately 3:1 and flap length extended to the scapular spine in most cases. Optimal wound healing occurred in five of 16 (31%) dogs and six of 12 (50%) cats. Wound dehiscence without flap necrosis occurred in one of 16 (6%) dogs and one of 12 (8%) cats. Wound dehiscence with flap necrosis occurred in 10 of 16 (63%) dogs and five of 12 (42%) cats. Revision surgery was performed in eight of 16 (50%) dogs and three of 12 (25%) cats. CLINICAL SIGNIFICANCE: The caudal auricular axial pattern flap can provide full thickness skin coverage for large defects on the head in dogs and cats. Partial flap necrosis is a common complication, and revision surgery may be required in order to achieve final wound closure.

Outcome and prognostic factors in medically treated canine prostatic carcinomas: A multi-institutional study.

Literature describing medical treatment of canine prostatic carcinoma (PC) is sparse. The aims of this study were to assess outcomes, including time to progression (TTP) and median survival time (MST), of canine PC treated with non-steroidal anti-inflammatory drugs (NSAIDs) and/or chemotherapy, and to identify prognostic factors. Records from 8 institutions were searched for dogs with cytologically or histologically confirmed PC without bladder involvement: 67 dogs were included. Presenting signs were urinary (25), gastrointestinal ([GI], 11) and systemic (3); 16 dogs had GI and urinary signs, 7 dogs had systemic signs with concurrent GI or urinary signs and in 5 dogs the tumour was an incidental finding. Out of 27 dogs, 9 (33%) had positive urine culture. Metastases were identified in 26 dogs to lymph nodes (19), lungs (10), bone (2) and liver (1). Treatment included NSAIDs and chemotherapy (32), NSAIDs alone (31) and chemotherapy alone (4). The overall MST was 82 days (range 9-752) and median TTP was 63 days (range 9-752). Dogs receiving NSAIDs combined with chemotherapy experienced a significantly longer MST (106 vs 51 days; P = .035) and TTP (76 vs 44 days; P = .02) compared to dogs receiving NSAIDs alone. Intact dogs and those with metastatic disease had significantly shorter MST (31 vs 90 days, P = .018 and 49 vs 109 days, P = .037, respectively); intact dogs also had significantly shorter TTP (25 vs 63 days, P = .0003). This study suggests that a combination of NSAIDs and chemotherapy may improve outcomes in canine PC. Metastatic disease and being entire negatively influenced prognosis.

Temozolomide alone or in combination with doxorubicin as a rescue agent in 37 cases of canine multicentric lymphoma.

Temozolomide (TMZ) is an alkylating agent previously used in conjunction with doxorubicin (DOX) to treat dogs with relapsed lymphoma. However, there are very limited data for this drug when used as single agent. The aim of this retrospective study was to evaluate the efficacy and toxicity of TMZ in dogs with relapsed multicentric lymphoma that failed multi-agent chemotherapy protocols, and compare the outcome to a group of dogs receiving the same drug in combination with DOX. Twenty-six patients were included in the TMZ group and 11 in the TMZ/DOX group. Responses were evaluated via retrospective review of the medical records. The overall median survival time (MST) for both groups was 40 days (range 1-527 days). For the TMZ group, median time to progression (TTP) was 15 days (range 1-202 days) and MST 40 days (range 1-527 days), with an overall response rate (ORR) of 32% and 46% recorded toxicities. For the TMZ/DOX group, median TTP was 19 days (range 2-87 days) and MST 24 days (range 3-91 days), with an ORR of 60% and 63% recorded toxicities. However, a proportion of haematological toxicoses may have gone undetected due to the absence of associated clinical signs. The difference in MST and TTP between the 2 groups was not statistically significant. Similarly, no negative prognostic factors were identified. Although responses were generally short lived, this study suggests that TMZ may achieve similar efficacy to TMZ/DOX whilst being associated with a lower frequency of recorded toxicities.

Indications, outcome and complications with axial pattern skin flaps in dogs and cats: 73 cases.

OBJECTIVE: To determine the indications, frequency of complications and long term outcome associated with axial pattern flaps used to repair wound defects in dogs and cats. METHODS: Medical records from two independent referral centres for dogs and cats undergoing wound repair with an axial pattern flap were reviewed. RESULTS: Seventy-three animals were included, 49 dogs: 24 cats. Indications for axial pattern flaps were chronic wounds (43/73; 59%) and closure following tumour resection (30/73; 41%). Axial pattern flaps used were: thoracodorsal, caudal superficial epigastric, reverse saphenous conduit, superficial brachial, deep circumflex iliac, superficial cervical, caudal auricular, lateral thoracic, cranial superficial epigastric, genicular and superficial temporal. Postoperative complications occurred in 64 patients (89%) and 8 patients (11%) had no complications. Complications were: dehiscence, swelling of the flap, necrosis, infection, discharge and seroma. Flap outcome was excellent in 16 patients (23%), good in 29 (41%), fair in 21 (30%) and poor in 5 (7%). CLINICAL SIGNIFICANCE: There is a high complication rate associated with axial pattern flaps but these are usually easily managed and long term outcome is excellent, in either species.

Recombinant canine IgE Fc and an IgE Fc-TRAIL fusion protein bind to neoplastic canine mast cells.

Screening for expression of the high affinity receptor for IgE by reverse transcriptase PCR, revealed that almost all canine mast cell tumors expressed FcɛRIα mRNA, supporting the rationale for developing anti-neoplastic treatments based on molecules that could target this receptor. Use of cytotoxic cytokines to trigger an apoptotic signal is one strategy for inducing cell death in malignant mast cells. The coding sequences for canine IgE and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) were identified through genome analyses. Selected regions of the coding sequences for these genes were cloned and compared to the predicted genome sequences. The Fc region of canine IgE, death domain of canine TRAIL and an IgE Fc: TRAIL fusion construct were generated and epitope-tagged proteins expressed, using a eukaryotic expression system. Specific binding of recombinant canine IgE Fc-containing proteins to recombinant human FcɛRIα and to a canine mast cell tumor line expressing FcɛRIα (C2), but not one failing to express FcɛRIα (MCLA), was demonstrated. Specific binding of the IgE: TRAIL fusion protein was not abrogated by the TRAIL moiety. These results are proof of principle that canine IgE targeting to FcɛRIα can be used as a platform for selective delivery of therapies to FcɛRIα-expressing cells, potentially enhancing their therapeutic index and efficacy.

Prevalence, outcome and risk factors for postoperative pyothorax in 232 dogs undergoing thoracic surgery.

OBJECTIVE: To determine the prevalence, outcome and risk factors for postoperative pyothorax in dogs undergoing thoracic surgery. METHODS: Case records were reviewed retrospectively to identify dogs with post thoracic surgery pyothorax, defined as septic neutrophilic inflammation within the pleural space based on cytology and/or a positive bacterial culture of pleural fluid. Those identified were reviewed for potential risk factors for postoperative pyothorax based on biological plausibility and previously published data. These potential risk factors were explored by multivariable logistic regression. RESULTS: Of 232 dogs undergoing thoracic surgery, 15 (6.5%) dogs developed pyothorax. Bacteria cultured included methicillin-resistant Staphylococcus aureus and multi-resistant Escherichia coli. Of these dogs, six died, four were euthanased and five were treated successfully. A diagnosis of idiopathic chylothorax [Odds Ratio (OR)=12.5, 95% Confidence Interval (CI)=2.7-58.5, P=0.001], preoperative intrathoracic biopsy (OR=14.3, 95% CI=1.7-118.7, P=0.014) and preoperative thoracocentesis (OR=11.2, 95% CI=1.6-78.2, P=0.015) were identified as independent risk factors for development of postoperative pyothorax. CLINICAL SIGNIFICANCE: Idiopathic chylothorax, intrathoracic biopsy and prior thoracocentesis are independent risk factors for postoperative pyothorax, which was associated with a 67% mortality rate.

Current British veterinary attitudes to the use of perioperative antimicrobials in small animal surgery.

A questionnaire was sent to 2951 mixed and small animal veterinary practices to examine the use of perioperative antimicrobials in cats and dogs in the UK. The percentage of respondents who always used antimicrobials in two surgical procedures classified according to NRC criteria as 'clean' was 25.3 per cent for removal of a 1 cm cutaneous mass and 32.1 per cent for routine prescrotal castration. Factors considered important in decision-making about when to use antimicrobial agents included immunosuppression, presence of a drain, degree of wound contamination, potential for spillage of visceral contents and implantation of prosthesis. The most common antimicrobial agents mentioned were potentiated amoxicillin (98.0 per cent), amoxicillin (60.5 per cent), clindamycin (21.8 per cent), enrofloxacin (21.7 per cent), cephalexin (18.6 per cent) and metronidazole (12.7 per cent). Forty-three per cent of all responding veterinarians listed a long-acting preparation for perioperative use. The routes used were subcutaneous (76.1 per cent), intravenous (25.8 per cent), intramuscular (19.8 per cent), oral (13.5 per cent) and topical (7.7 per cent). Antimicrobials were given before surgery (66.6 per cent), during surgery (30.2 per cent), immediately after surgery (12.0 per cent) and after surgery (6.3 per cent). This survey has identified the suboptimal use of perioperative antimicrobials in small animal surgery with improvements needed with respect to timing, duration, choice of antimicrobial and a more prudent selection of surgical cases requiring prophylaxis.

Duodenal Brunner's gland adenoma causing chronic small intestinal obstruction in a dog.

An eight-year-old, neutered, female English springer spaniel was presented with a 14-month history of vomiting, marked weight loss and lethargy, all of which were non-responsive to medical therapy. Abdominal radiographs and ultrasonography showed an intraluminal soft tissue mass extending from the pyloric antrum to the proximal duodenum. Two spherical masses both approximately 8 cm in diameter were removed via a duodenotomy. Histopathological examination showed the first mass to be a trichobezoar and the aboral mass to be a Brunner's gland adenoma. Surgery resulted in a complete resolution of the clinical signs.

Histological examination of the intestine from dogs and cats with intussusception.

OBJECTIVES: To review the histological findings in the intestine from dogs and cats with intussusception. METHODS: Medical records and histopathology reports of dogs and cats with intussusception were reviewed retrospectively. RESULTS: Fourty-nine animals (31 dogs and 18 cats) were identified for inclusion. Tissues examined com-prised the intussusception alone in 29 animals (16 dogs and 13 cats), and the intussusception with additional intestinal biopsies in 20 animals (15 dogs and 5 cats). Twenty-eight of 49 (57·1%) animals, comprising 19 of 31 (61·3%) dogs and 9 of 18 cats (50%) had abnormalities detected on histological examination of tissue. Eleven of 29 (46·9%) cases where only the intussusception was submitted achieved a histological diagnosis, compared to 17 of 20 (85%) where additional biopsies were submitted (P=0·003). Cats (median age 36 months, range 2 to 174) were significantly older than dogs (median age 7·5 months, range 1 to 125 months, P=0·010) and were significantly more likely to have underlying neoplasia (5 of 9; 55·6%) compared to dogs who were more likely to have inflammatory causes (17 of 19; 89·5%, P=0·020). There was no association between histological diagnosis and location of the intussusception (P=1·000). CLINICAL SIGNIFICANCE: Histological abnormalities were detected in more than half of the animals. Diagnosis of intestinal disease in animals with intussusception may be improved by submission of additional biopsy samples. Cats with intussusception are more likely to be older and have underlying neoplasia than dogs which are more likely to have inflammatory disease.

Computed tomographic findings in canine pyothorax and correlation with findings at exploratory thoracotomy.

OBJECTIVES: To describe computed tomographic (CT) findings in canine spontaneous pyothorax and compare them to surgical findings and to assess the utility of CT in guiding case management. METHODS: Records from 2003 to 2010 were reviewed to identify dogs, with spontaneous pyothorax, which had undergone CT. Cases were managed medically or surgically. CT images and surgery reports were reviewed and compared for surgical cases. RESULTS: Twelve dogs were included. Eight were managed surgically, three were managed medically and one died before management. Pleural fluid was present in all dogs on CT (n=12) and at surgery (n=8). Pleural gas was identified in five dogs on CT. Pleural thickening was detected in eight dogs on CT (seven visceral, one parietal and six mediastinal) and eight dogs at surgery (seven visceral, eight parietal and six mediastinal), six of which were identified by CT. Abnormal pulmonary parenchyma was detected in 10 dogs on CT and 5 dogs at surgery, all of which were identified by CT. Mediastinal involvement was detected in 10 dogs on CT and 6 dogs at surgery, 5 of which were identified by CT. CONCLUSIONS: CT and surgical findings are similar in most cases of canine spontaneous pyothorax. CT may be a useful diagnostic tool for guiding case management.

Targeted knockdown of canine KIT (stem cell factor receptor) using RNA interference.

Canine mast cell tumours often express KIT mutations that result in constitutive activation of the c-kit receptor and which are associated with more aggressive disease. The aim of the current study was to determine whether small inhibitory RNA (SiRNA) molecules could specifically target canine KIT mRNA for knock-down. Canine beta-2 microglobulin (B2M), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and KIT sequences were cloned into the psiCHECK™-2 vector. SiRNA molecules, designed to target gene-specific sequences, were co-transfected with plasmid DNA into Chinese hamster ovary (CHO) cells. Renilla and firefly luciferase activity was measured using the Dual-GLO(®) Luciferase Assay (Promega). Using this reporter system, canine housekeeping gene-specific SiRNA molecules demonstrated knockdown of their targets (72.0% knockdown for B2M and 94.5% knockdown for GAPDH). An SiRNA molecule targeting exon 2 of canine KIT successfully knocked-down reporter gene expression of a KIT(26-407) construct (90.8% knockdown). An SiRNA molecule targeting a 48 base-pair in-tandem duplication mutation in KIT exon 11 selectively knocked down expression of the KIT(1569-1966mutant) construct (93.1% knockdown) but had no effect on the KIT(1569-1918wild-type) construct. The results show that RNA interference can be used to inhibit canine KIT mRNA expression and has the potential to selectively target the mutant version of KIT that is expressed by some malignant mast cells.

Transformation of a thymic branchial cyst to a carcinoma with pulmonary metastasis in a dog.

A 9-year-old, female neutered Dalmatian was evaluated for acute onset of dyspnoea. Thoracocentesis on presentation yielded 1300 ml sanguineous fluid, while thoracic radiology and ultrasonography showed a mixed-echoic cavitary cranial mediastinal mass, sternal lymph node enlargement and pleural effusion. Surgical exploration of the thorax revealed a multi-lobulated red/brown cranial mediastinal mass and multiple similarly coloured ovoid nodules within several lung lobes. Histopathology revealed thymic branchial cysts with neoplastic transformation and examination of the lung was consistent with metastasis. Despite initially recovering well, acute sepsis and pyothorax resulted in cardiac arrest 8 days postoperatively. This is the first veterinary report of neoplastic transformation of a thymic branchial cyst with pulmonary metastasis.

Spontaneous gastroduodenal perforations in dogs: a retrospective study of 15 cases.

The clinical findings and outcomes following surgical management of spontaneous gastroduodenal perforations in 15 dogs were reviewed in a retrospective study to identify related risk factors. Clinical and clinicopathological findings were diverse. Use of multiple diagnostic procedures yielded a strong index of suspicion for gastrointestinal perforation. There was a trend towards improved survival for animals with perforation of the gastric fundus/body compared to pyloric or duodenal perforation, although the difference was not statistically significant. Five dogs were euthanased at surgery; two dogs died within two days after surgery. Seven of the eight surviving dogs had a favourable long-term outcome. Previous administration of NSAIDs was the only identified predisposing factor in ten of 10 of the dogs.

Haemangiosarcoma in the uterine remnant of a spayed female dog.

A 11-year-old, female, spayed greyhound was presented with a haemorrhagic discharge from the vulva. Clinical examination, vaginoscopy and a computed tomography scan showed an irregular egg-sized mass in the region of the cervix and uterine stump. An endoscopic grab biopsy (incisional) suggested a malignant mesenchymal tumour. Following this, surgical excision of the cranial vagina, cervix and the uterine remnant was performed. The final diagnosis of haemangiosarcoma was based on histological examination of the larger excisional biopsy specimen and was confirmed by positive immunolabelling of the neoplastic endothelial cells for the von Willebrand factor.

Susceptibility of the C2 canine mastocytoma cell line to the effects of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL).

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a member of the TNF family, which preferentially induces apoptosis in cells that have undergone malignant transformation. In humans, non-neoplastic cells are normally protected from the effects of TRAIL by expressing decoy receptors, lacking death domains. In contrast, neoplastic cells tend to downregulate their decoy receptor expression, increasing their susceptibility to the pro-apoptotic effects of TRAIL, via the functional TRAIL receptors. The aim of the current study was to investigate the effect of TRAIL on the canine C2 mastocytoma cell line to determine whether this agent might be a suitable treatment for mast cell tumors in dogs. C2 and MDCK cells were cultured with recombinant human TRAIL. Apoptosis was assessed using a Caspase 3 and 7 chemiluminescence assay and flow cytometry following Annexin V:FITC labelling. Cell metabolism was assessed using a colorimetric MTT-based assay. C2 cells demonstrated greater sensitivity to TRAIL-induced apoptosis compared to MDCK cells by all assessment methods. The dog genome assembly was searched for orthologs of TRAIL and its receptors using published sequences from other species for reference. Although a canine ortholog for TRAIL was identified, only one TRAIL receptor ortholog (TNFRSF11B) could be found. C2, but not MDCK, cells expressed mRNA for TNFRSF11B, detected by RT-PCR. In other species, TNFRSF11B is a decoy receptor, as even though it has a death domain it is secreted due to its lack of a transmembrane domain. The effect of TRAIL on the C2 cell line suggests that this cytokine might be suitable for treatment of mast cell tumors in dogs.

Arteriovenous haemangioma in two dogs and a cat.

Haemangiomas are benign vascular tumours and several types can be distinguished based on microscopical features. Capillary and cavernous haemangiomas are most commonly reported in man and domestic animals. Arteriovenous haemangiomas are rare variants in man and herein we describe this subtype in two dogs and one cat. One dog and the cat presented with a cutaneous vascular lesion, the other dog with a bleeding mass in the tongue. Surgically excised masses comprised non-encapsulated proliferations of variably sized arterial- and venous-like vessels, accompanied by clusters of capillaries and immature vascular structures in the feline cutaneous tumour and the canine lingual neoplasm. All vasoformative elements had von Willebrand factor-positive endothelia enclosed by a smooth muscle actin-positive tunica media or by pericytes. The results of this study expand the range of differential diagnoses for vascular neoplasms in the dog and cat.