Perioperative complications and outcomes following partial ear canal ablation and lateral bulla osteotomy in pet rabbits: 20 cases (2009-2021).

OBJECTIVE: To investigate the perioperative complications and outcomes of rabbits undergoing partial ear canal ablation and lateral bulla osteotomy for treatment of chronic otitis. MATERIALS AND METHODS: Surgical logbooks were searched to identify rabbits that underwent partial ear canal ablation and lateral bulla osteotomy between December 2009 and September 2021. Data collected included signalment, history, clinical signs, historical and current medical management, physical examination findings, preoperative diagnostic imaging and aural bacterial culture results, surgical procedure information, duration of hospitalisation, complications and final outcome. RESULTS: Twenty rabbits with chronic, medically unresponsive otitis underwent 27 partial ear canal ablation and lateral bulla osteotomies. Ten rabbits had pre-existing neurologic deficits and 17 had an ear base abscess at the time of surgery. A total of 13 (65%) rabbits developed at least one complication, either in the perioperative period or between discharge and recheck. Three of these rabbits (15%) underwent revision surgery for persistent or recurrent ear base abscess. Complete resolution of clinical signs ultimately occurred in 12 (60%) rabbits. Three (15%) rabbits showed improved but not completely resolved clinical signs (three facial asymmetry). Five (25%) rabbits died of causes potentially related to chronic otitis and/or partial ear canal ablation and lateral bulla osteotomy; two of these rabbits had undergone revision surgery. CLINICAL SIGNIFICANCE: Although this study reports a high complication rate (65%), most complications resolved, with 15 (75%) rabbits having a good to excellent final outcome. Since the majority of rabbits in this study had chronic and severe ear disease, further studies are required to determine if surgical intervention earlier in the disease process could result in a lower complication rate.

Patent ductus arteriosus in cats (Felis catus): 50 cases (2000-2015).

OBJECTIVES: To describe signalment, clinical characteristics, diagnostic, treatment, and outcome data in a large case series of cats with patent ductus arteriosus (PDA). ANIMALS: Fifty cats with confirmed PDA. METHODS: Retrospective review of medical records from five referral veterinary hospitals for cats with PDA between 2000 and 2015. Cats were included if a PDA was visualized echocardiographically, during surgery, or on post-mortem examination. RESULTS: Median age at presentation was 6 months (range: 36 days-9.7 years; n = 50), and sex distribution was approximately equal (27 male, 23 female). Most cats did not have clinical signs (70.2%; 33/47) at the time of presentation. Murmurs were classified as continuous (55%; 22/40) or systolic (45%; 18/40). Echocardiography confirmed left-to-right shunting in 33 cats (82.5%; 33/40) and right-to-left shunting in 7 (17.5%; 7/40). Concurrent cardiac anomalies were identified in 54.5% (18/33) and pulmonary hypertension in 45.7% (16/35). Closure was pursued in 68% (34/50), and complications associated with the procedure occurred in 14.7% (5/34) of cats, including one intraoperative mortality. Long-term follow up was available in 80% (40/50) of cats. CONCLUSIONS: Cats with PDA often do not display clinical signs and may not have the characteristic physical examination findings typical of PDA in dogs. An increased prevalence of concurrent cardiac anomalies and pulmonary hypertension were found relative to previous reports. Thoracic radiographs and echocardiogram may provide the most comprehensive information for making a diagnosis and treatment recommendations. PDA closure was associated with a favorable long-term outcome in cats included in this study.

Serial Evaluation of Abdominal Fluid and Serum Amino-terminal pro-C-type Natriuretic Peptide in Dogs with Septic Peritonitis.

BACKGROUND: Serum N-terminal pro-C-natriuretic peptide (NT-proCNP) has shown promise as a diagnostic biomarker for sepsis. Its sensitivity to detect dogs with septic peritonitis (SP) is reportedly low, perhaps attributable to the compartmentalization of NT-proCNP in the abdominal cavity. OBJECTIVES: To evaluate the use of an ELISA for the measurement of NT-proCNP in canine abdominal fluid and to describe the peri-operative pattern of abdominal fluid and serum NT-proCNP concentrations in dogs with SP. ANIMALS: Five client-owned dogs with nonseptic abdominal effusion of varying etiologies and 12 client-owned dogs with SP undergoing abdominal surgery and placement of a closed-suction abdominal drain (CSAD). Six dogs were included upon hospital admission; 6 were included the day after surgery. METHODS: Prospective pilot study. A commercially available ELISA kit was analytically validated for use on canine abdominal fluid. The NT-proCNP concentrations were measured in the abdominal fluid of control dogs, and in serum and abdominal fluid of dogs with SP from admission for CSAD removal. RESULTS: In dogs with SP, admission abdominal fluid NT-proCNP concentrations were lower than the concurrent serum concentrations (P = 0.031), and lower than control canine abdominal fluid concentrations (P = 0.015). Postoperatively, abdominal fluid NT-proCNP concentrations remained lower than serum concentrations (P < 0.050), except on day 4. CONCLUSIONS AND CLINICAL IMPORTANCE: The ELISA kit was able to measure NT-proCNP in canine abdominal fluid. In dogs with SP, low serum NT-proCNP concentrations cannot be explained by abdominal compartmentalization.

Comparison of manual and suction pump aspiration techniques for performing bronchoalveolar lavage in 18 dogs with respiratory tract disease.

BACKGROUND: Different aspiration techniques to retrieve bronchoalveolar lavage fluid (BALF) affect sample quality in healthy dogs. Studies evaluating these techniques in dogs with respiratory disease are lacking. OBJECTIVES: To compare sample quality of BALF acquired by manual aspiration (MA) and suction pump aspiration (SPA). ANIMALS: Eighteen client-owned dogs with respiratory disease. METHODS: Randomized, blinded prospective clinical trial. Manual aspiration was performed with a 35-mL syringe attached directly to the bronchoscope biopsy channel and SPA was performed with a maximum of 50 mmHg negative pressure applied to the bronchoscope suction valve using the suction trap connection. Both aspiration techniques were performed in each dog on contralateral lung lobes, utilizing 2 mL/kg lavage volumes per site. Samples of BALF were analyzed by percentage of retrieved infusate, total nucleated cell count (TNCC), differential cell count, semiquantitative assessment of slide quality, and diagnosis score. Data were compared by paired Student's t-test, Wilcoxon signed-rank test, chi-squared test, and ANOVA. Cohen's kappa coefficient was used to assess agreement. RESULTS: The percentage of retrieved BALF (P = .001) was significantly higher for SPA than MA. Substantial agreement was found between cytologic classification of BALF obtained with MA and SPA (kappa = 0.615). There was no significant difference in rate of definitive diagnosis achieved with cytologic assessment between techniques (P = .78). CONCLUSIONS AND CLINICAL IMPORTANCE: Suction pump aspiration, compared to MA, improved BALF retrieval, but did not significantly affect the rate of diagnostic success of bronchoalveolar lavage (BAL) in dogs with pulmonary disease.

Agreement between magnetic resonance imaging, myelography, and surgery for detecting recurrent, thoracolumbar intervertebral disc extrusion in dogs.

OBJECTIVES: Although magnetic resonance imaging (MRI) is reported to be superior to myelography to determine the location and site of first time disc herniation, comparison of these diagnostic methods in cases of recurrent intervertebral disc disease (IVD) herniation after a first surgery has not been evaluated. The objective was to compare the diagnostic accuracy of MRI and myelography in a series of dogs undergoing repeat surgical decompression for recurrent IVD extrusion when compared to the gold standard of surgery. METHODS: Ten dogs with recurrent IVD herniation underwent MRI and myelography followed by surgical decompression. Three observers reviewed the images to determine the site and side of the first surgery and the recurrent lesion. Agreement was determined by calculating a kappa (κ) score. RESULTS: Substantial interobserver agreement was noted for recurrent lesion site using MRI and myelography (κ = 0.77 vs. 0.73) and when comparing MRI and myelography to the reported surgical site (κ = 0.73 vs. 0.67). Interobserver agreement was greater with MRI for circumferential location compared to myelography (κ = 0.76 vs. 0.43), similar to what was found when comparing to surgical side (κ = 0.82 vs. 0.49). The previous surgical site in this study had no effect on ability to identify the new lesion. CLINICAL SIGNIFICANCE: Despite the limitations of MRI, there was greater agreement between observers using MRI for both the recurrent and first lesion.

Spinal fracture and luxation in dogs and cats: a retrospective evaluation of 95 cases.

The purpose of this retrospective study was to review cases of spinal fractures or luxations (SFL) treated with various modalities in order to describe fracture location, neurological status, treatment, outcome and complications in a patient population at a single centre. The medical records of dogs and cats that had been diagnosed with a SFL between C1 and L7 between January 1995 and June 2005 were reviewed in order to collect pertinent data. Ninety-five cases were included in this study. The severity of spinal cord injury was graded on a scale from 0 to 5. Vehicular trauma was the most common cause of SFL. Spinal fractures were localized between C1-C5 in 10 cases, C6-T2 in one case, T3-L3 in 54 cases, L4-L7 in 36 cases. Thirty patients that were euthanatized without treatment had a median neurological score of 5. Twenty-eight patients, all of which had motor function, were treated conservatively and there was not any change in their median neurological grade at the time of discharge. Thirty-seven patients had surgery, 27 of which were non ambulatory. Thirty-five of 37 were stabilized using pins and/or screws and PMMA or various other techniques. The median neurological grade of surgically treated patients improved by one point between the time of initial diagnosis and discharge. Implant removal was performed in five cases. The patients that were treated with pins and/or screws and PMMA were significantly more improved than conservatively managed patients at the time of discharge, although the surgically treated patients were hospitalized significantly longer than the conservatively managed patients. Our results suggest that dogs that retain pain sensation prior to surgery have a good prognosis for functional recovery. In this study, the dogs that were treated conservatively retained purposeful movement and had a good prognosis for recovery.

Invasive epithelial mesothelioma in a dog.

This report describes the gross, microscopic, and immunohistochemical features of an invasive epithelial mesothelioma in an 11-year-old neutered male Golden Retriever. The tumor involved the pericardium, pleura, mediastinum, and peritoneum and invaded into submesothelial tissues. Neoplastic cells in the thoracic fluid showed prominent features of malignancy in a background of mixed inflammatory cells and scattered erythrocytes. Histologically, the tumor consisted of nests of epithelioid cells with frequent mitotic figures and multinucleation that infiltrated submesothelial tissues. Neoplastic cells strongly coexpressed vimentin and cytokeratin intermediate filaments, which assisted in the differentiation from other epithelial tumors of nonmesothelial origin.

Management of obstructive urolithiasis and concurrent urethral rupture in a goat.

A 4-month-old, male castrated Alpine White goat presented to the University of Guelph, Veterinary Teaching Hospital, with urolithiasis and a ruptured urethra. A tube cystostomy was performed using an indwelling Foley catheter. Postoperatively, the goat remained in good health, and was discharged with the cystostomy catheter in situ. Five weeks following surgery, the goat was noted to pass urine through its urethra. Seven weeks following surgery, the catheter became dislodged and the goat was observed to urinate normally. Six months following surgery, the goat was apparently healthy and urinating normally. Tube cystostomy may be a useful therapeutic option in the management of small ruminants with obstructive urolithiasis with concurrent rupture of the urethra, especially for cases in which treatment cost is a limiting factor.

Detection of free radicals in ischemic and reperfused canine gracilis muscle flaps by use of spin-trapping electron paramagnetic resonance spectroscopy.

OBJECTIVE: To determine whether free radicals are produced in ischemic and reperfused canine skeletal muscle, whether free radicals can be detected from effluent blood by use of spin-trapping electron paramagnetic resonance (EPR) spectroscopy, and whether free radical-induced skeletal muscle damage is detectable by use of light microscopy. ANIMALS: 6 healthy mixed-breed dogs. PROCEDURES: Dogs were anesthetized and both gracilis muscles were isolated, leaving only the major vascular pedicle intact. Ischemia was induced in 1 flap for 4 hours; the contralateral flap served as the control. Ischemic flaps were then reperfused for 15 minutes. alpha-Phenyl-N-tert-butylnitrone, a spin-trapping agent, was administered intravenously to each dog 1 hour prior to reperfusion. Following reperfusion, effluent blood samples from muscle flaps were obtained and processed for EPR spectroscopy. Muscle biopsy specimens were obtained for histologic evaluation, and dogs were euthanatized. RESULTS: Spin adducts were not detected in blood from control flaps. However, spin adducts were detected in all ischemic-reperfused muscle flaps. Principal signals identified were characteristic of oxygen- and carbon-centered radicals. Significantly more muscle damage was detected in ischemic-reperfused flaps, compared with control flaps. CONCLUSIONS AND CLINICAL RELEVANCE: Free radicals may be an important component of injury induced by ischemia and reperfusion of canine skeletal muscle. Spin-trap adducts of free radicals can be detected in effluent blood of canine muscle flaps by use of spin-trapping EPR spectroscopy. Spin-trapping EPR spectroscopy may be useful for the study of antioxidants and free radical scavengers in attenuating ischemia and reperfusion-mediated skeletal muscle damage.

Use of pericardial patch graft reconstruction of the right atrium for treatment of hemangiosarcoma in a dog.

Atrial mass resection is possible in a limited number of dogs with hemangiosarcoma in which only the right atrial appendage or atrial free wall is involved, A pericardial patch graft can be used to reconstruct the right atrium after resection of large atrial tumors. Tumor-free margins can be obtained by use of this technique.

Tamoxifen and mammographic breast densities.

The extent of breast tissue density on mammograms is one of the strongest risk factors for breast cancer. The aim of this analysis was to evaluate whether tamoxifen can affect mammographic breast density. Subjects were participants in the National Surgical Adjuvant Breast Project Breast Cancer Prevention Trial (BCPT), recruited and followed at the Breast Center of Saint-Sacrement Hospital in Quebec City, Canada. The Breast Cancer Prevention Trial is a double-blind trial in which women at high risk of breast cancer were randomized to receive either 20 mg tamoxifen per day or placebo. Mammograms were taken before treatment began and yearly thereafter. For the purpose of this analysis, Wolfe's parenchymal pattern and the percentage of the breast showing tissue densities were assessed by review of pre- and posttreatment mammograms without knowledge of treatment assignment. Among the 69 women included in this analysis, 36 received tamoxifen and 33 received placebo for an average of 3.3 and 3.5 years, respectively. Among women receiving tamoxifen, 16 of 36 (44.4%) changed to a parenchymal pattern of lower density compared with 5 of 33 (15.2%) women receiving placebo (P = 0.010). Moreover, in the tamoxifen-treated group, the difference in the percentage of the breast showing tissue densities between the pre- and posttreatment mammograms reached -9.4% on average compared with a reduction of -3.6% in the placebo group (P = 0.010). Our data show that tamoxifen can reduce high-risk mammographic features. Breast densities should be evaluated as possible early markers of the preventive effect of selective estrogen receptor modulators.