Kyle G. Mathews

Objective: To evaluate the diagnostic utility of abdominal fluid bilirubin concentration-to-serum bilirubin concentration ratio (AFB:SB) measurement in detecting biliary tract rupture or leakage in dogs with gallbladder mucocele (GBM; GBM group) versus no GBM (non-GBM group). Methods: For this retrospective cross-sectional study, a search of medical records identified dogs with concurrent measurements of abdominal fluid bilirubin and serum bilirubin concentrations prior to surgery or postmortem examination for biliary tract rupture or leakage between July 1, 2007, and January 31, 2022. Results for AFB:SB and other variables of interest were compared between the GBM versus non-GBM group and those with versus without biliary tract rupture or leakage. Results: 29 dogs were included (GBM group, n = 12; non-GBM, n = 17). Eleven GBM dogs and 7 non-GBM dogs had biliary tract rupture or leakage. The AFB:SB was > 2 for 2 of 11 (18%) GBM dogs with rupture, 6 of 7 (86%) non-GBM dogs with biliary tract rupture or leakage, and 2 non-GBM dogs without identified rupture/leakage. Abdominal fluid cytology confirmed the presence of bile in all dogs with a ruptured GBM. Conclusions: The use of AFB:SB alone frequently fails to detect biliary tract rupture or leakage in dogs with GBM; however, cytological analysis of abdominal fluid is valuable in helping to detect potential GBM rupture. Clinical Relevance: It is essential that primary care and emergency veterinarians be aware that an AFB:SB > 2 can be indicative of biliary tract rupture or leakage in dogs; however, the ratio may not be > 2 in dogs with ruptured GBM.

Objectives: There is a critical need for effective focal therapies for patients with inoperable or anatomically complex tumors where conventional ablation techniques pose high risk or are ineffective. Integrated Nanosecond Pulsed Irreversible Electroporation (INSPIRE) is a novel non-thermal ablation modality which uses real time temperature feedback during pulse delivery to safely treat tumors near critical structures. This study evaluated the impact of exposed electrode length on ablation zone size, reproducibility, and cardiac safety in a large animal model. Methods: INSPIRE treatments were performed in an in vivo healthy porcine liver model. All treatments administered 6000 V 1000 ns pulses with a 45 °C temperature set point. Treatments were administered percutaneously via an electrode and grounding pad approach using an internally cooled electrode applicator. The exposed electrode region at the distal end of the applicator was set to either 0.5, 1.0, 1.5, or 2.0 cm. Ablation zones were assessed via ultrasound, contrast-enhanced CT, and gross pathology one week post-treatment. Cardiac safety was evaluated by measuring pre- and post-treatment serum Troponin levels. Results: All treatments were completed without adverse events. Troponin levels remained stable (pre: 0.249 ng/mL; post: 0.224 ng/mL), indicating no measurable cardiac injury. The 1.5 cm exposure length produced the largest and most consistent ablation volumes, with a mean volume of 12.8 ± 2.6 cm³ and average dimensions of 3.7 × 2.7 cm in under 6 min. Increasing exposure length beyond 1.5 cm introduced greater variability and reduced treatment volumes. Conclusions: INSPIRE enables safe, large-volume, single-applicator ablation without a need for electrical pulse synchronization with R wave in cardiac rhythm. The 1.5 cm exposure length offers optimal balance between energy delivery and treatment consistency. These findings support further clinical investigation of INSPIRE for non-thermal ablation of inoperable tumors.

OBJECTIVE: To describe the clinical characteristics, treatments, complications, and outcomes in dogs with nasal planum squamous cell carcinoma (SCC) undergoing local treatment. METHODS: A retrospective, multi-institutional study was performed. Medical records were searched to identify dogs diagnosed with nasal planum SCC. Variables were recorded from medical records and statistically analyzed. RESULTS: 89 dogs were included. The most common presenting complaint was a visible mass on the nasal planum (89%). Metastasis was detected in 12% of dogs at the time of local therapy. Local therapy consisted of surgical excision alone in 63 of 89 dogs (71%) and radiation therapy alone in 20 of 89 dogs (22%); 6 dogs had multiple local therapies. Tumor size decreased in 12 dogs (60%) undergoing radiation therapy alone. Local recurrence was reported in 19 of 89 dogs (21%), including 16 of 63 dogs (25%) treated with surgery alone. Median survival time of all dogs was 452 days (95% CI, 285 to 576). Median survival time among 33 dogs with documented disease progression was 336 days (95% CI, 189 to 458), versus 685 days (95% CI, 334 to 1,042) in 56 dogs that did not have documented disease progression, which was significantly different (P = .038). Documented disease progression was significantly associated with hazard of death (hazard ratio, 1.93; 95% CI, 1.03 to 3.63; P = .041). CONCLUSIONS: Dogs undergoing local treatment of nasal planum SCC had a favorable prognosis. Metastasis at the time of treatment was uncommon. Long-term survival was possible, particularly in cases without disease progression. CLINICAL RELEVANCE: Aggressive local therapy, particularly surgical resection, should be considered in dogs with nasal planum SCC.

There are a variety of surgical conditions impacting the canine vagina and vestibule that require access through a caudal approach. A standard vertical episiotomy involves making an incision beginning ventral to the anus and extending ventrally through the dorsal commissure of the vulva and into the lumen of the vestibule and distal vagina. The objective of this study was to determine if complex vaginal procedures could be performed via a transverse perineal approach, thus eliminating the need to incise and reconstruct the vulva as performed in a standard episiotomy, and to evaluate the feasibility of vaginal resection with vulvar-sparing vestibular urethrostomy using this transverse approach. Ten canine, female cadavers were obtained and randomly split into two equally sized groups. Cadavers in Group A (n = 5) had a vaginal resection-anastomosis cranial to the urethral papilla. Cadavers in Group B (n = 5) had a complete vaginectomy and vulvar sparing vestibular urethrostomy. Procedures for both groups were approached through a transverse perineal incision. Postoperatively, cadavers of both groups had right lateral pelvic radiographs taken with a calibration marker in the field. The distance between the location of the anastomosis (Group A) or vaginectomy site (Group B) and the skin incision was measured. The procedures in both Group A and Group B were successfully performed through a transverse perineal approach in all 10 cadavers. The mean transverse perineal incision length was 2.88 cm ± 0.49 cm, compared to a mean standard episiotomy length of 5.83 cm ± 0.79 cm. The mean distance between the location of the anastomosis (Group A) or vaginectomy site (Group B) and the skin incision measured on pre-contrast right lateral pelvic radiographs was 2.54 cm ± 0.34 cm. The results of this study confirm the feasibility of performing complex vaginal procedures through a transverse perineal approach. The described approach is shorter than the standard episiotomy, which may result in diminished discomfort and decreased surgical/anesthetic time. This approach also eliminates the need to reconstruct the vulva. Further evaluation in clinical patients is warranted.

OBJECTIVE: To evaluate nonsurgical management outcomes of cleft palate (CP) in dogs and identify any association between cleft size, prevalence of clinical signs, and quality of life (QoL). METHODS: 65 dogs treated conservatively for CP from January 2006 through December 2023 were retrospectively identified. Diet, activity, medical history, and QoL were recorded for dogs that survived to the transition to solid food. Results were compared to those from 24 control dogs. Measurements of cleft area, width, and percentage of the hard palate occupied by the cleft were made with the use of calibrated photographs. Clefts were divided into 3 types: wide throughout, wide rostrally, and slit throughout. RESULTS: Sneezing was the most frequent clinical sign (43 of 65 over the past month, 34 of 65 when most affected). There was a greater frequency of material lodging in the cleft in the wide-throughout clefts (13 of 16 dogs) compared to the slit-throughout clefts (7 of 19 dogs). Veterinary removal of material was required in 10 of 68 episodes (7 of 31 dogs). There was no correlation between cleft size and prevalence of clinical signs or QoL. Sixty-three percent of dogs had a perfect QoL on a weighted scale, while 83.3% had a perfect score on a visual analog scale. Sixty-four of 65 owners would adopt another dog with a CP. CONCLUSIONS: Measures of QoL were favorable among dogs treated conservatively for CP. CLINICAL RELEVANCE: Conservative management appears to be a viable option for treatment of CPs in some dogs.

Open surgical treatment of idiopathic chylothorax via thoracic duct ligation and pericardiectomy requires a lengthy procedure with two thoracotomy incisions. The objectives of this report were to describe an approach for thoracic duct ligation and pericardiectomy via a single thoracotomy at the left fourth intercostal space and to describe the clinical outcome in two dogs with idiopathic chylothorax. Dogs were prospectively enrolled in a pilot study to evaluate the clinical efficacy of thoracic duct ligation at the left fourth intercostal space, combined with subphrenic pericardiectomy performed through the same incision. Dogs had a preoperative CT lymphangiogram to evaluate the anatomy of the thoracic duct and its branching pattern prior to surgery. Recheck radiographs were performed every 2–4 weeks until effusion resolved. Pleural effusion became non-chylous by 5 days postoperatively. Pleural effusion volume decreased by day 5 postoperatively, allowing removal of thoracostomy tube and discharge from the hospital. Radiographically, effusion resolved within 6 weeks without a need for further drainage after discharge. Dogs remained symptom-free at last follow up (>11 months postoperatively). CT lymphangiograms were repeated >11 months postoperatively and revealed no recurrence of pleural effusion. No intraoperative or postoperative complications directly related to surgery were noted for either dog. Collateral lymphatic vessels were not identified on recheck CT lymphangiograms. The left fourth intercostal approach to thoracic duct ligation and pericardiectomy has potential to be a safe and effective alternative to an open approach requiring two lateral thoracotomies. Further investigation of this approach using open or minimally invasive techniques is warranted.

A 1‐year‐old, female, spayed dachshund presenting with clinical signs associated with cholangiohepatitis and cholangitis was found to have synthetic linear foreign material causing a common bile duct obstruction. The patient underwent a cholecystectomy, and foreign material was removed from the common bile duct via retrograde flushing into the duodenal papilla and manual retrieval. At the 6‐month post‐operative follow up visit, the patient had an improved cholestatic hepatopathy, with only a mild alkaline phosphatase elevation, moderate dilation of the common bile duct on ultrasonography, and was doing clinically well at home. 8 months post‐operatively, the patient re‐presented for an episode of septic cholangiohepatitis, with linear foreign material visualised within a dilated common bile duct on ultrasound. This episode was medically managed and was resolved with a 2‐week course of antibiotics. 1.5 years post‐operatively, the patient is doing clinically well, but continues to have persistent, moderate elevations of alanine transaminase and alkaline phosphatase.

Background: Gallbladder disease in people is frequently associated with disorders of lipid metabolism and metabolic syndrome. A recently emergent gallbladder disease of dogs, referred to as mucocele formation, is characterized by secretion of abnormal mucus by the gallbladder epithelium and is similarly associated with hyperlipidemia, endocrinopathy, and metabolic dysfunction. The cause of gallbladder mucocele formation in dogs is unknown. Methods: A prospective case-controlled study was conducted to gain insight into disease pathogenesis by characterization of plasma lipid abnormalities in 18 dogs with gallbladder mucocele formation and 18 age and breed matched control dogs using direct infusion mass spectrometry for complex plasma lipid analysis. This analysis was complemented by histochemical and ultrastructural examination of gallbladder mucosa from dogs with gallbladder mucocele formation and control dogs for evidence of altered lipid homeostasis of the gallbladder epithelium. Results: Gallbladder mucocele formation in dogs carried a unique lipidomic signature of increased lipogenesis impacting 50% of lipid classes, 36% of esterified fatty acid species, and 11% of complex lipid species. Broad enrichment of complex lipids with palmitoleic acid (16:1) and decreased abundance within complex lipids of presumptive omega-3 fatty acids eicosapentaenoic (20:5) and docosahexaenoic (22:6) was significant. Severe lipidosis of gallbladder epithelium pinpoints the gallbladder as involved causally or consequently in abnormal lipid metabolism. Conclusion: Our study supports a primary increase in lipogenesis in dogs with mucocele formation and abnormal gallbladder lipid metabolism in disease pathogenesis.

Objective: To investigate a left‐sided fourth intercostal approach to thoracic duct (TD) ligation and unilateral subphrenic pericardiectomy in dogs.Study design: Retrospective computed tomography (CT) review and cadaveric study.Animals: Thirteen dogs with idiopathic chylothorax and 10 canine cadavers.Methods: A retrospective study of CT lymphangiograms in client‐owned dogs with idiopathic chylothorax evaluated location and branching of the TD at the left fourth intercostal space. A cadaveric study evaluated the efficacy of TD ligation at this site. Following methylene blue mesenteric lymph node injection, TDs were identified through a left fourth intercostal thoracotomy, ligated, and sealed. Unilateral subphrenic pericardiectomy was performed through the same incision. Computed tomography scans were performed to determine the success of TD ligation.Results: A review of lymphangiograms revealed a single TD in 10/13 clinical cases at the fourth intercostal space. Three cases had additional branches. Thoracic duct ligation via a left fourth intercostal thoracotomy was successful in nine out of 10 cadavers. A single branch was noted intraoperatively in six out of 10, and two branches were noted in four out of 10 cadavers. All branches were observed on the left side of the esophagus.Conclusion: TD ligation at the left fourth intercostal space was successfully performed in 9/10 canine cadavers and appeared feasible in a retrospective review of 10/13 clinical cases. Unilateral subphrenic pericardiectomy can also be performed via this approach.Clinical significance: Fewer thoracic duct branches at this location in comparison with the standard caudal location may simplify TD ligation. If elected, unilateral subphrenic pericardiectomy can be performed through the same incision. Further investigation in clinical patients is warranted.