Clinical features and treatment results of 25 cases of ear canal tumors in dogs and cats, surgically resected in one private hospital between 2001 and 2015, were reviewed. Twenty one cases were small, well defined masses arising from ventral canal (VC, 18 cases) or horizontal canal (HC, 3 cases), and other 4 cases were feline inflammatory polyps. Out of 19 dog cases, 17 were diagnosed histopathologically, in which 12 (71%) were benign, and 5 were cerminous gland adenocarcinoma (CGAC, 3 were non-invasive, 2 were unknown). All dogs received conservative surgery (mainly lateral ear canal resection: LECR), after which no recurrence was observed except for a dog with CAGC at HC (recurred 1.5 months after excisional biopsy following LECR). Two cats with CGAC (non-invasive) located at HC or VC were disease free for 43 months after total ear canal resection or for 35 months after LECR, respectively. Inflammatory polyps in 4 cats did not recur after resection by traction followed by prednisolone administration. These results suggest that benign or non-invasive tumors are predominant in well-defined, ear canal masses in dogs and cats, most of which can be cured by conservative surgery.

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The aim of this study was to investigate the pattern of drug distribution and analgesic area of a paravertebral block using a nerve stimulator in dogs. Six healthy adult beagles were used in the study. After anesthesia was induced and maintained with isoflurane, a paravertebral block was performed at the 11th, 12th, and 13th thoracic spinal levels. A 3 ml solution consisting of contrast media mixed with bupivacaine and saline was injected at each spinal level. Proper needle placement was confirmed using the nerve stimulator and a CT scan was performed to assess the distribution of the contrast media. After completion of the paravertebral block and CT scan, tetanic stimulation was applied at the paramedian region of the umbilicus (umbilical region), outside of the umbilical region, outermost umbilical region, upper abdomen, lower abdomen, and control (contralateral of the umbilical region). Changes in the heart rate and mean arterial pressure were simultaneously assessed. The contrast media distributed into the paravertebral space in 33 of 36 injections (91.6%). The median (range) of the longitudinal distribution was 4 (3-5) vertebrae. The tetanic stimulation at the umbilical region caused significantly lower increases in heart rate and mean arterial pressure than those at the control. In conclusion, the probability that local anesthetics distributed into the paravertebral space was high. In dogs, the umbilical region was effectively blocked when the paravertebral blocks between the 11th and 13th thoracic spinal levels were performed using the nerve stimulator.

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A 13-year-old, spayed female, Japanese domestic cat was presented with ureteral calculus and showed symptoms of ureteral obstruction. Ureterotomy was planned, and the cat was intubated under general anesthesia. Five minutes after intubation, we could palpate subcutaneous emphysema at lower body. Radiography demonstrated pneumomediastinum, pneumothorax, pneumoretroperitoneum and subcutaneous emphysema. Tracheal rupture was suspected, and then tracheal tube was advanced deeper, and thoracocentesis was done until air could not be aspirated. After the treatment the cat was maintained with synchronized intermittent mandatory ventilation for 90 minutes. As air leakage and pneumothorax did not recur, ureterotomy was performed routinely. Extubation and awaking from anesthesia were very favorable, and there were no symptoms of recurrence until date of discharge.

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