Description of a new approach for great auricular and auriculotemporal nerve blocks: A cadaveric study in foxes and dogs.

Otitis externa is a painful condition that may require surgical intervention in dogs. A balanced analgesia protocol should combine systemic analgesic agents and local anaesthesia techniques. The aim of the study was to find anatomical landmarks for the great auricular and the auriculotemporal nerves that transmit nociceptive information from the ear pinna and to develop the optimal technique for a nerve block. The study consisted of two phases. In phase I, one fox cadaver was used for dissection and anatomical localization of the auricular nerves to derive landmarks for needle insertion. Eight fox cadavers were subsequently used to evaluate the accuracy of the technique by injecting methylene blue bilaterally. In phase II findings from phase I were applied in four Beagle canine cadavers. A block was deemed successful if more than 0.6 cm of the nerve's length was stained. Successful great auricular nerve block was achieved by inserting the needle superficially along the wing of the atlas with the needle pointing towards the jugular groove. For the auriculotemporal nerve block the needle was inserted perpendicular to the skin at the caudal lateral border of the zygomatic arch, close to the temporal process. The overall success rate was 24 out of 24 (100%) and 22 out of 24 (91%) for the great auricular and the auriculotemporal nerves, respectively, while the facial nerve was stained on three occasions. Our results suggest that it is feasible to achieve a block of the auricular nerves, based on anatomical landmarks, without concurrently affecting the facial nerve.

The quadriceps angle: reliability and accuracy in a fox (Vulpes vulpes) pelvic limb model.

OBJECTIVES: To evaluate the effect of measurement technique and limb positioning on quadriceps (Q) angle measurement, intra- and interobserver reliability, potential sources of error, and the effect of Q angle variation. STUDY DESIGN: Cadaveric radiographic study and computer modeling. ANIMALS: Pelvic limbs from red foxes (Vulpes vulpes). METHODS: Q angles were measured on hip dysplasia (HD) and whole limb (WL) view radiographs of each limb between the acetabular rim, mid-point (Q1: patellar center, Q2: femoral trochlea), and tibial tuberosity. Errors of 0.5-2.0 mm at measurement landmarks alone and in combination were modeled to identify the effect on Q angle. The effect of measured Q angles on the medial force exerted on the patella (F(MEDIAL)) was calculated. RESULTS: The HD position yielded significantly (P < .001) more medial Q angles than the WL position. No significant difference was observed between Q1 and Q2, but Bland-Altman plots indicated they were not equivalent. Intra- and interobserver agreement was substantial. Q2 errors were inherently greater than Q1: the mid-point and tibial tuberosity are the most important sources of Q angle variability. Increasing Q angles significantly increased the exerted F(MEDIAL) (P < .0001, gradient 1.7%). CONCLUSIONS: Measurements are reliable, but Q2 is more prone to error than Q1, and the 2 measurement techniques are not interchangeable. Positional errors must be kept below 1.3 mm (Q1) or 0.8 mm (Q2).

Rapid prototyping and inclined plane technique in the treatment of maxillofacial malformations in a fox.

An approximately 9-month-old fox (Pseudalopex vetulus) was presented with malocclusion and deviation of the lower jaw to the right side. Orthodontic treatment was performed using the inclined plane technique. Virtual 3D models and prototypes of the head were based on computed tomography (CT) image data to assist in diagnosis and treatment.

Surgical embryo transfer resulted in birth of live offspring in farmed blue fox.

Finland blue fox (Alopex lagopus) has great reputation in pelt industry around the world for its large size and top-ranking fur quality; however, both the herd size and the average survival rate of purebred offspring are rather low in production systems in China. Surgical transfer of blue fox embryos was investigated as a means to increase the population fox and also as a possible means to conserve endangered canine species. The animals were chosen on the basis of synchrony in natural oestrus. During the reproductive season of blue fox, 59 embryos were flushed from 6 farmed donors 9-11 days after the first insemination, and 53 embryos were transferred surgically into the uteri of the 6 paired recipients with natural synchronized oestrous. Two of the recipients littered 46-49 days after embryo transfer; one gave birth to 7 pups and the other 1 pup. This report describes the first successful embryo transfer in the farmed blue fox in China.

Surgical implantation of radio transmitters in arctic foxes (Alopex lagopus) on Svalbard, Norway.

Twelve captive wild-caught adult arctic foxes (Alopex lagopus) were anesthetized a total of 24 times for an equal number of surgical procedures involving implantation of heart rate (HR) and core body temperature transmitters (Tb) between October 1995 and April 1997. Xylazine-ketamine and medetomidine-ketamine anesthesia was used, resulting in an unacceptably high death rate. One out of four foxes anesthetized with xylazine-ketamine died, whereas two of nine foxes anesthetized with medetomidine-ketamine died out of a total of 20 surgical procedures. Durations of the surgeries for implantation of Tb transmitters and HR transmitters were 73 +/- 7 min and 95 +/- 13 min, respectively.

Physiological responses of red foxes (Vulpes vulpes) to surgery.

Radio transmitters were surgically implanted into the abdomens of red foxes (Vulpes vulpes). Blood samples were taken before, immediately after, and 8 hr after surgery and analyzed for hormonal, biochemical, electrolyte and hematologic changes. Samples were taken at the same times from control foxes. Adrenocorticotropin increased after surgery (P less than 0.05), but returned to pre-surgery values after 8 hr. Cortisol increased and remained elevated in the surgery group relative to pre-surgery values or to control values (P less than 0.05); Triiodothyronine and thyroxine both decreased from post-surgery values 8 hr later (P less than 0.05). Creatine kinase, total bilirubin and aspartate aminotransferase increased after 8 hr in both surgery and control groups (P less than 0.05). Carbon dioxide increased under anesthesia in both groups, but returned to initial values after 8 hr (P less than 0.05). The white blood cell count increased after 8 hr only in the surgery group (P less than 0.05). There were no differences between the groups for any value obtained from the initial blood sample. These data indicate that abdominal surgery results in prolonged adrenocortical activity and decreased thyroid hormone levels, but otherwise has minimal systemic effects in red foxes.