DISTAL LIMB SWELLING AND PERIOSTEAL PRODUCTIVE REACTION IN PERIPARTURIENT SICHUAN TAKIN (BUDORCAS TAXICOLOR TIBETANA): FIVE CASES OF PRESUMPTIVE HYPERTROPHIC OSTEOPATHY.

Hypertrophic osteopathy, a syndrome characterized by painful distal limb swelling and proliferative periosteal reaction, primarily involves the metacarpal and metatarsal bones and phalanges. Lesions are often bilaterally symmetric and typically affect all four limbs. Hypertrophic osteopathy is frequently associated with primary intrathoracic disease, though this condition has also been reported secondary to intra-abdominal and intrapelvic disease and associated with pregnancy in both people and horses. Over a 20-yr period, five adult female Sichuan takin (Budorcas taxicolor tibetana), with 13 total pregnancies, were evaluated because of lameness and distal limb swelling. These clinical signs were observed between 2 and 32 days (mean = 19 days) prior to parturition (gestation period in takin approximately 200-240 days) and resolved in all animals following parturition. Lameness and limb swelling resolved between 8 and 168 days (median = 15 days) after parturition. Sixteen radiographic examinations, from four of the individuals, documented proliferative periosteal reaction, primarily of the metacarpal bones, metatarsal bones, and phalanges. The clinical progression, resolution of signs, and radiographic features in these cases are consistent with hypertrophic osteopathy, secondary to pregnancy. This is the first report describing presumptive hypertrophic osteopathy in takin.

Development of an avian brachial plexus nerve block technique for perioperative analgesia in mallard ducks (Anas platyrhynchos).

Surgical procedures of the wing are commonly performed in companion, captive, and wild avian species. To develop a clinically applicable brachial plexus nerve block technique for perioperative analgesia in birds, 8 adult female mallard ducks (Anas platyrhynchos) were anesthetized and used in several local anesthetic trials with bupivacaine (2 or 8 mg/kg) or a combination of lidocaine (15 mg/kg) and epinephrine (3.8 microg/kg) perineurally; equal volumes of saline were administered as control treatments. Both axillary and dorsal approaches to the brachial plexus were evaluated. With the axillary approach, radial and ulnar compound nerve action potentials (CNAP), sensory nerve conduction velocities (SNCVs), and cord dorsum potentials (CDPs) were recorded after distal sensory nerve stimulation. Values were recorded before and at 5, 30, and 60 minutes after injection of local anesthetic or saline. Birds were monitored for the presence of a wing droop and a change in motor function on recovery from anesthesia. Results were highly variable for all techniques. No technique significantly decreased CDPs or resulted in consistent wing droop. Radial and ulnar CNAPs, SNCVs, and CDPs were consistently recorded in all birds. Variable results might indicate that the treatment, concentration, or volume of local anesthetic used was ineffective in producing local anesthesia. Electrodiagnostic methods used in these ducks to assess loss of sensory nerve conduction might not be sensitive enough to assess the effects of local anesthesia. Further research is needed to identify methods for assessing the efficacy of brachial plexus nerve blockade in birds.

Somatosensory evoked potentials and sensory nerve conduction velocities in the thoracic limb of mallard ducks (Anas platyrhynchos).

OBJECTIVE: To develop a clinically applicable technique for recording cord dorsum potentials (CDPs) following stimulation of the radial and ulnar nerves and establish reference values for radial and ulnar sensory nerve conduction velocities (SNCVs) in the wings of ducks. ANIMALS: 8 clinically normal adult female mallard ducks (Anas platyrhynchos). PROCEDURES: Radial and ulnar compound nerve action potentials (CNAPs) and CDPs were recorded following distal sensory nerve stimulation. The CDPs were recorded from the interarcuate space between the last cervical vertebra and the first thoracic vertebra. Surgical dissection and transection of the brachial plexus in 1 anesthetized duck were performed to identify nerve root location and confirm functional loss of nerve conduction assessed by loss of the CDP. RESULTS: Radial and ulnar CNAPs and CDPs were consistently recorded in all birds. Median radial SNCV was 38.3 m/s (range, 36.0 to 49.0 m/s), and ulnar SNCV was 35.3 m/s (range, 28.0 to 40.0 m/s). Surgical transection of the brachial plexus resulted in complete loss of the CDP. CONCLUSIONS AND CLINICAL RELEVANCE: Measurement of radial and ulnar SNCV or CDP is feasible in isoflurane-anesthetized mallard ducks. The CDP accurately reflects sensory nerve conduction through the brachial plexus. Assessment of brachial plexus function in mallard ducks via evaluations of SNCVs and CDPs may have application for diagnosis of traumatic injuries to the brachial plexus, evaluation of neuropathies associated with exposure to toxic chemicals, and assessment of the efficacy of interventions such as brachial plexus nerve blockade.