AN ANATOMICAL STUDY OF THE THORACIC LIMB OF THE GIANT ANTEATER (MYRMECOPHAGA TRIDACTYLA) COMPARED WITH THE DOMESTIC DOG TO GUIDE SURGICAL APPROACHES TO THE HUMERUS AND RADIUS.

The giant anteater (Myrmecophaga tridactyla) is a neotropical mammal considered to be vulnerable to extinction. Recent increased interest in veterinary care in the giant anteater has prompted renewed interest in anatomical descriptions in this species. The terrestrial habits and slow movements of the giant anteater contribute to its susceptibility to vehicular trauma on highways, which is a significant cause of mortality in the species. This study describes the muscular anatomy of the thoracic limb and variations of the long bones with emphasis on the structures surrounding the humerus and radius. It also describes the possible surgical approaches for the management of fractures of humerus and radius, comparing these with the surgical approaches described in dogs (Canis lupus familiaris). Three giant anteater and three domestic dog cadavers, from deaths not related to this project, were used. The medial approach to the humeral diaphysis of the giant anteater resulted in the least tissue trauma, and provided access to the flattest surface for implant attachment. The lateral approach to the radius proved challenging, requiring total detachment of the extensor carpi radialis muscle and incision of the very robust abductor digitorum longus muscle to access the distal diaphysis. Although the giant anteater shares many similarities of the thoracic limb anatomy with the domestic dog, important differences exist. This comparative knowledge will allow veterinary practitioners to directly apply the principles of fracture repair in these species. Safe access to these bones for possible osteosynthesis is essential to allow implant placement and minimize postoperative complications in this species.

Trans-sinus fixation for correction of deviation of the gnathotheca in a hawk (Caracara plancus).

INTRODUCTION: For birds of prey, the integrity of the beak is extremely important for defence, hygiene, socialization and especially, feeding. This paper describes successful trans-sinus fixation of a lateral deviation of the mandible in a hawk (Caracara plancus). CASE REPORT: The patient was presented with malnutrition and dehydration due to severe left lateral deviation of gnathotheca, with significant malocclusion. Fixation was performed with a 1.0-mm pin and 0.4-mm cerclage, applying contralateral traction to the deviation. The placement of the cerclage enabled full opening of the beak to allow feeding in the postoperative period. At 21 days after surgery, occlusion was perfect and the patient had recovered normal beak function. When clinical follow-up indicated that the bird would be able to survive in the wild, it was released. CONCLUSION: Trans-sinus fixation was effective in correcting lateral deviation of the gnathotheca in a hawk (C. plancus).

USE OF ACRYLIC RESIN PROSTHESES IN THE TREATMENT OF RHINOTHECAL FRACTURES.

This report describes the use of synthetic acrylic resin prostheses in five birds with rhinothecal fracture. Satisfactory biomechanical and clinical results were obtained in all cases, enabling early return to function of the beak. The patients, a roadside hawk (Rupornis magnirostris; case 1), a cockatiel (Nymphicus hollandicus; case 2), two turquoise-fronted parrots (Amazona aestiva; cases 3 and 4), and a maritaca (Pionus maximiliani; case 5), all suffered rhinothecal fractures with extensive bone loss, resulting in malnutrition, dehydration, and difficulty in handling food. An acrylic prosthesis was chosen in all cases, with the resin mold formed with two 1.0-mm pins in four cases, and cerclage wires in case 2. All birds made an excellent recovery and showed early use of the beak, with no complications for up to 15 mon. After 21 d of observation, the patients were moved to zoo enclosures for rehabilitation. The treatment of rhinothecal fractures is very challenging and requires a combination of orthopedic and dental techniques to provide full recovery of the species' natural functions.

DOUBLE PLATING FOR FRACTURES IN GIANT ANTEATERS (MYRMECOPHAGA TRIDACTYLA).

The fixation of fractures in wild animals has been a great challenge for veterinarians, because they will inevitably face a unique anatomical characteristic with scarce studies or reports published. Fracture fixation should promote adequate stability and early return to limb function, taking into account biomechanical characteristics of the bones, body weight, and natural habits of wildlife. Three bone fractures from two giant anteaters (Myrmecophaga tridactyla) referred at the veterinary teaching hospital on different occasions were treated by a double plating technique. The two free-ranging anteaters incurred their injuries when struck by an automobile. The first anteater (Ant 1) had a complete oblique fracture of the proximal third of the right femur and a complete comminuted fracture of the distal third of the right tibia. Surgical stabilization was performed by double plating to stabilize the femur and tibia. The second anteater (Ant 2) had a complete transverse fracture of the mid-diaphysis of the right radius and ulna, and it was fixed with a medial plate on the radius and a caudal plate on the ulna. The patients were able to walk 24 hr after the surgical procedures. Bone consolidation was observed at 60 days postoperatively, with no complications. The biggest challenges were related to anatomical characteristics for surgical approaches and the ability to promote a fixation strong enough to support the weight and strength of the animal, allowing early return to limb function.