Bilateral Mandibular Fracture Repair with an External Skeletal Fixator Intramedullary Pin Tie-in in a Mallard Duck (Anas platyrhynchos).

Abstract

An approximately 5-year-old male mallard duck (Anas platyrhynchos) was presented for assessment and treatment of bilateral mandibular ramal fractures. Physical examination revealed the presence of complete, open mandibular fractures at the rostral third of both mandibles, with ventral displacement of the rostral segments. An initial repair attempt consisted of a suture passed between the proximal and rostral fragments to form a simple interrupted suture on each side, which failed soon after the procedure. The second repair used a 1.1-mm nonthreaded Steinman pin inserted through the fracture site into the right rostral mandibular fragment, then pulled retrograde into the right proximal fragment. The exposed rostral end of the pin was bent ventrally at a 90° angle. This was repeated on the left side. Next, 1.1-mm threaded pins were inserted ventrally into the mandibular rami and directed dorsally, engaging both ventral and dorsal mandibular cortices. The exposed ends of the nonthreaded and threaded pins were cut short and joined with intravenous tubing filled with methyl methacrylate, forming a type I extra-skeletal fixator on each side. An additional crossbar was applied to the rostral pins using intravenous tubing filled with methyl methacrylate, providing interfixator stability. The patient was housed in a protected environment and demonstrated immediate return to normal feeding behavior. Thirty-eight days after the second repair, the bird was found to have removed the entire fixator apparatus; however, on recheck, the fracture site showed excellent stability and functional healing. The bird remained fully functional 4.5 years after the mandibular fracture repair surgery.