Mandibular Prognathism Correction in a Juvenile Umbrella Cockatoo (Cacatua alba) With the Use of an Orthosis.

Abstract

A 9-week-old male umbrella cockatoo (Cacatua alba) presented with mandibular prognathism. The rostral rhinothecal tomial length appeared subjectively shorter than the rostral gnathothecal length, which was subjectively rostrally elongated. After an initial orthosis failed, a second orthosis was designed that employed the use of an orthopedic wire anchor in the rostral end of the rhinotheca, leaving the premaxillary bone undisturbed. Prior to placement of the anchor, skull radiographs were taken to measure the distance from the rostral tip of the rhinotheca to the rostral end of the premaxillary bone. This was done to mitigate iatrogenic trauma and prevent disruption of bone and underlying tissues when the orthopedic wire was deployed to anchor the rhinothecal tip. A hole was created in the rostral rhinotheca with a 20-gauge hypodermic needle rostral to the premaxillary bone. Orthopedic wire was placed through the hole and wrapped over the dorsal rhinotheca as an anchor. A second piece of orthopedic wire was formed into an elongated oval shape as a frame for the rhinothecal extension. Flexible, moldable plastic mesh was wrapped over the rhinotheca and orthopedic wire extension. Waterproof epoxy putty was placed over the rhinotheca and orthotic wires. The epoxy putty was replaced as needed until the rhinotheca had regrown into correct alignment. Twenty-five days post-placement, correct alignment was achieved, and the orthosis removed. The beak remained in correct alignment, and the bird developed normal use of the beak to engage in activities such as feeding, preening, and podomandibulation. Whereas methods for correcting mandibular prognathism have been described utilizing a variety of techniques and materials, there is a paucity of peer-reviewed literature on this procedure. This report describes the management and correction of this condition in a young bird as well as the involved anatomy, kinesiology, and details of this corrective procedure.