Technique for Correction of Chronic Mandibular Prognathism
Presenting Author: Brian L. Speer, DVM, Dipl ABVP (Avian), Dipl
The Medical Center for Birds. Author: "Birds for Dummies" ? 1999
(Available at The BIRD Clinic Veterinary Corporation)
Interpretive Review and comments by Dr. Nemetz:
Dr. Speer presented an orthopedic technique for the repair of Mandibular Prognathism. This is when the upper beak (rhinotheca) occludes inside the lower beak (gnathotheca). Beak pathology or malocclusions occur in many species of psittacines especially cockatoos and macaws or any bird that has had some trauma to the beak tissue. Many of these can be repaired and Dr. Nemetz along with the help of his father, a dentist, has been developing beak reconstructive techniques since 1989. As birds become older, beak corrections become more difficult due to the decreased growth rate of the beak tissue and acceptability of the apparatus by the patient.
Dr. Speer addressed this situation in a 10 year-old Moluccan cockatoo. The surgical procedure involved the following: Under anesthesia, first a pin is driven through the skull (nasal sinus) just behind the nasal openings (perpendicular to the beak). Once this pin is in place, each end is bent to form a triangle with the apex lying rostral to (in front of) the end of the rhinotheca. Next, a second pin is driven through the beak approximately midway front to back to act as a cantilever and support for this triangular apparatus. Finally a tension cerclage wire is placed between the tip of the upper beak and the end of the wires that form the apex of the triangle.
The net effect is to place forces to extend the naso-frontal hinge and force vectors to pull the tip of the upper beak forward and up (dorsal). Pain medication (analgesia) is administered pre-surgical and post-surgical for 24-48 hours and then discontinued as the bird adapts to the apparatus. The birds are checked at 2-week intervals. The abnormality in the 10 year-old Moluccan resolved and anatomic relations were normalized after a three month period of time. Once the beak was corrected the cerclage wire was removed, but the trans-sinus (skull) pin was retained for an additional 2 week period to ensure the correction maintained its position.