Diagnostic Approach Using Computerized Tomography and Successful Surgical Resolution of a Palatine Luxation and Entrapment in a Blue and Yellow Macaw (Ara ararauna)

A seven-month-old male blue and yellow macaw (Ara ararauna) was presented with an inability to move the maxillary beak after flying into a clothesline. Unsuccessful attempts to reduce the beak were performed, first by the owner at home and later within the same day by the referring veterinarian under general anesthesia. The patient was referred for assessment and treatment 5 days later. A palatine luxation and entrapment with a possible fissure of palatine bone was suspected based on history, a physical examination, and radiographic imaging. Another unsuccessful attempt to manually reduce the beak was performed under general anesthesia. A computed tomography (CT) scan was scheduled to evaluate the skull further. Rostrodorsal displacement and entrapment of the palatine bone on the rostral edge of the interorbital septum in the mesethmoid region were identified. In addition, the CT images provided useful information for the veterinary team to rule out other skeletal abnormalities, rendering a significantly more detailed evaluation of the skull bones before surgical intervention. Surgery was performed after the previously published pin insertion method over the dorsal aspect of the palatine bone. Pressure in the ventral direction was then applied on the pin while simultaneously further hyperextending the maxillary beak to unhook the palatine bone from the interorbital septum. The present case report describes an in vivo diagnosis of palatine luxation and entrapment in a blue and yellow macaw by means of a CT scan and successful surgical resolution.

Successful conservative management of multiple skull fracture and quadrate-mandibular medial luxation in a blue-and-yellow macaw (Ara ararauna)

BACKGROUND

We present a case of beak trauma not previously been reported in a blue-and-yellow macaw (Ara ararauna) and its successful conservative treatment. Several cases of fractures affecting the mandibular, maxillary and maxillofacial bones and pterygo-palatine dislocations, which have been studied using traditional radiology and CT; however, quadrato-mandibular luxation has never been described, individually or associated with other trauma.

CASE PRESENTATION

A 4-year-old blue-and-yellow macaw (Ara ararauna) was referred for a recent head trauma. The parrot exhibited right lower beak deviation, difficulty in grasping food and difficulty closing the beak. The parrot was referred for multiple traumatic fractures involving the pterygoid bone, jugal bone and right mandibular arch. The X-ray projections showed an incomplete fracture of the right pterygoid bone, two fracture sites on the right jugal arch, and slight mediorostral displacement of the right quadrate bones. Computed tomography (CT) confirmed the X-ray findings, and indicated additional trauma. The right quadrate bone luxation was manually reduced, and conservative treatment was elected. Analgesia and nonsteroidal anti-inflammatory drugs were provided. Moreover, a soft food-based diet was recommended for 3 weeks to facilitate recovery and reduce facial bone movements and tension. The parrot started eating dry food approximately 1 month after the trauma; full return of apparently normal beak function was achieved by 2 months.

CONCLUSIONS

The CT examination allowed us to obtain a more detailed and complete view of the fractures and traumas and to evaluate the complex articular system of the Psittaciformes beak. For these reasons, CT is recommended for birds with a history of head trauma to select the best treatment for the specific case.

Mortality rate of birds following intravenous administration of iodinated contrast medium for computed tomography

OBJECTIVE

To identify potential risk factors for death following IV or intraosseous (IO) administration of contrast medium in birds undergoing CT scans.

ANIMALS

120 birds that underwent 134 contrast-enhanced CT scans.

PROCEDURES

Medical records of birds of any species that underwent a CT scan which included administration of nonionic iodinated contrast medium from June 2013 to February 2020 were included. Information on birds and use of contrast medium was extracted from the medical records as well as information on deaths following IV or IO administration of contrast medium.

RESULTS

6 birds died shortly following administration of contrast medium. Necropsies were performed in 3 birds (2 cockatiels and 1 macaw), and all had lesions associated with the respiratory tract. When body weight was used as a binary variable to compare odds of death between small birds (≤ 150 g [0.33 lb]) and large birds (> 150 g), small birds had a 97-fold increased odds (OR, 97.5; 95% CI, 9.8 to 966.0) of dying following contrast medium administration. Following 131 CT scans with contrast medium administration (3 scans were excluded because of perivascular or subcutaneous leakage of contract medium), small birds had a mortality rate of 45.4% (5/11), compared with a mortality rate of 0.8% (1/120) for large (> 150 g) birds. Other variables (ie, sex, age, anesthesia or sedation, sedation protocol, and type of contrast medium) were not significantly associated with death after contrast medium administration.

CONCLUSIONS AND CLINICAL RELEVANCE

Although the administration of contrast medium cannot be conclusively confirmed as the cause of death in these birds, the high mortality rate for small birds coupled with the temporality of the event following contrast medium administration justifies the cautious use of contrast medium in small sick psittacine birds.

Avian Skull Orthopedics

Because the avian skull is the reflection of the wide biodiversity of birds, many anatomic, morphologic, and functional variations are encountered. The main objectives of this article are to review the surgical considerations associated with the functional anatomy of the avian jaw apparatus and its variation among species, and to describe the general medical and surgical management of head traumatic and developmental disorders in birds.