Humerus Fracture in a Buff-necked Ibis (Theristicus caudatus) - Anesthesia and Surgical Procedures

Abstract

Background: The medical science of birds, with the exception of aviculture, has a very short history compared to other subdisciplines of veterinary medicine. With this in mind, the current work aims to report the case of a buff-necked ibis with an open fracture of the left humerus, presenting the surgical treatment and anesthetic protocol used, in order to contribute to the avian medical literature.
Case: An adult buff-necked ibis (Theristicus caudatus) was referred to the University Veterinary Hospital with an open fracture of the left humeral shaft, 7 days after rescue. During the physical examination, a skin lesion was identified in the fracture area, with signs of low vascularization, devitalization, necrotic tissues, and purulent secretions being noted. On radiographic examination, the fracture was classified as comminuted, with exposure of the left humeral shaft. After evaluating
the limb, it was decided to amputate the wing, and 24 h later, the patient was referred to the operating room after fasting for 4 h. As pre-anesthetic medication, ketamine (20 mg/kg) and midazolam (1 mg/kg) were administered, both intramuscularly. Orotracheal intubation was performed, after which the tracheal tube was connected to a Baraka-type gas-free system and
the supply of isoflurane was started through a universal vaporizer, diluted in 100% oxygen. For transoperative analgesia, brachial plexus block was performed using 2% lidocaine (2 mg/kg). During the surgical procedure, an incision was made in the skin and subcutaneous tissue in the middle third of the left humerus, and detachment of the greater deltoid muscle was performed with a periosteal elevator, followed by excision of the tensor propatagialis. In the ventrodorsal region, circular ligation of the brachial vein, ulnar vein and artery, and median-ulnar nerve was carried out, and disarticulation of the scapulacoracoid-humeral region. Subsequently, abolition of dead space and a myorrhaphy were performed, followed by demorrhaphy. In the immediate post-operative period, morphine (5 mg/kg), meloxicam (0.1 mg/kg), and enrofloxacin (10 mg/kg) were administered intramuscularly. The patient was discharged from the hospital 6 h after the end of the surgical procedure.
Discussion: Interest in the conservation of wild birds is one of the causes of the increased demand for anesthetic and surgical procedures in these species. However, it is a challenge for professionals in the field. The use of analgesics is recommended for reasons of well-being, but also because of the possibility of reducing the concentration of inhalational anesthetics in surgical procedures. Ketamine associated with midazolam promotes sufficient sedation and muscle relaxation in the patient, enabling safe preoperative management, in addition to reducing the amount of inhaled anesthetics used during the transoperative period. Isofluorane promotes safe general anesthesia for birds and has an advantage over injectable drugs, as it provides better dynamic control of anesthetic depth in these species. The brachial plexus block performed is a simple procedure that promotes quality anesthesia and analgesia in the perioperative period. The choice for amputation was due to the absence of musculature for closure, severe skin, muscle, and bone devitalization, and the infectious process in the region, factors that would prevent osteosynthesis. Although amputation through the bone is preferable, the disarticulation technique was used due to the absence of a healthy proximal humeral fragment. The patient’s death can be explained by the poor nutritional status the bird was in, as it presented an open fracture with severe contamination, a concomitant injury that occurred during the possible trauma, and the excessive time between the day of the trauma and the day of medical attendance. However, the surgical and anesthetic procedures were adequate and satisfactory for the patient. The importance of identifying and treating diseases secondary to contaminated fractures in these species is emphasized.

Keywords: bird, avian medicine, fauna, lesions, recovery.

Título: Fratura de úmero em uma curicaca (Theristicus caudatus) - manejo anestésico e cirúrgico

Descritores: aves, medicina aviária, fauna, lesões, recuperação.