Abstract

Computed tomography (CT) is a sectional image obtained free of superposition by overlaying structures. Images may be obtained in transverse, dorsal, sagittal and oblique planes. The use of CT in the evaluation of the vertebral spine has been indicated after myelogram. The tomography exam can highlight the sight of the lesion and spinal cord compression. This work was conducted to describe the use of computed tomography in the clinical examination of an adult male orangutan (Pongo pygmaeus), belonging to Fundação Parque Zoológico de São Paulo, which had flaccid paresis of the pelvic limbs after being observed during ten days in a restraining cage for dyspnoea treatment. The animal was sent to Diagnostic of Imaging Service of Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo for survey radiography, myelogram and CT. Ketamine hydrochloride (Dopalen®, Vetbrands, 10 mg/kg) and midazolam (Dormire®, Cristália, 0.5 mg/kg) intramuscularly were used to induce anesthesia and maintenance was done with isoflurane in 100% oxygen. Survey films were taken of the spine, then myelogram and CT were performed. The survey radiographs revealed spondylosis at the thoracolumbar and lumbosacral regions. The myelogram detected contrast at the cervical region, and progression could not be determined. In thoracic and lumbar regions of the CT (5 mm thick slices) the interruption of the contrast column progression was seen between T9–T10. Soft tissue attenuation mass was observed in the right portion of the medullar canal, between T8–T9, extending cranially for approximately 1.5 cm, causing significant extradural compression. Therefore, CT was fundamental in diagnosing the extradural compression that was accountable for the pelvic limb flaccid paresis of this orangutan. Neoplasia was suspected as the cause of the illness. Surgery was conducted successfully and histopathology is being done to define the type of tumor affecting this orangutan.