Hypotensive infarction of the spinal cord in a rhesus macaque (Macaca mulatta)

A 6.5-year-old male rhesus macaque (Macaca mulatta) was presented with acut e paraplegia following a surgical procedure. During surgery, he experienced an acute hypotensive episode that required 3 hours of supportive therapy b efore hemodynamic stability was restored. Paraplegia remained unchanged unt il euthanasia 72 hours later. At necropsy, spinal cord segments T10-S3 had acute, massive panmedullary necrosis, which involved most of the central an d middle spinal cord, sparing the peripheral white matter. Additional lesio ns included arterial border zone necrosis of the brain, centrilobular hepat ic necrosis, and proximal renal tubular necrosis. The histologic findings o f central spinal cord necrosis with a preserved rim of white matter is cons istent with severely decreased flow in the anterior spinal artery. Such les ions can result from episodes of generalized hypoperfusion. Possible factor s contributing to the hypotensive episode in this case included the additio n of xylazine to ketamine and atropine in the preanesthetic medication, pos itioning during anesthesia, and decreased blood pressure during surgery.