A myelogram is a contrast-enhanced radiographical study of the cervical spinal cord. It is utilized in cases of suspected cervical vertebral malformation or wobblers to determine the site of your horse's spinal cord compression. Even if a diagnosis is made upon standing neck x-rays, a myelogram is still required to confirm the degree of compression and whether any other sites of compression are present prior to performing surgery.
The myelogram is performed under injectable or intravenous anesthesia and a contrast agent is injected into the spinal canal. The contrast outlines the spinal cord, and shows up as a bright white line surrounding the spinal. A diagnosis of compression is made by the presence of at least 50% compression of the width of the contrast dye column compared to the width of the column in a neutral position.