How is the specific location of the herniated disk found?
Special x-ray techniques are needed to highlight the area of the spinal column where the disk has herniated. Survey x-rays are usually done of the area of the back where the neurologic exam indicates a problem. When we are planning to do surgery, we need to know the exact location of the herniated disk. A procedure called a myelogram is the most common way to locate the herniated disk. A myelogram is a done with the dog under a general anesthetic. A spinal tap is done and a dye is injected into the space where fluid circulates around the spinal cord. Once the dye is in place, several x-rays are taken. When a herniated disk is present, the location can be determined because the disk material takes up all of the space around the spinal cord and pushes the dye away. The spinal cord segments where the disk has herniated are characterized by a lack of dye, seen on the x-ray as a gap or gaps in the white dye columns surrounding the vertebral segment(s) where the disk has come to lie. The dis
