The very tail end of the spinal cord forms somewhat differently by small bits of tissue coming together to form a solid mass. Tethering abnormalities generallly occur in this part of the spinal cord. As the embryo develops, the spinal cord and the bones surrounding it grow at different rates and, over time, the bones grow longer than the spinal cord. While the base of the bones and the tail end of the spinal cord start out together, by the time of birth the end of the spinal cord is at the first or second level of the lumbar vertebrae, just a bit below the rib cage. Effectively, this stretching of the cord can cause damage.
Patients usually experience problems with tethered cord syndrome after a growth spurt.
They may have difficulty with urinary, bowel or bladder control, feet deformities, difficulty walking or low back pain. In this case the muscles controling the bladder or legs, for example are weak and relatively flaccid. Sometimes the mass of fatty tissue or lipoma is evident right under the skin. MRI scans may reveal fat deposits in the tiny filament that usually comes out of the end of the spinal cord. Evaluating patients with these problems begins with a detailed neurological examination and often includes an MRI scan which shows the the cord tissue and lipomas, a CT scan to show bones which may also be abnormal, a pressure study or electrical study of the bladder, and sometimes specialized studies of the anal sphincters.