This disorder is caused when a thickened filum terminale(an elastic -like structure) limits the movement of, or "tethers" the spinal cord within the spinal column. The filum terminale or “terminal thread” is a normal structure that stabilizes the spinal cord within the spinal canal but has no real neurological function. Over time the tethered spinal cord is repeatedly stretched whenever the patient bends at the waist or flexes their neck. The repeated stretching of the spinal cord eventually causes symptoms such as bowel & bladder incontinence, leg & back pain and numbness, balance disturbance and weakness of the legs.
The tethering may affect the function of the entire spinal cord even though the structural problem lies at its lowest point. As a result, those affected by tethered cord syndrome may complain of headache, nausea and even arm pain.
Tethered spinal cord is frequently diagnosed in children, usually in conjunction with spina bifida. An adult tethered cord syndrome has also been described. This is not associated with spina bifida but may occur in patients with the Chiari 1 malformation. Some doctors believe that spinal cord tethering may be one of the causes of Chiari 1 malformation.