The spinal cord is tethered when it is not able to slide normally inside the spinal canal. Scarring from a previous spinal injury can cause the cord to be stuck to the spinal canal, or something at the bottom of the spinal canal can hold it down. This may be due a tumor or congenital malformation, or the band at the end of the spinal cord (filum terminale) can be too short or too tight.
Some Chiari I Malformation (CM-I) patients may also experience tethered cord syndrome.
Previous cases suggest that some CM-I patients may also have a tethered spinal cord from a tight band at the end of the spinal cord (filum terminale). This theory is new and controversial. No prospective studies (studies that collect information at the beginning and throughout treatment and follow-up, instead of only reviewing previous files) that evaluate the theory have been published.
Tethered cord can cause urinary urgency, urinary and/or stool incontinence, difficulty starting the urinary stream, constipation, diarrhea, difficulty with sexual relations, difficulty standing more than 60 minutes, low back pain, leg pain, numbness in the soles of the feet, difficulty riding or driving a car and severe growing pains during childhood and adolescence. It can also result in scoliosis. The relation of tethered cord to elongation of the brainstem in some persons with Chiari I Malformation is currently under investigation.
An MRI of the lumbar spine is generally the test of choice to determine if tethered cord is present.
If the tethered cord is due to scarring within the spinal canal, in some cases, the scarring can be released through surgery. For those with a short or tight filum terminale, an operation is performed to cut the band. The band itself is made of fibrous tissue. If the tethering is due to a tumor or a congenital abnormality, the surgery is usually more complex.