Tethered spinal cord

What is a Tethered Spinal Cord?

The spinal cord is one of the most incredible structures in the human body and is involved in many key functions. It is responsible for transmitting messages to and from the brain and is also involved in important autonomic responses such as maintaining blood pressure, keeping us breathing and bowel and bladder function.

Damage to the spinal cord can have wide-ranging and dramatic consequences. Not all damage, however, is caused by an accident or traumatic injury such as a fall or car crash.

A rare and often misdiagnosed condition that can be either congenital or acquired later on in life is tethered spinal cord syndrome.

What is a Tethered Spinal Cord?

Simply put it’s a condition that restricts the movement of the spinal cord at the base because the cord is tethered or tied to the spine by tissue or an abnormality.

As the body begins to develop in younger patients, this is likely to cause major issues with the spinal cord being stretched rather than growing naturally. This, in turn, can cause nerve damage and pain as time goes on which then needs to be rectified by surgery.

Tethered Spinal Cord in Infants

While a tethered spinal cord can be acquired in later life, it most commonly occurs in infants. It is often associated with spina bifida. This is a condition where the fetal spinal cord fails to close properly during development and a child is born with part of their spine exposed at the back.

Spina bifida x-ray
An x-ray image showing an example of spina bifida

The Spina Bifida Association estimates that between 20% and half of children will require medical intervention to deal with a tethered spine. With these conditions, the spinal cord does not separate from the skin of the back and needs to be operated upon.

A tethered spinal cord can also occur in children because of a fatty mass or lipomyelomeningocele that again restricts growth and requires removal.

The good news is that, once an accurate diagnosis has been made, tethered spinal cord surgery can make a big difference and has an excellent prognosis.

Tethered Spinal Cord Causes and Symptoms

While the association with spina bifida and a congenital fatty deposit on the spine are the most common causes of a tethered spinal cord, there are others.

  • Another congenital deformity which is very rare is a dermal sinus tract where tissue can extend to areas of the spinal cord causing issues.
  • In some children, there is another extremely rare condition where the spinal cord has split in two.
  • In some cases the tissue around the tailbone can become thickened, creating a tight channel for the delicate spinal filament.
  • If a tumor is found on the spine, this can have a similar effect of tethering. It can also occur following surgery or after trauma as part of the healing process.

A tethered spinal cord is not always diagnosed immediately after birth and there are several symptoms that may indicate there is a problem in this area. These include:

  • A noticeable lesion or fatty tumour on the lower back.
  • Discolouring of the skin in this area or a patch of hair.
  • Pain in the lower back
  • Pain in the legs and/or numbness and tingling sensations.
  • Over time the gait of the person can deteriorate and leg strength diminish.
  • There may be evidence of abnormal curvature of the spine or scoliosis.
  • There could be leg deformities.
  • The condition can cause other problems with organs such as the bowel and bladder.

Tethered Spinal Cord Diagnosis

MRI scanner
MRI scanner

If a person is suspected of having a tethered spinal cord, there are a number of tests that can confirm the diagnosis. These include an MRI scan, CAT scan, ultrasound and a myelogram. Testing often involves injecting a contrast material into the thecal sack so that any tethering will show up.

Tethered Spinal Cord Surgery

If tethered spinal cord syndrome is identified, the next step depends on the age of the patient and the cause of the tethering. In children, because the spine is still growing, surgery is preferred to ‘untether’ the cord. In adults, more conservative approaches may be taken depending on the severity of the problem and the symptoms.

The prognosis for children undergoing tethered spinal cord surgery is very good and many are able to return to normal activity within just a couple of weeks.

Summary

A tethered spinal cord is a rare health problem that is most often associated with other conditions such as spina bifida. Tissue attachments prevent the spinal cord from being able to grow properly. Though even rarer, it can also occur in adults for a variety of reasons, most notably because of previous trauma or spinal surgery.