What is tethered spinal cord syndrome?
Tethered spinal cord syndrome is a condition where the spinal cord is stuck to the tissue around it, instead of floating freely like it should. This can cause unhealthy tension in the spinal cord as a child grows, leading to problems like back pain, leg weakness, or trouble with bowel and bladder control. It can be present at birth or it can be caused by scar tissue after certain types of spinal cord surgery. Tethered cord syndrome treatment typically involves surgery, known as a tethered cord release. The goal of surgery is to untether the spinal cord and prevent further damage.
Causes of tethered spinal cord syndrome
Tethered cord happens when the spinal cord gets stuck to tissue around it, instead of floating freely within the spinal canal.
There are three main causes of tethered spinal cord syndrome:
- Simple tethered cord – This is caused by a thickened or shortened filum terminale, a small fiber at the bottom of the spine that connects the spinal cord to the bottom of the sacrum (pelvis). This can make the spinal cord too tight. It is considered “simple” because the cause of tethering is relatively easy to identify, there are no major associated spinal anomalies, and surgery to release the tethering is straightforward.
- Complex tethered cord – This involves closed spinal abnormalities like lipomyelomeningocele. In this condition, there is a fatty mass of tissue at the lower tip of the spinal cord that can attach to the thecal sac (the fluid-filled sac the spinal cord floats in), and often, the bones of the spinal column have not formed correctly. It is considered “complex” because the presence of spinal anomalies requires more intricate surgical techniques to successfully detether the spinal cord without damaging it.
- Post myelomeningocele – Myelomeningocele, the most serious form of spina bifida, is a birth defect in which an area of the spinal column doesn’t form properly. Part of the spinal cord and surrounding nerves push through an opening in the back and are exposed in a sac outside the body, or in some cases the spinal cord is exposed to the outside world without a sac around it. After surgery is performed to close the defect, scar tissue forms around the spinal cord and this becomes attached to surrounding tissue within the spinal column.
Signs and symptoms of tethered spinal cord syndrome
Sometimes, signs of tethered spinal cord are visible on the skin and are connected to the deeper structures in the spinal canal. These signs include:
- An abnormal butt crease that curves off to one side or forks, rather than going straight up
- A red spot or birthmark over the small or midline of the back
- A dimple or hole on the midline of the back (called a dermal sinus)
Physical symptoms of tethered spinal cord may include:
- Bowel and bladder issues. Children may have problems emptying their bladder or have issues with constipation. Patients who have more trouble with their bowel and bladder tend to have more complex tethered cords.
- Motor changes. The spinal cord being held (tethered) can cause tension and inflammation and lead to motor dysfunction as a child grows. This can range from a child catching their foot on things or having mild foot drop (in cases of simple tethered cord) to a child’s foot turning in, clubbed foot or toe walking (in complex tethered cord).
- Pain. As the spinal cord is stretched, a child is more likely to have pain in the small of the back or down the back of the legs. This pain is often present in the morning and gets better through the day.
Often, the first sign of tethered cord occurs in the toddler years, when a child who was potty trained suddenly starts having accidents. A child may also have physical symptoms during the ages when they experience growth spurts (usually ages 5–6 and 12–14).
Sometimes tethered cord can be associated with other conditions, such as VACTERL syndrome. This is a rare condition that involves a combination of birth defects, with each letter of the name VACTERL standing for a different part of the body that has an abnormality.
Testing and diagnosis for tethered spinal cord syndrome
At Children's Hospital of Philadelphia's Neuroscience Center, your child’s care begins with a comprehensive, personalized assessment of their medical history and symptoms.
The diagnosis of tethered spinal cord is made after a physical examination and the following tests:
- Magnetic resonance imaging (MRI) exam of the lumbar spine. An MRI uses powerful magnets to create a detailed picture of body structures. These pictures can identify many different types of abnormalities in the spinal cord, nerve roots and surrounding areas. MRI is a safe, painless test that produces detailed 3D images of structural differences in the spine that may be contributing to your child’s symptoms. MRI may require sedation in young children to help them stay still and comfortable. Your care team can discuss this further with you.
- Ultrasound. In this imaging test, we use a handheld device (transducer) to direct high-frequency sound waves to the spine to see images of the spinal cord moving in the thecal sac.
- Urodynamics. This is a test to assess bladder and lower urinary tract function. A small tube (catheter) is placed into the bladder through the urethra (the tube you pee through) to measure the pressure inside the bladder as it fills.
Treatment for tethered spinal cord syndrome
The goal of treatment for tethered spinal cord at CHOP's Neuroscience Center is to stop symptoms from interfering with a child’s normal growth and development, with as few treatment-related side effects as possible. We see the highest volume of patients with tethered spinal cord in the world and offer the highest level of care and surgical expertise. We perform hundreds of surgeries every year to correct the condition.
If a child’s health is deteriorating due to a tethered spinal cord, the only solution to relieve those symptoms is to take tension off the spinal cord through surgery. The goals of surgery are to stop the progression of symptoms, reverse deterioration, and restore function. The earlier we intervene, the more likely we are to preserve or even reverse some of the damage from the tension on the spinal cord.
Surgical options for tethered spinal cord include:
Tethered cord release surgery – This is a procedure to release the spinal cord from abnormal attachments that are causing it to be stretched. For simple tethered cord, we perform a minimally invasive surgery, using a small incision to cut the filum terminale (the small fiber that connects the spinal cord to the pelvis). This spinal cord untethering procedure typically takes 20 to 30 minutes and patients are discharged from the hospital the next day.
In complex tethered cord and post myelomeningocele, there is a greater amount of tissue that needs to be removed. The goal of surgery is to release the spinal cord, nerves and tissue from the attachment points without damaging them. Then, we close the muscle and skin over the spinal canal in layers. Surgery in these cases can take anywhere from two to five hours, and patients remain in the hospital for five to 10 days.
- Spinal column shortening – This is a relatively new, alternative treatment option that is considered in skeletally mature or nearly skeletally mature children. It can be performed in challenging or recurrent cases of tethered cord, but it can also be a first option in some cases. In this surgery, a vertebra is removed from the back to shorten the distance that the spinal cord needs to travel from the brain down to the pelvis. This relieves spinal cord tension without directly operating on the spinal cord itself. The remaining vertebra are stabilized using screws and rods. Surgery takes around four to five hours, and patients remain in the hospital for five to 10 days.
Follow-up care for tethered spinal cord syndrome
Ongoing follow-up care by a multidisciplinary team is essential to monitor for any changes in function and bowel and bladder health. Long-term follow-up care for tethered spinal cord often involves regular MRIs and urodynamic studies, as well as physical therapy and occupational therapy.
Spinal cord untethering and spinal column shortening surgeries can sometimes irritate the nerve roots. It's not uncommon after surgery for a child to have some numbness or weakness that can last from weeks to months.
About 10% of children will need to have the tethered cord release surgery repeated after growth spurts. At the first signs of re-tethering after surgery, a child will be evaluated for repeat tethered cord surgery or an option like spinal column shortening to intervene before permanent damage is done.
Long-term outlook for children with tethered spinal cord syndrome
The long-term outlook for children with tethered cord depends on several factors, including the severity of the condition, the presence of other congenital abnormalities, and how early the condition is diagnosed and treated.
Many children with mild tethered cord can lead active, independent lives after treatment. They may need braces on their ankles and may have variable degrees of dysfunction in their bladder and bowel, but many are able to walk and run after tethered cord surgery. Those with more severe conditions may have more persistent challenges.
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Reviewed by Gregory Heuer, MD, PhD, Adam J. Kundishora, MD