Tethered Spinal Cord
Tethered spinal cord syndrome is a congenital abnormality that results in the lower end of the spinal cord becoming fixed or attached in place, which causes intermittent pulling or stretching of the spinal cord. If left untreated, this condition can lead to neurological damage as the child grows and the stretching increases. Surgical untethering is usually needed to prevent further neurological deterioration and, ideally, to improve any lost function.
Early in development, the spinal cord and skin come from the same cell layer, the outer covering of the embryo called the ectoderm. During normal development, the spinal cord extends the entire length of its bony housing, the spine. As the embryo and spinal cord develop, the spinal cord ascends within the spinal canal.
By the time of birth or soon thereafter, the bottom of the spinal cord, known as the conus, is at its “adult” location . The conus is attached to the coccyx, or tailbone, by tissue called filum.
In some children the filum can be infiltrated by fat, which may behave as a tether to the spinal cord. In other children, the filum may be tightened or thickened, but not infiltrated by fat. In either case, the terminal end of the spinal cord, the conus, may be tethered as a result.
Types of Tethered Cords
There are several types of tethered cords.
Open Spina Bifida or Myelo Meningocele
In this condition, children are born with the spinal cord open to the surface. The spinal cord is exposed and attached (tethered) to the skin. These children require surgical release of their spinal cord and closure of the nervous system within a few days of birth.
In this condition, a lump of fat from under the skin extends through an opening in the bone, known as occulta spina bifida, and attaches to the spinal cord, “tethering” the cord to the overlying skin.
This condition is similar to a lipomyelomeningcele. In this type of tethering, the spinal cord extends through its bony housing and is surrounded by fat.
In this situation, the spinal cord splits into two hemicords that may or may not rejoin into a single structure prior to ending at the filum. In this condition, there may be a bony spur or fibrous septum (or wall) between the two hemicords.
Dermal Sinus Tracts
These are remnants of incomplete closure of the neural tube, the embryonic tissue that contains the spinal cord during development. During the early stages of in utero development, the skin and nervous system originate from the same cell layer. As the tissue that forms the spinal cord separates from what will become the overlying skin an adhesion may form, a condition known as myelomeningocele manqué. This may result in skin tissue being pulled into the spinal canal, which may or may not be attached to the spinal cord.
Likewise, an adhesion between the skin and nervous tissue may also result in nervous tissue being pulled out and attaching to the overlying skin. Either condition may result in tethering symptoms.
The most common symptoms of tethered cord include:
- Loss or decrease of motor function
- Changes in gait or walking pattern
- New onset or rapid progression of scoliosis, or curving of the spine
- Changes in bowel or bladder function
- Spasticity, or involuntary muscle contractions
- Sensory loss
- Back pain
By the time the child's first symptoms are noticed, non-surgical treatment for tethered cord is usually not effective. The primary goal of surgical untethering is to prevent further progression of the neurological deterioration that has led to the functional symptoms. It is also hoped that surgery will restore some of the neurological function lost, however some neurological function may never be recovered.
The Spina Bifida Center provides comprehensive care for children with tethered cord syndrome. Led by neurosurgeon Robin Bowman, MD, our team of experts offers the most advanced treatment options available for children with this condition.