Syringomyelia is a cavitation of the spinal cord caused by disturbances of CSF circulation in the spine. It can lead to various neurological disabilities, including loss of sensation, weakness, paralysis, muscle atrophy, bladder dysfunction, and scoliosis.
Spinal arachnoid cysts are relatively common among patients with myelomeningocele and can cause neurological disabilities by spinal cord compression.
Diastematomyelia is a birth defect involving the spinal cord. It is a rather frequent fellow traveler with myelomeningocele, in perhaps 20% of cases, and it can cause spinal cord tethering and progressive neurological problems if it escapes recognition.
Dermoid cyst is another fellow traveler. It may arise as an associated birth defect, or it can occur as a complication of myelomeningocele repair. Through whatever process, a small patch of skin becomes displaced among the neural tissues in the spinal canal. The skin survives and proliferates to form the cyst membrane, and skin debris collects inside. Dermoid cysts are usually incidental findings in the investigation of other problems; they seldom cause symptoms on their own.
Normally the spinal cord dangles free in the spinal canal, and with normal movements the spinal cord slips up and down within the spinal canal. When the spinal canal is anchored at the bottom by a birth defect or by scar tissue, spinal cord “tethering” has occurred. Tethering can cause mechanical damage to the segments of the spinal cord immediately above, leading to progressive neurological disability. ALL patients with myelomeningocele have tethering of the spinal cord at the site of the repair, but the lifetime risk of clinical problems from tethering is only 30 – 40%.
