Myelomeningocele
- What is a myelomeningocele?
- Who gets a myelomeningocele?
- What is your experience with myelomeningoceles?
- What surgery do you use to treat myelomeningocele?
What is a myelomeningocele?
A myelomeningocele (pronounced my-e-lo-MENING-o-seal) is a congenital (present at birth) deformity of the spine and spinal cord, which do not form and close normally. The spinal canal is open.
A myelomeningocele is the most serious form of spina bifida. It can occur anywhere along the spinal cord.
The lesion is like a small sac covered with a membrane and contains cerebrospinal fluid and tissues that protect the spinal cord called the meninges. It may also contain portions of the spinal cord and nerves. The sac may or may not be ruptured at birth.
This causes abnormal body functions and malformations at and below the level of the lesions. These can include:
- Problems with physical movement
- Loss of sensation — like hot or cold
- Loss of bowel and bladder control
- Twisted or abnormal legs and feet; for example, club foot
- Hydrocephalus (excess CSF in the head)
- Chiari II malformation
Who gets a myelomeningocele?
Myelomeningocele occurs in one to five babies per 1,000 live births in the United States. It develops in the third week of a mother’s pregnancy. Its cause is unknown, although there is probably a genetic component.
If a woman has one child with this defect, she has a 3 to 5 percent chance of having another.
We believe that too little folic acid can result in the neural tube not closing normally.
Normally, the neural tube in a fetus develops into its brain and spinal cord. For this to happen, it is essential the mother has enough folic acid in her diet during her early pregnancy.
What is your experience with myelomeningoceles?
Neurosurgeons at Children’s treat many children with myelomeningoceles. These children also have other complex problems.
We follow each child in our multidisciplinary clinic, which includes neurosurgeons on its team.
Doctors refer around 10 to 20 newborns with myelomeningocele to Children’s each year. Doctors in the community diagnose most of the babies with this problem before they are born.
Therefore, the hospital where the baby is born is ready to transfer the baby to Children’s immediately after birth. Our neurosurgeons are on hand to close the baby’s back, usually within 24-48 hours.
Most children with a myelomeningocele develop hydrocephalus. The neurosurgeons at Children’s also have a great deal of experience putting in shunts, a common treatment for hydrocephalus.
They also have a lot of experience treating children with the related problems of spinal cord tethering, Chiari II malformations and syringomyelia.
What surgery do you use to treat myelomeningocele?
Closing the defect in the child’s back
Closing the defect on your child’s back is the first surgery he needs, and he needs it immediately. Because of the large risk of infection, our neurosurgeons will operate within your infant’s first 24 to 48 hours of life.
The goal of the surgery is to prevent infection and more trauma to his spinal cord. Surgery does not create function that is absent at birth.
The neurosurgeon does this operation in steps.
First, he closes the covering (dura mater) around the spinal cord so it is watertight. Then he closes the muscles around the spinal cord. And finally, he closes the skin over the open area.
Some defects require the help of a plastic surgeon who creates and uses a skin graft flap to close the area. He usually takes skin for the graft from the baby’s back or buttocks.
Placing a shunt in the baby’s head
When an infant has severe hydrocephalus at birth, he may need a temporary drainage system, or shunt, in the first few days after birth. If a temporary system is used first a shunt will be placed after the baby is stable. If the baby does not have hydrocephalus at birth, we wait to see if it develops later. At that time, we put in a shunt. Most infant who need a shunt will need it within the first 4-8 weeks after birth.
Not all infants with a myelomeningocele need a shunt. Read more about hydrocephalus and shunts.