Spina Bifida: A Neural Tube Defect
Neural tube defects are disorders that involve the incomplete development of the brain and/or spine. One of the most common neural tube defects is Spina Bifida. This condition occurs when, during the first month of pregnancy, the bones around the spinal cord fail to close properly allowing nerves to bulge out from the back and become expired. In mild cases, there are no symptoms or only minor physical disabilities are the result. However, in many patients, this leads to severe disability.
A clinical photo demonstrating an example of
the lumbar bump associated with Spina Bifida.
Types of Spina Bifida
There are three types of Spina Bifida:
Occulta - this is the least severe form of Spina Bifida and in many patients causes no problems at all. In this type, the spinal cord is normal. There is no opening in the back and no nerve damage, but one or more vertebrae may be deformed in that there is incomplete closure of the back portion of the vertebra.
Meningocele - the spinal cord develops normally but its protective covering (meninges) protrudes like a cyst out of an opening in the spine. There is usually no nerve damage but patients may have some minor physical disabilities.
Myelomeningocele - this is the most severe form of Spinal Bifida and occurs when both the protective covering of the spinal cord (meninges) and spinal nerves protrude through and opening in the spine. There is usually severe nerve damage and profound physical disabilities.
The extent of disability in each case of Spinal Bifida differs with each patient. Paralysis is largely determined by where on the spine the opening occurs, the size of the opening, whether skin covers the affected area, and whether or not spinal nerves are involved.
Who gets Spina Bifida?
Spina Bifida occurs in 7 out of every 10,000 live births in the United States. It is estimated that approximately 70,000 people in the United States have Spina Bifida. Spina Bifida occurs more frequently in females and more often in Hispanic populations. An exact cause is not clearly understood, however there are a few risk factors, including:
• A previous pregnancy in which the fetus had a neural tube defect
• Insulin-dependant diabetes
• The use of certain medications (particularly for seizures)
• High temperatures in early pregnancy (due to fever or use of a hot tub)
How is Spina Bifida treated?
Unfortunately, because nerve tissue cannot be replaced or repaired, there is no cure for Spina Bifida. Infants with myelomeningocele usually require surgery within the first 24 hours of life to close the opening in the spine and reduce the risk of infection. These children may also need subsequent surgeries to correct deformities. In milder cases of Spina Bifida, such as meningocele, the cyst that protrudes from the spinal opening may need to be surgically removed, usually without any further complications.
Can Spina Bifida be prevented?
The exact cause of Spina Bifida is not known. However, research has proven that when a woman takes 400 micrograms of folic acid (especially before she gets pregnant), she cuts her risk of neural tube defects by as much as 70%. A healthy diet that includes foods rich in folic acid is also helpful.