Spina Bifida: A Neural Tube Defect

Neural tube defects are disorders involving the incomplete development of the brain and/or spine prior to birth. Spina bifida is the most common type.

Neural tube defects are disorders involving the incomplete development of the brain and/or spine prior to birth. One of the most common neural tube defects is spina bifida, which means split spine. This condition occurs when the bones around the spinal cord fail to close properly during the first month of pregnancy, which puts the baby’s spinal cord and nerves at risk. In mild cases, the disorder causes no symptoms or only minor physical disabilities. However, spina bifida often leads to severe, permanent disability.

young boy in a wheelchair in front of school lockersThe extent of disability differs with each patient. Photo Source:123RF.com

Types of Spina Bifida
Doctors classify spina bifida into 3 main types based on severity:

  1. Occulta: This is the least severe form of spina bifida, and it causes no problems in most patients. In this type, the spinal cord is normal—there is no opening in the back and no nerve damage. However, one or more vertebrae may be deformed (incomplete closure of the back portion of the vertebra).
  1. Meningocele: In this type of spina bifida, 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.
  1. Myelomeningocele: This is the most common and severe form of spinal bifida. Irregularities in the spine caused by this type of spina bifida may be detected in the first trimester fetal ultrasounds. Myelomeningocele occurs when both the protective covering of the spinal cord (meninges) and spinal nerves protrude through an opening in the spine. This type usually features severe nerve damage and profound physical disabilities.

Spina Bifida illustrationEighty percent of myelomeningocele cases occur in the lumbar (low back) or sacral region of the spine. But, it can occur at any level in the spine. Photo Source: Shutterstock.

More About Myelomeningocele Spina Bifida

In myelomeningocele, the spinal neural tube doesn’t close completely. This causes the spinal cord and vertebral column to form improperly, and it can cause a host of physical and cognitive problems.

Eighty percent of myelomeningocele cases occur in the lumbar (low back) or sacral region of the spine. But, it can occur at any level in the spine.

People with this form of spina bifida typically have symptoms that affect their legs, bladder, and bowel. In fact, 97% of patients with myelomeningocele have bladder and bowel incontinence.

The extent of disability differs with each patient. In addition to bladder and bowel problems, many people with myelomeningocele experience problems feeling or moving their legs properly. In fact, paralysis—or the partial or complete loss of feeling and function—is associated with this type of spina bifida. Paralysis is largely determined by the location of the opening on the spine, the size of the opening, whether skin covers the affected area, and whether spinal nerves are involved.

Most people with myelomeningocele are also born with a Chiari malformation, which causes brain dysfunction. There are several types of Chiari malformation, but the one closely connected to spina bifida is Type II. In Type II Chiari malformation, brain tissue pushes through the foramen magnum, which is the opening normally reserved only for your spinal cord. Chiari malformation can cause several problems, including hydrocephalus, which occurs when too much cerebrospinal fluid accumulates in the brain.

Shortly after birth, a baby born with myelomeningocele will undergo surgery. You can learn more about that below.

Who Gets Spina Bifida? 

The incidence of spina bifida and other neural tube defects depends greatly on where you live and your ethnic background. These disorders range from less than 1 to 7 per 1,000 births, and babies born in China, Ireland, Great Britain, Pakistan, India, and Egypt have the highest rates of neural tube defects.

Within the United States, the rate of neural tube defects is approximately 0.2 per 1,000 births. Spina bifida occurs more frequently in females and in Hispanic populations.

An exact cause is not clearly understood, but research has connected the condition to the following risk factors:

  • A previous pregnancy in which the fetus had a neural tube defect (women with a previous pregnancy with a neural tube defect have a 2.5% chance of it happening again, which is approximately 20 times the rate of the general population).
  • Type 1 diabetes
  • Certain medications (particularly for seizures)
  • Obesity
  • High temperatures in early pregnancy (due to fever or use of a hot tub)

How Is Spina Bifida Treated?

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.

Babies with spina bifida will also be checked for hydrocephalus with an ultrasound of the child’s head. If the child has hydrocephalus, the doctor may use a device called a shunt (a long tube inserted into the fluid-filled area in the brain) to drain the excess fluid.

Additional treatments may depend on what other conditions the child has besides spina bifida, but babies with myelomeningocele generally receive life-long treatment for their condition. These treatments include:

  • Wheelchair use or bracing to help walk
  • Using a catheter for bladder health
  • Subsequent surgeries to correct spinal deformities

In milder cases of spina bifida, the cyst that protrudes from the spinal opening may need to be surgically removed, usually without any further complications.

Can Spina Bifida Be Prevented? 

While spina bifida’s exact cause is not known, prenatal maternal serum screening programs have been connected to lower neural tube defect rates. Also, research has proven that when a woman takes 400 micrograms (mcg) of folic acid daily—before and during pregnancy—she may cut the risk of neural tube defects by as much as 70%.

Folic acid and folate are forms of vitamin B9, an essential nutrient for cell growth and DNA formation. Folic acid is a synthetic form of vitamin B9 used in supplements and fortified foods (like breakfast cereal), and folate is its naturally derived counterpart.

In addition to taking a daily folic acid supplement, eating foods rich in folate—such as spinach, asparagus, avocados, and Brussels sprouts—is an excellent way to meet your daily vitamin B9 needs and potentially prevent spina bifida in an unborn child.

Updated on: 07/26/19
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Spina Bifida: Complications Include Scoliosis and Kyphosis
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Spina Bifida: Complications Include Scoliosis and Kyphosis

Myelomeningocele is the most common and severe type of spina bifida. Potential complications include paralysis, bowel and bladder problems, scoliosis, kyphosis, Chiari malformation, clubfoot, and spinal cord tethering.
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