Overview

Spina bifida is a birth defect that occurs when the spine and spinal cord don’t form properly. It falls under the broader category of neural tube defects. The neural tube is the embryonic structure that eventually develops into the baby’s brain and spinal cord and the tissues that enclose them.

Normally, the neural tube forms early in pregnancy, and it closes by the 28th day after conception. In babies with spina bifida, a portion of the neural tube fails to develop or close properly, causing defects in the spinal cord and in the bones of the spine.

Spina bifida can range from mild to severe, depending on the type of defect, size, location and complications. When early treatment for spina bifida is necessary, it’s done surgically, although such treatment doesn’t always completely resolve the problem.

Symptoms

Signs and symptoms of spina bifida vary by type and severity. Symptoms can also differ for each person.

• Spina bifida occulta. Because the spinal nerves usually aren't involved, typically there are no signs or symptoms. But visible indications can sometimes be seen on the newborn's skin above the spinal defect, including an abnormal tuft of hair, or a small dimple or birthmark.

• Meningocele. The membranes around the spinal cord push out through an opening in the vertebrae, forming a sac filled with fluid, but this sac doesn't include the spinal cord.

• Myelomeningocele. In this severe form of spina bifida:

  • The spinal canal remains open along several vertebrae in the lower or middle back.

  • Both the membranes and the spinal cord or nerves protrude at birth, forming a sac.

  • Tissues and nerves usually are exposed, though sometimes skin covers the sac.