Overview

Spina bifida is a birth defect that occurs when the spine and spinal cord don't form properly. It's a type of neural tube defect. The neural tube is the structure in a developing embryo that eventually becomes the baby's brain, 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 doesn't close or develop 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 necessary, early treatment for spina bifida involves surgery — although such treatment doesn't always completely resolve the problem.

Types

Spina bifida can occur in different types: spina bifida occulta, myelomeningocele (my-uh-lo-muh-NING-go-seel) or the very rare type meningocele (muh-NING-go-seel).

Spina bifida occulta

"Occulta" means hidden. It's the mildest and most common type. Spina bifida occulta results in a small separation or gap in one or more of the bones of the spine (vertebrae). Many people who have spina bifida occulta don't even know it, unless the condition is discovered during an imaging test done for unrelated reasons.

Myelomeningocele

Also known as open spina bifida, myelomeningocele is the most severe type. The spinal canal is open along several vertebrae in the lower or middle back. The membranes and spinal nerves push through this opening at birth, forming a sac on the baby's back, typically exposing tissues and nerves. This makes the baby prone to life-threatening infections and may also cause paralysis and bladder and bowel dysfunction.