What is Spina Bifida Occulta?
Spina bifida occulta is the mildest form of spinal birth defect where the bones of the spine (vertebrae) don't close completely during development in the womb, but the spinal cord and nerves remain protected inside the body and covered by skin. 1
Understanding the Condition
Think of it as a small gap or opening in the backbone that you can't see from the outside. The term "occulta" means "hidden" because unlike more severe forms of spina bifida, there's no visible opening or sac protruding from the back. 2, 1
- The vertebral arches (the bony parts that normally form a complete ring around the spinal cord) fail to close completely, but the spinal cord and nerves don't push through this gap. 2
- This happens very early in pregnancy—within the first month after conception—when the neural tube (which becomes the brain and spinal cord) is forming. 2
- Most people with spina bifida occulta never know they have it and live completely normal lives without any symptoms. 1
How It Differs from More Serious Types
Spina bifida occulta is fundamentally different from the more severe "open" forms of spina bifida (like myelomeningocele), where the spinal cord and nerves are exposed or protrude through the back. 2
- In the severe forms, the spinal cord and nerves are damaged or exposed, leading to paralysis, bladder and bowel problems, and often intellectual disabilities. 2
- With spina bifida occulta, the spinal cord and nerves are typically intact and protected, so most people have no disabilities at all. 1
- Only 10-15% of all spina bifida cases are the "closed" or covered type like spina bifida occulta. 2
When Symptoms Do Occur
While most people with spina bifida occulta have no problems, some may develop symptoms later in life. 1, 3
- Sometimes there are subtle skin changes over the affected area—like a small dimple, birthmark, or tuft of hair—that can be a clue the condition is present. 4
- A condition called "tethered cord syndrome" can develop over time, where the spinal cord becomes abnormally attached and stretched, causing back pain, leg weakness, or bladder problems. 5, 1
- Chronic lower back pain that doesn't respond to typical treatments may be a sign of spina bifida occulta that wasn't previously diagnosed. 3
- Bladder dysfunction can occasionally develop and requires monitoring with specialized testing. 5, 1
Prevention
Taking folic acid (a B vitamin) before and during early pregnancy can prevent up to 72-87% of neural tube defects, including spina bifida. 2
- Women of childbearing age should take 400 micrograms (0.4 mg) of folic acid daily, either through supplements, fortified foods, or multivitamins. 2
- This needs to start at least one month before conception because the neural tube closes so early in pregnancy—often before a woman even knows she's pregnant. 2
- Over 95% of neural tube defects occur in families with no prior history, which is why all women of reproductive age should take folic acid. 2
Management When Diagnosed
Most newborns and children with spina bifida occulta require only observation rather than immediate treatment. 1
- A baseline ultrasound of the kidneys and bladder is recommended to check for any urinary system abnormalities. 1
- Ongoing monitoring for signs of tethered cord syndrome is important as children grow. 5, 1
- Unlike severe forms of spina bifida, routine bladder catheterization and medications are not needed unless specific problems develop. 1
- If symptoms do develop—such as progressive back pain, leg weakness, or bladder problems—surgical decompression may be necessary. 3