Spina bifida is the name for a group of congenital abnormalities (birth defects) in which the spinal cord and the structures of the lower back don’t form correctly. The spinal cord originates from something called the neural tube, which should close when a foetus is 3-4 weeks old in the womb. If the neural tube doesn’t close, several different types of spina bifida may occur, and these types vary in their severity.
The most severe form of spina bifida is myelomeningocele, where the vertebrae (backbone) that should cover the spinal cord has a missing piece in the lower back, forming a gap. Nerves and the spinal cord pop out of this gap, along with some spinal fluid. If there is skin covering the protrusion of the spinal cord, then a pouch will form at the lower back. In severe myelomeningocele, there is no skin there, and the nerves and spinal cord are just freely exposed to the air. This damages the nerves and can lead to significant disabilities.
The second type of spina bifida, meningocele, is less severe and may cause mild disabilities. Babies born with meningocele also have pieces of their backbone missing, and the gap there lets spinal fluid leaks out, forming a pouch at the lower back. But in meningocele, the spinal cord does not protrude through this gap and the pouch contains only fluid. Finally, the mildest form of spina bifida is spina bifida occulta. In spina bifida occulta only a small amount of vertebrae missing, leading to a tiny gap. This gap is not big enough for fluid to leak out, so no pouch is formed. However, there may be other signs of spina bifida occulta like a birthmark or hairy patch over the area.
The symptoms of spina bifida can be divided by the types of spina bifida they occur in.
Myelomeningocele symptoms:
Typically, meningocele has no symptoms. Still, some meningocele symptoms include:
Spina bifida occulta:
The exact cause of spina bifida remains unknown, but there are a few well-known risk factors for it.
Risk factors include:
Most types of spina bifida can be diagnosed while a woman is still pregnant with her baby. This is typically done through a blood test of the mother, to look for the levels of certain proteins which indicate spina bifida. Ultrasound scans can be done to visualize the low-back pouch. If neither of these tests gives the diagnosis, amniocentesis may be done. Amniocentesis is a procedure where a bit of amniotic fluid that a baby swims in within the womb is taken out and tested.
In myelomeningocele, a pre-natal surgery may be done while the baby is still in the womb. This surgery can be quite dangerous for the baby and mother, so a post-natal (after birth) surgery may be done instead. This surgery is ideally done within 3 days of birth, to decrease the chance that the spine gets infected.
Meningocele and spina bifida occulta usually don’t require surgery. They may require physical therapy. Meningocele may require long-term monitoring by doctors to make sure new symptoms aren’t developing.