Spina bifida, meaning “cleft” or “split” spine, encompasses several types of congenital (present at birth) defects involving the neural tube. Usually, the neural tube closes up four weeks after inception and develops into the embryo’s spinal cord, brain, and accompanying tissue (the meninges). When a defect results in the spinal bone’s or cord’s failure to close or develop normally, this is spina bifida. Here is a look at the different types of spina bifida.
4 Types of Spina Bifida
The different types of spina bifida are labeled according to severity. From most to least severe, they are:
- Spina bifida occulta
- Closed neural tube defects
- Meningocele
- Myelomeningocele
While some forms can be mild enough to cause no obvious symptoms, others can be severe enough as to cause paralysis.
Spina Bifida Occulta
Spina bifida occulta is not only the least severe form, but also the most common; it is present in an estimated 10-20% of the population. One or more of the vertebrae making up the spinal cord are malformed or open—a small gap between the vertebrae may be the only indication of an issue. Occulta means “hidden,” indicating the layering of skin over the abnormality. In most cases, because there are no nerves involved in the abnormality, there are few to no symptoms or issues.
Closed Neural Tube Defects
Closed neural tube defects are characterized by a variety of malformations of the fat, bone, and membranes or meninges surrounding the spinal cord. These types of defects are often included in the occulta grouping. Again, there may be no symptoms in some people; others, however, may have issues with bowel control or even partial paralysis depending upon where and what the malformation is. Often, a patch of hair, birthmark, skin dimpling, or compilation of fatty tissue will be evident at the spot.
Meningocele
Meningocele spina bifida is an opening of the vertebrae through which spinal fluid and the meninges bulge out. Again, symptoms vary widely from absence to bowel dysfunction and/or partial paralysis. The meninges are the most affected by the malformation, which means the spinal cord itself generally forms without issue (aside from the opening). Thus, this type of spina bifida is usually surgically treatable by removing the protruding meninges while leaving bone and nerves alone.
Myelomeningocele
Myelomeningocele is the most extreme type of spina bifida. The spinal cord does not close during development, leaving the cord and other spinal anatomy exposed in a bulging sac, generally evident on the back. If the sac is not covered by skin, life threatening infections can be a serious problem, especially as an infant with little to no immune system, which is the more common scenario.
Any extremities controlled from the spot of issue to the base of the spinal cord will experience paralysis; thus, depending upon placement, paralysis may be nearly complete or only partial. The opening generally occurs in the middle or lower back, according to the Mayo Clinic. Myelomeningocele spina bifida may hinder walking or bowel and bladder control and cause seizures or orthopedic abnormalities.
