Spina bifida is a term that is used to describe a series of birth defects that affect the development of the spine and central nervous system. The central nervous system is made up of the brain, nerves and spinal cord. The spinal cord runs from the brain to the rest of the body and consists of nerve cells and bundles of nerves that connect all parts of the body to the brain.
The neural tube
During the first month of life, an embryo (developing baby) grows a primitive tissue structure called the neural tube. As the embryo develops, the neural tube begins to change into a more complicated structure of bones, tissue and nerves that will eventually form the spine and nervous system.
However, in cases of spina bifida, something goes wrong with the development of the neural tube and the spinal column (the ridge of bone that surrounds and protects the nerves) does not fully close. Spina bifida is a Latin term that means split spine.
Types of spina bifida
There are different types of spina bifida, including:
- spina bifida occulta
- spina bifida meningocele
- myelomeningocele
This article focuses on myelomeningocele and this is the type of spina bifida that will be referred to whenever the term spina bifida is used. See the box to the left for information about spina bifida occulta and spina bifida meningocele
Myelomeningocele
Myelomeningocele is the most serious type of spina bifida. It is estimated that it affects one baby in every 1,000 that are born in Britain.
In myelomeningocele, the spinal column remains open along several vertebrae (the disc-shaped bones that make up the spine). The membranes and spinal cord push out to create a sac in the baby’s back. Sometimes the sac is covered with membranes called meninges, although it often remains open, leaving the nervous system vulnerable to infections that may be fatal.
In most cases of myelomeningocele, surgery can be carried out to close the defect. However, extensive damage to the nervous system will usually have already taken place. Damage can result in a range of symptoms including:
Most babies with myelomeningocele will also develop hydrocephalus, which is a condition where there is excess cerebrospinal fluid (CSF). CSF is the fluid that surrounds the brain.
The build-up of CSF is caused by problems with the development of the neural tube. Hydrocephalus needs to be treated with surgery because the extra pressure that the fluid places on the brain can cause brain damage.
See the Health A-Z topic about Hydrocephalus for more information about the condition.
Outlook
Over recent years, advancements in the treatment of spina bifida have resulted in a more positive outlook for the condition.
For example, before the 1960s, most children with spina bifida would die during their first year of life. However, today it is likely that children will survive into adulthood. Spina bifida can be a challenging condition to live with, but many adults with the condition are able to lead independent and fulfilling lives.
See Spina bifida - treatment for information about the range of different techniques that can be used to treat the condition.