Types of Spina Bifida

Types of Spina Bifida
There are three main types of spina bifida :

Spina Bifida Occulta (hidden)
This is a very mild and common form and very rarely causes disability. There is usually a slight deficiency in the formation of one of the vertebrae. It can take the form of a dimple or small hair growth on the back. However, many people are unaware that they have spina bifida occulta as they display absolutely no symptoms of the condition.

How many people are affected?
Not many people have this condition. The vast majority of these will experience no symptoms or problems.

Spina bifida occulta may be detected by X-ray when investigations of back injury, for example, are being made. In such cases, it can be extremely frightening to be labelled as having spina bifida. It must be emphasised that it is of no consequence whatsoever for the vast majority of people having spina bifida occulta.

People with spina bifida occulta should ask their doctor to prescribe the higher dosage of folic acid when they plan to become pregnant - to help reduce the risk of their baby being affected by spina bifida.

Are there any complications?
However, in some cases the cleft in the spine may cause problems. Sometimes the spinal cord may become tethered - that is, caught against the vertebrae. With growth, tension can cause inefficient functioning, affecting bladder control and mobility.

When these symptoms are observed, it is very important to consult a GP who, if appropriate, can refer to a neurosurgeon.

Spina Bifida Cystica (cyst-like)
The visible signs are a sac or cyst, rather like a large blister on the back, covered by a thin layer of skin.

There are two forms:
Meningocel
In this form, the sac contains tissues which cover the spinal cord (meninges) and cerebro-spinal fluid. This fluid bathes and protects the brain and spinal cord. The nerves are not usually badly damaged and are able to function, therefore there is often little disability present. This is the least common form.

Myelomeningocele (meningomyelocele)
This is the commoner of the two meningoceles and also the most serious. Here the sac or cyst not only contains tissue and cerebro-spinal fluid but also nerves and part of the spinal cord. The spinal cord is damaged or not properly developed. As a result, there is always some degree of paralysis and loss of sensation below the damaged vertebrae. The amount of disability depends very much on where the spina bifida is and the amount of nerve damage involved. Many children and adults with this condition experience problems with bowel and bladder control.

Cranium Bifida
This is when the bones of the skull fail to develop properly. The sac which forms is known as encephalocele. It may contain tissue and cerebro-spinal fluid only. However, in some cases, part of the brain may also be present in the sac resulting in brain damage.

The most severe forms of cranium bifida are iniencephaly and anencephaly. Here, the brain does not develop properly or is absent, and the baby is either stillborn or dies shortly after birth.

The babies born with spina bifida also have hydrocephalus (from the Greek hydro = water, cephalie = brain).

Spina Bifida Occulta
This is a mild form of spina bifida which is very common. Estimates vary but between 5% and 10% of people may have spina bifida occulta. It must be emphasised that, for the vast majority of those affected, having spina bifida occulta is of no consequence whatsoever. Often people only become aware that they have spina bifida occulta after having a back x-ray for an unrelated problem.

However, for a few (about 1 in 1,000) there can be associated problems.