What is Spina Bifida?
Spina Bifida is a fault in the spinal column in which one or more vertebrae (the bones which form the backbone) fail to form properly, leaving a gap or split, causing damage to the central nervous system. To help understand what it is, let us explain about the composition of the nervous system.
The Central Nervous System
The central nervous system consists of the brain and the spinal cord. All activities are controlled by the brain which receives information from touching, seeing, feeling, tasting and hearing - responding to this information by initiating the appropriate movements of different parts of the body. Messages from the brain are carried to different parts of the body by the spinal cord which runs down the centre of the spinal column. This communication system for the body is very important and needs protection
The Spine
The spine is made up of 33 bones or vertebrae. The vertebrae have two main functions. One is to provide anchorage for muscles so that we can move as we dictate to those muscles. The other is to provide protection to the spinal cord.
The Neural Tube
The central nervous system and spine develop between the 14th and 28th day after conception. Spina bifida occurs when there is a failure of development of the boney canal which surrounds the brain and spinal cord. In the spine, the affected vertabrae have a defect posteriorly (at the back) so that a boney ring does not completely surround the spinal cord. This leaves a gap so that, instead of the posterior arm being whole it is divided - that is bifid. The fault may occur in one or more of the vertabrae but it is most common around waist-level.
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 a slight deficiency in the formation of (usually) one of the vertebrae. It may have visible signs of a dimple or small hair growth on the back. However, many people are unaware that they have spina bifida occulta as they have no symptoms or signs.
How many people are affected ?
Many people have this condition. One survey suggested the proportion could be one in 10 of the population. The vast majority of these will have no symptoms or problems.
Spina bifida occulta may be detected by X-ray when, for example, investigations of back injury are being made. In such cases, it can be extremely frightening to be labelled as having spina bifida butit must be emphasised that, for the vast majority, it is of no consequence whatsoever.
Women 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 ?
Unfortunately, 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.
If these symptoms are observed, it is 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.
