A congenital defect that is a type of neural tube defect in which part of 1 or more vertebrae fails to develop completely. As a result, a portion of the spinal cord is left exposed.
spinal anaesthesia Injection of an anaesthetic into the cerebrospinal fluid in the spinal canal to block pain sensations before they reach the central nervous system. It is used mainly during surgery on the lower abdomen and legs.
(See also epidural anaesthesia.)
(rachischisis) a developmental defect in which the newborn baby has part of the spinal cord and its coverings exposed through a gap in the backbone. The symptoms may include paralysis of the legs, incontinence, and learning disabilities from the commonly associated brain defect, *hydrocephalus. Spina bifida is associated with an abnormally high level of *alpha-fetoprotein in the amniotic fluid surrounding the embryo. The condition can be diagnosed at about the 16th week of pregnancy by a maternal blood test and confirmed by amniocentesis and ultrasound. The risk of spina bifida is reduced if supplements of *folic acid are taken by women while trying to conceive and during the first three months of pregnancy. See also neural tube defects.
This is one of the most common of the congenital (present at birth) malformations. It is one of the three types of neural-tube anomaly, the other two being ANENCEPHALY and cranium bi?dum. It takes two main forms – spina bi?da occulta being much the commoner. There is a de?cit in the posterior part of the SPINAL COLUMN, usually in the LUMBAR region, and it is generally asymptomatic unless the underlying spinal cord is affected. Occasionally it is associated with a hairy patch or birthmark on the back, and a few children develop a mild spastic gait or bladder problems.
Much more serious is spina bi?da cystica, in which the spinal-wall defect is accompanied by a protrusion of the spinal cord. This may take two forms: a meningocele, in which the MENINGES, containing CEREBROSPINAL FLUID, protrude through the defect; and a meningomyelocele, in which the protrusion contains spinal cord and nerves.
Meningocele is less common and has a good prognosis. HYDROCEPHALUS and neurological problems affecting the legs are rare, although the bladder may be affected. Treatment consists of surgery which may be in the ?rst few days of life or much later depending upon the precise situation; long-term follow-up is necessary to pick up any neurological problems that may develop during subsequent growth of the spine.
Meningomyelocele is much more serious and more common, accounting for 90 per cent of all cases. Usually affecting the lumbo-sacral region, the range of severity may vary considerably and, while early surgery with careful attention in a minor case may achieve good mobility, normal bladder function and intellect, a more extensive protrusion may cause complete ANAESTHESIA of the skin, with increased risk of trauma; extensive paralysis of the trunk and limbs, with severe deformities; and paralysis and insensitivity of the bladder and bowel. Involuntary movements may be present, and hydrocephalus occurs in 80 per cent of cases. The decision to operate can only be made after a full examination of the infant to determine the extent of the defect and any co-existent congenital abnormalities. The child’s potential can then be estimated, and appropriate treatment discussed with the parents. Carefully selected patients should receive long-term treatment in a special centre, where full attention can be paid to all their various problems.
There is growing evidence of the value of vitamin supplements before and during pregnancy in reducing the incidence of spina bi?da. Parents of affected infants may obtain help, advice, and encouragement from the Association for Spina Bi?da and Hydrocephalus which has branches throughout the country, or the Scottish Spina Bi?da Association.... spina bifida
Health Encyclopedia