INTRODUCTION
Spina bifida is a failure in the closure of the
vertebrae at the base of the neural tube resulting
in the herniation or exposure of the spinal cord
and/or meninges. The incidence of spina bifida is
similar to that of anencephalus. As with other neural
tube defects there are reported associations with
maternal insulin dependent diabetes, hyperthermia,
obesity at conception, autosomal trisomies, and low
serum folate concentrations.
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ANTENATAL
In the West Midlands programmes for the prenatal
diagnosis of neural tube defects are based on maternal
serum AFP screening performed at 16 to 20 weeks gestation
and ultrasound screening, which is widely performed
at 16 to 22 weeks for this purpose. AFP serum screening
is thought to be 80% sensitive for open spina bifida.
Ultrasound is based on examination of the fetal head,
particularly the shape of the skull and the appearance
of the cerebellum. Spina bifida is most often diagnosed
using the cranial signs of an abnormal shape of the
fetal skull (lemon shape) and flattening and loss
of the median sulcus in the cerebellum (banana shape).
Hydrocephalus is often associated with spina bifida
and the spine itself can be examined to demonstrate
failure of closure of the vertebral arches, lack
of skin cover and herniation.
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POSTNATAL
The prognosis for cases of spina bifida is not
necessarily fatal and depends on the location, size,
and extent of the defect, and the presence of hydrocephalus.
Cases with high extensive lesions with obvious hydrocephalus
at birth and other congenital defects are universally
poor. In surviving infants, spina bifida can result
in severe disability affecting the sensory and motor
function of the lower limbs, bowel, and bladder.
Predicting the outcome of open spina bifida cases
is problematic, with some cases having a good outcome,
while others have severe disability. The options
are either early surgical closure, with or without
shunting of hydrocephalus or waiting for a time to
allow the lesion to heal by granulation.
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WEST
MIDLANDS DATA
To be added.
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