Developmental
anomalies
The commonest problem to affect the spinal column is failure of the
neural tube to close fully, producing one of many patterns of neurospinal
dysraphism or spina bifida.
• Spina bifida aperta. The neural tube is open with no skin coverage,
through a defect in the posterior vertebral arch. CSF leakage usually occurs
with an associated risk of infection (see Fig. 33.25).
• Spina bifida cystica. In this situation there is skin covering
• Spina bifida occulta. The posterior vertebral arch has a defect
within it, but there is no herniation of the neural tube. This defect may be
found within 10 per cent of the population. On the skin over the defect various
skin changes may be seen, for example a hairy patch (see Fig.
33.26), an area of
pigmentation, a fatty lump or
Management
Any discussion regarding the treatment of children with this condition
should include inheritance. Whilst the majority (90 per cent) of cases occurs
sporadically, with an incidence ranging from one to eight per 1000 of the
population, children of parents with spina bifida have a 5 per cent risk
of having the condition as well.
Prenatal
screening to detect alpha-fetoprotein in blood or amniotic fluid, obtained by
amniocentesis, together with the use of ultrasound allows the detection of such
defects in over 80 per cent with an open neural tube.
Problems
of development tend to occur in the lumbo-sacral area and are especially
associated with changes in bladder and bowel function. These changes may not
become apparent for the first few years of life and can be associated with a
totally normal neurological examination.
The
higher the lesion the more severe the defect and the worse the neurological
condition. In severe cases it can be associated with a complete failure of
development of the legs with a complete paraplegia and loss of bladder and bowel
function.
If
the lesion is open then there are attendant risks of meningitis as well.
Other
associated disorders include Arnold—Chiari malformations and, in up to 80
per cent, hydrocephalus.
Investigations
The investigations include:
• complete neurological examination;
• head circumference measurements;
• plain X-rays of the spine (see Fig.
33.27);
• MRI scan of brain and whole spine.
Treatment
For the majority of cases of open dysraphism, closure should be carried
out as soon as possible with treatment of the hydrocephalus. Often this is the
first of many procedures best provided by a team of surgeons, paediatricians,
therapists and nurses.
As
regards the patients with closed lesions at birth, they may require surgery at a
later stage should progressive neurological signs develop. It should be noted,
however, that any procedure may be associated with neurological deterioration.