1164H
Fig. 17.20 A palatal training plate designed to improve lip and tongue posture.
17.4 PHYSICAL IMPAIRMENT⎯SPINA BIFIDA
17.4.0 Introduction
Spina bifida occurs as a result of non-fusion of one or more posterior vertebral arches,
with or without protrusion of some or all of the contents of the spinal canal. It may be
accompanied by hydrocephalus in up to 95% of cases. It is estimated that in 50-60%
of affected children the defect is inherited and that environmental agents may be
responsible for the remainder. In the United Kingdom the incidence is 2.5 per 1000
births and, unlike other malformations, is commoner in females. A quarter of children
will also have epilepsy and about a third will have some degree of intellectual
impairment.
17.4.1 General considerations
Children with spina bifida will, unless the defect is slight, spend much of their time
confined to a wheelchair (1165HFig. 17.21) and be incontinent. Urinary tract infections are
common and the child may be on frequent courses of antibiotics. Hydrocephalus,
unless arrested, is treated by the insertion of a shunt (fitted with a Spitz-Holter valve)
to drain fluid from the ventricles into either the superior vena cava or more usually the
peritoneum. It is important to protect the venous shunt from blockage, which may
arise from a bacteraemia of oral origin, otherwise intracranial pressure will increase,
causing convulsions. Although opinion is divided on the necessity to cover invasive
dental procedures in children who have a shunt, those erring on the side of caution
will use the same prophylaxis regimen as in cardiac disease (1166HChapter 16). However,
there is no indication for antibiotic prophylaxis if the shunt is a ventriculo-peritoneal
one.
Children who are confined to a wheelchair for much of the time will need to be
treated either in their chair or transferred carefully to the dental chair. There are
commercially available chair adaptations to accommodate a patient in their
wheelchair (1167HFig. 17.22). These are helpful if the child is too heavy to transfer easily to
the dental chair or if the procedure is more easily accomplished for the operator and
patient in this position. Shaped body supports, which are essentially modifications of
a bean bag, are also available for use in the dental chair for any patient with a
physical disability who cannot otherwise be comfortably accommodated. These