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Please note: This is a basic revision aid, not a comprehensive and reliable statement of medical fact. These notes should not be used to guide treatment. For reliable information and advice, consult a qualified practitioner.
Images on this page are used courtesy of the Association for Spina Bifida and Hydrocephalus (ASBAH)
Spina Bifida is an umbrella term that covers three conditions of varying severity: Spina Bifida Occulta, Spina Bifida Cystica Menigocele and Spina Bifida Cystica Myelomenigocele. These are described in more detail below. Spina Bifida is a neural tube defect or spinal dysraphism -- a failure of normal closure of the neural tube during the development of the embryo. The other neural tube defect is anencephaly, but as this is fatal before or very shortly after birth, it has little relevance for occupational therapy.
Spina Bifida Occulta is present in between 5 and 10% of the population, but is usually not noticeable.
Spina Bifida Cystica is present in approx. 1:1000 pregnancies. Slight gender bias -- approx. 3:2 women to men. Increased incidence among some ethnic groups such as Chinese and Celts.
Congenital (present at birth -- remember that congenital does not necessarily imply a genetic cause). Spina Bifida actually appears within the first 25 days of pregnancy.
There seem to be both genetic and environmental factors. Environmental factors are indicated by the fact that folic acid supplements (taken from at least one month prior to conception to the twelfth week of pregnancy) reduce incidence by approx. 70%. This is of use only in planned pregnancies, so proposals to include folic acid in flour are being considered.
Some anticonvulsants, notably Sodium Valproate, taken during pregnancy, have been suggested to cause a modest increase in risk. Insofar as there is a genetic component, it is suggested that the cause is a combination of genes rather than a single, isolated gene, perhaps including trisomy 13 or 18. History of spina bifida in a sibling is another risk factor. The risk of an adult with spina bifida having a child with the same condition is approx. 1:35. Genetic counseling is important.
Failure of normal closure of the neural tube during early pregnancy with a defect in the posterior part of the vertebrae and overlying skin, possibly causing the protrusion of a meningeal sac, possibly containing spinal cord tissue. Usually occurs in the lumbar-sacral region. There may be resultant damage to the spinal cord, usually in Myelomenigocele.
Damage to the spinal cord tends to mimic a complete or incomplete paraplegia, with associated disturbance of continence. Problems with continence can involve both urine and faeces. The site of lesion (usually lumbar-sacral) has impact on the level of disability. Disturbance of motor function tends to resemble flaccid paralysis rather than spasticity but there is a need to be aware of the risk of contractures.
As both motor and sensory nerves are affected, there is likely to be reduced lower limb sensation. Proprioception may often also affected, further complicating the motor difficulties.
Hydrocephalus is present in about 80% of people born with Spina Bifida Cystica and in these cases is caused by abnormalities in the structure of the brain that block CSF drainage. These abnormalities are sometimes called Arnold-Chiari malformations. Obstruction of the drainage of CSF results in increased intracranial pressure and associated damage, especially to areas adjacent to ventricles. Hydrocephalus is dealt with more fully in a separate document -- click here.
Reduced lower limb use and resultant reduction in general metabolism tend to cause difficulty in controlling body weight due to reduction in energy requirements.
There may be sexual dysfunction, and, in males, erectile dysfunction.
With good medical management and control of hydrocephalus, there should be no drastic reduction in life expectancy.
Surgery may be appropriate in the period shortly after birth to close the lesion on the back. Other treatment is symptomatic and may include:
The Association for Spina Bifida and Hydrocephalus (ASBAH) has specialist advisors who can be a valuable source of advice for professionals, parents and later for the person themselves. Contact with ASBAH should be discussed with parents at an early stage.
Children with SB may have delays in attaining good sitting balance, so consideration should be given to postural support to enable free use of the hands.
Reduced lower limb sensation means an increased risk of burns. Radiators should be boxed in and hot water pipes must be lagged. Special attention should be paid to hot water pipes under wash hand basins for wheelchair users.
Pressure care is especially important given the presence of several risk factors: reduced lower limb sensation, reduced mobility, incontinence and possible reduced lower limb circulation.
Mobility is one of the most obvious issues. Some people elect to use wheelchairs rather than walk with difficulty using calipers and walking aids because of the back and other joint pain caused by the unusual gait. This is obviously a difficult decision and one in which professionals should be wary of assumptions. The decision is one that must include full multidisciplinary input and full discussion with client and family. If wheelchairs are to be used, housing adaptations, or perhaps rehousing, may be necessary.
Problems associated with Hydrocephalus are dealt with in a separate document.
If you have any comments, corrections or suggestions about this page, please email me.
Last updated: 05 June 2002
Author: Mike Griffin PGDipOT, SROT
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