Spina Bifida is one of the commonest developmental anomaly of the spinal cord in which there is failure of fusion of the neural tube to close perfectly and to separate completely from the surface ectoderm.
It is associated with a defect in the closure of the bony vertebral canal and is labeled as Spina Bifida. It is not uncommon and in 90 per cent of cases it involves the lumbo sacral region and in small percentage lower cervical region.
A number of varieties of Spina Bifida are described depending on t:e nature and severity of spinal defect. But two forms – Spina Bifida Occulta and Spina BifidaAperta are well recognized.
Spina Bifida Occulla
In this form there is failure of fusion of vertebral arch. Skin over it remains intact and there is no protmsion of either meninges or spinal cord. Usually at the site of lesion there is either skin pigmentation, a naevus or tuft of hair.
It usually affects the fifth lumbar or 1st sacral vertebrae and is often an incidental finding on routine X-ray of spine. Its incidence in general population ranges from 3-5%. Usually there are no symptoms but in childhood and early young age, as the child grows, there may be tension at the lower and of the spinal cord and cauda equina.
Compression may be caused by pulling of the spinal cord which in such cases is often tethered at the lower end. Symptoms are in the form of weakness and wasting of muscles of lower limb especially below the knee. There is difficulty in walking. Sensations are impaired in areas supplied by the lower sacral segments.
Deformity of the foot in the form of Pescavus is present. Control over the sphincters of bladder and rectum is POOL Anikie and kneejerks are either diminished or absent. Very often a child in late stage presents with enuresis either constantly or intermittently.
Noctumal enuresis is associated with precipitate micturition during day time. Presence of a pin head opening at the lower end of spine in such cases is helpful in making a diagnosis.
Cervical Spina Bifida may be associated with symptoms resembling syringomyelia in the upper limbs. Diagnosis is confirmed by radiology. MRI is very useful since it shall give details about other congenital anomalies. An asymptomatic Spina Bifida requires no treatment while in symptomatic cases suigery is helpful.
Spina Bifida Aperta
Here besides Spina Bifida there is hemiation of elements of the spinal cord and lumbosacral roots contained within meninges through a defect in the vertebra. This type of defect occurs in the lumbosocral region and is present at birth.
It may be in the form of meningocele or meningomyelocele. Hydrocephalus is associated with these abnormalities. Meningocele presents as a sessile globular swelling over the lower end of spine while sac of meningomyelocele is membranous, thin and transparent. Cases of spina bifida aperta have severe form of neurological deficit ranging from para presis, urinary incontinence to trophic lesions in lower limbs along with areas of anesthesia on the feet and buttocks. Gangrene of the toes may occur.
Diagnosis is made by radiological studies. MR imaging is the investigation of choice. Cerebro spinal fluid shows no abnormality.
Treatment of this condition shall vary with the type of anomaly. Management of hydrocephalus if present is important. If the sac of meningocele is excised, hydrocephalus may be further intensified. Infants with leaking sac shall require immediate surgery.
It shall depend on the type of Spina Bifida the child or young adult is suffering from. An asymptomatic Spina Bifida carries excellent prognosis and these people lead normal span of life but those with advanced neurological deficit may not survive long. Urinary tract infection is the major cause of morbidity. Association of other congenital anomalies shall further govern the prognosis.