What is Spina Bifida

Spina bifida literally means split spine. It is one of the most common birth defects involving the nervous system and occurs between 14-28 days of fetal development. When one or more of the vertebrae (bones which make up the spine) fail to fuse in the middle, the spinal cord gets damaged. The meninges, the membrane which covers the spinal cord, protrudes through the hole in the spine instead of growing down the spinal column. Typically spina bifida occurs at the baby's waistline.

Three types of Spina bifida

• There are three types of spina bifida. Spina bifida occulta (which means hidden) is fairly common. Majority of such babies go on to have no problems whatsoever after birth and therefore require no treatment. Signs include a dimple on the skin, hair growth or a birth mark in the small of the back
• The second type, spina bifida myelomeningcocele is the most serious of the three. The membranes meant to cover and protect the spine form a fluid-filled sac in the small of the back to contain both the meninges and the cerebrospinal fluid. It pushes through the hole in the vertebrae and is clearly visible at birth. Because of the damaged spinal cords these babies typically have hydrocephalus and paralysis in varying degrees. Surgery is performed within a day or two after birth in the more severe cases and during some point of infancy for the less serious cases.
• The last type is the meningcocele. Here too the sac forms which contains just the cerebrospinal fluid. The damage is less severe than the second type.

Checking for Spina bifida

• There are two ways to detect spina bifida. One is to check on the levels of alpha-fetoprotein (AFP) in the mother's blood. Alpha-fetoprotein is one of the 3 components of the triple test commonly performed at bout 14 weeks of pregnancy. A raised level of AFP is indicative of an increased risk of spina bifida and the mother will be offered further scanning. The protein, AFP made in the baby's liver can seep from a break in the baby's skin and into the mother's blood, which is detected in the test. The leakage results in a much higher level of AFP than the expected level in the amniotic fluid.
• Second, ultrasound at 18 weeks can detect most cases of spina bifida as the features of abnormality in the spine and brain are obvious during the study.

FYI

• Spina bifida is a congenital disorder of the neural tube; there is an opening in the spinal cord and the spinal column (backbone) of the developing fetus.
• The neural tube is a structure that forms as a fold of tissue from which the fetus's brain and spinal cord develop.
• The neural tube begins to develop about 10 days after conception and its development continues throughout pregnancy.
• By 6 weeks of gestation this fold closes into a tube. If it does not close properly, severe birth defects can result, with spina bifida being one of them.
  
• Many babies born with the severe form of spina bifida also have hydrocephalus (literal meaning is water in and around the brain). This is caused by the abnormal circulation of the cerebrospinal fluid. The increased pressure inside the skull can damage the brain cells. A procedure to place a shunt inside the brain will be necessary to help drain the excess fluid.
• The location determines the severity of the defect. The higher the position of the defect on the spine, the greater the intensity of the complication.
• Because the spinal cord is not enclosed in the backbone, the infant has a high risk for meningitis, a serious infection of the spinal fluid, brain, and the lining covering the brain and spinal cord.
• Generally there is a loss of body functions below the level of the opening in the spinal cord. In the more severe cases, the child will have permanent problems with urination and defecation, experience paralysis and face learning disabilities
• Surgery soon after birth can prevent further deterioration. Newer surgical methods are being introduced to correct the problem while the fetus is still inside the utero.
• There is no cure to spina bifida. Surgery at best will repair the opening by pushing the meninges and closing the hole in the vertebrae. Surgery will not change the loss of function. Children with spina bifida often do not walk unassisted and frequently have learning disabilities. Despite this, with corrective measures or aids, many children with spina bifida grow up to live productive lives.

Prevention of Spina Bifida is Important

Deficiency of folic acid in the mother appears to be an important factor in the development of spina bifida. Studies reveal that adequate amounts of folate or folic acid (synthetic form of folate) can reduce the incidence of neural tube defects by up to 70%. However folic acid can only prevent the spinal and brain defects in the very early stages of pregnancy. That makes folic acid before conception and in the first 3 months of pregnancy all the more necessary.