Shubhra Mukherjee, MD
Spina Bifida (SB) is a condition that is present at birth, and results from an abnormality in the development of the neural tube, which forms the spinal cord. SB is estimated to be prevalent in 1 out of 1000 births (Shaer et al, 2007). This neural tube defect is more commonly seen among males than females and is caused by genetic and environmental factors, which may include deficiencies in maternal folic acid, selenium, and zinc during the development of the fetus. Depending on the abnormality, there is weakness in the areas that the damaged nerves control, such as sensory areas and muscles to the abdomen, legs, and bowel and bladder. Most people with SB also have a shunt, to help drain the cerebrospinal fluid out of the brain ventricles. Involvement may be cervical (at the neck), or thoracic (chest), lumbar (low back) or sacral (base of spine).
There are three primary classifications of SB: SB occulta, meningocele, and myelomeningocele (also termed spina bifida cystica or meningomyelocele).
SB occulta encompasses a group of conditions affecting the spinal cord, in which the nerves are usually intact. SB occulta is characterized by an aperture in the spine that is covered by a layer of skin. SB occulta is a mild form of SB that rarely results in disability or symptoms.
Meningocele is characterized by a protruding sack of nerve fluid from the spine. While the nerves are usually intact, an individual with meningocele may possess minor disabilities (similar to neural tube defects).
Myelomeningocele occurs when parts of the spinal cord, combined with innervating nerves, protrude through an opening of the spine. This may result in complete or partial paralysis below the location of the protrusion. This form of SB typically results in nerve damage and other forms of disabilities, making it the most severe form of SB. It is common for spinal fluid draining to be compromised in Myelomeningocele, which may lead to excessive fluid accumulation in the head and cause damage to brain.