The human nervous system develops from a small, specialized plate of cells along the back of an embryo.  Early in development, the edges of this plate begin to curl up toward each other, creating the neural tube—a narrow sheath that closes to form the brain and spinal cord of the embryo.  As development progresses, the top of the tube becomes the brain and the remainder becomes the spinal cord.  This process is usually complete by the 28^th day of pregnancy.  But if problems occur during this process, the result can be brain disorders called neural tube defects, including spina bifida.

The exact cause of spina bifida remains a mystery.   No one knows what disrupts complete closure of the neural tube, causing a malformation to develop.  Scientists suspect genetic, nutritional, and environmental factors play a role.  Research studies indicate that insufficient intake of folic acid—a common B vitamin—in the mother’s diet is a key factor in causing spina bifida and other neural tube defects.   Prenatal vitamins that are prescribed for the pregnant mother typically contain folic acid as well as other vitamins.  (See “Can the disorder be prevented?” below for more information on folic acid.)

Complications of spina bifida can range from minor physical problems to severe physical and mental disabilities.   It is important to note, however, that most people with spina bifida are of normal intelligence.   Severity is determined by the size and location of the malformation, whether or not skin covers it, whether or not spinal nerves protrude from it, and which spinal nerves are involved.  Generally all nerves located below the malformation are affected.  Therefore, the higher the malformation occurs on the back, the greater the amount of nerve damage and loss of muscle function and sensation.

In addition to loss of sensation and paralysis, another neurological complication associated with spina bifida is Chiari II malformation—a rare condition (but common in children with myelomeningocele) in which the brainstem and the cerebellum, or rear portion of the brain, protrude downward into the spinal canal or neck area.  This condition can lead to compression of the spinal cord and cause a variety of symptoms including difficulties with feeding, swallowing, and breathing; choking; and arm stiffness.

Chiari II malformation may also result in a blockage of cerebrospinal fluid, causing a condition called hydrocephalus, which is an abnormal buildup of cerebrospinal fluid in the brain.  Cerebrospinal fluid is a clear liquid that surrounds the brain and spinal cord.  The buildup of fluid puts damaging pressure on the brain.  Hydrocephalus is commonly treated by surgically implanting a shunt—a hollow tube—in the brain to drain the excess fluid into the abdomen.

Some newborns with myelomeningocele may develop meningitis, an infection in the meninges.  Meningitis may cause brain injury and can be life-threatening.

Children with both myelomeningocele and hydrocephalus may have learning disabilities, including difficulty paying attention, problems with language and reading comprehension, and trouble learning math.

Additional problems such as latex allergies, skin problems, gastrointestinal conditions, and depression may occur as children with spina bifida get older.

There is no cure for spina bifida.   The nerve tissue that is damaged or lost cannot be repaired or replaced, nor can function be restored to the damaged nerves.  Treatment depends on the type and severity of the disorder.  Generally, children with the mild form need no treatment, although some may require surgery as they grow.

The key priorities for treating myelomeningocele are to prevent infection from developing through the exposed nerves and tissue of the defect on the spine, and to protect the exposed nerves and structures from additional trauma.  Typically, a child born with spina bifida will have surgery to close the defect and prevent infection or further trauma within the first few days of life.

Doctors have recently begun performing fetal surgery for treatment of myelomeningocele.   Fetal surgery—which is performed in utero (within the uterus)—involves opening the mother’s abdomen and uterus and sewing shut the opening over the developing baby’s spinal cord.  Some doctors believe the earlier the defect is corrected, the better the outcome is for the baby.   Although the procedure cannot restore lost neurological function, it may prevent additional loss from occurring.   However, the surgery is considered experimental and there are risks to the fetus as well as to the mother.

The major risks to the fetus are those that might occur if the surgery stimulates premature delivery such as organ immaturity, brain hemorrhage, and death.   Risks to the mother include infection, blood loss leading to the need for transfusion, gestational diabetes, and weight gain due to bed rest.

Still, the benefits of fetal surgery are promising, and include less exposure of the vulnerable spinal nerve tissue and bones to the intrauterine environment, in particular the amniotic fluid, which is considered toxic.   As an added benefit, doctors have discovered that the procedure affects the way the brain develops in the uterus, allowing certain complications—such as Chiari II with associated hydrocephalus—to correct themselves, thus, reducing or, in some cases, eliminating the need for surgery to implant a shunt.

Many children with myelomeningocele develop a condition called progressive tethering, or tethered cord syndrome,    in which their spinal cords become fastened to an immovable structure—such as overlying membranes and vertebrae—causing the spinal cord to become abnormally stretched and the vertebrae elongated with growth and movement.  This condition can cause loss of muscle function to the legs, bowel, and bladder.  Early surgery on the spinal cord may allow the child to regain a normal level of functioning and prevent further neurological deterioration.

Some children will need subsequent surgeries to manage problems with the feet, hips, or spine.  Individuals with hydrocephalus generally will require additional surgeries to replace the shunt, which can be outgrown or become clogged.

Some individuals with spina bifida require assistive devices such as braces, crutches, or wheelchairs.  The location of the malformation on the spine often indicates the type of assistive devices needed.  Children with a defect high on the spine and more extensive paralysis will often require a wheelchair, while those with a defect lower on the spine may be able to use crutches, bladder catherizations, leg braces, or walkers.

Treatment for paralysis and bladder and bowel problems typically begins soon after birth, and may include special exercises for the legs and feet to help prepare the child for walking with braces or crutches when he or she is older.

Folic acid, also called folate, is an important vitamin in the development of a healthy fetus.   Although taking this vitamin cannot guarantee having a healthy baby, it can help.  Recent studies have shown that by adding folic acid to their diets, women of childbearing age significantly reduce the risk of having a child with a neural tube defect, such as spina bifida.  Therefore, it is recommended that all women of childbearing age consume 400 micrograms of folic acid daily.  Foods high in folic acid include dark green vegetables, egg yolks, and some fruits.   Many foods—such as some breakfast cereals, enriched breads, flours, pastas, rice, and other grain products—are now fortified with folic acid.  A lot of multivitamins contain the recommended dosage of folic acid as well.   

Women who have a child with spina bifida, have spina bifida themselves, or have already had a pregnancy affected by any neural tube defect are at greater risk of having a child with spina bifida or another neural tube defect.  These women may require more folic acid before they become pregnant.

Children with spina bifida can lead relatively active lives.  Prognosis depends on the number and severity of abnormalities and associated complications.  Most children with the disorder have normal intelligence and can walk, usually with assistive devices.  If learning problems develop, early educational intervention is helpful.