Spina bifida can occur between the third and fourth week of pregnancy if a portion of the fetal spinal cord does not close properly. Spina bifida can cause the child to be born with an partly exposed spinal cord on the back.
CAUSES
Spina bifida is the most frequent and permanently disabling birth defect. According to the CDC in 2005, there are around 18 cases of myelomeningocele for every 100,000 live births in America. It has been estimated that there are 70,000 people in America living with this condition according to the Spina Bifida Association. This condition has begun to decrease in numbers because of preventative measures mothers have taken during pregnancy. Having a second child affected by this condition increases by 2-3%. Having a third child affected by this condition increases by 10%. Some scientists argue that spina bifida occurs because of genetics and factors from the environment. It is shown, though, that 95% of children with spina bifida do not have a family history of the condition. Some chronic health issues like diabetes and seizure disorders (treated with certain anticonvulsant medications) have been shown to increase the risk of a woman having a child with spina bifida (1/100).
SYMPTOMS
Spina bifida symptoms can vary depending on where the spinal cord and structures have been developed incorrectly, and to what extent. There are three main subtypes:
Occulta is also known as hidden spina bifida because there is no exposed spinal cord on the back and the nerves/spinal cord and typically normal. Occulta spina bifida causes a small gap in the vertebrae. This is estimated to occur in 12% of the population. It is possible to have a mild case of occulta spina bifida and have normal spinal function. In some cases, people do not know they have this condition until an X-ray has been performed. Around 1/1000 people will have occulta spina bifida that causes neurological deficits or disabilities. The disabilities can include loss of function of the bowel or bladder, back pain, weakening of the legs, or scoliosis.
Meningocele happens when the bones are not closed around the spine and the meninges are pushed out of the opening, leading to a sac of fluid to form. The dura mater, arachnoid mater, and pia mater are the three layers of membranes covering the spine of the meninges. With this condition, the nerves and spinal cord are often intact and have not been extremely affected. This may need surgery because the sac is usually covered by skin. This form of spina bifida is extremely rare.
Myelomeningocele is a severe form of spina bifida and occurs in 75% of all spina bifida cases. In this condition, the spinal cord is exposed on the back. Sometimes sac can be covered with skin, but other times tissues and nerves can be uncovered. Depending on how severe the condition is and the location, neurological defects will vary. Having a spinal cord defect on the bottom of the spine can lead to dysfunction of the bowel or bladder. The more extreme cases may cause complete paralysis of the legs alongside less of function of the bowel and bladder.
SEEKING MEDICAL CARE
Spina bifida is usually seen during maternal screening tests or ultrasounds of the fetus. Otherwise, the condition will be discovered after the baby is born.
When spina bifida is detected, parents should reach out to specialists and form a team. One this team should be a pediatric neurosurgeon. The pediatric neurosurgeon will evaluate the condition and create a prognosis and plan.
TESTING AND DIAGNOSIS
- Maternal serum alpha feto-protein test
- 20 week ultrasound
- Infant ultrasound
- Fetal MRI
TREATMENT
Prenatal
Women can take 400 micrograms of folic acid every day before conception to decrease the risk of having a child with spina bifida. Folic acid is water soluble and so it can pass quickly through the body. Since it is water soluble, the folic acid should be taken daily to be most proactive against neural defects. Around 50% of pregnancies are not planned so folic acid should be taken whether or not a woman is planning to become pregnant. According to research, the risk of neural tube defects can be lower by 70% when taking folic acid.
Fetal Surgery
There are mixed results of repair after birth and repair of the fetus in the uterus according to a randomized study (MOMS Trial). Undergoing fetal repair leads to less need of a ventriculo-peritoneal shunt (44 vs. 84%) and are most likely able to walk (44% vs. 24%). Repair while the baby is in the uterus had more complications. Due to a higher risk of complications and few long term follow ups, it is currently recommended by the American COllege of Obstetricians and Gynecologists that fetal surgery should only be done at specialty centers with highly qualified fetal surgeons.
INFANT SURGERY
To prevent future injury or infection, babies with spina bifida need to repair the exposed part of the spine. To do so, a neurosurgeon puts the neural tissues into the spinal canal. Then the neurosurgeon will close the muscle and skin. In some cases, a plastic surgeon will work on the case. Previously this surgery was done hours after the baby's birth, being a medical emergency. This surgery is now often done within the first two days after birth.
Many babies with spina bifida (80-90%) can develop hydrocephalus. Hydrocephalus is a condition in which CSF, or cerebral spinal fluid, builds up within the ventricles of the brain causing an increase in pressure in the head. Many of these children will need a ventricular shunt to limit the build of CSF. This shunt will stay in place during the individual's life, although it may need to be changed and replaced.
FOLLOW UP
The patient should have imaging and neurological and muscular exams done. This condition can be treatable and it is important to identify it early.
OUTLOOK
A paraplegic child will need a wheelchair. A child is paraplegic if he or she has no movement in the legs from the hips down. There is a good chance a child will be able to walk or walk assisted if born with movement of the thigh muscles and feeling below the knee. With no abnormalities of the brain, the child could have high intelligence, even if the child has extreme hydrocephalus when born.
With medical attention, most children with spina bifida can live active and functional lives. Studies done following children with spina bifida twenty years later show that they are generally well off, in college, and employed. As medical care progresses, children with spina bifida have increasingly functional lives.
