Spina Bifida

What spina bifida is

Early in pregnancy, a flat strip of cells rolls up to form the neural tube, which becomes the brain and spinal cord. It closes by about day 28 after conception, often before a person knows they are pregnant. If part of the tube does not close, the bones of the spine (vertebrae) and sometimes the spinal cord and its coverings do not form properly. Spina bifida means "split spine". It is one of the neural tube defects, along with anencephaly and encephalocele.

Types of spina bifida

Myelomeningocele is the most serious and most common form of open spina bifida. The higher on the spine it is, the greater the effect on movement.

Signs of hidden spina bifida

Skin markers over the lower back can signal an underlying closed defect: a dimple above the buttock crease, a tuft of hair, a birthmark, a fatty lump or a skin tag. A baby with these may need an ultrasound or MRI of the spine.

Causes and risk factors

The exact cause is unknown, but genes and environment both play a role. Risk factors include:

• Low folate before and in early pregnancy
• A previous pregnancy with a neural tube defect, or a close family history
• Certain anti-seizure medicines, especially valproic acid, and to a lesser degree carbamazepine
• Poorly controlled diabetes before and in early pregnancy
• Obesity before pregnancy
• High body temperature in early pregnancy, such as from a fever or hot tub use
• Hispanic ethnicity in the US, where rates are somewhat higher

Preventing spina bifida with folic acid

Up to about 70% of neural tube defects can be prevented with folic acid.

• Everyone who could become pregnant should take 400 micrograms (mcg) of folic acid every day, starting at least 1 month before conception and continuing through early pregnancy. Most multivitamins contain this amount.
• People who have had a pregnancy affected by a neural tube defect, or who take certain anti-seizure medicines, are usually advised to take a higher dose prescribed by their doctor.
• In the US, enriched grain products such as bread, pasta and breakfast cereals are fortified with folic acid. Folate-rich foods include leafy greens, beans and citrus fruit, but supplements are still recommended.

See folate deficiency for more on folate.

How spina bifida is diagnosed

During pregnancy:

• Maternal blood test (AFP): between 15 and 20 weeks. A raised alpha-fetoprotein level can indicate an open neural tube defect.
• Anatomy ultrasound: around 18 to 22 weeks, which detects most open defects and associated brain changes.
• Fetal MRI and sometimes amniocentesis for more detail and genetic testing.

After birth: open defects are visible. Closed defects are found through skin markers, ultrasound in young babies or MRI.

Treatment

Surgery to close the defect

• Fetal surgery: in selected pregnancies, surgeons repair the defect before 26 weeks in the womb. A major trial showed it reduced the need for a brain shunt and improved leg function, at the cost of higher risks of preterm birth and uterine problems.
• Surgery after birth: the usual approach. Closure is done within the first day or two of life to protect the spinal cord and prevent infection.

Hydrocephalus and Chiari II malformation

Most babies with myelomeningocele have a Chiari II malformation, in which the lower brain is pulled down into the neck, and many develop hydrocephalus, a build-up of fluid in the brain. Hydrocephalus is treated with a shunt that drains fluid to the belly, or a procedure called endoscopic third ventriculostomy. Shunts can block or become infected, so parents learn the warning signs.

Bladder and kidney care

Most people with myelomeningocele have a neurogenic bladder, meaning the nerves controlling the bladder are affected. Clean intermittent catheterization, often started in infancy, empties the bladder regularly and protects the kidneys. Medicines, Botox injections or surgery can increase bladder capacity or improve continence. Regular ultrasounds and urodynamic tests check bladder pressure and kidney health.

Bowel management

A neurogenic bowel causes constipation and accidents. A bowel program with diet, laxatives, suppositories or enemas, or rinsing the bowel through a surgically created channel, helps achieve continence.

Mobility and orthopedic care

• physical therapy from infancy
• braces, crutches, walkers or wheelchairs, depending on the level of the lesion
• treatment of clubfoot, hip problems and scoliosis
• daily skin checks, because numb skin is prone to pressure sores and burns

Learning and development

Most children with spina bifida have normal intelligence. Some have learning challenges, especially with attention, organization, math and processing visual information. Early intervention and school support plans help.

Complications to watch for

• Shunt malfunction: headache, vomiting, drowsiness, irritability or seizures.
• Tethered cord: the spinal cord becomes stuck to surrounding tissue and stretches as a child grows, causing back pain, weaker legs, changes in walking or bladder control and worsening scoliosis. Surgery can release it. See tethered cord syndrome.
• Latex allergy: common in people with spina bifida because of repeated early exposure. Use latex-free products from birth.
• Urinary tract infections and kidney damage.
• Weight gain, sleep-related breathing problems and skin breakdown.
• Depression and anxiety, especially in adolescence.

Living with spina bifida and life expectancy

Children with spina bifida do best with a coordinated team: neurosurgery, urology, orthopedics, rehabilitation, nursing and psychology. Many attend mainstream schools, play adapted sports, work, drive with hand controls and have families. Most children with spina bifida now survive into adulthood, and many adults live into their 50s, 60s and beyond. Life expectancy depends mostly on the level of the lesion, kidney health and shunt problems. Planning the move from pediatric to adult services is an important step.

Frequently asked questions

What are the types of spina bifida?

The main types are spina bifida occulta, a small hidden gap in the spine that usually causes no symptoms; meningocele, where a sac of fluid pushes out but the spinal cord stays in place; and myelomeningocele, the most serious form, where the spinal cord and nerves protrude and are damaged.

What causes spina bifida?

It happens when the neural tube does not close completely in the first 4 weeks of pregnancy. The exact cause is unknown, but low folate, a family history, some anti-seizure medicines such as valproate, poorly controlled diabetes, obesity and high fever in early pregnancy increase the risk.

Is spina bifida occulta serious?

Usually not. Spina bifida occulta is common, is covered by normal skin and typically causes no problems, so many people never know they have it. If there are skin markers such as a hair tuft or fatty lump, or symptoms in the legs, bladder or bowel, further imaging is recommended.

What is the life expectancy of someone with spina bifida?

With modern surgery, shunt care and bladder management, most children with spina bifida live into adulthood, and many live into later life. Outlook depends on the type and level of the defect, kidney health, and how well hydrocephalus and other complications are managed.

Can spina bifida be prevented?

The risk can be reduced greatly. Taking 400 micrograms of folic acid daily, starting at least a month before pregnancy, prevents many cases. People with a previous affected pregnancy or on certain medicines need a higher prescribed dose. Good diabetes control and avoiding overheating in early pregnancy also help.

Can spina bifida be detected before birth?

Yes. A maternal blood test for alpha-fetoprotein at 15 to 20 weeks and a detailed anatomy ultrasound at 18 to 22 weeks detect most open spina bifida. Fetal MRI gives more detail, which helps families plan delivery and discuss fetal surgery.