Spina bifida

Overview

Spina bifida is the most common permanently disabling birth defect in the United States, affecting about one out of every 1,000 pregnancies. An estimated 70,000 people live with the condition. It occurs in the first month of pregnancy when the spinal column of the fetus doesn't close completely.

The condition can be diagnosed before a baby is born, and in some cases, after an extensive risk assessment of the mother and fetus, surgery can be performed before birth in an effort to repair or minimize the defect before birth.

Most children with this birth defect survive but develop disabilities which may include paralysis, difficulty controlling bowel and bladder function, hydrocephalus or excessive fluid in the brain, as well as impaired cognitive, learning, social and psychological development. The degree of disability is usually related to where the opening is located on the back; the higher the opening, the greater the impairment.

In most cases, the exact cause of spina bifida is unknown, although certain genetic and environmental factors may contribute to the condition. Due in part to improved treatments, many people with spina bifida now live longer — well into adulthood — and have a better quality of life, even though they may need lifelong treatment.

Signs & symptoms

Symptoms of spina bifida depend on the type of the disease and how severely the spinal cord and surrounding nerves are affected.

Spina Bifida Occulta

Occulta is the mildest form of the disease. Vertebrae are malformed but the spinal cord and its covering are undamaged. The condition typically doesn't cause disability or symptoms. About 5 to 10 percent of the population may have spina bifida occulta, but are unaware of it. In many cases, the only visible signs are an abnormal tuft of hair, birthmark or dimple at the defect.

Spina Bifida Meningocele

Meningocele is more severe. The meninges — membranes that cover and protect the spinal cord — protrude from the spinal opening and form a fluid-filled sac visible on a baby's back. The sac may be covered by a thin layer of skin. Some babies have few or no symptoms, while others experience complications, such as partial paralysis and urinary and bowel dysfunction.

Spina Bifida Myelomeningocele

Myelomeningocele is the most severe form of the disease. The meninges and spinal cord are exposed through the opening in the spine. Babies born with this condition may develop a variety of health problems, including partial or complete paralysis below the spinal cord, urinary and bowel dysfunction, hydrocephalus or excessive fluid in the brain and mental retardation, as well as impaired educational, social and psychological development.

Women who are pregnant with a fetus affected with spina bifida don't experience symptoms. However, there are several tests available to detect spina bifida before a baby is born.

Diagnosis

Prenatal Testing

The following prenatal tests for pregnant women detect spina bifida before babies are born.

• Alpha Fetoprotein (AFP) Test — AFP is the prenatal test most commonly used to detect spina bifida. This simple blood test is performed between 15 and 20 weeks of pregnancy. It measures levels of alpha fetoprotein (AFP), a protein released by the baby's liver, as well as human chorionic gonadotropin (hCG), a hormone produced during pregnancy, and estriol, another hormone produced in significant amounts during pregnancy. Abnormal results may indicate a spinal cord defect, such as spina bifida. It may also indicate fetal brain defects, multiple fetuses, a miscalculated due date or Down syndrome.
  
  Typically, AFP screening is performed by an obstetrician. If test results are high, the test may be repeated. If results still indicate a potential risk for birth defects, patients may be referred to the UCSF Prenatal Diagnosis Center for follow-up testing.
• Ultrasound — This harmless, non-invasive test uses high-frequency sound waves to create images of the fetus. It may detect a spinal cord defect caused by spina bifida or discover other reasons for high levels of AFP.
• Amniocentesis — This test is performed between weeks 15 and 20 of pregnancy. The test may be recommended to women who have high levels of AFP that couldn't be explained by an ultrasound. During the procedure, a small sample of the amniotic fluid surrounding the fetus is taken. Higher than average levels of AFP in the fluid may indicate spina bifida or other birth defects.

In some cases, after an extensive evaluation of mother and fetus, surgery can be performed before birth in an effort to repair or minimize the defect. This procedure is performed by fetal surgeons.

Postnatal Testing

If spina bifida is mild, it may not be detected until after a baby is born. Imagining tests such as magnetic resonance imagining (MRI) or computed tomography (CT) scans may be used to detect any abnormalities in the baby's spine or vertebrae.

If hydrocephalus — a condition in which excessive fluid accumulates in the brain — is suspected, doctors may perform a CT scan or ultrasound of the baby's brain.

Treatment

Currently, there is no cure for spina bifida, but there are a number of treatments available to help manage the disease and prevent complications.

In some cases, if diagnosed before birth, the baby can undergo surgery while still in the womb in an effort to repair or minimize the spinal defect. The procedure is performed by fetal surgeons after an extensive risk assessment of mother and fetus.

Treatment after birth may include ongoing surgery, medications and physical and behavioral therapy, depending on the type and severity of the defect, your child's age and overall health as well as personal preferences.

Children with the mildest form of the disease, spina bifida occulta, usually don't need treatment.

Children with spina bifida meningocele typically can be treated without surgery. However, they may develop complications, such as bladder problems and hydrocephalus, or excessive fluid in the brain. If untreated, it may cause movement disorders or mental retardation.

Fluid can be drained from the brain through a surgical procedure that uses a special tube called a shunt. The shunt runs under the skin into the abdomen and the fluid passes into the child's body without harm.

Myelomeningocele, the most severe form of spina bifida, generally requires surgery to correct the spinal defect and prevent infections, further injury or trauma to the exposed spinal cord and nerves.

The majority of babies with myelomeningocele also develop hydrocephalus, which requires treatment. Children with this form of spina bifida may also develop a progressive tethering of the spinal cord, in which the spinal cord and vertebrae don't stretch and grow normally as the child grows. This may cause loss of muscle function in the legs, bowel and bladder.

Surgery on the spinal cord may be performed to help restore function. Children with bladder function problems are treated by a urologist, who may suggest catheterization, in which a small tube is inserted into the bladder to help drain urine.

Devices, Physical Therapy

Many children with spina bifida experience partial or complete paralysis and need devices such as braces, crutches or wheelchairs. These children work with specialists in orthopedics and physical therapy to learn special muscle-strengthening exercises. Some children may also need surgery on the hips, legs and feet.

Latex Allergy

It's also common for children with spina bifida to develop an allergy to latex, or natural rubber, which may be caused by early exposure during surgeries and medical procedures. If your child has this allergy, avoid exposing him or her to latex products, such as baby bottle nipples, pacifiers and balloons. There are latex-free options for many products.