Spina bifida

Overview

Spina bifida is the most common permanently disabling birth defect in the United States, affecting about one 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 the baby is born, and in some cases, after an extensive risk assessment for mother and fetus, surgery can be performed before birth in an effort to repair or minimize the defect.

Most children with this birth defect survive but develop disabilities, which may include paralysis; difficulty controlling bowel and bladder function; hydrocephalus (excess fluid in the brain); and impaired cognitive, social and psychological development. The degree of disability is usually related to the location of the opening 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. Due in part to improved treatments, many people with spina bifida now live well into adulthood and have a good quality of life, even though they may need lifelong treatment.

The UCSF Fetal Treatment Center is a world leader in evaluating and treating birth defects, such as spina bifida, before delivery. In 1981, we performed the first successful open fetal surgery ("open" is the traditional approach in which the surgeon works through a large incision), and we have more experience than any institution worldwide with both open and minimally invasive fetal surgery. Our team includes fetal and pediatric surgeons, radiologists, perinatologists, neonatologists, cardiologists, urologists, geneticists, anesthesiologists, pediatric neurologists, pediatric neurosurgeons, nurses and social workers, and these experts work collaboratively to ensure our patients receive care that meets all of their needs.

Signs & symptoms

When a fetus is affected with spina bifida, the pregnant person doesn't experience symptoms. However, several tests can detect spina bifida before the baby is born. Signs in the fetus depend on the type of spina bifida 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. In fact, about 5 to 10% of the population may have spina bifida occulta without being aware 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 the 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. Most babies born with this condition survive but have a variety of health problems, including partial or complete paralysis; urinary and bowel dysfunction; hydrocephalus, a Chiari malformation (the back of the brain protruding into the spinal cord); and impaired cognitive, social and psychological development. In general, the higher the opening on the spine, the greater the impairment.

Diagnosis

Spina bifida is usually detected by prenatal tests conducted at different points in a pregnancy. These include:

• 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 AFP (a protein released by the baby's liver) and of human chorionic gonadotropin and estriol (two hormones produced by the mother's body during pregnancy). Abnormal results may indicate a spinal cord defect, such as spina bifida. They may also indicate fetal brain defects, multiple fetuses, a miscalculated due date or Down syndrome.
  Typically, AFP screening is performed by an obstetrician. If the results are abnormal, the test may be repeated. If the results still indicate a risk of birth defects, the patient may be referred to the UCSF Prenatal Diagnostic Center for follow-up testing.
• Amniocentesis — This test is performed between weeks 15 and 20. The test may be recommended to patients with high AFP levels that weren't 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 sample may indicate spina bifida or other birth defects.
• Ultrasound — This noninvasive test uses high-frequency sound waves to create images of the fetus. It may detect a spinal cord defect caused by spina bifida or reveal other reasons for high levels of AFP.

If testing detects spina bifida, you will be referred to our Fetal Treatment Center for further evaluation and counseling. Our evaluation process includes the following:

• Level II ultrasound (anatomic survey) for fetal abnormalities
• Fetal echocardiogram (heart ultrasound) to assess both structure and function
• Fetal MRI of the brain and spine for presence and severity of a Chiari malformation
• Consultations with our team of experts in specialties including anesthesia, fetal surgery, neurosurgery, nursing, perinatology and social work

When spina bifida is mild, it may not be diagnosed until after the baby is born. Imaging tests, such as magnetic resonance (MR) or computed tomography (CT) scans, may be used to detect abnormalities in a newborn's spine or vertebrae.

If hydrocephalus is suspected, doctors may perform a CT scan or ultrasound of the baby's brain.

Treatment

There is no cure for spina bifida, but we have a number of treatments for managing the disease and preventing complications.

In some cases, when spina bifida is diagnosed before birth, the fetus can undergo surgery in utero 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 surgery, medications, and physical and behavioral therapy. Elements of the treatment plan depend on the type and severity of the defect and 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. Untreated hydrocephalus may cause movement disorders or developmental delays. It is treated with a ventriculoperitoneal (VP) shunt, a thin tube implanted in the brain that drains the excess fluid into the abdomen, where it can be absorbed by the body.

Treatment for myelomeningocele, the most severe form of spina bifida, requires surgery:

• Postnatal treatment: Usually the baby undergoes surgery shortly after birth to close the normal tissues of the back. This is done to protect the spinal cord and prevent infection. Since most babies with myelomeningocele develop hydrocephalus, they also require placement of a VP shunt. In addition, these children may develop a progressive tethering of the spinal cord, in which the spinal cord and vertebrae don't stretch as the child grows. This may cause a 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 drain urine.
• Prenatal treatment: In some cases, we can surgically repair the defect before the baby is born. The neurosurgeon makes incisions in the mother's abdomen and uterus to reach the fetus and close the exposed spinal cord and layers of the back. Not all fetuses with myelomeningocele are candidates for this surgery, but research shows that it may reverse the development of myelomeningocele and reduce its complications. In the MOMS (Management of Myelomeningocele Study) trial, the surgery reduced the need to shunt fluid from the brain, improved motor function and increased the likelihood of being able to walk unassisted.

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.