Spina bifida refers to a range of spine deformities in which the bones of the spine do not fuse as a fetus develops. It is the most common abnormality of the spine seen at birth. Spina bifida may also involve the brain, nerves and coverings of the nerves (meninges). The two types are:
- Occulta, in which abnormalities of the bones can be seen by X-ray. Skin changes or hairy patches can indicate that nerves may be involved.
- Open, which is usually seen at birth. It involves abnormalities of the bones, nerves, spinal fluid or meninges.
The spinal abnormalities are most commonly seen in the lower half of the spine. The baby may have an enlarged head from hydrocephalus, which sometimes develops as a consequence of spina bifida. When the spinal cord or the nerve roots in the lower back are involved, varying degrees of paralysis may be present below the involved level, usually affecting bladder and bowel functions. Since spina bifida occurs in the fetus, many problems can be seen at birth, such as a clubfoot or dislocated hip. There may be other birth defects as well.
Causes and Risk Factors
The cause of spina bifida is not well understood. Genetics may have a large role, but nutritional and environmental factors could play a part. Getting enough folic acid during pregnancy may prevent spina bifida.
The open form is usually discovered at birth or during prenatal ultrasound screening. A mass may be apparent outside the body at the base of the spine. (A mass that contains nerves is called myelomeningocele, and one that does not is called meningocele.) Usually the deformity is covered with a thin membrane (spina bifida cystica), but it can also be open to the environment (spina bifida aperta). Spinal fluid may be seen draining from it. Tests and procedures that may be used to diagnose spina bifida include:
- Blood tests
- Evaluation of the fluid that surrounds the brain and spinal cord
- Urinary tract evaluation, including a urinalysis of the spine, skull, hips and legs if they are badly formed
The infant's health, the presence of any other abnormalities and the type, level and extent of the deformity all need to be assessed before treatment begins. There is no specific treatment for occult spina bifida if it is limited to the bone. If there are deformities of the spine, intervention may be necessary to prevent degenerative changes later in life. If spinal fluid is leaking from the defect, antibiotics and surgery are urgently needed to prevent spinal and brain infections. A shunt may be needed if hydrocephalus is present.
Open spina bifida and the spinal abnormalities that come with occult spina bifida are treated by a neurosurgeon. The goal of surgery is to preserve the nerves, restore the normal anatomy and close the defect. This delicate surgery is carefully performed under magnification using special monitors to help identify the nerves. Surgery helps reduce the risk of infection (meningitis) and the development of long-term disability.
Kidney function must be followed closely. Obstructions or infections of the kidney or bladder must be treated aggressively. If a clubfoot is present, it should be put in a cast to correct the deformity. Hip joints should be checked carefully. The infant should be monitored for the development of scoliosis, abnormal fractures, muscle weakness or spasm or pressure sores as he or she grows up to prevent further deformities.