Topic summary
Spina bifida
Spina bifida (SB; ; Latin for 'split spine') is a birth defect in which there is incomplete closing of the spine and the membranes around the spinal cord during early development in pregnancy. There are three main types: spina bifida occulta, meningocele and myelomeningocele. Meningocele and myelomeningocele may be collectively referred to as spina bifida cystica (also called spina bifida aperta) due to the protrusion of the spinal cord and/or meninges through defects in the vertebral arches, resulting in a meningeal cyst. The most common location is the lower back, but in rare cases it may be in the middle back or neck.
Occulta has no or only mild signs, which may include a hairy patch, dimple, dark spot or swelling on the back at the site of the gap in the spine, while cystica shows clear external meningeal cyst from the protrusion of the meninges and cerebrospinal fluid. Meningocele typically causes mild problems, with a sac of fluid present at the gap in the spine. Myeloschisis, also known as open spina bifida, is the most severe form. This occurs when the spinal cord in the affected area is exposed to the environment due to failure of neural folds and overlying skin to fuse. Problems associated with this form include poor ability to walk, impaired bladder or bowel control, accumulation of fluid in the brain, a tethered spinal cord and latex allergy, and usually results in permanent paralysis or weakness of the lower limbs. Some experts believe such an allergy can be caused by frequent exposure to latex, which is common for people with spina bifida who have shunts and have had many surgeries. Learning problems are relatively uncommon.
Spina bifida is believed to be due to a combination of genetic and environmental factors. After having one child with the condition, or if one of the parents has the condition, there is a 4% chance that the next child will also be affected. Not having enough folate (vitamin B9) in the diet before and during pregnancy also plays a significant role. Other risk factors include certain antiseizure medications, obesity and poorly controlled diabetes. Diagnosis may occur either before or after a child is born. Before birth, if a blood test or amniocentesis finds a high level of alpha-fetoprotein (AFP), there is a higher risk of spina bifida. Ultrasound examination may also detect the problem. Medical imaging can confirm the diagnosis after birth. Spina bifida is a type of neural tube defect related to but distinct from other types such as anencephaly and encephalocele.
Most cases of spina bifida can be prevented if the mother gets enough folate before and during pregnancy. Adding folic acid to flour has been found to be effective for most women. Open spina bifida can be surgically closed before or after birth. A shunt may be needed in those with hydrocephalus, and a tethered spinal cord may be surgically repaired. Devices to help with movement such as crutches or wheelchairs may be useful. Urinary catheterization may also be needed. In addition to the medical and surgical treatment options, physical therapy interventions may be implemented to treat complications of spina bifida, such as neurogenic bladder. Physical therapists may implement techniques such as electrical stimulation, which have been shown to improve bladder compliance and reduce detrusor muscle pressure in those with spina bifida. Additionally, pelvic floor physical therapy can facilitate neuromuscular re-education and improve bladder control by supporting continence and reducing urinary symptoms. Physical therapy offers a less invasive approach to improving overall bladder function.
Rates of other types of spina bifida vary significantly by country, from 0.1 to 5 per 1,000 births. On average, in developed countries, including the United States, it occurs in about 0.4 per 1,000 births. In India, it affects about 1.9 per 1,000 births. Europeans are at higher risk compared to Africans.