Spina Bifida: Types, Causes, Symptoms, and Treatment
Explore spina bifida, from its origin as a neural tube defect to the comprehensive medical and therapeutic approaches that support individuals throughout life.
Spina bifida is a birth defect that occurs when the spine and spinal cord do not form properly. It is a type of neural tube defect, resulting from the failure of the embryonic structure that forms the brain and spinal cord to close completely during the first few weeks of pregnancy. This incomplete closure leaves an opening in the spine.
What is Spina Bifida and Its Different Types?
Spina bifida originates early in pregnancy, as the neural tube forms and closes by the 28th day after conception. An interruption in this process creates a gap in the vertebrae. The condition’s severity depends on the opening’s size and location, and whether the spinal cord and its protective membranes are involved.
Myelomeningocele is the most severe and common form. The spinal canal remains open along several vertebrae, allowing the spinal cord and its protective membranes (meninges) to push through and form a sac on the baby’s back. This exposure results in damage to the spinal cord and nerves.
Another type, meningocele, involves a sac of spinal fluid pushing through an opening in the back, but the spinal cord itself is not in the sac. Because the spinal cord is not displaced, nerve damage is less likely, and this form generally causes minor disabilities. The mildest and most common form is spina bifida occulta.
This type involves a small gap in the spine but no opening or sac on the back, and the spinal cord and nerves are usually unaffected.
Symptoms, Associated Conditions, and Diagnosis
The symptoms of spina bifida vary by type and location. With myelomeningocele, damage to the spinal cord and nerves leads to weakness or paralysis in the legs, loss of sensation in the lower body, and a lack of bowel and bladder control. Orthopedic issues like clubfoot or hip problems are also common.
Many babies with myelomeningocele also develop hydrocephalus, a buildup of excess fluid that increases pressure in the brain and can cause injury. Other associated conditions include Chiari II malformation, where brain tissue extends into the spinal canal. A tethered spinal cord, where the cord attaches to surrounding tissues, can cause further nerve damage as a child grows.
Diagnosis of spina bifida often occurs during pregnancy. A maternal blood test can check for high levels of alpha-fetoprotein (AFP), which can indicate an open neural tube defect. An ultrasound is the most accurate method for detecting the condition prenatally. If initial tests suggest spina bifida, a doctor may recommend amniocentesis, a procedure where a small amount of amniotic fluid is tested.
If not found before birth, the condition may be identified by a sac on the baby’s back. In spina bifida occulta, a dimple or tuft of hair on the spine may be the only external sign.
Identified Causes, Risk Factors, and Prevention
The exact cause of spina bifida is unknown, but it involves a combination of genetic and environmental factors. Having one child with a neural tube defect increases the risk for subsequent pregnancies, suggesting a genetic predisposition.
Folate (vitamin B-9) deficiency is a primary risk factor. For this reason, the most effective prevention is consuming adequate folic acid, the synthetic form of folate, before and during early pregnancy. Health organizations recommend daily folic acid for all women of childbearing age, as this has been shown to reduce the incidence of neural tube defects.
Other risk factors are linked to maternal health. These include poorly controlled diabetes, obesity, and the use of certain anti-seizure medications during pregnancy. An elevated body temperature in early pregnancy, from a fever or hot tub use, may also increase the risk.
Treatment Pathways and Living with Spina Bifida
Treatment is tailored to the condition’s severity and begins shortly after birth. For myelomeningocele, surgery to close the opening in the baby’s back is performed within the first few days of life to protect the spinal cord. In some cases, fetal surgery can be performed before the 26th week of pregnancy to close the opening while the baby is in the womb.
Ongoing medical care from a multidisciplinary team is required. If hydrocephalus is present, a surgeon will implant a shunt, a thin tube that drains excess fluid from the brain to the abdomen. Management includes support from physical and occupational therapists to improve mobility and help with daily living activities.
Assistive devices like braces, crutches, or wheelchairs are often used to aid mobility. Urological and bowel management programs are necessary to address control issues and prevent kidney damage. Regular medical check-ups help monitor complications. With comprehensive support, including educational and community resources, many people with spina bifida achieve independence and lead full lives.