Spina bifida is a birth defect of the spinal cord caused by the failure of the neural tube (the structure of the embryo from which the brain and spinal cord develop) to close during the first month of intrauterine life. In spina bifida, the bones of the canal in which the spinal cord is located do not close and therefore the underlying structures can cause a hernia through the bone canal. If the herniation affects only the meninges, it is referred to as spina bifida with meningocele; if it also involves the spine, it is referred to as myelomeningocele. Finally, if the spinal cord is also fissured, this is referred to as neuroschisis.
The damage that can derive from this is very variable. In severe cases, the spinal cord protrudes from the spine (cystic spina bifida). This leads to injury not only of the spinal cord, but also of the nerve endings that are connected to it.
Symptoms mainly depend on the severity of the condition and range from the so-called “clubfoot” to more or less serious difficulties in moving the lower limbs up to paralysis. Other issues include problems with the nerves of the bladder and the nerves of the sphincters, which cause incontinence problems. Many cases of spina bifida involve hydrocephalus, which is an increase in the volume of the cerebrospinal fluid (“liquor”). In other words, there is an abnormal accumulation of fluids within the brain itself.
The causes that determine the onset of spina bifida are still unknown, but the pathology certainly depends on numerous factors. It is known as a multifactorial disease, meaning it is caused by the interaction of genetic factors with environmental factors, such as geographical area, socio-economic conditions, drug intake and, above all, a maternal diet low in folate (vitamin B9), which is essential from conception for the development of the embryo and fetus since the requirement for it increases considerably during this time.
Spina bifida can be diagnosed even before birth via ultrasound, but the diagnostic possibilities depend on many factors, including the severity of the deformation.
There are also other tests that indicate a higher risk of the fetus having spina bifida, such as:
- The concentration of alpha fetoprotein in the mother’s blood at 15-17 weeks of pregnancy. This is a screening test that can be done without risk.
- The dosage of alpha fetoprotein in the amniotic fluid (liquid that envelops the fetus in the uterus), which is taken by amniocentesis via a puncture in the abdomen of the mother. Amniocentesis is an invasive examination that is carried out in particular cases when there is a specific indication for it.
Spina bifida still represents one of the major causes of childhood handicaps. Thanks to advances in medicine and the particular attention given in recent years to prevention and treatment, it is possible to guarantee the survival of almost all newborns with this disease. Furthermore, with proper follow-up at qualified centers, these children can reach adulthood in good physical and mental condition and have a satisfactory quality of life.
A decisive step in the field of prevention was taken with the demonstration that the daily intake of folic acid at a dosage of 400 micrograms (0.4 mg) at least one month before conception and during the first trimester of pregnancy significantly reduces the risk of having a child with neural tube defects. However, this type of prevention presents some practical problems. The data indicate that to be totally effective, the intake of folic acid must be implemented before pregnancy, which requires a high level of family planning that is not always implemented by couples.
Spina bifida therapy is mainly surgical. Generally, newborns with this pathology are operated on in the first days of life to limit both the possibility of infection and any spinal damage. However, the final result of the interventions depends above all on the initial damage suffered by the spinal cord.
Thanks to the development of treatments and advances in research, the life expectancy of children with spina bifida has now greatly increased. Furthermore, it is possible to make a diagnosis even before birth using ultrasound and biochemical analyses. This technique, which must be performed by an experienced operator, enables the identification of most defects of the open neural tube.
