Most spinal cord malformations are caused by the abnormal closure of neural envelopes at weeks 3 and 4 of pregnancy. The malformations that are produced, known as neural tube defects, can affect the meninges, teguments, vertebrae and muscles. The severe neural tube defects, which involve neural and non-neural structures, occur at around 1/1.000 births. However, the incidence may vary depending on the population studied and may reach up to 1/100 births in certain areas, such as the northern part of China.
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What Spina Bifida Means?
Spina bifida is a congenital malformation, which means that the spinal cord isn`t completely closed.
The name “spina bifida” comes from Latin, which literally means “broken” or “open” column. Babies that are born with spina bifida occulta often show external symptoms. The spinal cord doesn`t come out of the skin, although it may have a birthmark, a skin patch or a tufted hair over the bottom of the spinal cord.
Spina bifida occurs when a neural tube development of the fetus doesn`t take place. The 2 parts of the spinal cord don`t manage to unit and leave an open area, known as fistula. The spinal cord and nerves don`t form properly.
Although it isn`t the exact cause of this defect, it`s believed to be influenced by genetic and environmental factors. Statistically, it was determined that there`s an increased risk (around 3%) for this abnormality to occur in women who didn`t gave birth to babies with this defect. Also, this malformation is associated with a lack of folic acid even at the beginning of pregnancy (during embryonic development, when the women isn`t even aware that she`s pregnant). That`s why is recommended to take folic acid supplements when trying to conceive. Other factors that increase the risk of occurrence of this defect are: an increased body temperature due to a cold or hot bath, drugs for diabetes or obesity.
Spina Bifida Types
There are 2 types of spina bifida: spina bifida occulta si spina bifida manifesta.
Spina bifida occulta is the easiest form of spina bifida (occulta = hidden).
Most children who have this defect don`t ever have a healthy issue. The spinal cord is often unaffected.
Spina bifida manifesta includes 2 subtypes of spina bifida: meningocele and myelomeningocele.
Meningocele involves meninga, the membranes which cover and protect the brain and spinal cord. If the meninges go out through the space between the vertebrae (small bones in the shape of a ring that form the spinal cord), their sac is known as meningocele.
Myelomeningocele is the most severe type of spina bifida. They appear when the meninges go out through the space from the back, and the spinal cord goes out as well. Most children who were born with this type of spina bifida have hydrocephalus, a fluid build-up in the brain and around the brain.
Due to the abnormal marrow development and damage, a child who has the myelomeningocele types of spina bifida, usually has a form of paralysis. The degree of paralysis depends quite a lot from the position of the space from the spinal cord. The higher is the space, the most severe tends to be the paralysis.
Children who have spina bifida often have issues controlling sphincters, and some might experience (ADHD, which means attention deficit hyperactivity disorder) or other learning difficulties.
The signs of spina bifida are characteristic to each individual, depending on the type of spina bifida. Most often, the defect is located in the sacral and lumbar areas.
In the case of spina bifida occulta, the skin of the lesion area is normal or shows some kind of a dent, birthmark or hair.
Cystic spina bifida outlines the protrusion of a bag full of fluid on the back of the affected person. Meningocele shows this sac covered of a thin layer of skin, while the myelomeningocele exposes at the exterior a portion of tissue from the spinal cord.
The exact cause of spina bifida remains a mystery. Researchers support the idea that genetic, environmental or nutritional factors are involved. Research have identified a direct connection between the incomplete close of neural tube (the segment from which the fetal nervous system develops) and the insufficient folic acid intake of the mother. Researchers believe that lots of cases of spina bifida can be prevented if the women found at a fertile age consume 0.4 mg (400 mcg) of folic acid on a daily basis and continue consuming it during the first trimester of pregnancy. Among the good sources of folic acid are eggs, orange juice, cereals and vegetables with dark green leaves. Also, lots of the multivitamins from pharmacies contain the recommended dose of folic acid.
The prenatal diagnosis of cystic bifida is established using ultrasounds and by determining the alpha-fetoprotein level in the maternal blood and amniotic liquid. Vertebrae become visible in the week 12 of pregnancy, so that vertebral artery closure abnormalities can be detected. A new therapeutic technique for spina bifida consists of surgery inside the uterus performed around the week 28 of pregnancy, the fetus being exposed to C-section, the defect corrected and then the fetus being reintroduced back inside the uterus.
Preliminary results show the fact that this approach reduced the incidence of hydrocephalus, improves the control of urine and defecation, and leads to a better motor development of the inferior limbs.
Neural tube defects may be caused by hypervitaminosis A, hyperthermia, valproic acid as well as many teratogenic factors. The etiology of most neural tube defects is multifactorial, and the probability of having a child with this particular defect increases quite a lot when the respective couple already has an affected child. Recent studies have proven that the incidence of neural tube defects can be reduced with up to 70% by administrating folic acid of doses of 400µg/day. This treatment needs to be started 2 months in advance before conception and continued through the entire pregnancy.
The neurosurgeon treats most of the times by closing the open area on the back during surgery. The developed centers also use fetal surgery (mini-invasive or open). For hydrocephalus, it`s placed an artery (a thin tube which eliminates the liquid in excess) in the brain.
Lots of children need repeated surgeries for their hips, legs or spinal cord. Throughout their lives, patients are helped by prostheses or wheelchairs, and those with urinary issues need urethral catheterization (inserting a probe into the bladder). – More similar info!
There are a lot of cases of spina bifida that aren`t manifested, but the severity of the ones associating symptoms hampers the life of the patient and his family quite a lot. All that you can do to prevent the occurrence of this defect in your child is to consume folic acid before conceiving and throughout pregnancy.