The spina bifida ( EB ) is a type of malformation or birth defect in which the structures associated with spinal cord and spine does not develop normally in the early stages of pregnancy (World Health Organization, 2012)
These alterations will cause permanent damage to the spinal cord and nervous system that can cause paralysis in the lower extremities or different alterations at the functional level (World Health Organization, 2012).
The term spina bifida is used to define a wide variety of developmental disorders, whose common denominator is an incomplete fusion of the vertebral arches. This malformation can be related both to deficits in the superficial soft tissues and in the structures that are located within the spinal canal (Tirapu-Ustarroz et al., 2001).
This pathology is part of the congenital alterations of the neuronal tube . Specifically, the neuronal tube is an embryonic structure that during pregnancy is transformed into the brain, the spinal cord and the tissues that surround it (Mayo Clinic, 2014).
At a more clinical level, spina bifida is characterized by incomplete formation or development of defective spinal cord and vertebral bones (National Institute of Neurological Disorders and Stroke, 2006).
In addition, in association with spina bifida, hydrocephalus is frequently present , an alteration that causes an abnormal accumulation of cerebrospinal fluid in different brain areas and that can cause important neurological deficits.
There are different forms of spina bifida that vary its range of severity. When this pathology produces significant alterations, it will be necessary to use a surgical approach to treat anatomical alterations (Mayo Clinic, 2014).
What is spina bifida?
Spina bifida is a type of congenital disorder that is characterized by the development or incomplete formation of different structures related to the brain, spinal cord or meninges (National Institute of Neurological Disorders and Stroke, 2006).
Specifically, spina bifida is one of the most frequent neural tube closure defects .
The neural tube is an embryonic structure whose fusion usually takes place around days 18 and 26 of gestation. The caudal area of the neural tube will give rise to the spine; the rostral part will form the brain and the cavity will constitute the ventricular system. (Jiménez-León et al., 2013).
In babies with spina bifida, a portion of the neural tube fails to fuse or close properly, causing spinal cord and spinal cord defects (Mayo Clinic, 2014).
Depending on the affected areas, we can distinguish four types of spina bifida: occult, closed neural tube defects, meningocele and myelomeningocele (National Institute of Neurological Disorders and Stroke, 2006).
In the case of the United States, spina bifida is the most frequent neural tube defect; it has been estimated that it affects approximately 1,500-2,000 children of the more than 4,000 live births each year (National Institute of Neurological Disorders and Stroke, 2006).
On the other hand, in Spain, between 8 and 10 children of every 1,000 live births present some type of anomaly in the formation of the neural tube. Specifically, more than half of these are affected by spina bifida (Spina Bifida and Hydrocephalus Spanish Federation of Associations, 2015).
Despite this, in recent years there has been a decline in the incidence of spina bifida due to the use of folic acid in the planning phase of pregnancy and prevention campaigns aimed at health and users (Spina Bifida and Hydrocephalus Federation). Spanish Association, 2015).
Types of spina bifida
Most scientific reports distinguish three types of spina bifida: spina bifida occulta , meningocele and myelomeningocele :
Hidden bifid spina
It is the most common and mildest form of spina bifida. In this type, structural abnormalities result in a slight separation or gap between one or more bones of the spine (Mayo Clinic, 2014).
It is possible for hidden spina bifida to produce a malformation of one or several vertebrae. In addition, the hidden attribute implies that the structural abnormality is covered by the cutaneous tissue (National Institute of Neurological Disorders and Stroke, 2006).
Generally, there is no involvement of the spinal nerves, so that most affected with this type of pathology usually have no obvious signs and symptoms, so they usually do not experience neurological problems (Mayo Clinic, 2014).
Despite this, in some cases visible indications of spina bifida on the skin of newborns can be observed (Mayo Clinic, 2014):
- Accumulation of fat.
- Dimple or birthmark.
- Accumulation of hair.
Approximately 15% of healthy people suffer from hidden spina bifida and do not know it. It is often discovered incidentally in x-ray studies (Spina Bifida Association, 2015).
It is a rare type of spina bifida, in which the meninges (protective membranes that are located, in this case, around the spinal cord, protrude through the vertebral spaces (Mayo Clinic, 2014).
In this case, therefore, the meninges tend to protrude from the spinal opening and this malformation can be hidden or exposed (National Institute of Neurological Disorders and Stroke, 2006).
When this happens, the spinal cord can develop defectively, so it is necessary to remove the membranes through surgical procedures (Mayo Clinic, 2014).
In some cases of meningocele, symptoms may be absent or very mild, while in others, paralysis of the limbs, urinary and / or intestinal dysfunction may occur (National Institute of Neurological Disorders and Stroke, 2006).
The myelomeningocele or spina bifida open, is the most serious type. In this alteration, the spinal canal remains open along several spinal segments , especially in the lower or lower back. As a consequence of this opening, the meninges and the spinal cord protrude, forming a sac on the back (Mayo Clinic, 2014).
In some cases, the cutaneous tissues coat the sac, while in others the spinal tissues and nerves are exposed to the outside directly (Mayo Clinic, 2014).
This type of pathology seriously threatens the patient’s life and also presents a significant neurological involvement (Mayo Clinic, 2014):
- Muscle weakness or paralysis in the lower limbs.
- Bowel and bladder problems.
- Convulsive episodes, especially if associated with the development of hydrocephalus.
- Orthopedic alterations (malformations in the feet, imbalance in the hip or scoliosis, among others).
The presence / absence of the symptoms and the seriousness of their presentation, will depend to a great extent on the type of spina bifida that the person suffers.
In cases of occult spina bifida, it is possible that this alteration occurs asymptomatically, without showing external signs. However, in the case of meningocele, marks or physical signs may appear on the skin at the site of the spinal malformation (National Institute of Neurological Disorders and Stroke, 2006).
Generalemnte, is the Myelomeningocele, the alteration that will cause more signs and symptoms both physically and neurologically. Due to direct exposure , damage to the spinal cord can result (NHS, 2015):
- Total or partial paralysis of the legs.
- Inability to walk and adopt different postures.
- Loss of sensitivity
- On the skin of the legs and in nearby regions.
- Intestinal and urinary incontinence.
- Hydrocephalus development.
- Learning difficulties.
Do people with spina bifida present a “normal” intelectual level?
Most people suffering from spina bifida present a normal intelligence, in line with what is expected for their age and level of development.
However, the development of secondary pathologies such as hydrocephalus can cause damage to the nervous system that results in different neuropsychological deficits and learning difficulties.
Hydrocephalus develops when there is an abnormal accumulation of cerebrospinal fluid (CSF) that begins to be stored in the cerebral ventricles , causing a widening of the same and that, therefore, the different brain tissues are compressed (Tirapu-Ustarroz et al., 2001).
The increase in cerebrospinal fluid levels, the increase in intracranial pressure and the compression of different brain structures, will cause a series of neuropsychological alterations of special importance, especially when those affected are children (Tirapu-Ustarroz et al. al., 2001).
The neuropsychological alterations may appear reflected in:
- Reduction of the scores in the intellectual coefficient.
- Deficits in motor and tactile abilities.
- Problems of visual and spatial processing.
- Difficulties in the production of language.
Currently, the specific cause of spina bifida is not known. Despite this, in the medical and scientific scene there is an agreement about the parallel contribution of both genetic and environmental factors (Spina Bifida and Hydrocephalus Spanish Federation of Associations, 2015).
A genetic predisposition has been identified, through which, if there are family history of defects or alterations of the neural tube, there is a greater risk of giving birth to a drink with this type of pathology (Spina Bifida and Hydrocephalus Spanish Federation of Associations , 2015).
Although we still do not know exactly the causes of spina bifida, some factors have been identified that increase its probability (Mayo Clinic, 2014):
- Sex : a higher prevalence of spina bifida has been identified in females.
- Family history : Parents who have a family history with a history of neural tube closure abnormalities or defects will have a higher probability of having a child with a similar pathology.
- Folate deficiency : Folate is an important substance for the optimal and healthy development of babies during pregnancy. The synthetic form found in food and food supplements, is called folic acid. A deficit in folic acid levels increases the risk of neural tube defects.
- Medication : Some anticonvulsant drugs, such as valproic acid, can cause abnormalities in neural tube closure during pregnancy.
- Diabetes : High blood sugar levels that occur without medical supervision can increase the risk of having a baby with spina bifida.
- Obesity : the condition of obesity before and during pregnancy is associated with a high risk of developing this type of pathology.
In almost all cases, the presence of spina bifida is diagnosed prenatally. Some of the most commonly used methods are alpha fetoprotein and fetal ultrasound (National Institute of Neurological Disorders and Stroke, 2006).
However, there are some mild cases that are not detected until the postnatal phase. At this stage, x-ray or neuroimaging techniques can be used.
The type of treatment used in spina bifida depends to a large extent on the type and severity of the pathology. Generally, spina bifida does not require any type of therapeutic intervention, however, other types do (Mayo Clinic, 2014).
When the presence of an abnormality related to neural tube formation abnormalities is detected during the embryonic period, especially spina bifida, various surgical procedures can be used to try to repair these defects (Mayo Clinic, 2014).
Specifically, before week 26 of gestation, it is possible to perform an intrauterine repair of the spinal cord of the embryo (Mayo Clinic, 2014).
Also Read: What are Apraxias? (Motor Disorders)
Many specialists defend this procedure based on the neurological worsening of babies after birth. So far, fetal surgery has reported enormous benefits, however, it poses some risks for both the mother and the baby (Mayo Clinic, 2014).
In cases of myelomeningocele, in which there is a high risk of infection, in addition to severe paralysis and serious developmental problems , early surgery in the spinal cord can allow the recovery of functionality and control the progress of deficits cognitive diseases (National Institute of Neurological Disorders and Stroke, 2006).