SPINA BIFIDA: SYMPTOMS, CAUSES, TYPES, TREATMENT - NEUROPSYCHOLOGY - 2025

The spina bifida (EB) is a type of malformation or congenital defect in which the structures associated with spinal cord and spine are not normally develop 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, the common denominator of which 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 gestation is transformed into the brain, spinal cord, and surrounding tissues (Mayo Clinic, 2014).

At a more clinical level, spina bifida is characterized by incomplete formation or development of defective disease at the level of the spinal cord and vertebral bones (National Institute of Neurological Disorders and Stroke, 2006).

In addition, associated with spina bifida, hydrocephalus is common, a condition that causes an abnormal accumulation of cerebrospinal fluid in different brain areas and that can cause significant neurological deficits.

There are different forms of spina bifida that vary in severity. When this pathology produces significant alterations, it will be necessary to use a surgical approach to treat the anatomical alterations (Mayo Clinic, 2014).

Spina bifida characteristics

Spina bifida is a type of congenital disorder characterized by an incomplete development or 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 common neural tube closure defects.

The neural tube is an embryonic structure whose fusion usually takes place around the 18th and 26th day 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 defects in the spinal cord and bones of the spine (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).

Statistics

In the United States, spina bifida is the most common 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 out of every 1,000 live births have some type of abnormality in the formation of the neural tube. Specifically, more than half of these are affected by spina bifida (Spina Bifida and Hidrocephaly Spanish Federation of Associations, 2015).

Despite this, in recent years there has been a decrease in the incidence of spina bifida thanks to the use of folic acid in the pregnancy planning phase and prevention campaigns aimed at health workers and users (Spina Bifida and Hidrocephaly Federation Española de Asociaciones, 2015).

Types of spina bifida

Most scientific reports distinguish three types of spina bifida: spina bifida occulta, meningocele and myelomeningocele:

Spina bifida occult

It is the most common and mildest form of spina bifida. In this type, structural abnormalities result in a slight gap or gap between one or more bones of the spine (Mayo Clinic, 2014).

Spina bifida occulta may cause a malformation of one or more vertebrae. In addition, the hidden attribute implies that the structural abnormality is covered by skin tissue (National Institute of Neurological Disorders and Stroke, 2006).

Generally, there is no involvement of the spinal nerves, so most of those affected with this type of pathology do not usually have obvious signs and symptoms, so they do not usually experience neurological problems (Mayo Clinic, 2014).

Despite this, in some cases visible indications of spina bifida can be seen on the skin of newborns (Mayo Clinic, 2014):

• Fat accumulation.
• Dimple or birthmark.
• Accumulation of hair

About 15% of healthy people have spina bifida occulta and do not know it. It is frequently discovered incidentally in x-ray studies (Spina Bifida Association, 2015).

Meningocele

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 may be hidden or exposed (National Institute of Neurological Disorders and Stroke, 2006).

When this occurs, the spinal cord can develop poorly, making it 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 appear (National Institute of Neurological Disorders and Stroke, 2006).

Myelomeningocele

Myelomenigocele, or open spina bifida, is the most serious type. In this alteration, the spinal canal remains open along various spinal segments, especially in the middle or lower back. As a consequence of this opening, the meninges and the spinal cord protrude forming a sac in the back (Mayo Clinic, 2014).

In some cases, the skin tissues line the sac, while in others the spinal tissues and nerves are directly exposed to the outside (Mayo Clinic, 2014).

This type of pathology seriously threatens the life of the patient and also has significant neurological involvement (Mayo Clinic, 2014):

• Muscle weakness or paralysis in the lower limbs.
• Bowel and bladder problems.
• Seizure episodes, especially if associated with the development of hydrocephalus.
• Orthopedic disorders (malformations in the feet, imbalance in the hip or scoliosis, among others).

Symptoms

The presence / absence of symptoms and the severity of their presentation will largely depend on the type of spina bifida that the person suffers.

In cases of occult spina bifida, this alteration may present 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).

Generally, it 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 cause (NHS, 2015):

• Total or partial paralysis of the legs.
• Inability to walk and adopt different postures.
• Loss of sensation.
• On the skin of the legs and in nearby regions.
• Bowel and urinary incontinence.
• Development of Hydrocephalus.
• Learning difficulties.

Do people with spina bifida have a "normal" intellectual level?

Most people with spina bifida have normal intelligence, consistent with expectations 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 them to widen and 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 the different brain structures will cause a series of neuropsychological alterations of special importance, especially when those affected are in childhood (Tirapu-Ustarroz et al. al., 2001).

Neuropsychological alterations may appear reflected in:

• Lowering of IQ scores.
• Motor and tactile skills deficits.
• Visual and spatial processing problems.
• Difficulties in the production of language.

Causes

The specific cause of spina bifida is not currently known exactly. Despite this, in the medical and scientific panorama there is an agreement about the parallel contribution of both genetic and environmental factors (Spina Bifida e Hidrocefalia Federación Española de Asociaciones, 2015).

A genetic predisposition has been identified, through which, if there is a family history of neural tube defects or alterations, there is a greater risk of giving birth to a drink with this type of pathology (Spina Bifida and Hidrocephaly Spanish Federation of Associations, 2015).

Risk factor's

Although we still do not know the exact causes of spina bifida, some factors that increase its probability have been identified (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 alterations or defects of the neural tube closure 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 gestation. The synthetic form found in food and dietary supplements is called folic acid. A deficit in folic acid levels increases the risk of neural tube defects.
• Medication: Some antiseizure drugs, such as valproic acid, can cause abnormalities in the closure of the neural tube during pregnancy.
• Diabetes: Uncontrolled high blood sugar levels can increase the risk of having a baby with spina bifida.
• Obesity: obesity before and during pregnancy is associated with a high risk of developing this type of pathology.

Diagnosis

In almost all cases, the presence of spina bifida is diagnosed prenatally. Some of the most commonly used methods are alpha fetoprotein analysis 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.

Treatment

The type of treatment used for spina bifida depends largely on the type and severity of the condition. Generally, spina bifida does not require any type of therapeutic intervention, however, other types do (Mayo Clinic, 2014).

Prenatal surgery

When the presence of an alteration related to abnormalities in the formation of the neural tube, especially spina bifida, is detected during the embryonic period, various surgical procedures can be used to try to repair these defects (Mayo Clinic, 2014).

Specifically, before the 26th week of gestation, it is possible to perform an intrauterine repair of the spinal cord of the embryo (Mayo Clinic, 2014).

Many specialists defend this procedure based on the neurological deterioration of babies after birth. So far, fetal surgery has reported enormous benefits, yet it poses some risks to both mother and baby (Mayo Clinic, 2014).

Postnatal surgery

In cases of myelomeningocele, in which there is a high risk of contracting infections, in addition to presenting severe paralysis and serious developmental problems, early surgery on the spinal cord can allow the recovery of functionality and the control of the progress of the deficits cognitive (National Institute of Neurological Disorders and Stroke, 2006).

References

1. EB. (2015). Spina bifida Obtained from Spina Bifida and Hydrocephalus Spanish Federation of Associations.
2. Mayo Clinic. (2014). Diseases and Conditions: Spina bifida. Obtained from Mayo Clinic.
3. NHS. (2015). Spina bifida. Obtained from NHS choices.
4. NIH. (2014). Spina Bifida. Retrieved from MedlinePlus.
5. NIH. (2015). Spina Bifida Fact Sheet. Obtained from National Institute of Neurological Disorders and Stroke.
6. WHO. (2012). Spina bifida and hydrocephalus. Obtained from World Health Organization.
7. SBA. (2015). What is SB? Obtained from the Spina Bifida Association.