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Spina bifida - a congenital neural tube malformation
Spina bifida (colloquially "open back" or "vertebral gap") is a common developmental disorder of the neural tube in early embryonic development. This malformation causes developmental damage to the spine and spinal cord. Depending on the extent and position of the neural tube defect, there are very different effects. Risk-minimizing measures, such as taking folic acid, early diagnosis in the womb and various treatment methods make it possible to prevent this malformation to a certain extent and to give surviving children a relatively high quality of life and life expectancy.
A brief overview
The following summarizes what exactly characterizes the neural tube defect of a spina bifida and how to reduce the risk of this malformation as best as possible. Every woman who wants to have children should be informed about this and be given medical advice. The detailed descriptions of the clinical picture and the corresponding therapeutic options are listed below.
What is an open back?
The term “open back” in German is used to summarize neural tube malformations in the development phases of the early embryonic period, which developmental disorders can be assigned to a so-called spina bifida. This defect manifests itself in the third to fourth week of pregnancy because the neural tube does not close completely. The resulting damage to the spine (vertebral gap), and possibly also to the spinal membranes and the spinal cord itself, lead to different forms and degrees of severity of the disease. In addition to an externally invisible and usually lighter form, the spina bifida occulta, open and visible malformations, the spina bifida aperta, occur far more frequently. While simpler forms can remain symptom-free or often have only mild symptoms, spina bifida aperta often results in severe symptoms and far-reaching consequences that severely affect the life of the newborn.
Most important prevention: folic acid
Every pregnant woman bears the risk of approximately 1: 1000 that a spina bifida develops in her unborn child. So far, the greatest risk factor for this type of malformation is the lack of folate in early embryonic development. Therefore, the most important preventive measure is that women of childbearing age, and especially women who want to and can get pregnant, increase the intake and availability of folate with appropriate folic acid supplements. The official recommendation for this target group is to start taking 400 micrograms of folate equivalents at least four weeks before pregnancy. The intake should continue until the end of the first trimester of pregnancy.
The term spina bifida comes from Latin and means "split spinous process", which refers to the backward process of the vertebral arch (Spinosus process). In German, the disease is also referred to as a "vertebral gap" or even more often as an "open back". Strictly speaking, the term "open back" describes only one of the existing forms of the disease, the so-called spina bifida aperta.
Spina bifida is the second most common congenital malformation, and about one in every 1,000 newborns in Central Europe. Girls have this disorder somewhat more often than boys.
Spina bifida aperta
With this open and visible form of the disease, in addition to the vertebral arches, spinal cord skins (Meninges spinales) and, if necessary, the spinal cord are also included in the malformation. These bulge visibly outwards. In the simplest variant of this form, the so-called meningocele, only the spinal cord skins come out through a gap in the vertebral arch. The position of the spinal cord itself has not changed. This type of malformation is visible through a skin-covered cyst.
In the severe and most common form, the meningomyelocele, the spine is split and, in addition to spinal membranes, parts of the spinal cord (myelon) also come out. The resulting protrusion is usually only covered by a thin skin. In rare cases, the spinal cord is even completely exposed (rickishisis).
Spina bifida occulta
The hidden or invisible clinical picture is called spina bifida occulta. There is a vertebral arch gap, but the spinal cord and spinal cord skins are not affected. This expression does not appear on the outside and is therefore often only discovered by accident when examining the back.
A dermal sine is the easiest form of cleft formation, which usually remains without symptoms. However, further consequential damage is not completely excluded. The small passage between the skin surface and the spinal canal usually shows up as a small pore on the back. Since this minimal opening is a possible source of infection, this is often closed surgically.
With the rather light and invisible form, it is possible that (initially) no symptoms appear and the disease may therefore go undetected.
If, on the other hand, it is the open form, the spina bifida aperta, and if the spinal cord skins and the spinal cord are affected, this can have mild to very strong effects for those affected. The complaints caused are of very different types and depend on the location of the gap formation (e.g. lumbar or thoracic vertebrae area) as well as the presence and extent of spinal cord damage.
In this context, mild complaints are understood to mean impairments of walking ability of different strengths. However, the symptoms can also be serious. They range from organ dysfunction to complete paraplegia.
If the internal organs are affected by damage to the spinal cord, the stomach, intestine and bladder usually malfunction. In the event of an impaired bladder function, emptying disorders of the bladder (incontinence, continuous bladder and overflow bladder) and urinary tract infections often occur in the course of the disease. In turn, this can impair kidney function in the long term. Sensory disorders, for example for pain, can also occur.
Consequences and complications
In connection with damage to the bony spine or as a result of muscle paralysis, skeletal deformities and joint misalignments occur. A well-known consequence is the so-called club foot.
In severe spina bifida aperta, circulatory and drainage disorders of the cerebral and spinal fluid (cerebrospinal fluid) often occur. The resulting CSF congestion causes the ventricles (brain chambers) to expand and a so-called water head (hydrocephalus) to form. This can already arise before birth. Depending on the severity, this can lead to epileptic seizures in the further course.
The term “Chiari malformation” (after the first descriptor Hans von Chiari) summarizes various changes in the cerebellum that are mainly associated with hydrocephalus. With a certain form, the so-called Chiari malformation type II, there is a displacement of the cerebellum and a malformation of the brain stem. This clinical picture almost always occurs with a spina bifida in the lumbar region and about 80 percent of those affected have hydrocephalus.
The exact causes of this defect in the spine are not yet known. However, it should be noted that genetic factors and external influences play a certain role in this prenatal malformation.
Risk factors also include illnesses and medication intake during pregnancy. If there is poorly controlled diabetes mellitus in early pregnancy or if a woman develops gestational diabetes at this time, this can promote the occurrence of spina bifida. Epilepsy, taking antiepileptics, fever and obesity in the first weeks of pregnancy are also associated with an increased risk of illness.
Folate deficiency poses a high risk
The most important and well-known risk factor, however, is a lack of folate, which belongs to the group of B vitamins and plays an important role in growth processes, cell division and blood formation. The likelihood of neural tube defects due to folate deficiency can be significantly reduced by taking so-called folic acid preparations. Folic acid is the synthetically produced form of the vitamin folate. It has been shown that the risk drops by 70 percent if there is sufficient folic acid substitution before pregnancy. According to the German Nutrition Society, every woman is recommended to take an additional 400 micrograms of folate equivalents, usually in tablet form, at least four weeks before and until the end of the first third of pregnancy. The increased folate requirement shortly before and during pregnancy can often not be met, even with a targeted diet.
Taking into account different statements and studies as to whether too much folic acid or too much folate could cause health damage, the European Food Safety Authority (EFSA) has defined safe daily maximum levels. This is 1000 micrograms per day for adults. However, this is not an upper limit to prevent possible risks of excessive folic acid intake. Rather, this restriction is intended to help ensure that neurological symptoms of a possible vitamin B12 deficiency are not masked.
Various examinations often allow signs of spina bifida to be recognized before birth. With prenatal ultrasound, a reduced skull size, enlarged brain chambers and signs on the head and brain (lemon sign, banana sign) indicate the malformation. The so-called triple test, a blood test between the 15th and 20th week of pregnancy, also provides information on the possible presence of an open back.
Furthermore, an additional amniotic fluid examination can help to confirm the first suspicion. If certain hormones and enzymes are detected, conclusions can be drawn about the likelihood of an existing neural tube defect. A reliable diagnosis cannot be made at this point with 100 percent certainty. It is not uncommon for a water head to be found at a later point in time during pregnancy and only then to a neural tube defect be recognized. However, the possible effects cannot yet be assessed. Only the location of the malformation of the spine allows one to speculate about possible future impairments.
After birth, the visible malformations on the back are easily recognizable. Skin changes (abnormal hair), dimples or appendages in the midline can also provide clues. Various examination methods are also available to determine the severity. The following processes are used, among others:
- general neurological, orthopedic and ophthalmic examinations,
- Computed tomography (CT),
- Magnetic resonance imaging (MRI).
It is different with the hidden form, the spina bifida occulta. This is usually only discovered accidentally during an X-ray examination of the spine or it often remains undetected.
The treatment of a spina bifida depends on the type and extent of the malformation present - insofar as this can be determined. In the case of mild malformations with little impact or a completely symptom-free course of the disease, treatment can be dispensed with entirely. In the more severe, open forms, the arched structures are usually closed by surgery to minimize the risk of infection and increase the chances of survival. However, this does not improve the clinical picture.
Surgery can also take place before birth. This fetal surgical procedure originates from the USA and has hardly been practiced in Europe. In 2016, doctors at Heidelberg University Hospital operated on a baby with an open back while still in the womb. The nerves and spinal cord structures are better protected in the womb. If these can be closed appropriately, it is possible that the changes will reverse and the effects and consequential damage will be prevented or minimized. The operation also harbors other risks for the unborn child and its further development.
During operations on the spine and spinal canal it is not uncommon for scars and adhesions to form, which are referred to as "tethered cord". As the length increases, tensile stress is exerted on the spinal cord and nerve fibers. This can cause other neurological disorders that may require follow-up surgery.
Treatment of a water head by a shunt
As a rule, operative interventions only take place after childbirth. It must be decided individually whether an operation is advisable in the first days or in the first week of life. If there is hydrocephalus in a newborn, a cerebral shunt or liquor shunt is usually used to regulate the increased intracranial pressure. In a shunt, the excess brain fluid is drained internally. A plastic tube with integrated valves is implanted in the brain chamber and laid under the skin, for example, into the abdominal cavity.
If the bladder is affected by the disease, surgery may also take place, but medication or a catheter are often considered. Above all, the aim is to prevent the kidneys from being affected by the existing bladder dysfunction.
Possible deformations on the skeleton and on the joints can be counteracted with physiotherapy and orthopedic aids (e.g. splints and corsets) in order to remedy certain functional disorders as far as possible. In the case of severe forms, corrective interventions can also be considered here. However, an open back is not completely curable. Individuals need lifelong medical care and some remain dependent on a wheelchair.
Naturopathic methods can be used to support some of the possible symptoms, such as treating urinary tract infections. However, the possibilities are limited. Due to the origin of the symptoms, an often complicated malformation with its consequences, spina bifida usually requires special and permanent medical treatment.
Current state of research
The causes of spina bifida are still largely unknown and are the subject of international research. New studies are also being carried out on the far-reaching consequences and symptoms. The findings should help to improve the quality of life and life expectancy of those affected. Experts in the USA are pioneers in the new treatment methods through prenatal surgery. A US study showed that the benefits of spina bifida surgery in the womb clearly outweigh post-operative surgery.
In Heidelberg, such an intervention with international expertise was carried out for the first time in 2016. Such prenatal procedures are also practiced at the German Center for Fetal Surgery and Minimally Invasive Therapy.
When discussing whether excessive obesity could be the cause of spina bifida, the focus is not on obesity itself, but on risk factors associated with obesity (e.g. diabetes mellitus).
There are currently still different opinions in Germany about the benefits and risks of a basic folic acid fortification in staple foods (such as bread). In other countries, such as the United States and Canada, flour has been fortified with folic acid for years. According to various studies, a decrease in neural tube defects and other diseases that manifest during pregnancy has been observed. A recently published statement by the Federal Institute for Risk Assessment nonetheless recommends that folic acid intake in Germany should not be increased across the board, but should be specifically increased in women of childbearing age and in early pregnancy. This not only adequately prevents spina bifida, but also takes into account the as yet unexplained possible health risks for other population groups with a high folic acid intake. (tf, cs; updated 08/17/2018)
For further reading:
Nationwide self-help group ASbH - Arbeitsgemeinschaft Spina Bifida und Hydrocephalus e. V.
Author and source information
This text corresponds to the requirements of the medical literature, medical guidelines and current studies and has been checked by medical doctors.
Dr. rer. nat. Corinna Schultheis
- Working group Spina Bifida and Hydrocephalus e. V. (ASBH): Spina bifida (access: 10.07.2019), asbh.de
- Merck & Co., Inc .: Spina bifida (accessed: July 10, 2019), msdmanuals.com
- Professional Association of Pediatricians e. V .: Open back (Spina bifida) (accessed: 10.07.2019), kinderaerzte-im-netz.de
- Stanford Children's Health: Spina Bifida (accessed: July 10, 2019), stanfordchildrens.org
- National Organization for Rare Disorders (NORD): Spina Bifida (accessed: 10.07.2019), rarediseases.org
- American Association of Neurological Surgeons: Spina Bifida (accessed: July 10, 2019), aans.org
ICD codes for this disease: Q05, Q76ICD codes are internationally valid encodings for medical diagnoses. You can find e.g. in doctor's letters or on disability certificates.