Spina bifida: definition, causes, what life expectancy?

What is spina bifida?

Spina bifida comes from the Latin “bifid spine“. It’s a congenital malformation which occurs during 4th week of development embryonic and is characterized by a neural tube closure defect of the unborn child. This is a incomplete development of the spine : THE vertebrae do not close over the spinal cord. Most often this concerns the bottom of column vertebral. This malformation can affect one or more vertebrae. There are two families of malformations : spina bifida aperta or myelomeningoceleand spina bifida occulta.

What are the types of spina bifida?

There are two families of malformations : THE spina bifida aperta Or myelomeningoceleand spina bifida occulta.

• Spina bifida aperta or myelomeningocele

“Spina bifida aperta or myelomeningocele is a severe malformation of the lower region of the spinal cord which appears from embryonic stage. It consists of an absence of formation of the terminal part of the spinal cord, the vertebrae which cover it, the muscles and the skin, explains Professor Michel Zerah, pediatric neurosurgeon specialist in vertebral and spinal cord malformations at Necker Hospital. These are deformities frequent (1 per 1000 pregnancies) which cause dysfunction of the lower part of the spinal cord. In France, this malformation is diagnosed in more than 90% of cases before birth during the second trimester ultrasound. It most often leads to a medical termination of pregnancy (85%). In rare cases, antenatal surgery may be discussed. In other cases, the children will be born with a malformation which will be diagnosed by an opening in the skin through which the spinal cord will come out. This malformation will lead to a more or less significant paralysis but most often preventing these children from walking and causing sphincter disorders (urine and stool) still present. They can be accompanied in more than half of the cases by a brain pain (hydrocephalus).”

• Spina bifida occulta

This is another less common type of spina bifida. “Spina bifida occulta is a different malformation from myelomenigocele, much less serious. It is most often diagnosed after birth on skin abnormalities. This diagnosis is based on MRI. Some forms will never have any signs and will not require surgery. Others may manifest as motor and/or sphincter disorders will require intervention. says Professor Michel Zerah.

What does it look like ?

The risk is multiplied by 10 in the event of a history of pregnancy carrying this type of anomaly

What are the causes ?

The known risk factors are mainly in women the folate deficiency (vitamin B9)THE diabetes And obesity. The protective effect of a folic acid supplementation of women even before the start of pregnancy has been demonstrated even if prevention is not total because genetic and environmental factors are also involved in the occurrence of this type of malformation. “These abnormalities occur in the absence of a history in approximately 95% of pregnancies indicated the Ministry of Health in 2001. The risk is multiplied by 10 in the event of a history of pregnancy carrying this type of anomaly.

What are the symptoms ?

The symptoms caused by spina bifida aperta depend on the height of the attack. Typically, we observe:

• a malformation on the back, visible as a red mass not covered with skin, sometimes in the open air, from birth;
• a paralysis located more or less high:
• few motor disorders if the lesion is very low, at the level of the sacral vertebrae;
• relative motor disorders of the lower limbs if the damage is located on the lumbar vertebrae;
• major motor disorders of the lower limbs with impossibility of walking in the event of damage to the L3 vertebra.
• sensory disturbances in areas normally innervated by the nerves located below the injury;
• urinary and digestive disorders and faecal incontinence.
• genital damage with erectile and ejaculation disorders in men.

Spina bifida is often associated with other abnormalities, including hydrocephalus: excess cerebrospinal fluid in the brain, for lack of its normal flow. This hydrocephalus can be responsible for other symptoms and the evolution towards cognitive disorders.

“The diagnosis of spina bifida is made before birth. by ultrasound and after birth by MRI brain and spinal cord” says the pediatric neurosurgeon.

What are the consequences for life expectancy?

“If the patient is properly cared for, life expectancy is almost normal, but with more or less severe handicaps” answers François Haffner, president of the association Spina Bifida Associated Disabilities on France Assos Health. “THE prognosis postnatal and the extent of disability permanent depend on the location and extent of the anomaly, the existence of associated anomalies (extra-rachidian or in the case of a chromosomal syndrome, in particular the Trisomy 21)”, explain Public Health France. The disability also depends on the upstream consequences (ventricular dilation of the brain, Arnold Chiari syndrome) but also on the downstream consequences (immobility of the limbs, urinary incontinence, club feet, etc.).

“Prevention of spina bifida is possible by taking vitamin B9 before pregnancy.”

What are the treatments ?

“The treatment will be a closure at the lower back and possibly a hydrocephalus treatment when it exists. The aim of these treatments is to avoid overhandicap but does not improve the functional prognosis of this malformation. These malformations will require neurosurgical, orthopedic, rehabilitation and urological care in childhood, adolescence and during their adult life. continues the pediatric neurosurgeon.

“Prevention of spina bifida is possible. It is important to start it at least four weeks before the start of pregnancy. It is a treatment based on vitamin B9“, exposes the specialist. Taking this vitamin (0.4mg/d) has the effect of reducing the risk of certain malformations, including spina bifida. Folic acid must be taken in higher doses (5mg/d) for certain women: those who have already had a child with spina bifida, those with diabetes and those in need of treatment for epilepsy. Women can also increase their folate intake by focusing on foods that specifically contain it, such as leafy green vegetables, pulses, citrus fruits.

Thanks to Professor Michel Zerah, pediatric neurosurgeon specializing in spinal and spinal malformations at Necker Hospital.

Sources:

French Public Health. Neural tube defects.

National Spina Bifida & Associated Disabilities Association