Spina bifida is an atypical development of the spinal cord and spine where a gap is left in a spine. The spinal cord is responsible for sending messages between the brain and the rest of the body. When a baby is born with a gap in the spine where the spinal cord can grow out of the body, this is called spina bifida which literally means ‘split spine’.
Spina bifida is a serious birth defect affecting 1 in 1000 babies born each year and is caused by an abnormal development of the spine and spinal cord. Routine ultrasound scans are used to diagnose spina bifida. The abnormality leaves a gap in the spine which is typically repaired with surgery. Resulting complications vary from case to case, ranging in scope from slight learning disabilities and issues with limbs to severe physical disability including paralysis. Treatment may include surgery, physiotherapy and proscription of mobility aids.
What May Cause Spina Bifida?
At the beginning of pregnancy, a foetus forms tissue named the neural plate. The sides of the neural plate curl in towards one another during the early stages of development. This curl forms the neural a tube, the neural tube encloses to become the babies brain and spinal cord. In some cases, the bone that protects the nerves inside of it, called the spinal column, does not close completely, causing spina bifida. The exact reason for this defect is unknown.
Types Of Spina Bifida
Occulta – The least serious of the cases; the gap in the spine is small and covered by a layer of skin so will usually go unnoticed. Most people with this type are unaware they even have it, as very few if any symptoms are evident. The most common complication from occulta is scoliosis, a curvature of the spine; or bladder as well as bowel problems.
Cystica – This occurs when the lining, or membranes, of the spinal cord or the spinal cord itself push their way through the gap in the spine. Spina bifida cystica is split into two categories, meningocele and myelomeningocele.
- Meningocele – A more rare type of spina bifida where the protective membranes, or meninges, that surround the spinal cord are pushed out through the opening of the gap in the spine, just between the vertebrae. There are no nerves in the protruding sac. Sometimes a layer of skin covers the meningocele and can typically be treated with surgery. Symptoms can vary in severity: sometimes there are no problems; in other cases people may suffer with severe weakness in the legs, bladder in addition to bowel problems as well.
- Myelomeningocele – This is the most serious of the spina bifida types. Along the bones of the spine the spinal column remains open, which can leave the nervous system open to risk of infection, as the membranes and spinal cord are pushed out into the sac on the baby’s back. Surgery is typically an option; however damage to the nervous system will already have taken effect. Nerve damage can cause a range of complications including weakness or paralysis of the legs; also a loss of feeling to the skin of the legs. There may also be difficulties with bowel and bladder function.
Who Is At Increased Risk Of Having A Baby With Spina Bifida?
A lack of folic acid before and during pregnancy is the greatest known risk for having a baby born with spina bifida. Folic acid, a vitamin that occurs naturally in some foods like broccoli, peas and brown rice can also be added to foods such as breakfast cereals. 70% of cases of spina bifida can be prevented by taking a folic acid supplement before and during the first stage of pregnancy.
A family history of the defect can also be cause for concern; only a small percentage of cases run in families, however, siblings and children of people with spina bifida have a higher risk of the defect. Certain medications may also be factors; these include sodium valproate, carbamazapine and lamotrigine, which are used to treat epilepsy and bipolar disorder. Consult your GP if you are taking any medications and are planning to have a baby. Never stop taking prescription medicine without speaking to your doctor first.
Women who are overweight have an increased risk of having a baby born with spina bifida over women who are in a healthy weight range. Also women with diabetes have a higher chance of the defect affecting their child.
What Are The Signs Of Spina Bifida?
Some cases of spina bifida can go unnoticed, especially in cases of spina bifida occulta, where no skin defects over the spine are noticeable. Spina bifida cystica produces a swelling around the defect, and this may contain nerve, or spinal cord, tissue. Meningocele and myelomeningocele tend to display a fluid filled sac on the baby’s back, at the base of the spine. The sac may be covered by a layer of skin but in most cases of myelomeningocele, spinal cord tissue can be seen as there is typically no layer of skin protecting the defect.
How To Diagnose Spina Bifida?
Spina bifida can be detected in the second trimester of pregnancy through scans and ultrasounds. Blood can be taken from the mother where it is screened for a protein called alpha fetoprotein (AFP) in a maternal serum alpha fetoprotein (MSAFP) test. If high levels of this protein are detected in the mother’s blood it can indicate that the foetus has an open neural tube defect. This test however, is not specifically designed to detect spina bifida and cannot exclusively determine whether or not there are any developmental issues with the foetus.
In rare events, mild case of spina bifida is detected after birth using plain film x-ray examinations. At this stage in the most severe of these cases the child will have developed muscle weakness in the hips, legs or feet. Should spina bifida be a concern doctors may order further tests: a MRI or a computed tomography (CT) scan will give a clearer view of your baby’s head, and which looks for signs of extra fluid in the brain.
What Are The Effects Of Spina Bifida?
Complications brought on by the presence of spina bifida may vary from case to case. The size and position of the defect on the spine, whether it is open or closed and which nerves have been affected will determine the severity of each prognosis. There are however some physical and neurological complications that can be typically tied to spina bifida. Complications include:
- Leg weakness and in some cases paralysis
- Orthopaedic abnormalities which include scoliosis, club foot or hip dislocation
- Bladder and bowel control problems
- Skin irritation and abnormal eye movement
- Meningitis, an infection of the lining of the brain which can cause brain injury and be life threatening
- Hydrocephalus – An increased pressure in the brain caused by an excess of fluid surrounding the brain called cerebrospinal fluid (CSF), which develops in children with myelomeningocele. Hydrocephalus must be treated urgently as brain damage can occur due to the pressure on the brain. Treatment typically involves a shunt insert that drains the excess fluid from the brain into the abdomen
- Chiari II malformation – A serious condition associated with myelomeningocele that involves portion of the brain being pushed out of a skull and into a spinal canal in the neck. This can lead to squashing, or compressing, of the spinal cord, which can cause a variety of complications such as difficulties with eating, swallowing, breathing and limb weakness. A Chiari malformation can also cause blockage of CSF (hydrocephalus)
- Tethering – Progressive tethering can develop in cases of myelomeningocele where the spinal cord gets stuck to overlying membranes and vertebrae. This causes spinal cord to get stretched as the child grows which may cause loss of muscle strength in the legs. Early surgery to correct tethered spinal cord could prevent more damage to the spinal cord
- Learning difficulties which include struggles with paying attention, mathematical accuracy, speed and problem solving. Fine motor control deficits can cause issues with writing, however most people with spina bifida have a normal range of intelligence.
How Can Spina Bifida Be Treated?
There is no cure available for spina bifida. However, there are many treatment options available to help manage symptoms and conditions caused by the defect. Some of these options include:
- Surgery – Closing the gap in the spine reduces the risk of infection; many children suffering from spina bifida undergo corrective Orthopaedic surgery to help improve mobility with their legs or feet; surgery to improve bladder size and function is also an option
- Shunt insertion – A shunt inserted into the brain ventricles helps to drain the excess cerebral fluid and reduces pressure in the brain (hydrocephalus)
- Therapy – Physiotherapy, speech therapy and occupational therapy are all avenues that can be explored as your child grows
- Other assistance – Computer software has been developed to assist your child’s educational needs and equipment that includes wheelchairs and walking aids are also beneficial.
What Is The Outcome?
Prognosis varies from case to case and depends on the type of spina bifida and how much permanent damage has been sustained to the spinal cord and brain. A number of people with spina bifida will suffer from severe physical disabilities or learning disabilities.
Many children who have spina bifida may lead active lives and survive into adulthood. Many adults who have spina bifida are able to live a fulfilling and independent life.
Is Spina Bifida Preventable?
There are no definitive preventative measures to prevent spina bifida however there are supplements women who are planning a child can take before conception, especially if the family has a history of the defect. A folic acid supplement is highly recommended before conception and during the first twelve weeks of pregnancy especially, as this is the time the baby’s spine is developing.
Women who take a daily dose of folic acid either naturally in their food or as a supplement prior to conception can decrease the risk of spina bifida developing by almost 70%. A healthy diet will aid in keeping the baby healthy: fruits, whole grains, dried beans and leaf vegetables are all sources of folic acid.