Myelomeningocele

What is Myelomeningocele?

Neural tube defects refer to a range of birth defects that involve the brain, skull, spine, or spinal cord. These defects can either be visible, known as open spinal dysraphisms or ‘spina bifida aperta’, or hidden, referred to as closed spinal dysraphisms or ‘spina bifida occulta’.

Visible defects often include abnormalities such as myelomeningocele, which can be identified during physical check-ups. Hidden defects are typically not visible to the eye and show no obvious signs during physical examinations. As a result, patients with these defects often do not have any symptoms or future health issues, and usually require no treatment.

Myelomeningocele occurs when the spinal neural tube, which should close during the first month of pregnancy, does not close properly. This defect leads to the exposure of neural tissue or protective layers around the brain and spinal cord (meninges), along with a sac filled with fluid, sticking out at the affected spine level.

Myelomeningocele can result in numerous neurological issues and complications, depending on the part of the spine involved. These complications can lead to severe health problems and multiple disabilities. Therefore, the outcome is often worse if the condition is diagnosed late or not treated at all.

What Causes Myelomeningocele?

Myelomeningocele, a type of spina bifida, is caused by a combination of many factors that include the environment, a mother’s health, and genetics. Certain environmental factors like exposure to radiation, pollution, pesticides, harmful chemicals, and substances known to cause birth defects may contribute to its occurrence.

Some factors related to the mother’s health can also play a role. These include poor nutrition, low intake of folic acid (a type of vitamin), drinking caffeine or alcohol, smoking, using seizure medications, along with having certain health conditions such as diabetes, obesity, overheating, and anxiety.

However, most of the time, myelomeningocele occurs by chance and isn’t due to inherited genetic factors. That being said, some genetic factors may increase the risk, like having a specific chromosomal abnormality (extra copies of chromosome 18 or 13), or when a twin or close relative has the condition. In experiments with mice, there’s been over 40 different genetic strains found that are linked with a type of spina bifida known as spina bifida aperta.

As for humans, research has shown that some people with spina bifida have certain genetic mutations involving changes to the structure of amino acids in the sequences of specific genes related to cell orientation and enzymes involved in processing folic acid, an essential nutrient.

Risk Factors and Frequency for Myelomeningocele

Each year, there are nearly 140,000 cases of neural tube defects reported worldwide. Specifically, the rate of spina bifida is around 0.5 per 1,000 births globally, but in the United States, it increases to over 3 per 10,000 births. Myelomeningocele is another condition which occurs in about 0.8 to 1 per 1,000 live births worldwide, whereas in the United States, the rate is significantly lower, around 0.2 to 0.4 per 1,000 live births.

A study done in northern China showed that the risk of having another child with neural tube defects in a subsequent pregnancy was 1.7% — a higher rate than in the United States. In the case of myelomeningocele specifically, the risk of having a child with the condition in a subsequent pregnancy was reported to be between 2 to 5% in the United States.

Interestingly, another study showed that the likelihood of myelomeningocele occurring again in future pregnancies was around 2% to 3%. The study also found that the occurrence of neural tube defects was higher in females, older mothers, and those from lower socioeconomic backgrounds. Out of all the ethnicities in the United States, Latin Americans were found to be the most affected.

Signs and Symptoms of Myelomeningocele

Spina bifida, a condition present at birth, often shows as a sac extending from the spine, filled with fluid and neural tissue. The severity of the condition and prognosis depends on how high up on the spine the issue lies. The higher the lesion, the worse the symptoms and outlook for the patient.

This is one of the common causes of neurogenic bladder in children, a condition where the child can’t control their bladder due to a brain-spinal cord-nerve issue. Patients may also experience other issues, like paralysis of the lower limbs, loss of control over bowel movements, and motor and sensory impairments. These issues can get worse with age. Some may also develop sexual development issues when they grow up.

People with this condition often have concorrent medical issues, such as the Arnold-Chiari II malformation. This is when brain tissue extends into the spinal canal. It is typified by the downward displacement of the brainstem and the fourth ventricle more than 5 mm below the foramen magnum as well as having the spina bifida, excess fluid in the brain, with or without a fluid-filled cyst in the spinal cord. Other issues one might experience include pain, increased muscle tone, spinal abnormalities, a tethered spinal cord, and mental health and cognitive difficulties.

Children with spina bifida often struggle with delays in developmental milestones, particularly in motor functions. Lack of leg movement is an example of lower motor neuron dysfunction caused by the lesion. However, some children may exhibit spontaneous leg movements due to functional neuronal conduction, which can be improved with therapy and exercises. Sensory impairment generally relies on the level of the spinal lesion affecting nerves that carry signals from the sensory organs to the brain. Examination should focus on light touch and two-point discrimination to identify problems in pathways that sense pain and temperature as well as pathways that help with coordination of movement and sensing vibrations.

Testing for Myelomeningocele

Myelomeningocele, a type of spina bifida, can be diagnosed in the first few months of pregnancy. A procedure called amniocentesis, where a small amount of fluid is taken from around the baby in the womb, can help with this diagnosis. This procedure is usually carried out in situations where there is a high risk, such as a family history of the condition. It’s been observed that the fluid in such cases often contains high levels of a protein known as alpha-fetoprotein.

However, ultrasound scans, which use sound waves to create an image of the baby in the womb, are a safe and effective way to detect myelomeningocele without the need for invasive procedures. During this scan, the technician will examine the baby’s spine very carefully to look for any abnormal shapes, like sacs or cysts, or any signs of damage to the spine. Sometimes, babies with spina bifida have a head size that is smaller than usual, which may be an additional indicator of the condition.

There are also some specific features that can be seen on an ultrasound scan indicating spina bifida. For example, there are two signs called the “banana sign” and the “lemon sign”. The banana sign can be seen when the two sides of the baby’s cerebellum, which is a part of the brain, appear stretched out, compressed and displaced downwards, giving them an appearance similar to a banana. The lemon sign, on the other hand, describes an unusual curve and indentation of the skull bones.

Other signs of spina bifida that may be apparent on an ultrasound include an excessive build-up of fluid in the spaces in the brain (hydrocephalus), a smaller than usual size of the brain, and abnormal skull bones. In some cases, other problems associated with spina bifida, like chromosomal abnormalities, an unusually dilated renal tract or a deformity of the foot known as talipes, can also be picked up on an ultrasound.

If the ultrasound results aren’t conclusive, then doctors might order more detailed scanning methods such as fetal karyotyping (a test to study the baby’s chromosomes) or magnetic resonance imaging (MRI). An MRI scan provides a more detailed picture of the baby’s spine and other organ systems, and can help the doctor plan delivery and prepare for any necessary surgery after birth. It can also identify other conditions associated with spina bifida, such as issues with spinal alignment and abnormalities within the spinal cord.

Treatment Options for Myelomeningocele

Once doctors diagnose a spinal issue, it’s very important to do surgery as soon as possible. This can stop more serious nerve damage from happening. Some studies have shown that doing surgery before the baby is born can lead to fewer future problems than doing surgery after the baby is born.

A trial study was done in the United States with 60 pregnant women whose unborn babies needed spinal surgery. This study took place from 2011 to 2017. The research showed that doing the spinal surgery while the baby is still in the womb can help preserve the baby’s nerve function and reduce the need for additional procedures that might be needed later.

It’s important to note that there have been cases of serious pregnancy complications, such as rupture of the uterus during delivery, associated with this type of fetal surgery. So, doctors usually recommend that the baby is delivered through cesarean section at either early term or late preterm. Also, the delivery should be at full term to avoid additional risks related to prematurity. It’s crucial to do a detailed exam of the baby right after delivery, making sure to avoid using latex gloves because many children with spina bifida, a type of birth defect that affects the spine, are allergic to latex.

If the surgery happens after birth, it is typically done within 24 to 48 hours to avoid infections. The procedure involves the baby being under general anesthesia and involves a surgical cut into the spinal lesion to repair it. Sometimes, if the lesion is too large, a flap or graft repair might be needed.

The doctors ensure sterile techniques are used during the surgery and antibiotics are also given to avoid infections. After surgery, medical imaging tests like X-rays and CT scans are done to rule out other anomalies or conditions. If a birth defect called Arnold-Chiari II malformation is found, another type of surgery can be done to help relieve symptoms. In cases of hydrocephalus, where fluid accumulates in the brain, a procedure called a ventriculoperitoneal shunt might be necessary. It’s crucial to have a team approach to care with different specialists working together to prevent further complications and nerve damage.

What else can Myelomeningocele be?

Here are some medical conditions related to defects in the end part of the spine:

• Terminal myelocystocele: This is a rare condition where the end of the spinal column swells. It falls under a group of conditions known as neural tube defects.
• Sacrococcygeal teratoma: This is a type of tumor that mostly grows from certain kinds of stem cells located at the base of the tailbone.
• Caudal neural tube defect: This term includes other forms of a condition called spina bifida, such as meningocele and myelocele.
• Tail remnants: These are harmless masses made of fat and fibrous tissue that usually show up near the anus and are not connected to the tailbone.
• Rhabdomyosarcoma: This is a type of cancer that begins in muscles.

Additional conditions include Curarino syndrome, which is typically inherited and involves a trio of problems affecting the anus, the sacrum, and the space in front of the sacrum. Neuroenteric cyst is another rare condition, it occurs during embryonic development and results from issues in remodeling the canal connecting the nervous and digestive systems. Caudal regression syndrome, which includes sacral agenesis or hypoplasia, occurs when there is an incomplete development of the tailbone during embryonic development.

What to expect with Myelomeningocele

A delayed diagnosis of myelomeningocele, a birth defect of the spine, can lead to worse outcomes and a lower survival rate. This birth defect can cause around half of infant deaths in less developed countries. If its treatment is also delayed or neglected, it can lead to other complications, like immobility, disability, muscle weakness, and issues with bladder and bowel control. Those with accompanying disorders, like hydrocephalus (fluid accumulation in the brain), are more likely to have a lower survival rate.

In a study conducted in Washington, U.S., survival rates for myelomeningocele increased from 60% to 90% between the 1960s and 1985 due to improvements in medicine and surgery. However, if a patient with myelomeningocele also has hydrocephalus, this can affect their long-term outcomes. This study showed that 75% of patients with a shunt (a device used to drain fluid from the brain) lived to the age of 34, compared to a 94% survival rate for those without a shunt. This suggests that some patients with asymptomatic (symptomless) hydrocephalus might be treated without a shunt. Yet, shunts are usually required for people with problematic fluid buildup in the brain. More aggressive treatments and early surgical repairs can play a crucial role in improving neurological recovery, survival rates, and the long-term prognosis.

Bowel dysfunction in patients with spina bifida is tied closely to the quality of life, and it seems that it affects the quality of life more than bladder dysfunction. Factors associated with bowel dysfunction include urinary tract disorders, male sex, and obesity. Techniques like retrograde and antegrade bowel enemas and surgical bowel management can might help improve bowel functionality. Yet, surgery is often seen as the last resort due to the high risk of complications.

Renal (kidney) failure is also a common cause of death in people with spina bifida. Therefore, to prevent neurogenic bladder (loss of bladder control due to nervous system damage) and kidney damage, a complete urological exam should be done after birth. This exam measures pelvic floor muscle activity and works to maintain low bladder pressure. After surgical repair, all patients should have clean intermittent catheterization (a method of emptying the bladder), along with medication to maintain low bladder pressure, avoid overactive bladder muscles, and reduce the risk of urinary tract infections.

Possible Complications When Diagnosed with Myelomeningocele

Complications from myelomeningocele, a type of spina bifida, can be grouped into two main categories: surgical complications and non-surgical complications.

Surgical complications could be:

• Infections at the lesion site
• Bleeding
• Delayed wound healing
• Reconnection of the spinal cord
• Leakage of cerebrospinal fluid, which is a protective fluid that cushions the brain and spinal cord

Non-surgical complications include a variety of neurological, musculoskeletal, physical, psychological, cognitive, social, and sexual issues.

Neurological complications could be:

• Hydromyelia, a condition where fluid fills the spinal cord
• Arnold-Chiari II malformation, a brain stem deformity
• Brain fluid build-up (hydrocephalus)
• Seizures
• Paraplegia, a condition that affects the lower part of the body
• Problems with movement and feeling
• Dysfunction of the bladder and bowel

Musculoskeletal complications include:

• Abnormalities of the spine like scoliosis
• Muscle weakness

Physical complications:

• Immobility
• Delayed walking development

Psychological and cognitive complications could be:

• Depression
• Suicidal tendencies
• Intellectual disability

Social and sexual complications:

• Educational problems
• Dependence on others
• Unemployment
• Sexual problems like erectile dysfunction and fertility problems

Additional complications:

• Obesity
• Kidney failure
• Heart and respiratory diseases

Also, a large percentage of people with spina bifida are allergic to latex, which is a type of rubber. This allergy can cause severe, potentially life-threatening allergic reactions.

Recovery from Myelomeningocele

The type of care given after surgery depends on the kind of operation performed. For example, if a baby had surgery to fix a defect in their spine called myelomeningocele before they were born, and they are delivered early, the baby needs to stay in a hospital area specialized in caring for newborns (neonatal intensive care unit) in an environment without latex.

After that, the baby should receive organized healthcare to prevent any other issues related to being born early or having surgery before birth. This ensures the best possible health outcomes for the baby. Even though surgery before birth generally has better results compared to surgery after birth, there can still be higher risks during and after the surgery. Some of these include other abnormalities such as excess fluid in the brain (hydrocephalus), a particular type of defect at the base of the brain (Arnold-Chiari malformation), significant defects in the space between the chest and the lower back (thoracolumbar defects), as well as abnormal movements of the baby’s legs or abnormal foot shape (clubbing).

There have been reports of complications after both prenatal (before birth) and postnatal (after birth) surgeries, which include infections of the wound or internal fluids like the shunt, a failure of the shunt, postoperative ileus (a lack of movement in the bowels that can cause blockage), a serious intestinal illness called necrotizing enterocolitis, pneumonia, symptomatic Arnold-Chiari malformation, and other complications related to the surgical correction of an abnormal curvature of the spine (kyphectomy).

To make sure the nervous system stays functional and to improve the quality of life, long-term care focused on recovery should be continued after the surgery. This includes measures to prevent complications, with an emphasis on strengthening the bones and muscles through physical therapy and exercise. This helps to avoid the risk of skin ulcers from prolonged pressure, wound infections, blood clots in the deep veins, obesity, and metabolic syndrome (a cluster of conditions that increase the risk of heart disease, stroke and type 2 diabetes). Moreover, patients with hydrocephalus should regularly see an eye doctor to monitor for vision problems and swelling of the optic disc (papilledema). Urodynamic testing, which measures how well the bladder, sphincters, and urethra are storing and releasing urine, should be done for those complaining of any urological issues to check for a neurogenic bladder.

Management of bowel function can be achieved by teaching the patient and caregivers about a program to trigger bowel evacuation reflexes as well as making changes to diet and using laxatives. These measures should be continued until the patient transitions to an adult care provider. Adult healthcare provides specialized care and activities designed to encourage independence and provide extended ongoing care for the patients.

Preventing Myelomeningocele

Myelomeningocele is a type of spina bifida, which is a condition that happens when a baby’s spine doesn’t fully form during early pregnancy. It looks like a sac filled with fluid that sticks out from a baby’s back and contains pieces of the spinal cord and nerves. A lot of the time, this can be prevented by taking enough folate (a type of vitamin B), which is important for a baby’s spine to grow properly, especially during the first month of pregnancy.

This condition can sometimes cause additional health problems for children. Some may have trouble going to the bathroom, walking, or learning at the same speed as their classmates. Others may develop scoliosis (a sideways curve of the spine) or weaker muscles. There’s also a chance that the fluid in their brain could build up too much, causing their head to enlarge. This condition is known as hydrocephalus, and if it happens, doctors may have to perform a surgery called a shunt procedure to drain the fluid. And, as a cautionary measure, it’s best for these kids to steer clear of latex products as they could be allergic to them.

Doctors can perform surgery within a day or two after a baby is born to help avoid worsening the spine problem. Besides helping to keep the child healthy, early surgery can also enhance the child’s quality of life especially if it is paired with consistent, well-rounded care. It’s crucial to have a team of doctors from different areas of medicine working together to look after the child’s needs. This can increase a child’s chances of living a healthy life and lower the chance of other medical issues showing up.

These children will likely need regular check-ups and hospital visits to monitor their health and take care of any issues. And since they might need extra help learning, early preparation at school can help them transition to higher-level education. It’s important to know that each child may have a specific area where they need help, so individual education programs should be made to fit their physical abilities and needs. Using some specific learning strategies at school can help improve some mental skills like memory and attention. Useful strategies might include noting down essential information, training the child to read clocks, breaking big tasks into smaller tasks, reducing anxiety, and encouraging the child to finish their work.

If a family has a child with spina bifida, it raises the chance of having another child with the same issue. To minimize the chance of this happening again, parents are advised to meet with a genetic counselor before planning another pregnancy. Genetic counselors provide information about family history and the chances of any genetic disorders happening in future children.

Thanks to recent advances in medicine, children with myelomeningocele can live better lives. However, it’s vital to catch and treat any health problems early to avoid them getting worse, particularly issues that affect how the child moves or their ability to go to the bathroom. That’s why having access to medical care from different doctors and early surgery is so critical – it helps avoid more serious problems and increases the chances for improvement in the future.