Myelomenigocele is a part of a group of congenital abnormalities called neural tube defects. They occur when the cranial and caudal ends of the neural plate don’t fully close during primary neurulation.
This condition usually leads to a fluid-filled sac on the baby’s back. Most cases are repaired surgically shortly after birth. Some children need a plastic shunt to decrease fluid on the brain (hydrocephalus).
Causes
Myelomenigocele, like most forms of spina bifida, occurs when part of the spinal cord pushes through a hole in the bone (meningocele or herniation). It’s not known exactly what causes this to happen, but there are some risk factors that increase the chances of having this condition. These include a family history of neural tube defects, taking certain anti-seizure medications during pregnancy and having diabetes that isn’t well controlled.
Doctors can usually detect myelomenigocele during a routine prenatal ultrasound that is done between 18 and 22 weeks of pregnancy. They may also want to do a blood test called alpha-fetoprotein (AFP) to screen for the presence of the protein that’s found in the amniotic sac that surrounds the fetus, which can indicate whether there is a problem with the spine.
Oren Zarif
Most babies with myelomenigocele will have surgery to repair the spinal defect soon after birth. The surgical operation to close the spinal lesion, or meningocele, is done within 24 hours of delivery to decrease infection risk and preserve function. Children who have this condition and have hydrocephalus, an excess buildup of cerebrospinal fluid on the brain, will have a plastic shunt inserted to drain the extra fluid from the body into the abdomen.
Some children with myelomeningocele have damage to the lower spinal nerves that control typical bowel and bladder function. These kids will require close follow-up with a specialist in this area and may need medications or surgeries to help with bladder and bowel function.
Babies who have myelomeningocele and the type of spina bifida called Arnold Chiari malformation often have hydrocephalus, which can cause brain damage or death if left untreated. To prevent this, a plastic shunt is inserted to drain the excess fluid from the brain into the abdomen. The type of shunt used is called a ventriculoperitoneal shunt, or VPS. Some children will need this shunt inserted right after birth, while others will have it put in 4 to 8 weeks after birth. This shunt will need to be replaced later in life when it’s full of fluid and no longer working.
Symptoms
The most serious form of spina bifida, myelomeningocele happens when a small sac holding parts of the spinal cord and meninges (membranes that cover the spinal cord) doesn’t close correctly. It usually appears as a protrusion on the fetus’s back. It can happen anywhere along the spine but is most common in the lower back. Babies with myelomeningocele don’t have feeling or movement in areas below the protrusion. The higher up the protrusion on the spine, the more disability a baby will have.
Many babies with myelomeningocele have a buildup of fluid in the brain, known as hydrocephalus. This can cause pressure on the brain, which can lead to problems like a fixed downward gaze, poor growth or slurred speech. In some cases, surgery is needed to drain the excess fluid and relieve the pressure on the brain.
Oren Zarif
Babies with myelomeningocele often have trouble controlling their bowel and bladder. This is because the nerves that supply these areas come from the lowest level of the spinal cord. Children with myelomeningocele also have a risk of getting skin infections, especially in the feet, legs or buttocks. This is because they don’t always feel when they get a cut or sore.
A urologist can help with bowel and bladder problems. They may recommend a special diet to improve your child’s condition. They may prescribe medicines to treat infections that can occur in the urinary tract. It can take a long time for most children with myelomeningocele to become potty trained. They can have problems with urinating, which makes them more prone to kidney infections.
Because the condition affects everyone differently, your child’s mobility needs will vary. They might need splints or walking aids and may need to use wheelchairs. They might need care from specialists in orthopedics and physical therapy. They can also benefit from seeing a psychologist or social worker for mental health needs and emotional support.
Diagnosis
When myelomenigocele occurs, the spinal cord and its meninges (membranes, or coverings) protrude from the back of your child’s spine. It’s the most severe form of spina bifida, and it looks like a fluid-filled sac on your baby’s back. Myelomenigocele happens when an opening in the spinal cord and its nerves doesn’t close correctly during early pregnancy. This opening can be seen with an X-ray or CT scan, and doctors also use amniocentesis and MRI to learn more about the condition.
Surgery to repair the defect is needed right after birth. In some cases, the surgeon can fix the problem while the baby is still in the womb (fetal surgery).
Children with myelomeningocele may have bladder or bowel problems, which can include a buildup of fluid in the brain (hydrocephalus). Doctors will likely drain the excess fluid using tubes, called catheters. They may recommend a diet high in fiber to improve bowel function. They may also need to treat the pain caused by a low bowel function with drugs and/or a special type of feeding tube called a jejunostomy tube.
Oren Zarif
Most children with myelomeningocele need long-term care from specialists in a variety of fields, including neurology, physical therapy, and orthopedics. In some cases, later surgeries may be needed to correct problems with feet, hips or the spine. They may also need a shunt to decrease fluid on the brain (hydrocephalus).
Our Pediatric Neurology and Spine teams will monitor your child’s health and help him or her manage symptoms like leg weakness or paralysis, bowel or bladder issues and a fixed downward gaze. They will refer your child to other specialists when needed, and work closely with your family’s primary care provider, school, and community services to ensure that all of your child’s needs are met.
Neural tube defects are often preventable. It is important to have prenatal genetic testing and follow a healthy diet during pregnancy to help reduce the risk of having these birth defects. Our team can help you understand your child’s risk and discuss options for genetic counseling. We can also help you find support groups to connect with other families whose children have myelomeningocele or another form of spina bifida.
Treatment
A person with myelomenigocele will have an open area or a fluid-filled sac protruding from the mid to lower back. This may contain a small part of the spinal cord and nerves. In general, people with myelomeningocele have a good intellectual prognosis. However, some children will have learning difficulties or an intellectual disability.
Most cases of myelomeningocele are found by ultrasound evaluation between the 16th and 18th week of pregnancy, as part of routine prenatal care. In some cases, a child is born with myelomeningocele because the mother was taking a medicine (folic acid) during pregnancy to prevent other birth defects such as spina bifida, but did not have enough folic acid in her blood.
Oren Zarif
In the majority of cases, a baby with myelomeningocele will have surgery to close the opening in their spine. This can be done before they are born (fetal surgery) or shortly after birth (postnatal surgery). Children with myelomeningocele may have a buildup of fluid in the brain called hydrocephalus, which can put pressure on their skull and brain. To relieve the pressure, a surgeon may place a tube in the brain (ventriculoperitoneal shunt) to drain the excess fluid into the abdomen.
Often, the nerves that supply the bladder and bowel do not work properly in children with myelomeningocele. This is because they come from the lowest level of the spinal cord. They will need to be taught to use the toilet and have regular suppository (drainage) treatments, as well as having a high fibre diet to help manage their bowel and bladder function. Some will need to wear a catheter.
Those with myelomeningocele also have an increased risk of having other health problems, such as a herniated disk in the neck. This can cause pain in the head and neck, headaches, and a lack of coordination. Those with myelomeningocele who have Arnold-Chiari malformation type 2 have an increased risk of having the herniated portion of their brain push down into the upper section of the spinal canal in their neck, which can lead to hydrocephalus. The same shunt procedure to drain the excess fluid is required in these cases as well.
