Myelomeningocele is the most severe form of spina bifida. The spinal cord and backbone fail to close while a fetus grows, causing a sac containing parts of the spinal cord to protrude out its back.
Myelomeningocele may cause severe complications that may lead to disabilities and malformations. Some types of imaging tests help diagnose myelomeningocele and spina bifida.
Myelomeningocele severity may vary depending on the nerve protrusion’s position.
This article will explain myelomeningocele, its symptoms, causes, diagnosis, and treatment.
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Myelomeningocele is the most severe type of spina bifida. It occurs when the neural tube fails to close before the birth of a baby, forming a sac that holds some parts of the spinal cord and nerves. This protrusion will appear on their back, near their spine.
The baby may not have movement or sensation in parts of the body below the protrusion. The higher the myelomeningocele is, the less movement they may have.
Learn more about spina bifida.
Share on PinterestDiagram showing myelomeningocele, with a sac protruding from a baby’s back. The cross-section shows damaged nerves, open spinal canal, and cerebrospinal fluid inside the sac, which protrudes from a gap in the spinal cord. Infographic by Jason Hoffman.
A person with myelomeningocele may experience symptoms such as:
- lack of sensation in their feet and legs, and sometimes parts of the abdomen
- problems moving parts of their body below the protrusion on their back
- sensory impairments (loss of the sensation of touch)
- poor or absent bladder or bowel control
- hydrocephalus
- cognitive impairment
- learning difficulties
- problems in the development of the back of their brain
- skin problems
- latex allergy
The causes of myelomeningocele are unknown, but experts believe environmental and genetic factors may be involved.
Environmental factors may include:
Maternal factors that may cause myelomeningocele include:
Most myelomeningocele cases are sporadic, but some genetic factors may increase the risk of occurrence. This includes the presence of abnormalities in certain chromosomes and having a first-degree relative with the condition.
Healthcare professionals can identify if a fetus is at risk for spina bifida by conducting an Alpha-Fetoprotein (AFP) blood test in the second trimester of pregnancy. If a pregnant person has high levels of AFP, that may be a sign that the fetus has spina bifida.
Other tests that may detect risk for spina bifida include amniocentesis, an amniotic fluid test that detects chromosomal abnormalities in a fetus.
An ultrasound scan can diagnose spina bifida before a fetus is born, as it can be used to look at images of the fetus and check for a myelomeningocele sac.
If the doctor finds myelomeningoceles after birth, they may prescribe some imaging tests to see the spine. These tests may include:
- CT scan
- X-ray
- ultrasound
- MRI
Myelocele, also known as myeloschisis, is a rarer congenital spinal cord malformation. It is also caused by the neural tube failing to close during a fetus’s development. This results in an incomplete section of the spinal cord that is exposed to the environment.
However, this malformation does not protrude beyond the skin’s surface like myelomeningocele. Clinical aspects, such as an association with Chiari II malformation, are similar to myelomeningocele.
In myelomeningocele, a sac containing nerves that hold some parts of the spinal cord protrudes out of a person’s back near the spine.
Myelomeningocele is the most severe type of spina bifida. Other spina bifida types include:
- Spina bifida occulta: This is the most common and mildest form of spina bifida. This occurs when one or more vertebrae have a malformation. Doctors often find spina bifida occulta by accident after an imaging test, such as an X-ray. It rarely causes symptoms or disabilities.
- Meningocele: This occurs when spinal fluid creates a sac through the spine. This type of malformation does not contain nerves but only liquid. People with meningocele may have only minor symptoms.
- Close neural tube defects: This is a malformation of fat, membranes, or bone covering the spinal cord. This defect requires surgery and can cause leg weakness and difficulty controlling bowel and bladder functions.
According to the Centers for Disease Control and Prevention (CDC), the outlook for people with spina bifida depends on its severity. Myelomeningocele is the most severe form of spina bifida. It causes moderate to severe disabilities that can impact a person’s physical mobility and intellectual abilities.
Some people with myelomeningocele might experience more difficulty moving or functioning. In more severe cases, people may even experience paralysis. They may be unable to walk to move part of their body.
A 2021 review suggests that the presence of hydrocephalus is a factor in long-term outlooks for people with myelomeningocele. People with myelomeningocele who needed to have a shunt fitted had a survival rate of 75% when they were 34 years old. However, people who did not have a shunt had a survival rate of 94% of 34.
The review also found that kidney failure is a key cause of death in people with myelomeningocele, and bowel problems are a key cause of decreased quality of life.
People with myelomeningocele can still lead full lives. The earlier a person receives a diagnosis, the better their outlook.
Learn more about treatment options for babies born with spina bifida.
A person can contact a healthcare professional during pregnancy to request a maternal serum alpha-fetoprotein (MSAFP) screening and fetal ultrasound if they have not received these tests. These tests can help diagnose myelomeningocele in fetuses.
A person with a diagnosis of myelomeningocele should contact a doctor if they notice a worsening of their symptoms. They should also seek medical help if they notice new symptoms, including those involving the function of the bowels or bladder.
A person should seek emergency medical attention if signs of an infection or blockage around the site of a shunt are present.
Family and carers of people with spinal bifida can find support through communities that offer information and resources for managing spina bifida and myelomeningocele.
The Spina Bifida Association runs a network of chapters and communities where people can connect with other families experiencing similar challenges.
Myelomeningocele is the most severe type of spina bifida. It requires surgery to repair the spinal damage. Doctors can also carry out prenatal surgery.
To help diagnose myelomeningocele, doctors can prescribe X-ray, CT, and MRI scans to understand the severity of the damage.
After the diagnosis is important to treat the myelomeningocele as soon as possible in order to prevent additional damage.
Myelomeningocele may lead to different types of complications, such as hydrocephalus, meningitis, kidney failure, bowel, and bladder problems.
Many spinal deformities in children with myelomeningocele will worsen. As a spinal curvature progresses, risks for skin and functional problems increase. In addition, severe curves can collapse space in the chest, which can potentially cause heart and lung problems.
Bracing. If a child is still growing and the spine curvature is flexible, the doctor may recommend wearing a brace. Although bracing cannot straighten a spinal curve, it may slow down the curve progression and allow the child more growth before surgery is required.
Braces need to be custom-made so that they fit the child and do not cause any skin irritation or other problems.
Wheelchair modification. If a child has a shifted pelvis that affects balance, the wheelchair can be modified to improve posture. Like bracing, wheelchair modification can improve a child's function and slow the progression of a curve, but it should not be viewed as a cure.
If bracing and/or wheelchair modifications are not effective at controlling the progression of spinal curve, or if a child comes to the doctor with a severe curvature of the spine, surgery may be necessary.
The operation for a spinal curve is a spinal fusion. The basic idea is to realign and fuse together the curved vertebrae so that they heal into a single, solid bone. Screws, rods, hooks, or wires will keep the bones in place. Spinal fusion can:
- Straighten the spine to improve posture and alleviate the need for the child to use their hands and arms to support their upper body
- Avoid pressure points from developing due to uneven sitting that can cause the skin to break down
The surgical treatment of children with spinal deformities associated with myelomeningocele can be difficult because of:
- An increased risk of surgical complications
- Additional medical problems, such as hydracephalus, skin conditions, and urinary tract infections
However, careful preoperative planning with a team of medical professionals, as well as new fusion implant designs, can result in successful outcomes.