Myelomeningocele

What is Myelomeningocele?

Myelomeningocele, also known as open spina bifida, is a severe type of spina bifida where the spinal cord and nerves grow outside of the body and are contained in a fluid-filled sac that is visible outside of the back region.

Spina bifida is a congenital (present at birth) condition or birth defect in which there is abnormal development of the back bones, spinal cord, surrounding nerves, and the fluid-filled sac that surrounds the spinal cord. This is a neurological condition that causes a section of the spinal cord and the surrounding structures to develop outside, instead of inside, the body. The defect can occur anywhere along the spine.

A myelomeningocele is a type of neural tube defect (NTD) that occurs during fetal development. Neural tube defects are congenital conditions that involve the incomplete development of the neural tube, which forms the spinal cord and brain. In the case of myelomeningocele, there is a specific defect in which the bones of the spine (vertebrae) do not fully close, leaving a gap through which the spinal cord and its protective covering, the meninges, protrude. This usually results in a sac or cyst on the baby's back, containing neural tissue.

Causes of Myelomeningocele

The exact cause of myelomeningocele is not fully known. Myelomeningocele, like other neural tube defects, is thought to result from a combination of genetic and environmental factors. While the exact cause is not always clear, several risk factors have been identified, such as:

• Genetic Factors: There appears to be a genetic component to the development of myelomeningocele. Individuals with a family history of neural tube defects may be at a higher risk.
• Folic Acid Deficiency: Sufficient intake of folic acid (a type of vitamin B) before and during early pregnancy is important for averting neural tube defects. Inadequate folic acid during pregnancy is a known risk factor for myelomeningocele and other neural tube defects.
• Maternal Health Conditions: Women with certain health conditions, such as epilepsy or obesity, may have a higher risk of having a child with myelomeningocele.
• Ethnicity and Geography: There are variations in the prevalence of neural tube defects based on ethnicity and geographical location. For instance, women of Hispanic descent have been found to have a higher risk compared to women of other ethnic backgrounds.
• Environmental Factors: Certain environmental factors may increase the risk of myelomeningocele. These factors include maternal exposure to certain medications, maternal obesity, uncontrolled diabetes, and hyperthermia (elevated body temperature) during early pregnancy.

Signs and Symptoms of Myelomeningocele

The severity of myelomeningocele can vary, and the condition is associated with potential complications such as paralysis, problems with bladder and bowel control, and issues with the development of the brain. The location and size of the defect in the spine influence the extent of neurological impairment.

In general, signs and symptoms of myelomeningocele include:

• Visible spinal sac, usually in the lumbar or sacral region. This sac contains neural tissue, including the spinal cord and meninges, and it is often covered by a thin layer of skin.
• Neurological deficits, including paralysis or weakness in the legs, hips, and lower body. The severity of paralysis depends on the level of the spinal cord defect.
• Orthopedic issues, such as deformities of the spine, hips, and feet, are common in individuals with myelomeningocele. These issues may affect mobility and require orthopedic interventions.
• Hydrocephalus, a condition characterized by an accumulation of cerebrospinal fluid in the brain. This can lead to an enlarged head size and increased intracranial pressure, requiring the placement of a shunt to divert the excess fluid.
• Tethered spinal cord or spinal cord attached to surrounding tissues, which can cause pain, neurological symptoms, and may require surgical intervention.
• Bladder and bowel dysfunction, leading to problems with urinary and fecal incontinence. 

Diagnosis of Myelomeningocele

Diagnostic tests can be performed during pregnancy to evaluate the fetus for myelomeningocele. The most common diagnostic tools include:

• Blood test: A sample of the mother’s blood is analyzed to see if the blood has a protein called AFP (alpha-fetoprotein) that the baby produces. If the level of AFP is found to be high, it could mean the baby has a myelomeningocele or neural tube defect.
• Prenatal ultrasound: A diagnostic imaging technique that uses high-frequency sound waves to form images of tissues, blood vessels, and organs on a video monitor. If the baby has myelomeningocele, you may notice the characteristic sac or cyst on the baby's back, indicating a neural tube defect.
• Amniocentesis: In some cases, if abnormalities are detected during screening or if there are other risk factors, an amniocentesis may be performed. This involves collecting a sample of amniotic fluid, which surrounds the developing fetus, and testing it for genetic and chromosomal abnormalities.
• MRI (Magnetic Resonance Imaging): If myelomeningocele is suspected or confirmed, an MRI may be recommended to provide more detailed images of the spine and surrounding structures. This can help healthcare professionals assess the extent of the defect and plan for appropriate medical care.

Treatment for Myelomeningocele

The treatment for myelomeningocele usually involves a combination of medical management, surgical interventions, and ongoing supportive care. The main objectives of treatment are to safeguard the exposed spinal cord, avert infection, manage related complications, and foster the best possible functional results. Some of the key aspects of the treatment for myelomeningocele include:

• Skin Care: Because of the exposed nature of the spinal cord, patients with myelomeningocele are at an increased risk of infection and skin breakdown. Diligent skin care, including regular monitoring and cleaning for signs of infection, is crucial.
• Orthopedic Interventions: Musculoskeletal problems are common in patients with myelomeningocele. Orthopedic interventions may include surgeries to address spinal deformities, hip dislocations, and foot abnormalities. Physical therapy and bracing are also often used to improve mobility and prevent complications.
• Urological Management: Myelomeningocele can impact bowel and bladder function. Urological interventions may include medications, catheterization, and surgical procedures to manage incontinence and foster healthy bowel and urinary function.
• Physical and Occupational Therapy: Rehabilitation services, including physical and occupational therapy, play a key role in aiding individuals with myelomeningocele to maximize their physical abilities and independence. Therapy may address strength, coordination, mobility, and activities of daily living.
• Ongoing Medical Care: Patients with myelomeningocele require lifelong medical care to handle potential complications and address evolving needs. Regular follow-up with a multidisciplinary team of healthcare professionals is key to monitoring growth, development, and overall health.
• Hydrocephalus Management: Many patients with myelomeningocele also develop hydrocephalus. If hydrocephalus occurs, a surgical procedure may be needed to insert a shunt. A shunt is a drainage system that helps divert excess cerebrospinal fluid away from the brain to another part of the body, such as the abdominal cavity, where it can be absorbed.
• Surgery: Surgical closure of the myelomeningocele is usually performed shortly after birth. The procedure involves placing the exposed spinal cord and nerves back into the spinal canal and closing the opening in the skin and underlying tissues. The timing of surgery is important to prevent infection and further damage to the exposed neural tissue.

It is crucial to note that the specific treatment plan for myelomeningocele may vary based on the severity of the condition, associated complications, and the individual needs of the patient. Early intervention and comprehensive care provided by a team of specialists are essential for optimizing outcomes and improving the quality of life for individuals with myelomeningocele.