Meningomyelocele is the most severe form of spina bifida, a birth defect that occurs when the neural tube does not close completely during the first month of pregnancy. This results in an opening in the baby’s back through which a sac protrudes, containing parts of the spinal cord and its protective membranes, called the meninges. Because the exposed spinal cord and nerves are damaged, this condition leads to health challenges that vary depending on the location of the opening.
Causes and Risk Factors
The precise cause of meningomyelocele is unknown but is understood to result from a mix of genetic and environmental factors. A primary factor is insufficient intake of folic acid, a B vitamin, before and during early pregnancy. Folic acid is needed for the proper closure of the neural tube, and a deficiency increases the risk of such defects.
A family history of neural tube defects can elevate the risk, suggesting a genetic predisposition. Certain medications taken during pregnancy, such as some drugs used to control seizures, have been linked to a higher incidence. Additionally, maternal health conditions like poorly controlled diabetes and obesity are recognized as contributing factors.
Associated Health Conditions
The nerve damage from meningomyelocele leads to lifelong health issues. A common effect is on mobility, with individuals experiencing muscle weakness or paralysis in their legs. This impacts the ability to walk and may require the use of braces, crutches, or a wheelchair.
Challenges with bladder and bowel control are nearly universal due to disrupted nerve signals. This requires management strategies like catheterization to empty the bladder and prevent kidney damage. Many children with this condition also develop hydrocephalus, a buildup of cerebrospinal fluid in the brain that increases pressure and can affect development.
A related structural brain issue, a Chiari II malformation, is also frequently present. In this condition, brain tissue extends into the spinal canal, which can interfere with cerebrospinal fluid flow and contribute to hydrocephalus. Other common orthopedic problems include clubfoot and scoliosis, an abnormal curvature of the spine.
Diagnosis Methods
Meningomyelocele is often diagnosed before birth through prenatal screening. One common test is the maternal alpha-fetoprotein (AFP) blood screening. High levels of AFP in the mother’s bloodstream can indicate an open neural tube defect, but this test is not definitive.
A prenatal ultrasound is a primary tool for diagnosis, as it can visualize the physical opening on the fetus’s spine. If screening tests indicate a high probability of a defect, amniocentesis may be performed. This involves testing a sample of the amniotic fluid to confirm the diagnosis.
If the condition is not detected during pregnancy, it is immediately visible at birth by the sac-like protrusion on the newborn’s back. Following birth, imaging tests like an MRI or CT scan may be used to get a more detailed view of the spine and brain to guide treatment.
Treatment and Management Strategies
The initial treatment for meningomyelocele is surgery to close the opening on the baby’s back, performed within 24 to 72 hours of birth. This procedure helps protect the exposed spinal cord from infection and further damage. In some specialized centers, fetal surgery is an option, where surgeons repair the defect while the baby is still in the womb to reduce the severity of some complications.
Long-term management is a continuous process involving a team of specialists. For hydrocephalus, a common treatment is the surgical placement of a shunt, a thin tube that drains excess cerebrospinal fluid from the brain to another part of the body. This helps to relieve pressure on the brain.
Ongoing care involves a multidisciplinary team that may include physical therapists, urologists, and orthopedic surgeons. Physical therapy is for maximizing mobility and strength, while urologists help manage bladder function. Orthopedic specialists address related issues like scoliosis or foot deformities through bracing or surgery.