Myelomeningocele

Myelomeningocele is the most severe form of spina bifida aperta, a neural tube defect in which the spinal canal and meninges herniate through a defect in the vertebral arches. The lesion is typically in the lumbosacral region and is usually open, with exposure of neural tissue at birth. It is commonly associated with Chiari II malformation and hydrocephalus.

Clinical features usually include motor and sensory loss below the level of the lesion, lower limb paralysis, neurogenic bladder and bowel, orthopedic deformities, and an increased risk of infection. Diagnosis can be suspected prenatally by ultrasound, and maternal serum alpha-fetoprotein is often elevated. After birth, a defect covered by meninges and neural tissue is evident; imaging confirms the extent.

Management includes prompt postnatal surgical repair to close the defect and cover neural tissue, reducing infection risk. In selected pregnancies, fetal or prenatal repair of the lesion can be offered and has been associated with improved motor outcomes in some studies. After birth, many children require ventriculoperitoneal shunting to treat hydrocephalus, and long-term multidisciplinary care is common, including physical therapy, urology, orthopedics, and continence management.

Prognosis depends on lesion level and associated anomalies. With comprehensive care, some individuals achieve ambulation with assistive devices, though many require ongoing therapy and may face complications such as tethered cord, syringomyelia, Chiari II-related issues, and shunt dependency.

Prevention focuses on folic acid supplementation before conception and during early pregnancy (commonly 400–800 micrograms daily; higher risk individuals may receive more). Risk factors include maternal diabetes, obesity, certain anticonvulsants, and folate deficiency. Spina bifida occulta is a different, closed form.