myelomeningocele
Pronunciation: MY-eh-loh-meh-NIN-goh-seel
The most severe form of spina bifida where the spinal cord and meninges protrude through a defect in the vertebral column.
Full Definition
Myelomeningocele is the most serious type of neural tube defect, characterized by herniation of the spinal cord, nerve roots, and meninges through a bony defect in the vertebral arches. This open spinal dysraphism results in neurological deficits below the level of the lesion, including paralysis, sensory loss, and bowel/bladder dysfunction. Most commonly occurs in the lumbar region. Prenatal diagnosis is possible with ultrasound and elevated maternal serum alpha-fetoprotein. Postnatal imaging with MRI evaluates the extent of neural tissue involvement and associated abnormalities such as Arnold-Chiari malformation and hydrocephalus. Immediate surgical closure is required to prevent infection and further neural damage.
Usage
Usage note: One word, not hyphenated. Distinguish from meningocele (no neural tissue involvement) in reports.
In Context
- "The L4-S1 myelomeningocele requires urgent neurosurgical repair." — Neonatal radiology report
- "MRI demonstrates the neural placode within the myelomeningocele sac." — Prenatal imaging study