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  • Updated 03.11.2024
  • Released 07.29.1996
  • Expires For CME 03.11.2027




Myelomeningocele is an open spinal dysraphism in which a segment of the spinal cord, most commonly in the lumbosacral region, and its associated nerves and meninges protrudes through a bifid spine and skin defect (11). It affects both the central and peripheral nervous systems and typically causes a spectrum of paralysis as well as bowel and bladder dysfunction. Myelomeningoceles may be associated with other anomalies, including hydrocephalus, tethered cord syndrome, and syringomyelia. New neurologic problems can present at any point throughout their lifespan. Patients require regular multidisciplinary follow-up to manage these conditions. A multicenter trial for prenatal myelomeningocele repair in 2011 showed that surgery performed before 26 weeks of gestation significantly reduced the need for cerebrospinal fluid shunting and improved motor function at 30 months. However, controversies still exist regarding the best timing for prenatal surgical intervention, the type of surgical approach, and the surgical risk to both the mother and fetus.

Key points

• Myelomeningocele is the most common and complex birth defect of the CNS compatible with long-term survival. It affects the complete neuroaxis and leads to multiple neurologic comorbidities, including hydrocephalus, Chiari II malformation, paralysis, sensory loss below the level of the lesion, and bowel and bladder dysfunction.

• Adequate folic acid intake and avoidance of medications in the periconceptual and early pregnancy periods significantly reduce the risk of myelomeningocele.

• Myelomeningocele level is the most important predictor of functional outcome.

• Myelomeningocele repair was traditionally done within 48 to 72 hours after birth to minimize the risk of infection.

• The pivotal MOMS trial, published in the New England Journal of Medicine in 2011, provided evidence that prenatal surgical closure improved outcomes as measured by ventriculoparietal shunt requirement and motor function at 30 months.

• The emergence of fetoscopic surgical techniques have further augmented the treatment landscape for myelomeningoceles.

• Up to 90% of patients with a myelomeningocele develop hydrocephalus, especially in resource-limited settings.

• Patients with myelomeningocele require close multidisciplinary follow-up throughout life to promote maximum functional outcomes and to minimize further neurologic decline from associated anomalies.

Historical note and terminology

Malformations involving the formation of the distal spinal cord and spinal column have been identified for centuries. The term "spina bifida" was used to describe these lesions, from the mildest to the most severe. The term "spinal dysraphism" is more suitable to describe myelomeningocele as "dysraphism" refers to the incomplete midline closure of osseous, mesenchymal, and nervous tissue (40). Most of these defects are thought to result from abnormal neurulation; therefore, they are also known as "neural tube defects." This section will discuss the most common clinically significant neural tube defect, myelomeningocele, a form of spina bifida. This form of spina bifida has effects on the entire neuroaxis, with a high association of hydrocephalus, brainstem dysfunction, paralysis, sensory loss, and bladder and bowel dysfunction.

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