Which defect is characterized by protrusion of meninges and spinal cord in a sac-like bundle with hydrocephalus and paraparesis; shunting is usually required?

• A. Spina bifida occulta
• B. Spinal lipoma
• C. Meningomyelocele
• D. Meningocele

Answer: (C)

This item tests recognizing the most severe form of spina bifida where neural tissue and meninges protrude through a vertebral defect in a sac, with neurological impairment below the lesion and commonly accompanying hydrocephalus. In meningomyelocele, the sac includes both meninges and the spinal cord, which leads to significant motor and sensory deficits (paraparesis) and often Arnold-Chiari II–related hydrocephalus. Because of the hydrocephalus, a shunt to drain CSF is usually required.

Spina bifida occulta lacks any protrusion of meninges or spinal cord, so there aren’t the same neurological symptoms or hydrocephalus risk. A meningocele involves protrusion of meninges and CSF but not the spinal cord itself, so neurological impairment at the level of the cord is typically less severe and hydrocephalus requiring shunting is not as characteristic. A spinal lipoma or lipomyelomeningocele features fatty tissue associated with the spinal cord and tethered cord symptoms rather than a sac containing both meninges and cord; this presentation does not align with the classic sac containing neural tissue plus hydrocephalus.