Spina bifida is one of the possible neural tube defects that can occur during early embryological development. Which of the following definitions most accurately describes meningocele?
A. Complete exposure of spinal cord and meninges
B. Herniation of the spinal cord and meninges into a sac
C. Sac formation containing meninges and spinal fluid
D. Spinal cord tumor containing nerve roots
Correct Answer: C. Sac formation containing meninges and spinal fluid.
Meningocele is a sac formation containing meninges and cerebrospinal fluid (CSF). Meningocele is the simplest form of open neural tube defects characterized by cystic dilatation of meninges containing cerebrospinal fluid without any neural tissue. A complex meningocele is associated with other spinal anomalies. Meningocele is a typically asymptomatic spinal anomaly and is not associated with acute neurologic conditions.
Option A: Meningocele doesn’t involve complete exposure of the spinal cord and meninges; this is a massive defect that’s incompatible with life. A simple meningocele composed of meninges and CSF protruded into the subcutaneous tissue through a spinal defect. Skin overlying meningoceles are usually intact.
Option B: Myelomeningocele is a herniation of the spinal cord, meninges, and CSF into a sac that protrudes through a defect in the vertebral arch. Myelomeningocele is the most common open neural tube defect. It is characterized by failure of the neural tube to close in the lumbosacral region during embryonic development (fourth-week post-fertilization), leading to the herniation of the meninges and spinal cord through a vertebral defect.
Option D: Tumor formation is not associated with this defect. Meningocele presents as a swelling over the back covered with skin, present at birth. Defects can present at thoracolumbar, lumbosacral, lumbar, thoracic, sacral, and cervical regions. Neurological involvement and deficits are rare in meningocele.