What Is Meningocele?
Meningocele disease is a congenital defect within the neural tube in which the meninges and cerebrospinal fluid bulge outward through an opening in the spine. A key feature that defines this condition is the absence of brain or spinal cord tissue inside the herniated sac. Because neural tissue remains intact, meningocele is generally regarded as one of the mildest neural tube malformations linked to the encephalocele and spina bifida spectrum.
Normally, the neural tube closes and fuses completely during the third and fourth weeks of pregnancy. When this developmental step is interrupted, the surrounding bone may fail to form properly, leaving a gap that allows the meninges to protrude and form a fluid-filled sac. Unlike meningoencephaloceles or encephalomyeloceles, meningocele does not involve herniation of neural tissue.
Depending on its location, a meningocele may appear inside the skull as part of the encephalocele group or along the spinal column as a form of spina bifida cystica.
Embryology and Pathophysiology
The condition arises from incomplete neural tube closure and abnormal mesenchymal formation during early embryogenesis. The bone defect permits the dura and arachnoid mater to extend outward, filled with cerebrospinal fluid.
Typical contents of the sac include:
Cerebrospinal fluid
Dura mater
Arachnoid mater
Brain tissue or spinal cord components are not found within the sac, which clearly distinguishes meningocele from more complex malformations involving neural herniation.
The biological mechanisms behind meningocele formation are influenced by a combination of genetic predisposition, nutritional factors, and maternal health conditions.
Typical Locations
The site of the defect determines the clinical form:
Spinal Meningocele (more common)
Primarily affects:
The lumbosacral spine
Thoracolumbar area
Cervical region (uncommon)
Cranial Meningocele (rare)
Most commonly appears in:
The occipital region
Parietal bones
Frontonasal midline
Etiology and Risk Factors
No single cause explains all meningocele cases. Instead, several influences act together.
Genetic Factors
Some patients show associations with:
Chromosomal anomalies
Family history of neural tube defects
Rare single-gene disorders
Maternal and Environmental Factors
Well-recognized contributors include:
Lack of folic acid before and during early pregnancy
Poorly controlled maternal diabetes
Use of teratogenic drugs such as certain antiepileptics
Exposure to high maternal temperature
Smoking or using alcohol in pregnancy
Obesity
Adequate folic acid intake around conception greatly reduces the overall risk of neural tube defects, including meningocele.
Clinical Presentation
The appearance and symptoms vary with location and size of the lesion.
Physical Findings
Visible fluid-filled swelling
Delicate skin stretched over the defect
Occasional cerebrospinal fluid leakage if the skin ruptures
Neurological Features
Most children with isolated meningocele retain normal neurological function since the nervous tissue remains inside the body. Some spinal cases may show:
Mild motor delays
Orthopedic issues such as clubfoot or scoliosis
Spinal meningoceles can be linked with tethered cord or vertebral defects, whereas cranial cases typically produce far fewer neurological complications.
Prenatal Diagnosis
Modern imaging allows detection before birth.
Ultrasound
Can show:
The bone opening
The protruding CSF-filled sac
Absence of neural tissue within the lesion
Fetal MRI
Provides clearer detail about sac composition and helps distinguish the condition from more severe defects.
Further fetal evaluation may search for:
Hydrocephalus
Chiari malformation
Vertebral anomalies
Additional structural abnormalities
Early diagnosis supports accurate prognosis, family counseling, and delivery planning.
Treatment and Outcome
Surgery
Meningocele is generally managed with surgical repair shortly after birth to:
Remove or collapse the sac.
Close the bone and dura defect.
Protect neural structures.
Avoid CSF leakage and infection.
Because neural tissue is preserved, surgical results are usually excellent.
Prognosis
Long-term outcome depends on accompanying abnormalities and lesion location.
Most children with isolated meningocele develop normally, showing:
Normal cognitive performance.
Good mobility.
Minimal neurological disability risk.
A minority of spinal cases may experience:
Tethered cord syndrome.
Orthopedic deformities.
Occasional bladder or bowel dysfunction.
Ongoing neurological monitoring and early intervention help maintain optimal function throughout growth.