A meningocele is formed when the meninges herniate through a defect in the posterior vertebral arches. The spinal cord is usually normal and assumes a normal position in the spinal canal, although there may be tethering, syringomyelia, or diastematomyelia. A fluctuant midline mass that may transilluminate occurs along the vertebral column, usually in the lower back. Most meningoceles are well covered with skin and pose no threat to the patient.
Careful neurologic examination is mandatory. Asymptomatic children with normal neurologic findings and full-thickness skin covering the meningocele may have surgery delayed.
Before surgical correction of the defect, the patient must be thoroughly examined with the use of plain roentgenograms, ultrasonography, and MRI to determine the extent of neural tissue involvement, if any, and associated anomalies, including diastematomyelia, tethered spinal cord, and lipoma. Urologic evaluation, usually including cystometrogram (CMG), will identify those children with neurogenic bladder who are at risk for renal deterioration.
Those patients with leaking cerebrospinal fluid (CSF) or a thin skin covering should undergo immediate surgical treatment to prevent meningitis. A CT scan of the head is recommended for children with a meningocele because of the association with hydrocephalus in some cases.
An anterior meningocele projects into the pelvis through a defect in the sacrum. Symptoms of constipation and bladder dysfunction develop due to the increasing size of the lesion. Female patients may have associated anomalies of the genital tract, including a rectovaginal fistula and vaginal septa. Plain roentgenograms demonstrate a defect in the sacrum, and CT scanning or MRI outlines the extent of the meningocele.