Meningocele¶

Definition¶

A meningocele is a herniation of the meninges (dura and arachnoid) through a defect in the posterior vertebral arch, forming a CSF-filled sac. Unlike myelomeningocele, the spinal cord and nerve roots remain within the spinal canal and are not included in the herniated sac. Meningoceles are typically covered by skin and are classified as closed spinal dysraphisms.

Imaging Findings¶

MRI¶

CSF-signal sac protruding through a posterior bony defect
The spinal cord and nerve roots remain in their normal position within the spinal canal — they do NOT extend into the sac
The conus medullaris is typically at a normal level
The sac contents follow CSF signal on all sequences (T1 dark, T2 bright)

CT¶

Posterior bony defect (spina bifida)
CSF-density sac without soft tissue elements

Ultrasound (Neonatal)¶

Anechoic (CSF) sac through a posterior defect
Normal cord position

Clinical Pearl

The critical distinction between meningocele and myelomeningocele is whether neural tissue extends into the sac. In meningocele, only CSF and meninges herniate — the cord and nerves stay in the canal. In myelomeningocele, the neural placode herniates into the sac. This distinction determines prognosis — meningoceles generally have a good neurological outcome, while myelomeningoceles have significant neurological deficits.

Management¶

Surgical repair to close the defect and prevent CSF leak or infection
Neurological prognosis is generally good because the neural elements are not involved

Key Points¶

CSF-filled meningeal sac herniating through a posterior bony defect
Neural tissue (cord, nerve roots) remains within the spinal canal
Better prognosis than myelomeningocele
MRI confirms that no neural tissue is in the sac
Surgical closure is standard treatment

References¶

Trapp B, Freddi TAL, Hans MOM, et al. A Practical Approach to Diagnosis of Spinal Dysraphism. RadioGraphics. 2021;41(2):559-575. https://pubs.rsna.org/doi/10.1148/rg.2021200103
Kumar J, Afsal M, Garg A. Imaging spectrum of spinal dysraphism on magnetic resonance: A pictorial review. World J Radiol. 2017;9(4):178-190. https://pmc.ncbi.nlm.nih.gov/articles/PMC5415887/
Oner AY, Uzun M, Tokgöz N, Tali ET. Isolated true anterior thoracic meningocele. AJNR Am J Neuroradiol. 2004;25(10):1828-1830. https://www.ajnr.org/content/25/10/1828
Caro-Domínguez P, Bass J, Hurteau-Miller J. Currarino Syndrome in a Fetus, Infant, Child, and Adolescent: Spectrum of Clinical Presentations and Imaging Findings. Can Assoc Radiol J. 2017;68(1):90-95. https://pubmed.ncbi.nlm.nih.gov/27887934/
Lee SC, Chun YS, Jung SE, Park KW, Kim WK. Currarino triad: anorectal malformation, sacral bony abnormality, and presacral mass--a review of 11 cases. J Pediatr Surg. 1997;32(1):58-61. https://pubmed.ncbi.nlm.nih.gov/9021570/
Karsonovich T, Nethi S, Arya K. Meningocele. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2024. https://www.ncbi.nlm.nih.gov/books/NBK562174/
Meningocele. Radiopaedia.org. https://radiopaedia.org/articles/meningocele-3