IDH correspond to a rare presentation of a common pathology, comprising ~0.28% of all disc herniations 2.
Symptoms are indistinguishable from the other disc hernias. A higher incidence of cauda equina syndrome has been reported when compared to extradural hernias 2.
Intradural disc herniations represent a challenge for pre-operative diagnosis, with most of the cases only confirmed in the surgery.
Although CT has a known limitation to assess the dural sac and spinal cord, when air is present in the degenerated intervertebral disc space (vacuum phenomenon), this can migrate to the herniated mass and delineates the intradural component of a hernia 3.
The intradural herniated disc may be delineated protruding into the dural sac. However, it can be difficult to differentiate from an intradural tumour. Post-contrast images will delineate an incomplete ring enhancement (chronic granulation tissue
and peripheral neovascularization), helping in distinguishing it from those tumours 3.
- 1. Fardon DF, Williams AL, Dohring EJ et-al. Lumbar disc nomenclature: version 2.0: Recommendations of the combined task forces of the North American Spine Society, the American Society of Spine Radiology and the American Society of Neuroradiology. Spine J. 2014;14 (11): . doi:10.1016/j.spinee.2014.04.022 - Pubmed citation
- 2. Ducati LG, Silva MV, Brandão MM et-al. Intradural lumbar disc herniation: report of five cases with literature review. Eur Spine J. 2013;22 Suppl 3 (S3): S404-8. doi:10.1007/s00586-012-2516-4 - Free text at pubmed - Pubmed citation
- 3. Kobayashi K, Imagama S, Matsubara Y et-al. Intradural disc herniation: radiographic findings and surgical results with a literature review. Clin Neurol Neurosurg. 2014;125: 47-51. doi:10.1016/j.clineuro.2014.06.033 - Pubmed citation
- spinal anatomy
- congential abnormalities of the spine
- spinal infection / inflammation / degeneration
- intervertebral disc
- intervertebral disc disease nomenclature
- lumbar disc disease
- acute calcific discitis
- acute disseminated encephalomyelitis (ADEM)
- Charcot-Marie-Tooth disease
- HIV vacuolar myelopathy
- HTLV-1 associated myelopathy (tropical spastic paraparesis)
- multiple sclerosis
- neuromyelitis optica (NMO) - (Devic's disease)
- transverse myelitis
- SCA3 (Machado-Joseph disease)
- subacute combined degeneration of the cord
- subacute necrotizing myelopathy
- tabes dorsalis
- spinal ischaemia
- spinal trauma
- spinal tumours and cysts
- spinal vascular malformations