Fact-sheet: Disk herniation
Updated on 04/23/2019 at 9:47 AM
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Definition
Disk herniation refers to a focal pathologic displacement of intervertebral disk material, with the following subtypes:
- Protrusion = disk herniation whose base is wider than any other dimension.
- Extrusion = disk herniation in which at least one dimension is greater than the width of the base.
- Sequestered fragment = separation of a disk fragment within the spinal canal
Broad-based bulging (>25% of the disk circumference) and circumferential bulging are not considered focal disk herniations. In these cases, the term "disk herniation" should not be used, as it may cause confusion.
Clinical features
Approximately 30% of the asymptomatic population has a disk herniation.
Acute low back pain (lumbago) and sciatica at the lumbar level.
Acute neck pain and cervicobrachial neuralgia at the cervical level.
Thoracic disk herniations are less common
Radiography
Indicated when painful symptoms persist despite 4 to 6 weeks of appropriate medical treatment, to look for signs of degenerative disk disease: disk space narrowing, osteosclerosis of the adjacent vertebral endplates, marginal osteophytosis
Rule out a tumoral cause of radiculopathy
CT
Posterior, posterolateral, or foraminal protrusion of disk material.
Assessment for disco-radicular compression
MRI
Reference examination, to be performed urgently in cases of cauda equina syndrome, motor deficit ≤3/5, or a patient with severe uncontrolled pain (pain resistant to opioids)
Standard protocol: Sagittal T1, T2, STIR sequences, and axial T1, T2 sequences through the pathologic disks
Describe the disk disease, the herniation, and its relationship to the nerve roots
Rule out a nondiscal etiology (tumoral or otherwise) for sciatica