Lumbar Disc Disease Workup

Updated: Sep 25, 2018
  • Author: Kamran Sahrakar, MD, FACS; Chief Editor: Brian H Kopell, MD  more...
  • Print

Imaging Studies

MRI is by far the most commonly ordered test to evaluate patients with sciatica. Often, MRI is performed prior to plain radiographs. MRI is very sensitive in delineating lumbar disc herniations. Far lateral discs are best evaluated with this test. In reoperations, MRI can delineate the full extent of scar tissue and, with moderate reliability, differentiate it from recurrent disc herniation. [9, 10, 11]

In an MRI study of 109 patients aged 17-80 years with lumbar disc degeneration, L4-L5 was the most common area involved. Decreased disc height was common at L5-S1. Most patients showed loss of lumbar lordosis. Annular disc tear, disc herniation, disc extrusion, narrowing of the spinal canal, narrowing of lateral recess, compression of neural foramen, ligamentum flavum thickening, and facet arthropathy were common at the L4 -L5 disc level. Disc bulge was common at L3-L4 and L4-L5. Posterior osteophytes were common at L3-L4 and L5-S1. L1-L2 disc involvement and spondylolisthesis were less common. [17]

In a meta-analysis of 20 studies evaluating MRI in asymptomatic individuals, the reported prevalence of disc abnormalities at any level were 20-83% for reduction in signal intensity, 10-81% for disc bulges, 3-63% for disc protrusion (versus 0 -24% for disc extrusion), 3-56% for disc narrowing, and 6-56% with annular tears. [2, 3]

CT scan myelography may be preferred by surgeons for evaluating patients before reoperation or for evaluating patients who have severely spondylotic changes. This is because CT scan myelography can delineate bony structures better than MRI.

Plain radiographs, especially with weight-bearing flexion and extension views, can be a useful adjunct to other radiographic evaluations. Some spine tumors, instabilities, malalignments, and congenital anomalies can be identified best with plain radiographs. Obtain plain films on all patients prior to surgery.