MRI may not be the best diagnostic for low back pain, sciatica

Sep 20 2011
New research shows that magnetic resonance imaging (MRI) may not be the best tool used to diagnose lower back pain resulting from disc herniations or spinal stenosis.

MRI is an imaging technique that uses magnetic fields and radio waves to create pictures of body parts that are of interest to doctors. Bodily structures will differ from each other in magnetic and water content, which allows these pictures to distinguish different organs, tissues, etc., according to the Food and Drug Administration. This characteristic gives MRI several advantages over other imaging techniques, such as x-rays.

The spinal column consists of the spinal cord, protected by vertebrae linked to each other by facet joints, and gel-like structures called discs that cushion the spaces between the vertebrae. Eight out of every 10 Americans will experience back pain at some point in their lives, which can be caused by age-related degeneration or injury to any of these structures.

A herniated disc occurs when an intervertebral disc bulges out or ruptures, putting pressure on the surrounding nerves and causing local pain that can radiate out to other parts of the body. Spinal stenosis is a condition in which parts of the spinal canal narrow because of osteoarthritis or disc degeneration, which can cause the surrounding bones and ligaments to thicken, according to the American Academy of Orthopaedic Surgeons.

When it comes to lower back pain, medical professionals may use MRI to try to discern the exact cause. However, the imaging technique may leave some patients with the wrong diagnosis, according to new research published in European Spine Journal.

The new review analyzed eight past studies on the use of MRI in diagnosing lower back pain, taken from three databases updated through December of 2009. These included five investigations comparing MRI diagnoses of herniated discs in the lumbar region to what doctors actually saw during surgery. The review concluded that the imaging technique correctly diagnosed 75 percent of true herniations, and 77 percent of cases dealing with causes other than herniated discs. Similar data was not available for spinal stenosis.

The researchers acknowledge their review is limited by the small number of studies and other factors.