Most adults in the United States will experience disabling lower back pain at least once in their lives, but their doctors frequently can't find a specific physical cause. In a four-year investigation that followed patients who initially had no lower back pain, researchers studied their subjects' spines using both disc injection and magnetic resonance imaging, or MRI. And they also got to know their research subjects through psychological evaluations. It turned out that psychological factors more accurately predicted who would develop lower back pain than the two diagnostic techniques.
In people both with and without back pain, MRI can detect cracks or tears in the spongy cartilage disc that cushions each unit of the spine. Some doctors also have suggested that if a patient feels pain when fluid is injected into one of the spine's discs in a procedure called discography, the patient will soon develop back pain even if he or she doesn't already feel discomfort.
"It was thought that discography could separate the wheat from the chaff," said Eugene Carragee, MD, professor of orthopedic surgery and lead author of the study, which is published in the May 15 issue of Spine. "But the bottom line is that it didn't predict who would go on to develop back pain." Carragee and colleagues also found that the invasive discography procedure itself does not injure the spinal disc enough to cause back pain.
Carragee and his team examined 46 discography subjects and 49 control individuals annually over the four-year study period. Some of them had undergone cervical surgery or had
Contact: Michelle Brandt
Stanford University Medical Center