Study shows new MRI findings not attributed to serious first-time LBP episodes

Researchers concluded most MRI changes they saw were due to normal wear and tear on the spine from ADLs.

BERGEN, Norway — Age, nontraumatic progression of degenerative disc disease or facet arthrosis are more likely to account for new findings on a low-back MRI than specific disc injury associated with first-time episodes of low back pain, according to researchers from Stanford University, Palo Alto, Calif.

In their 5-year study, investigators found patients previously involved in workers’ compensation cases were far more likely to have another MRI for a low back pain (LBP) episode, after baseline.

But, few new MR findings developed during that time overall.

"The overwhelming majority of the findings and pathology were there at baseline," said Eugene J. Carragee, MD. He predicted there was a 1 in 10 to a 1 in 15 chance of detecting a new LBP event this way.

Carragee presented these results at the International Society for the Study of the Lumbar Spine 33rd Annual Meeting here.

5-year study

Carragee and colleague Eric Hurwitz, PhD, recruited 200 healthy working participants for the study who were at high risk of degenerative back disease due to a history of herniated cervical discs but who had no lumbar pain, deformity or serious pathology.

Investigators took radiographs and did MRIs of the participants' spines at baseline. They then followed up with them regarding any back symptoms or new injuries via phone interviews done at six-month intervals; they reviewed additional MRIs only for those who experienced an episode of severe acute back pain during the study period and had the new study as part of usual care with their private physicians.

The investigators performed all MRIs with a 1.5 Tesla magnet (minimum) and included T1, T2 and T2 axial studies. Blinded spine specialists the scans. Once the researchers combined the scans of the asymptomatic participants with those of real patients, they then graded levels L2 through L5-S1.

LBP events

"Back pain episodes are clearly common even when defined as [pain] >6/10 for more than a week," Carragee said. However, based on a review of symptoms vs. injuries, researchers could not link most of those LBP episodes to a particular event, only to activities of daily living or spontaneous back pain incidents.

Although many patients reported having painful events, there were few additional MRIs done in the 5 years: 67 in 51 subjects (25%). They were usually done within 12 weeks of an episode. "Mainly people with abnormal psychometrics at baseline, chronic lumbar pain at baseline, and even a history of a disputed compensation claim all predicted who would get MRI scans for back pain episodes. ... Multiple MRIs were seen exclusively or nearly exclusively in compensation cases," Carragee said.

The mean time to a second MRI in the same individual: 2.2 years. Participants mostly had the additional imaging for primary LBP.

According to results published in the abstract, only 2 new findings appeared to be clinically significant (4%): One new case of degenerative spondylolisthesis with a disc protrusion and stenosis, and 1 large extruded disc.

In 8 patients investigators detected progression of changes, but 5 of them improved, Carragee said.

For more information:
Carragee E, Hurwitz E. Are first-time episodes of serious LBP associated with new MRI findings? #1. Presented at the International Society for the Study of the Lumbar Spine 33rd Annual Meeting. June 14-17, 2006. Bergen, Norway.