Low back pain (LBP) is one of the most common reason for physician visits in the United States. Under the pressuer to “do something”, MRI is often quickly performed. Unfortunately, several randomized clinical trials have shown that among patients without clinical signs and symptoms indicating serious underlying conditions, early MRI imaging before a trial of conservative therapy, does not improve overall outcomes. It must be remembered that the as many as 70% of acute LBP patients, especially younger patients without signs of serious illness, have nothing more than-spinal muscle strain or sprain. On the other hand, where there are signs, such as sacroiliac joint pain, MRI is the method of choice with sensitivity of 25–85% and specificity of 90–100% . Other signs pointing to radiation if pain, neurological symptoms or a space occupying lesion, such as tumor or abscess, also argue for prompt imaging.
In 1994,Agency for Health Care Policy and Research (AHCPR) published a set of guidelines to assist physicians in the management of LBP less than 3 months in duration.This guidelien was subsequently revised. The European Commission, Research Directorate-General, Department of Policy, Coordination, and Strategy and the American College of Physicians and the American Pain Society published guidelines as well. All of them emphasize the importance of a focused history and thorough physical examination before any imaging is ordered. In addition, all agree that for patients with acute LBP and without any risk factor for serious spine abnormalities, MRI imaging within the initial 4–8 weeks should not be performed. After this period, with conservative management tried and ineffective, imaging is appropriate.
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