MULTIFIDUS MUSCLE RECOVERY IS NOT AUTOMATIC AFTER RESOLUTION OF ACUTE, FIRST-EPISODE LOW-BACK-PAIN

Study Design. A clinical study was conducted on 39 patients with acute , first-episode, unilateral low back pain and unilateral, segmental in hibition of the multifidus muscle. Patients were allocated randomly to a control or treatment group. Objectives. To document the natural cou rse of lumbar multifidus recovery and to evaluate the effectiveness of specific, localized, exercise therapy on muscle recovery. Summary of Background Data. Acute low back pain usually resolves spontaneously, b ut the recurrence rate is high. Inhibition of multifidus occurs with a cute, first-episode, low back pain, and pathologic changes in this mus cle have been linked with poor outcome and recurrence of symptoms. Met hods. Patients in group 1 received medical treatment only. Patients in group 2 received medical treatment and specific, localized, exercise therapy. Outcome measures for both groups included 4 weekly assessment s of pain, disability, range of motion, and size of the multifidus cro ss-sectional area. Independent examiners were blinded to group allocat ion. Patients were reassessed at a 10-week follow-up examination. Resu lts. Multifidus muscle recovery was not spontaneous on remission of pa inful symptoms in patients in group 1. Muscle recovery was more rapid and more complete in patients in group 2 who received exercise therapy (P = 0.0001). Other outcome measurements were similar for the two gro ups at the 4-week examination. Although they resumed normal levels of activity, patients in group 1 still had decreased multifidus muscle si ze at the 10-week follow-up examination. Conclusions. Multifidus muscl e recovery is not spontaneous on remission of painful symptoms. Lack o f localized, muscle support may be one reason for the high recurrence rate of low back pain following the initial episode.