Bilateral Multifidus Pathophysiological Changes In Patients With Unilateral Symptoms Caused By Lumbar Disc Herniation

Objective:To investigate the pathophysiological changes of bilateral multifidus muscles by means of imaging and electrophysiological analyses in patients with unilateral symptoms caused by lumbar disc herniation.Methods:36 patients with unilateral low back and leg pain caused by lumbar disc herniation - 18 males and 18 females with age from 23 to 65(average 47.56 yrs), scored from 11 to 23(average 16.67 point) of the Roland-Morris Disability Questionnaire - were enrolled. All of them were diagnosed as disc herniations of L4/5 or L5/S1 by magnetic resonance imaging (MRI). We checked their bilateral multifidus with MRI and electromyography(EMG). MRI pictures were analyzed by the free acquired Image J software. The percentage of pimelosis area and the mean value of gross signal intensity of each multifidus were measured; the amplitude and duration of each multifidus'light contraction were recorded. These four series of data above were compared between groups. Results:Bilateral multifidus had varied degrees of pimelosis on MRI, and the symptomatic sides were more severe than the contralateral sides (P<0.05). The mean values of gross signal intensity of bilateral multifidus had increased, and the symptomatic sides were higher than the contralateral sides(P<0.05). The amplitudes and durations of bilateral multifidus' light contractions had also changed in different degrees-higher amplitudes and wider durations, and the changes of the sympathetic side was significantly more severe than the contralateral side(P<0.05).Conclusions:The radiological and electrophysiological changes of bilateral multifidus were identified in patients with unilateral symptom caused by lumbar disc herniation. The multifidus of the symptomatic sides had greater changes than the contralteral one. Our finding provides theoretical basis of multifidus-targeted exercise for the physical therapy of chronic low back pain.