MOVEMENT DISTURBANCES OF THE LUMBAR SPINE AND ABNORMAL BACK MUSCLE ELECTROMYOGRAPHIC FINDINGS IN RECURRENT LOW-BACK-PAIN

Study design. A cross-sectional analysis was done of patients with rec urrent-low back pain referring to the lower limbs. Objectives. To anal yze dynamic radiographs of forward and backward,bending of the lumbar back and to. determine, using routine neurophysiologic measurements,th e functional state of the lower nerve roots in patients with recurrent low back pain radiating to the, lower limbs. Methods. Clinical and ne urophysiologic Studies showed eight of the 108 patients with low back pain to have ventral root impingement at either L5 or S1 level. The re maining 100 patients, 56 women and 44 men (mean age, 37.6 years; range , 17-62 years), made up the study group for continuing investigation. History of tow back pain ranged from 4 months to 20 years. Results. Di sturbed intervertebral movement Was found in 51 of 100 patients. Twent y-seven percent had L5 or L4 anterolisthetic hypermobility, and 35% ha d L4; or L3 vertebral retrolisthesis. Vaguely delineated radiating sen sations in the lower limbs were common (62%). Back muscle electromyogr aphs graphs were mostly (86%) normal in patients whose low back pain w as localized. Conversely, almost three-fourths of those experiencing r adiating or referred pain had abnormal electromyographs, consistent wi th a mild degree of axonal damage in the posterior branch of the lumba r nerve root innervating the medial paraspinal muscles. This finding w as most Common among patients with retrolisthesis and simultaneous deg enerative changes. Conclusions. Evaluation of low back pain should inc lude tests for degenerative retrolisthesis, especially in patients exp eriencing radiating sensations with no evidence of root impingement, b ecause abnormal electromyographic findings showing denervation of the paraspinal muscles was most common in patients with degenerative retro listhesis.