Electromyographical Activity of Erector Spinae and Gluteus Medius Muscles in Patients with Adolescent Idiopathic Scoliosis during Gait

Understanding the muscle activity during gait in patients with adolescent idiopathic scoliosis (AIS) is clinically important. The objectives of this study was to analyze electrical activity of erector spinae muscles at T6 (EST6), T10 (EST10) and L3 (ESL3) levels as well as gluteus medius (GM) muscle during walking in female adolescents with and without idiopathic scoliosis.

Twenty female adolescents with right thoracic scoliosis and 18 healthy adolescent control females (all 11 to 17 years old) participated in this study. An imaging system synchronized with a MA300-16 electromyography system and bipolar surface electrodes were used to measure electrical activities of EST6, EST10, ESL3 and GM muscles during gait. Repeated measure analysis of variance and MANOVA were used for the comparisons within and between groups.

During the right stance phase, the activity of right EST6 and left GM muscles in scoliotic patients were significantly (1.8 and 1.4 times) greater than that of control group (P=0.03). In the left stance phase, scoliosis group showed higher activity at right and left GM muscles than control group (P=0.04). In the right and left swing phase, the EMG activity of right GM and right EST6 muscles of scoliotic patients was respectively greater than that of controls. The right over left ratio of EST6 muscle activity for scoliosis group was higher than that for control group at all phases of gait cycle except for the right swing phase.

AIS patients displayed greater activity in the right EST6 and the right and left GM muscles during walking. AIS patients presented asymmetrical muscle activity in EST6 muscle. EMG assessment during gait might have clinical importance in the detection of scoliotic curvature progression.