Non-invasive Assessment of the Gracilis Muscle by Means of Surface Electromyography Electrode Arrays

Purpose The purpose of the study was the non-invasive investigation of the innervation zone (IZ) location of the gracilis muscle of both thighs by means of surface electromyography (EMG). Materials and methods Multichannel EMG signals were detected by means of a flexible array of 16 equally spaced silver bar electrodes. Tests were performed on both gracilis muscles on 15 subjects. Motor unit (MU) action potentials were visually identified and extracted. The locations of the IZs of the recognized MUs were statistically analyzed to find significant differences between the subjects and between the right and left muscle of each subject. Results and conclusions A statistically significant difference was found between the gracilis IZ position in the two sides, with more proximal IZs on the left side. This difference suggests a possible role of surface EMG in preoperative evaluation of patients prepared for the dynamic graciloplasty procedure. This test would provide an objective criterion for the choice of the gracilis muscle to be transposed with the highest probability of success.