The objective of this study was to identify the histopathological features of paravertebral muscles after long-term Lateral Electrical Surface Stimulation (LESS). LESS has been applied for the treatment of idiopathic scoliosis in children and adolescents. Former studies reported the negative effect on the mental state of treated patients, as well as functional disturbances of organs, endocrine glands, and muscle metabolism. The experiment was performed on rabbits (aged 3.5 months), (n = 5 in treated, n = 5 in non-treated group). Stimulation was performed using electrical stimulator SCOL-2. The rabbits were stimulated with the traditional long-term lateral electrical surface stimulation (LESS) method as in clinical applications for children and adolescents. After microscopic examination, atrophy of fibers and cross striation of paravertebral muscles were seen, as well as degenerative lesions, necrosis, and hyperemia. Furthermore, proliferation of nuclei and infiltration of monocytogenic phagocytes mononuclear cells were observed, as well as a wide differentiation of glycosoaminoglycanes in muscle fibers on the stimulated side. However, within the tissue undergoing regression, this resulted in a clear decrease in glycosoaminoglycane levels. The observed lesions may indicate that the damage to the neuromuscular system is an effect of long-term LESS application. Thus, standard LESS therapy may deepen idiopathic scoliosis.