The effect of lateral electrical surface stimulation (LESS) on motor end-plates in an animal model of experimental scoliosis.

The treatment of idiopathic scoliosis is challenging because of its diverse etiology, age of onset, and long duration of intensive treatment. We examined the effect of lateral electrical surface stimulation (LESS) in an animal model of experimental scoliosis (ES) assessing the number of motor end-plates (MEPs) as a study end-point. The control group (n=5) was adapted to the experimental apparatus without stimulation, whereas ES was induced in rabbits by one-sided LESS of the longissimus dorsi muscle (LDM) for a duration of 2 months. The ES group (n=5) were subjected to a short-term corrective electrostimulation applied at the contralateral side of the spine compared to the previous LESS stimulation for 2 h daily for 3 (n=5) or 6 months (n=5). Another group of ES rabbits was subjected to a long-term corrective electrostimulation applied for 9 h daily for 3 (n=5) or 6 months (n=5). LESS applied for 2 months (ES), significantly increased the number of MEPs in LDM. The short-term corrective electrostimulation for 3 months resulted in an increased number of MEPs. However, a decrease was observed in the animals treated for 6 months. The long-term corrective electrostimulation for 3 months did not change the density of MEPs in the LDM, but for 6 months the number of MEPs in the LMD significantly decreased by ES and control groups. Thus, the results of the present study clearly show that the short-term LESS is able to influence both the number of MEPs and the effectiveness of muscle correctional adaptation in a more efficient and harmless manner than the long-term procedure.