The effect of various modes of electrical influence on the skeletal muscles of the lengthened ­segment during distraction of the lower leg according to Ilizarov

BACKGROUND: When using electrical muscle stimulation in clinical practice, it is important to select the optimal mode of this effect, since muscles largely determine the movement of the limb during the rehabilitation period.

AIM: Study of the tibialis anterior muscle reaction during Ilizarov distraction of the tibia in combination with the direct effect of direct electric current on the regenerated area in the experiment.

MATERIAL AND METHODS: The tibialis anterior muscle and biochemical parameters of blood serum (creatin kinase activity, lactate concentration) of 27 male Soviet chinchilla rabbits aged 12 months, weighing 3.85±0.18 kg, tibia length 11.2±0.13 cm, were studied. The animals were divided into three groups: control (n=9), first (n=9) and second experimental (n=9). The right tibia was fixed with an Ilizarov apparatus, a transverse osteotomy was performed in the middle third of the diaphysis, and from the 5th day, distraction began at a rhythm of 0.125 mm in 4 steps to an amount of 10% of the original length for 26 days. Fixation lasted 40 days, the period without the device was 30 days. For electrical stimulation, wire-electrodes were inserted into the diaphysis, and electrical stimulation of the bone regenerate was performed for 1 minute with a current intensity of 150 mAm. In the first group, electrical stimulation was performed starting from the day of surgery and on days 2, 4, 6, 8, 10 of the experiment. In group 2, electrical stimulation began on the 10th day after surgery and on the 12th, 14th, 16th, 18th, and 20th days of the experiment. In the control group, no electrical stimulation was applied. Using the methods of stereometric analysis of digitized images of tibialis muscle’s cross sections, the volumetric density of myosymplasts, microvessels, endomysium and nuclear component, the numerical density of myosymplasts and microvessels were determined, and the vascularization index was calculated. For statistical processing of data, the Wilcoxon W test and the Mann–Whitney T test were used; numerical data were presented in tables.

RESULTS: A positive effect of electrical stimulation on the muscles of the experimental groups was established in comparison with the control group, where fibrosis of muscle tissue at the end of the experiment was 0.2777±0.0055 mm3/mm3, which was 230% relative to the parameter of the first group (0.1217±0.0121 mm3/mm3) and 370% relative to the second group (0.0752±0.0062 mm3/mm3). An advantage was noted for the second group, where electrical stimulation was carried out from the 5th day of distraction and at the end of the experiment the histostructure of the muscle, characteristic of the intact norm, prevailed.

CONCLUSION: Electrical impact on bone regenerate from the 5th day of distraction stimulates reparative processes in the tibialis anterior muscle and serves as an organ-saving method.