THE ORGAN MODEL COMPARATIVE STUDY FOR THE ELECTRIC WELDING ANASTOMOSIS INVESTIGATION NEEDS LABORATORY EXPERIMENT

Abstract

In animal replacement by organ model for experimental human intestine modeling, it is incomprehensible the porcine organ complex remain, first of all, its intestinal wall dielectric properties as well as electrically welded compound forming possibility.

The aim of the work – to determine the selected organ model conformity to the needs of the laboratory experimental conditions for creating an intestinal anastomosis by electric welding method, instead of animal acute experiment providing.

Material and Methods. The features of thickness, impedance and substrate formation of an electrically welded tissues connection between the small intestines by 24–27 mm diameter or colon by 27–31 mm were studied. Swine organ complex was chosen as the organ model. It was cooled to 4 ºC and delivered to the laboratory within 6–10 hours. The bioimmitant was immersed in a warm (26–32 ºC) solution of 0.9 % NaCl for 10–20 min. The obtained indices were compared with those obtained in an acute experiment on a 45 kg male pig, with the consent of the bioethics committee. Eight electric welded anastomoses were created in the animal model and 52 in the organ complex. The pressure of 2.1 N/mm² or 3.0 N/mm² was applied to the electrodes. A pulsed high-frequency voltage, increasing from 80 V to 120 V, was applied for 0.2 seconds. The intestinal anastomosis site was removed for histological examination.

Results. The similarity of both groups’ tissues in elasticity and density, at the elasticity boundary, was noted under pressure. The animal had higher volume resistance of the muscle layer, but the dynamics of thinning – the same, which indicates a similar structural strength of the tissue layers. During the initial impulse, tissue impedance decreased smoothly, after which it gradually grew. During next impulse, the impedance had fallen peak, and then almost linearly increased during the entire impulse. This form of impedance reactivity stabilized to second impulse observed in 92.3 % organ probes and 96.2 % in animal. In all studies, a dense connection of the walls was formed as a result of coagulation changes in the bundles of smooth muscles and collagen fibers nonlineary, but as continuously formated structure.

Conclusions. The dynamics under compression, the electric welding impulses flow through the tissue and the electric welding anastomosis structure were the same as in organocomplex as during the animal acute experiment. As for synergistic effect on the intestinal tissues during electric welding anastomosis creating, the technology development at this field requires numerous experimental studies. Considering the basic mechanical and electrical characteristics of living tissue as well as expected morphological electrowelded transformations reproduction in the examined organ model, it looks possible to fully replace the animal model at this experimental stage, and to conduct a long laboratory experiment.