Influence of small intestine wall changes after electrically welded anastomoses of different types for the anastomotic tensile strength

Abstract

The aim — to study the effect on the clinical rupture properties of the electric welded anastomosis, the morphological transformations in the wall of the small intestine after the linear and multi­point methods application.Materials and methods. In the areas of the small intestine with a diameter of 25 to 26 cm, under the conditions of a complex acute experiment on pigs, two double­row staple anastomoses with a stapler and 72 electro welded spot welds (toothed tweezers with a tip pressure of 1.8 N/mm2) and linear circular (2.1 N/mm2) as an end­to­end type. The program of the electric welding machine «Patonmed» EKVZ­300 (440 kHz) was used. Anastomoses were tested with a slow (up to 15 mm Hg/min) injection of liquid. A blind option was chosen for each type of electro welded connection: before the rupture or to the level of loss of tightness by the bracket anastomosis (24.5 mm Hg). Unbroken anastomoses were sent for histological examination.Results and discussion. All electrically welded anastomoses remained sealed at a bursting pressure of 24.5 mm Hg. A linear discontinuity was observed at 56.6 ± 9.2 mm Hg, point — at 38.2 ± 4.2 mm Hg. The thickness of the linear anastomosis compound was 0.1 to 0.16 mm and was slightly different in morphological characteristics in the segment from 1/2 to 1/3 of the circumference, in which a greater proportion of brakes and the number of gaps between connected coagulated muscle membranes was found, although in general, the integrity of the coagulation changes along the circumference persisted. The break occurred in this segment. The thickness of the point anastomosis fluctuated wavy from 0.8 to 3.4 mm. At the point of reduction of the jagged electrodes, there was a connection of the muscular membranes, a spatial orientation of the cell fragments and fibers, and the formation of a conglomerate. Perifocal muscular layers did not merge, although they were part of the coagulation conglomerate, which covered mainly the muscular and submucosa layers. Serous membranes were connected. On the example of a multipoint electrically welded junction of the intestinal walls, it is possible to estimate the margin of safety, which can have a continuous electro welded connection, and also characterize the permissible unevenness of the morphological transformations while providing clinically necessary strength and tightness parameters.Conclusions. Despite the fluctuations of the electrically welded tissues transformations depth along the ileum anastomosis circumference, the coagulated muscle layers merge presence and the integrity of the welding changes along the anastomosis line, which is based on parameters of the instrument and impulses, provides the significantly higher bursting pressure, comparing the stapled anastomosis. The tissues transformations depth as well as continuous merge density of coagulated muscles and fibers inside the linear type of welded anastomosis establishes it’s comparatively exceeded strength.