Mechanical and biological aspects of the problem of intestinal anastomosis of humans | Mekhanika | kompozitsionnykh | materialov i konstruktsii
> Volume 5 > №4 / 1999 / Pages: 109-135

Mechanical and biological aspects of the problem of intestinal anastomosis of humans

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The problem of reliability of intestinal anastomosis (i.e. joints of hollow organs) was and is quite actual for surgery. Failure of anastomosis (loss of leakproofness) often results in lethal outcome. In spite of more than a century long history of the modern doctrine of gastrointestinal stitches, an efficient scientific approach to the problem of joining of organs of alimentary canal has not been developed yet. At that, all the major fundamental questions were formulated long ago. One of the principal questions is a selection of stitch technique. What should be preferred – knot-type stitch or continuous stitch, one- or multi-row stitch; what is the optimal pitch of the stitch, how many material should be covered by stitches, etc. Based on analysis of the publications devoted to investigation of the problem of opulence of intestinal anastomosis of humans and animals, we come to the conclusion that determination of optimality of surgery technique is impossible in the experiments ‘in vivio’. The historical experience of investigations proves this. For example, the fact is that insolvency of anastomosis of large intestine is clinically registered in approximately 14% of cases and is roentgenographically registered in 40-51% of cases. That is why, the method of solution of the problem of intestinal anastomosis of humans (IAH) and the target of the study should be in the statement and solution of the problem of multiparametric optimization with respect to the whole set of parameters of anastomosis. The criteria of optimality must be also obtained and the problem of dynamical simulation must be stated. Among this variety of problems, the problems of mechanics are of a major importance. Solution of these problems of mechanics requires, first, the knowledge of mechanical behavior of the materials of bowels and stitching suture. The criterion for selection of optimal surgery technique should be the followed development of anastomosis, defined by competition of the processes of necrosis and healing. However, such an observation can be scarcely realized in practice. Yet, the problems can be also reduced to mechanical problems of filtration of blood and plasma in the anastomosis. In the work presented, we make an attempt to determine the complete set of problems of mechanics of intestinal anastomosis. We present the results of study of mechanical behavior of material of intestinal wall subjected to stretching in two principal directions. We are the first to show that the diagram s(e) of stretching along intestine axis has a form of a bimodal curve, that is, it is a curve with two maximums, and the diagram in the circular direction has a form of a unimodal curve. We propose a rational method for processing the results of tests. It is found that the presence of stitch qualitatively changes the character of the diagram of stretching along the axis of intestine. We make an attempt to explain this and some other phenomena disclosed.