Capacităţile rezistenţional-deformative ale ductului biliar comun

Abstract

Background: The fundamental directions of biology and medicine long ago included in the sphere of their research the study of physico-mechanical properties of the various anatomical structures. This information has direct use in medical practice, in the foreground in reparative interventions. At the present stage it is difficult to name any anatomical structures which have no interest in reconstructive surgery. Furthermore, each organ or tissue, viewed in terms of safety of biological materials, has certain tensometric parameter values that should be taken into consideration, including habitual daily practice, alongside with the medical one. So the safety of the biological materials (less matters the system that it represents) is one of the determining factors in adapting the organs to the new exceptional conditions of the ambient environment. At the present stage more and more anatomical structures are the subject for the tensometric research. Material and methods: Rezistentional-strain values of human common bile duct walls were established on a group comprising 30 cases. Ordinary tensometric methods were practiced. The samples were subjected to mechanical stresses only in the longitudinal direction. The length of the samples range from 4 to 6 cm. Kg/force unit of measurement was used. The limit resistance is determined by the ratio of the breaking strength in kg/f, and the sample cross-sectional area expressed in mm2 . Relative extension was expressed in %. Results: Analysis of data obtained showed the following values: d = 97.87:352.8 = 0.277 kgf/mm2 or 2.72 N/mm2 ; e = 4.55:3.11 × 100 = 146.3%; E = 277:146.3 = 1.893 gf/mm2 and 0.019 N/mm2 . So each sample was subjected to complete destruction under the action of the mechanical stresses which vary between 2.2 kg and 4.7 kg – 19.62 and 46.11 N, or between 22 and 47 MPa. Conclusions: There were set the major tensometric parameter values: force of destruction of evidence, the strength limit, maximum relative extension and the rigidity coefficient (Young’s modulus). High resistance to mechanical stress opposes human common bile duct walls, no matter how the samples were cut: strip-shaped or tubular segments (without dissecting them longitudinally). The force destruction of a sample strip is equivalent to 3.262 kg/f and tubular samples – 4.076 kg/f.