Department of Gynaecology, Jeanne de Flandre Hospital-CHRU de Lille, University Nord de France, Lille, France.
Urology. 2012 Apr;79(4):968.e17-22. doi: 10.1016/j.urology.2011.11.010. Epub 2012 Jan 13.
To comparatively define the biomechanical characteristics of the pelvic organs (the vagina, bladder, and rectum), which are crucial for the maintenance of pelvic support. Despite minimal fundamental studies, meshes are increasingly implanted into the vesicovaginal and rectovaginal spaces to replace disrupted native tissues and to treat pelvic organ prolapse. However, the mechanical characteristics of these materials have not yet been compared with those of the "functional unit," the vagina, bladder, and rectum.
Samples from 5 fresh female cadavers without prolapse were collected. Uniaxial tension tests under monotonic and cyclic loading were performed and the stress-strain curves obtained.
The biomechanical properties of the vaginal, bladder, and rectal tissues differed significantly. We were able to demonstrate a nonlinear relationship between the stress and strain and a visco-hyperelastic behavior with a Mullins effect of damage of the tissues examined. Comparable rigidity was found between the investigated tissues at low strains; however, at large strain levels, marked differences could be observed. The vagina was much more rigid and less extendible than the rectal tissue, which, in turn, was more rigid than the bladder tissue. The anterior and posterior vagina revealed a different stiffness, and the bladder tissue was anisotropic at large strain levels.
Our results underline the pivotal role of the vaginal tissue for the maintenance of pelvic support. The observed differences with respect to tissue rigidity should have pronounced effects on the physiologic organ function, pointing to the necessity of a differentiated view on using the same prosthetic material for different anatomic locations.
比较定义骨盆器官（阴道、膀胱和直肠）的生物力学特性，这些特性对维持骨盆支撑至关重要。尽管基础研究很少，但网片越来越多地被植入膀胱阴道和直肠阴道间隙，以替代受损的固有组织并治疗盆腔器官脱垂。然而，这些材料的机械特性尚未与“功能单位”（阴道、膀胱和直肠）进行比较。
收集 5 例无脱垂的新鲜女性尸体标本。对标本进行单调和循环加载下的单轴拉伸试验，并获得应力-应变曲线。
阴道、膀胱和直肠组织的生物力学特性有显著差异。我们能够证明所研究组织的应力-应变关系呈非线性，且具有粘弹性和损伤的 Mullins 效应。在低应变水平下，研究的组织之间具有相似的刚性；然而，在大应变水平下，可以观察到明显的差异。阴道比直肠组织更僵硬且不易拉伸，而直肠组织比膀胱组织更僵硬。阴道前壁和后壁的刚度不同，膀胱组织在大应变水平下具有各向异性。
我们的结果强调了阴道组织在维持骨盆支撑中的关键作用。组织刚性方面的观察到的差异应该对生理器官功能产生显著影响，这表明需要对不同解剖部位使用相同的假体材料有不同的看法。
