Biomechanical Properties of Human Pelvic Organs

in Urology (2012), 79(4), 96817-96822

OBJECTIVE: 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 ... [more ▼]

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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. [less ▲]

Vagina, abdominal skin, and aponeurosis: do they have similar biomechanical properties?

in International urogynecology journal (2011), 22(1), 23-7

INTRODUCTION AND HYPOTHESIS: despite minimal fundamental works, there is an increasing use of meshes in urogynecology. The concept is mainly based on experiences with abdominal wall surgery. We aimed to ... [more ▼]

INTRODUCTION AND HYPOTHESIS: despite minimal fundamental works, there is an increasing use of meshes in urogynecology. The concept is mainly based on experiences with abdominal wall surgery. We aimed to compare the biomechanical properties of vaginal tissue, abdominal aponeurosis, and skin. METHODS: samples from 11 fresh women cadavers without prolapse were collected. Uniaxial tension tests were performed and stress-strain curves were obtained. RESULTS: biomechanical properties of the vagina, aponeurosis, and skin differed significantly. The aponeurosis was much more rigid and less extendible than the vagina and skin. Vaginal tissue was less rigid but more extendible than skin. There was no difference between the vagina and skin at low strains (p = 0.341), but a highly significant difference at large strains (p = 0.005). CONCLUSIONS: skin and aponeurosis are not suited to predict vaginal tissue biomechanics. We should be cautious when transferring experiences from abdominal wall surgery to vaginal reconstructive surgery. [less ▲]