3D Finite Element Pelvic Floor Modeling
In order to get a better understanding of the patient specific
factors leading to pelvic floor weakness, we propose a new diagnostic tool
conceptualized in a virtual 3D finite element model of the pelvic region.
Current methods to evaluate pelvic region kinematics in vivo (under MRI or ultra sound) consist mostly of applying a downwards pressure by either the patient itself (intra-abdominal pressure) or by pushing externally on the belly region. This is rather inconsistent and cannot be precisely mechanically controlled. We develop a new procedure with which intra vaginal boundary conditions are applied and controlled precisely. In a preliminary study the influence of the interface between the bladder and vaginal canal on the kinematics of the pelvic system has been investigated. This interface (fascias and connective tissue) was included as an individual model part with adjustable mechanical characteristics (see images, soft interface on the left, hard interface on the right).
Additional responsibility: Continuation of the project of Dr. Barbara Röhrnbauer:
Prosthetic meshes are implanted to repair weaknesses in the
abdominal wall in case of hernia or to reconstruct the anatomy in case of pelvic
organ prolapse. The structural supporting function of these meshes requires
biocompatibility also in terms of their mechanical properties.
In vivo mechanical characterization of the vaginal wall
using the aspiration technique
Combined uniaxial and biaxial mechanical
characterization of prosthetic meshes in a rabbit model and using a
non-biological model system
Mechanical characterization and modeling of a
dry mesh including different length scales
A structural model of a representative mesh unit cell was developed based on the theory of multi-body systems (Figure). Geometry and force elements/laws were defined including physical considerations and observations.
A comparison between the experimental response and the model response show good descriptive capabilities of the model, both with respect to the force response and the kinematic response (Figure).