A computational study of organ relocation after laparoscopic pectopexy to repair posthysterectomy vaginal vault prolapse

ABSTRACT

Minimally invasive surgery such as laparoscopic sacrocolpopexy, pectopexy and cervicosacropexy are widely performed for the treatment of the vaginal vault/cuff prolapse using prosthetic mesh implants to strengthen lax apical ligaments. Depending on the patient’s anatomy and the surgeon’s preference, implants of different shapes, pore architectures and polymers can be selected. In this article, a 3D model of the pelvis was built and the pectopexy technique was reproduced. The finite element model of the textile implant was sutured to the cervical stump with a bilateral fixation to the iliopectineal ligament on either side of the pelvic walls. Pelvic soft tissues and prosthetic implants were modelled as hyperelastic and linearly elastic orthotropic materials, respectively. Numerical simulations were performed after surgery at rest and during Valsalva manoeuvre. The positions and the orientation of the vagina, during increased abdominal pressure were calculated in relation to the pubococcygeal line (PCL). We found from our simulation-model that the structure of the DynaMesh®-PRP Soft (17.18 mm above PCL line) provides better support to the vaginal cuff compared to GYNEMESH (11.95 mm) and ARTISYN (6.72 mm). And the treatment with, the stiffer DynaMesh seems to provide better urethral axis (24°) than the flexible Ethicon meshes (28.5° and 29°).

KEYWORDS:

• Posthysterectomy
• prolapse
• pectopexy
• sacrocolpopexy
• mesh implant
• biomechanical modelling

Acknowledgments

The first author has been partially funded by the German Federal Ministry of Education and Research through the FHprofUnt project “BINGO”, grant number 03FH073PX2. We thank Prof. Dr. med. Mircea C. Sora, Sigmund Freud University Vienna, Austria, for the CAD model of the plastinated cross sections and his advice on the thickness of hollow organs.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1. Subsequently, Gynecare GYNEMESH® PS Nonabsorbable Prolene Soft® is also abbreviated as GYNEMESH®.

2. www.surfdriver.com.

3. compdent.uthscsa.edu/dig/itdesc.html.

4. www.meshlab.net.

5. www.rhino3d.com.

6. www.salome-platform.org.

7. http://www.code-aster.org.

Additional information

Funding

This work was supported by the German Federal Ministry of Education and Research (Bonn, Germany) [03FH073PX2].

Notes on contributors

A. Bhattarai

A. Bhattarai is a scientific employee at the FH Aachen University of Applied Sciences, Germany. Since 2013 to present, he is working in the Biomechanics Laboratory, Institute for Bioengineering, FH Aachen. He received his PhD in engineering (Dr.-Ing.) from the University of Duisburg-Essen, Germany with a thesis on computational modeling of soft tissue surgical repairs using prosthetic mesh implants in 2018. Currently, he is involved in the electro-physiological modeling of heart cells. His current research interests include non-linear mechanics, development of non-linear homogenization methods, experimentation and characterization of heterogeneous material, implementations in finite element software and 3D printing.

M. Staat

M. Staat is retired professor and was director of the Institute of Bioengineering at the FH Aachen University of Applied Sciences, Germany. He studied mechanical engineering and received his PhD in engineering (Dr.-Ing.) from RWTH Aachen University in 1987. From 1988 to 1997 he worked at the Forschungszentrum Jülich, Germany, in the Institute of Safety Research and Reactor Technology on structural reliability, probabilistic fracture mechanics and plasticity. 1998–2002 he coordinated a European reserach project on limit and shakedown analysis. His current research interests include mathematical and stochastic optimization, biomechanical modeling and numerical simulation of cells, tissues and organs, mechanical testing and modeling of soft materials including tissues and implants.