0
Research Papers

Preventing Mesh Pore Collapse by Designing Mesh Pores With Auxetic Geometries: A Comprehensive Evaluation Via Computational Modeling

[+] Author and Article Information
Katrina M. Knight

Department of Bioengineering,
Musculoskeletal Research Center,
University of Pittsburgh,
405 Center for Bioengineering
300 Technology Drive,
Pittsburgh, PA 15219
e-mail: kmk144@pitt.edu

Pamela A. Moalli

Department of Obstetrics and Gynecology and
Reproductive Sciences,
Magee-Womens Research Institute,
Magee Womens Hospital,
University of Pittsburgh,
204 Craft Avenue,
Pittsburgh, PA 15213
e-mail: moalpa@mail.magee.edu

Steven D. Abramowitch

Department of Bioengineering,
Musculoskeletal Research Center,
University of Pittsburgh,
Magee-Womens Research Institute,
Magee-Womens Hospital,
University of Pittsburgh,
309 Center for Bioengineering
300 Technology Drive,
Pittsburgh, PA 15219
e-mail: sdast9@pitt.edu

1Corresponding author.

Manuscript received August 22, 2017; final manuscript received January 8, 2018; published online March 1, 2018. Assoc. Editor: Jeffrey Ruberti.

J Biomech Eng 140(5), 051005 (Mar 01, 2018) (8 pages) Paper No: BIO-17-1379; doi: 10.1115/1.4039058 History: Received August 22, 2017; Revised January 08, 2018

Pelvic organ prolapse (POP) meshes are exposed to predominately tensile loading conditions in vivo that can lead to pore collapse by 70–90%, decreasing overall porosity and providing a plausible mechanism for the contraction/shrinkage of mesh observed following implantation. To prevent pore collapse, we proposed to design synthetic meshes with a macrostructure that results in auxetic behavior, the pores expand laterally, instead of contracting when loaded. Such behavior can be achieved with a range of auxetic structures/geometries. This study utilized finite element analysis (FEA) to assess the behavior of mesh models with eight auxetic pore geometries subjected to uniaxial loading to evaluate their potential to allow for pore expansion while simultaneously providing resistance to tensile loading. Overall, substituting auxetic geometries for standard pore geometries yielded more pore expansion, but often at the expense of increased model elongation, with two of the eight auxetics not able to maintain pore expansion at higher levels of tension. Meshes with stable pore geometries that remain open with loading will afford the ingrowth of host tissue into the pores and improved integration of the mesh. Given the demonstrated ability of auxetic geometries to allow for pore size maintenance (and pore expansion), auxetically designed meshes have the potential to significantly impact surgical outcomes and decrease the likelihood of major mesh-related complications.

FIGURES IN THIS ARTICLE
<>
Copyright © 2018 by ASME
Your Session has timed out. Please sign back in to continue.

References

U.S. Food and Drug Administration, 2011, “Surgical Mesh for Treatment of Women With Pelvic Organ Prolapse and Stress Urinary Incontinence—FDA Executive Summary,” U.S. Food and Drug Administration, Silver Spring, MD, accessed Jan. 29, 2018, http://www.thesenatorsfirm.com/documents/OBS.pdf
Altman, D. , Väyrynen, T. , Engh, M. E. , Axelsen, S. , and Falconer, C. , 2011, “ Anterior Colporrhaphy Versus Transvaginal Mesh for Pelvic-Organ Prolapse,” New Engl. J. Med., 364(19), pp. 1826–1836. [CrossRef]
Barone, W. R. , Moalli, P. A. , and Abramowitch, S. D. , 2016, “ Textile Properties of Synthetic Prolapse Mesh in Response to Uniaxial Loading,” Am. J. Obstet. Gynecol., 215(3), p. 326. [CrossRef] [PubMed]
Feiner, B. , and Maher, C. , 2010, “ Vaginal Mesh Contraction: Definition, Clinical Presentation, and Management,” Obstet. Gynecol., 115(2), pp. 325–330. [CrossRef] [PubMed]
Feola, A. , Pal, S. , Moalli, P. , Maiti, S. , and Abramowitch, S. , 2014, “ Varying Degrees of Nonlinear Mechanical Behavior Arising From Geometric Differences of Urogynecological Meshes,” J. Biomech., 47(11), pp. 2584–2589. [CrossRef] [PubMed]
Barone, W. R. , Amini, R. , Maiti, S. , Moalli, P. A. , and Abramowitch, S. D. , 2015, “ The Impact of Boundary Conditions on Surface Curvature of Polypropylene Mesh in Response to Uniaxial Loading,” J. Biomech., 48(9), pp. 1566–1574. [CrossRef] [PubMed]
Otto, J. , Kaldenhoff, E. , Kirschner-Hermanns, R. , Mühl, T. , and Klinge, U. , 2014, “ Elongation of Textile Pelvic Floor Implants Under Load Is Related to Complete Loss of Effective Porosity, Thereby Favoring Incorporation in Scar Plates,” J. Biomed. Mater. Res. Part A, 102(4), pp. 1079–1084. [CrossRef]
Greca, F. H. , De Paula, J. B. , Biondo-Simões, M. L. P. , Da Costa, F. D. , Da Silva, A. P. G. , Time, S. , and Mansur, A. , 2001, “ The Influence of Differing Pore Sizes on the Biocompatibility of Two Polypropylene Meshes in the Repair of Abdominal Defects: Experimental Study in Dogs,” Hernia, 5(2), pp. 59–64. [CrossRef] [PubMed]
Greca, F. H. , Souza-Filho, Z. A. , Giovanini, A. , Rubin, M. R. , Kuenzer, R. F. , Reese, F. B. , and Araujo, L. M. , 2008, “ The Influence of Porosity on the Integration Histology of Two Polypropylene Meshes for the Treatment of Abdominal Wall Defects in Dogs,” Hernia, 12(1), pp. 45–49. [CrossRef] [PubMed]
Klinge, U. , Klosterhalfen, B. , Birkenhauer, V. , Junge, K. , Conze, J. , and Schumpelick, V. , 2002, “ Impact of Polymer Pore Size on the Interface Scar Formation in a Rat Model,” J. Surg. Res., 103(2), pp. 208–214. [CrossRef] [PubMed]
Orenstein, S. B. , Saberski, E. R. , Kreutzer, D. L. , and Novitsky, Y. W. , 2012, “ Comparative Analysis of Histopathologic Effects of Synthetic Meshes Based on Material, Weight, and Pore Size in Mice,” J. Surg. Res., 176(2), pp. 423–429. [CrossRef] [PubMed]
Burriesci, G. , and Bergamasco, G. , 2007, “Annuloplasty Prosthesis With an Auxetic Structure,” U.S. Patent No. US8034103 B2.
Scarpa, F. , 2008, “ Auxetic Materials for Bioprostheses,” IEEE Signal Process. Mag., 25(5), pp. 126–128. [CrossRef]
Mühl, T. , Binnebösel, M. , Klinge, U. , and Goedderz, T. , 2008, “ New Objective Measurement to Characterize the Porosity of Textile Implants,” J. Biomed. Mater. Res. Part B Appl. Biomater., 84(1), pp. 176–183. [CrossRef] [PubMed]
Cobb, W. S. , Burns, J. M. , Kercher, K. W. , Matthews, B. D. , James Norton, H. , and Todd Heniford, B. , 2005, “ Normal Intraabdominal Pressure in Healthy Adults,” J. Surg. Res., 129(2), pp. 231–235. [CrossRef] [PubMed]
Howard, D. , Miller, J. M. , Delancey, J. O. , and Ashton-Miller, J. A. , 2000, “ Differential Effects of Cough, Valsalva, and Continence Status on Vesical Neck Movement,” Obstet. Gynecol., 95(4), pp. 535–540. [PubMed]
Hsu, Y. , Chen, L. , Tumbarello, J. , Ashton-Miller, J. A. , and DeLancey, J. O. , 2010, “ In Vivo Assessment of Anterior Compartment Compliance and Its Relation to Prolapse,” Int. Urogynecol. J., 21(9), pp. 1111–1115. [CrossRef] [PubMed]
Junginger, B. , Baessler, K. , Sapsford, R. , and Hodges, P. W. , 2010, “ Effect of Abdominal and Pelvic Floor Tasks on Muscle Activity, Abdominal Pressure and Bladder Neck,” Int. Urogynecol. J., 21(1), pp. 69–77. [CrossRef] [PubMed]
Noakes, K. F. , Pullan, A. J. , Bissett, I. P. , and Cheng, L. K. , 2008, “ Subject Specific Finite Elasticity Simulations of the Pelvic Floor,” J. Biomech., 41(14), pp. 3060–3065. [CrossRef] [PubMed]
Gao, S.-S. , Zhang, Y.-R. , Zhu, Z.-L. , and Yu, H.-Y. , 2012, “ Micromotions and Combined Damages at the Dental Implant/Bone Interface,” Int. J. Oral Sci., 4(4), pp. 182–188. [CrossRef] [PubMed]
Holt, B. , Tripathi, A. , and Morgan, J. , 2008, “ Viscoelastic Response of Human Skin to Low Magnitude Physiologically Relevant Shear,” J. Biomech., 41(12), pp. 2689–2695. [CrossRef] [PubMed]
Klinge, U. , Junge, K. , Stumpf, M. , Öttinger, A. P. , and Klosterhalfen, B. , 2002, “ Functional and Morphological Evaluation of a Low-Weight, Monofilament Polypropylene Mesh for Hernia Repair,” J. Biomed. Mater. Res., 63(2), pp. 129–136. [CrossRef] [PubMed]
Klinge, U. , Klosterhalfen, B. , Conze, J. , Limberg, W. , Obolenski, B. , Öttinger, A. P. , and Schumpelick, V. , 1998, “ Modified Mesh for Hernia Repair That Is Adapted to the Physiology of the Abdominal Wall,” Eur. J. Surg., 164(12), pp. 951–960. [CrossRef] [PubMed]
Klinge, U. , Klosterhalfen, B. , Muller, M. , Ottinger, A. P. , and Schumpelick, V. , 1998, “ Shrinking of Polypropylene Mesh In Vivo: An Experimental Study in Dogs,” Eur. J. Surg., 164(12), pp. 965–969. [CrossRef] [PubMed]
O'Dwyer, P. J. , Kingsnorth, A. N. , Molloy, R. G. , Small, P. K. , Lammers, B. , and Horeyseck, G. , 2005, “ Randomized Clinical Trial Assessing Impact of a Lightweight or Heavyweight Mesh on Chronic Pain After Inguinal Hernia Repair,” Br. J. Surg., 92(2), pp. 166–170. [CrossRef] [PubMed]
Nolfi, A. L. , Brown, B. N. , Liang, R. , Palcsey, S. L. , Bonidie, M. J. , Abramowitch, S. D. , and Moalli, P. A. , 2016, “ Host Response to Synthetic Mesh in Women With Mesh Complications,” Am. J. Obstet. Gynecol., 215(2), pp. 206.e1–206.e8. [CrossRef]
Feola, A. , Abramowitch, S. , Jallah, Z. , Stein, S. , Barone, W. , Palcsey, S. , and Moalli, P. , 2013, “ Deterioration in Biomechanical Properties of the Vagina Following Implantation of a High-Stiffness Prolapse Mesh,” BJOG: Int. J. Obstet. Gynaecol., 120(2), pp. 224–232. [CrossRef]
Liang, R. , Abramowitch, S. , Knight, K. , Palcsey, S. , Nolfi, A. , Feola, A. , Stein, S. , and Moalli, P. A. , 2013, “ Vaginal Degeneration Following Implantation of Synthetic Mesh With Increased Stiffness,” BJOG: Int. J. Obstet. Gynaecol., 120(2), pp. 233–243. [CrossRef]
Goel, V. K. , Lim, T. H. , Gwon, J. , Chen, J. Y. , Winterbottom, J. M. , Park, J. B. , Weinstein, J. N. , and Ahn, J. Y. , 1991, “ Effects of Rigidity of an Internal Fixation Device. A Comprehensive Biomechanical Investigation,” Spine, 16(3), pp. S155–S161. [CrossRef] [PubMed]
Jallah, Z. , Liang, R. , Feola, A. , Barone, W. , Palcsey, S. , Abramowitch, S. , Yoshimura, N. , and Moalli, P. , 2015, “ The Impact of Prolapse Mesh on Vaginal Smooth Muscle Structure and Function,” BJOG: Int. J. Obstet. Gynaecol., 123(7), pp. 1076–1085. [CrossRef]
Rumian, A. P. , Draper, E. R. , Wallace, A. L. , and Goodship, A. E. , 2009, “ The Influence of the Mechanical Environment on Remodelling of the Patellar Tendon,” J. Bone Joint Surg. Br., 91(4), pp. 557–564. [CrossRef] [PubMed]

Figures

Grahic Jump Location
Fig. 1

Schematic of a sacrocolpopexy in which the mesh is attached to the anterior and posterior walls of the vagina and fixed to the sacrum. In vivo intra-abdominal pressure exerts a downward force on the pelvic organs. This results in a tensile force along the longitudinal axis of the mesh.

Grahic Jump Location
Fig. 2

Orthographic frontal plain views of three-dimensional auxetic CAD models with eight different auxetic pore geometries. Note the models pictured represent only a portion of the total length of the CAD models utilized in the FEA.

Grahic Jump Location
Fig. 3

Standard CAD models (top images) were created with square, diamond, and hexagon shaped pores, which are commonly used pore shapes for commercial synthetic meshes (bottom images). Note, the outlined shapes (in bold) in the commercial images represent the geometry that was used to create the respective CAD model. Actual images of mesh (bottom images) are 10 mm × 10 mm.

Grahic Jump Location
Fig. 4

Finite element simulation of the square pore model with a Neo-Hookean material (Neo-Hookean, triangle) was able to accurately capture the ex vivo, nonlinear load-elongation behavior of Restorelle uniaxially loaded to 3 N (experimental, diamond)

Grahic Jump Location
Fig. 5

To simulate a uniaxial tensile test, the bottom edge of the models was fixed in translation and rotation, while the top edge was fixed to a rigid body

Grahic Jump Location
Fig. 6

FEA results at 0 N and 3 N for the standard models. The pores of the square model (SQ) remained relatively open, whereas the pores of the diamond (D) and hexagon(a) (Ha) models collapsed resulting in model contraction. RE = relative elongation.

Grahic Jump Location
Fig. 7

FEA results at 0 N and 3 N for the bowtie (B), spiral (S), hexagon(b) (Hb), and square grid (SG) auxetic models. Pore expansion is apparent for all models pictured. RE = relative elongation.

Grahic Jump Location
Fig. 8

FEA results at 0 N and 3 N for the triangle (T), chiral hexagon (CH), square chiral(a) (SCa), and square chiral(b) (SCb) auxetic models. The triangles and circles within these models all contracted. RE = relative elongation.

Grahic Jump Location
Fig. 9

Relative lateral contraction results with increasing tension for both the standard and auxetic models. As anticipated, the relative lateral contraction was positive for the nonauxetic models for all levels of tension. Initially, the relative lateral contraction was negative for all auxetic models. However, at 1.5 N and 2.4 N, the relative lateral contraction was positive (and remained positive) for the triangle and chiral hexagon models, respectively. A positive value indicates model contraction, and a negative value indicates expansion.

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In