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Research Papers

Deformation of Transvaginal Mesh in Response to Multiaxial Loading

[+] Author and Article Information
William R. Barone

Musculoskeletal Research Center,
Department of Bioengineering,
University of Pittsburgh,
405 Center for Bioengineering,
300 Technology Drive,
Pittsburgh, PA 15219
e-mail: william.r.barone@gmail.com

Katrina M. Knight

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

Pamela A. Moalli

Magee-Womens Research Institute,
204 Craft Avenue, Lab A320,
Pittsburgh, PA 15213
e-mail: moalpa@mail.magee.edu

Steven D. Abramowitch

Musculoskeletal Research Center,
Department of Bioengineering,
University of Pittsburgh,
405 Center for Bioengineering,
300 Technology Drive,
Pittsburgh, PA 15219;
Magee-Womens Research Institute,
204 Craft Avenue, Lab A320,
Pittsburgh, PA 15213
e-mail: sdast9@pitt.edu

1Corresponding author.

Manuscript received November 5, 2017; final manuscript received August 14, 2018; published online November 29, 2018. Assoc. Editor: David Corr.

J Biomech Eng 141(2), 021001 (Nov 29, 2018) (8 pages) Paper No: BIO-17-1506; doi: 10.1115/1.4041743 History: Received November 05, 2017; Revised August 14, 2018

Synthetic mesh for pelvic organ prolapse (POP) repair is associated with high complication rates. While current devices incorporate large pores (>1 mm), recent studies have shown that uniaxial loading of mesh reduces pore size, raising the risk for complications. However, it is difficult to translate uniaxial results to transvaginal meshes, as in vivo loading is multidirectional. Thus, the aim of this study was to (1) experimentally characterize deformation of pore diameters in a transvaginal mesh in response to clinically relevant multidirectional loading and (2) develop a computational model to simulate mesh behavior in response to in vivo loading conditions. Tension (2.5 N) was applied to each of mesh arm to simulate surgical implantation. Two loading conditions were assessed where the angle of the applied tension was altered and image analysis was used to quantify changes in pore dimensions. A computational model was developed and used to simulate pore behavior in response to these same loading conditions and the results were compared to experimental findings. For both conditions, between 26.4% and 56.6% of all pores were found to have diameters <1 mm. Significant reductions in pore diameter were noted in the inferior arms and between the two superior arms. The computational model identified the same regions, though the model generally underestimated pore deformation. This study demonstrates that multiaxial loading applied clinically has the potential to locally reduce porosity in transvaginal mesh, increasing the risk for complications. Computational simulations show potential of predicting this behavior for more complex loading conditions.

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References

Schultz, D. G. , 2008, “ Serious Complications Associated With Transvaginal Placement of Surgical Mesh in Repair of Pelvic Organ Prolapse and Stress Urinary Incontinence,” FDA Public Health Notification, Food and Drug Administration, Center for Devices and Radiological Health.
Chen, C. C. , Ridgeway, B. , and Paraiso, M. F. , 2007, “ Biologic Grafts and Synthetic Meshes in Pelvic Reconstructive Surgery,” Clin. Obstet. Gynecol., 50(2), pp. 382–441. [CrossRef]
Baessler, K. , Hewson, A. D. , Schuessler, B. , and Maher, C. F. , 2005, “ Severe Mesh Complications Following Intravaginal Slingpasty,” Obstet. Gynecol., 106(4), pp. 713–716. [CrossRef] [PubMed]
Krause, H. , Bennett, M. , Forwood, M. , and Goh, J. , 2008, “ Biomechanical Properties of Raw Meshes Used in Pelvic Floor Reconstruction,” Int. Urogynecology J. Pelvic Floor Dysfunct., 19(12), pp. 1677–1681. [CrossRef]
Shepherd, J. P. , Feola, A. J. , Abramowitch, S. D. , and Moalli, P. A. , 2012, “ Uniaxial Biomechanical Properties of Seven Different Vaginally Implanted Meshes for Pelvic Organ Prolapse,” Int. Urogynecology J. Pelvic Floor Dysfunct., 23(5), pp. 613–620. [CrossRef]
Cosson, M. , Debodinance, P. , Boukerrou, M. , Chauvet, M. P. , Lobry, P. , Crépin, G. , and Ego, A. , 2003, “ Mechanical Properties of Synthetic Implants Used in the Repair of Prolapse and Urinary Incontinence in Women: Which Is the Ideal Material?,” Int. Urogynecology J. Pelvic Floor Dysfunct., 14(3), pp. 169–178. [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. K. B. , 2011, “ Modified Classification of Surgical Meshes for Hernia Repair Based on the Analysis of 1000 Explanted Meshes,” Hernia, 16(3), pp. 251–258. [CrossRef]
Pierce, L. M. , Rao, A. , Baumann, S. S. , Glassberg, J. E. , Kuehl, T. J. , and Muir, T. W. , 2009, “ Long-Term Histologic Response to Synthetic and Biologic Graft Materials Implanted in the Vagina and Abdomen of a Rabbit Model,” Am. J. Obstet. Gynecol., 200(5), p. 546. [PubMed]
Barone, W. R. , Moalli, P. A. , and Abramowitch, S. D. , 2016, “ Textile Properties of Synthetic Prolapse Mesh in Response to Uniaxial Loading,” AJOG, 215(3), p. 326. [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, 120(2), pp. 233–243. [CrossRef] [PubMed]
Feiner, B. , and Maher, C. , 2010, “ Vaginal Mesh Contraction: Definition, Clinical Presentation, and Management,” Obstet. Gynecol., 115(2 Pt. 1), pp. 325–330. [CrossRef] [PubMed]
Kuehnert, N. , Kraemer, N. A. , Otto, J. , Donker, H. C. W. , Slabu, I. , Baumann, M. , Kuhl, C. K. , and Klinge, U. , 2012, “ In Vivo MRI Visualization of Mesh Shrinkage Using Surgical Implants Loaded With Superparamagnetic Iron Oxides,” Surg. Endoscopy Other Interventional Tech., 26(5), pp. 1468–1475. [CrossRef]
Henak, C. R. , Anderson, A. E. , and Weiss, J. A. , 2013, “ Subject-Specific Analysis of Joint Contact Mechanics: Application to the Study of Osteoarthritis and Surgical Planning,” ASME J. Biomech. Eng., 135(2), p. 021003. [CrossRef]
Henak, C. R. , Carruth, E. D. , Anderson, A. E. , Harris, M. D. , Ellis, B. J. , Peters, C. L. , and Weiss, J. A. , 2013, “ Finite Element Predictions of Cartilage Contact Mechanics in Hips With Retroverted Acetabula,” Osteoarthritis Cartilage, 21(10), pp. 1522–1529. [CrossRef] [PubMed]
Sigal, I. A. , Flanagan, J. G. , Tertinegg, I. , and Ethier, C. R. , 2009, “ Modeling Individual-Specific Human Optic Nerve Head Biomechanics—Part II: Influence of Material Properties,” Biomech. Model. Mechanobiol., 8(2), pp. 99–109. [CrossRef] [PubMed]

Figures

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Fig. 1

Experimental loading of DirectFix A using a custom testing rig. Mesh arms were placed in custom clamps and a 250 g weight was allowed to hang freely from tension posts as shown. In addition, two fixation rods located on a raised platform were placed through individual pores in the mesh body.

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Fig. 2

For experimental testing, two separate loading conditions were considered. Under the first condition, upper arms were loaded at 40 deg and the lower arms were loaded at −20 deg. For condition 2, upper arms were loaded at 10 deg, while lower arms were loaded at −45 deg. All angles are relative to the horizontal axis, with the origin at the device center. A weight of 250 g was applied to each mesh arm at the prescribed angle via soft tissue clamps.

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Fig. 3

In order to model the mesh microstructure, the physical pore geometry (a) was simplified and the computational pore geometry (b) was constructed from a network of fiber (light) and knot (dark) structures. Here, the primary fibers are oriented at 45 deg relative to the horizontal ((a) and (b)). To recreate the gross geometry of DirectFix A (c), the computational model (d) was cut from the repeating pattern of the pore geometry in SOLIDWORKS.

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Fig. 4

Young's modulus and Poisson's ratio for both the knot and fiber materials. Solid and dashed lines are representative experimental uniaxial load-elongation data for Restorelle tested with fibers 0 deg and 45 deg offset, respectively. Square and diamond symbols indicate are load-elongation data points from corresponding finite element simulations (0 deg and 45 deg orientations) with the calibrated model.

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Fig. 5

Image processing was used to automatically identify mesh pores and determine their minimum diameters. First, a gradient based method was used to identify isolated clusters, representing pores. Here, each shaded cell represents a cluster of pixels identified as a pore (a). Next, the centroid of each cluster was determined (represented by individual dots) and used to determine the minimum diameter for each pore (b).

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Fig. 6

Contour plots of normalized mesh burden for deformed DirectFix A geometries. Overall, computational and experimental results demonstrate good agreement for loading condition 1 (top) and 2 (bottom). Mesh burden values were normalized by the maximum mesh burden of the undeformed geometry. Warmer colors represent greater percent increases in mesh concentration.

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Fig. 7

Bland–Altman plots for average normalized mesh burden (left) and dmin (right). The y-axis represents the difference between experimental and finite element results. Condition 1 is represented by the circular symbols and condition 2 is represented by the triangular symbols. Error bars represent standard deviation. * represents significant differences between experimental and finite element measurements (p < 0.05).

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