Biocompatibility and tissue integration of a novel shape memory surgical mesh for ventral hernia: in vivo animal studies

Abstract

Approximately 400,000 ventral hernia repair surgeries are performed each year in the United States. Many of these procedures are performed using laparoscopic minimally invasive techniques and employ the use of surgical mesh. The use of surgical mesh has been shown to reduce recurrence rates compared to standard suture repairs. The placement of surgical mesh in a ventral hernia repair procedure can be challenging, and may even complicate the procedure. Others have attempted to provide commercial solutions to the problems of mesh placement, but these have not been well accepted by the clinical community. In this article, two versions of shape memory polymer (SMP)-modified surgical mesh, and unmodified surgical mesh, were compared by performing laparoscopic manipulation in an acute porcine model. Also, SMP-integrated polyester surgical meshes were implanted in four rats for 30-33 days to evaluate chronic biocompatibility and capacity for tissue integration. Porcine results show that the modified mesh provides a controlled, temperature-activated, automated deployment when compared to an unmodified mesh. In rats, results indicate that implanted SMP-modified meshes exhibit exceptional biocompatibility and excellent integration with surrounding tissue with no noticeable differences from the unmodified counterpart. This article provides further evidence that an SMP-modified surgical mesh promises reduction in surgical placement time and that such a mesh is not substantially different from unmodified meshes in chronic biocompatibility.

Keywords: hernia repair; laparoscopic surgery; mesh placement; shape memory polymer; surgical mesh.

FIGURE 1

(a) Unmodified mesh; (b) SMP-coated porous polyester surgical mesh.

FIGURE 2

(a) Abdominal wall defect is created; (b) repaired with implanted surgical mesh and the wound is closed with clips. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]

FIGURE 3

SMP/SMP-Mesh characteristics: (a) SMP alone shows T_g = 41.5 ± 0.7°C; (b) SMP + Mesh tested in lengthwise direction shows T_g = 41.0 ± 1.0°C; (c) SMP + Mesh tested in widthwise direction shows T_g = 36.4 ± 2.6°C.

FIGURE 4

Non-porous fully coated SMP-mesh automatically unrolls after 25 s as the sample reaches body temperature. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]

FIGURE 5

Porous SMP-Mesh automatically unrolls after 31 s as the sample reaches body temperature. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]

FIGURE 6

Abdominal view of a shaved rat 30 days post-op; red arrows (left) indicate unmodified (control) mesh suture locations and blue arrows (right) indicate SMP-mesh suture locations. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]

FIGURE 7

Unmodified control mesh tissue ingrowth. Inflammatory response is as expected, demonstrating tissue ingrowth into polyester fibers and mesh pores. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]

FIGURE 8

SMP-modified mesh demonstrates similar tissue ingrowth characteristics. Inflammatory response is similar, demonstrating expected tissue ingrowth into mesh pores. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]

FIGURE 9

Picrosirius Red stain shows collagen ingrowth into unmodified mesh. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]

FIGURE 10

Picrosirius Red stain show collage ingrowth into SMP-modified mesh. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]

FIGURE 11

Tissue ingrowth of: unmodified mesh (top), with collagen fibers extending between PET fibers and through mesh pores. SMP-modified mesh (bottom), with collagen fibers extending through mesh pores only, SMP coating prevents thick scar formation. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]