Textile analysis of heavyweight, midweight, and lightweight polypropylene mesh in a porcine ventral hernia model

Abstract

Purpose. The purpose of this study was to assess the burst strength and stiffness of lightweight (LW), midweight (MW), and heavyweight (HW) polypropylene mesh preimplantation and 5 months postimplantation in a porcine ventral hernia model. Methods. HW (95 g/cm 2), MW (45 g/cm 2), and LW (28 g/cm 2) polypropylene (PP) were tested as dry samples ( n = 8/mesh) before implantation using a stamp strain machine. The HW and MW PP mesh are constructed exclusively of polypropylene, and the LW PP mesh is woven with absorbable poliglecaprone monofilament. One month after creating four hernia defects in each mini-pig ( n = 6), the PP meshes (8 × 10 cm; n = 8/mesh type) were implanted in the preperitoneal space with 2 cm overlap circumferentially. At 5 months, the mesh was harvested en bloc with the abdominal wall, and testing was repeated. Specimens of the LW mesh were chemically degraded to remove the poliglecaprone and tested for comparison. Significance ( P < 0.05) was determined with a two-way ANOVA, Tukey’s test, or Student’s t-test. TABLE—ABSTRACT 107 Results: HW(a) MW(b) LW(c) LW absorbed P-value Burst strength (N) Pre-implant 1165.1 (b,c) 557.9 (a,c) 812.0 (a,b) 452.2 <0.0001 Post-implant 1111.5 (b,c) 590.88 (a) 575.0 (a) — <0.0001 Stiffness (N/mm) Pre-implant 57.22 (b,c) 52.90 (a,c) 68.57 (a,b) 39.47 <0.0001 Post-implant 62.77 (b,c) 50.16 (a,c) 41.52 (a,b) — 0.0002 Conclusion. A reduction in mean burst strength and stiffness occurs after 5 months implantation of LW PP mesh with an absorbable monofilament. The LW PP mesh has initial increased burst strength during the critical time period of tissue-mesh incorporation. Following tissue incorporation, the LW PP mesh maintains mean burst strength comparable to MW PP mesh, while becoming less stiff than HW and MW PP meshes. This may contribute to more physiologic abdominal wall compliance after lightweight PP mesh implantation long term.