Characterization of the Mechanical Strength, Resorption Properties, and Histologic Characteristics of a Fully Absorbable Material (Poly-4-hydroxybutyrate—PHASIX Mesh) in a Porcine Model of Hernia Repair

Abstract

Purpose. Poly-4-hydroxybutyrate (P4HB) is a naturally derived, absorbable polymer. P4HB has been manufactured into PHASIX Mesh and P4HB Plug designs for soft tissue repair. The objective of this study was to evaluate mechanical strength, resorption properties, and histologic characteristics in a porcine model. Methods. Bilateral defects were created in the abdominal wall of n = 20 Yucatan minipigs and repaired in a bridged fashion with PHASIX Mesh or P4HB Plug fixated with SorbaFix or permanent suture, respectively. Mechanical strength, resorption properties, and histologic characteristics were evaluated at 6, 12, 26, and 52 weeks (n = 5 each). Results. PHASIX Mesh and P4HB Plug repairs exhibited similar burst strength, stiffness, and molecular weight at all time points, with no significant differences detected between the two devices (P > 0.05). PHASIX Mesh and P4HB Plug repairs also demonstrated significantly greater burst strength and stiffness than native abdominal wall at all time points (P < 0.05), and material resorption increased significantly over time (P < 0.001). Inflammatory infiltrates were mononuclear, and both devices exhibited mild to moderate granulation tissue/vascularization. Conclusions. PHASIX Mesh and P4HB Plug demonstrated significant mechanical strength compared to native abdominal wall, despite significant material resorption over time. Histological assessment revealed a comparable mild inflammatory response and mild to moderate granulation tissue/vascularization.

Surgical mesh for ventral incisional hernia repairs:Understanding mesh design

“…Vicryl (Ethicon, USA) and Dexon (American Cyanamid Co, USA), for example, are used in open abdominal wounds. The drawback to these meshes, however, is that they degrade within one to three months and are associated with high recurrence rates (23)(24)(25)(26)(27). To overcome early degradation, newer synthetic biomaterial meshes have been developed.…”

“…For example, Gore Bio-A (WL Gore and Associates, USA) mesh degrades in six months and has been shown to reduce recurrence rates, infection and pain (23,28,29). Phasix (Bard Davol Inc, USA) (23,30) and Tigr Matrix (Novus Scientific, USA) (31-33) also degrade over several months and are useful in hernia repair, as has been demonstrated in preclinical animal (23,31,32) and human pilot (33) studies. The long-term effectiveness of these newer synthetic degradable meshes remains to be tested in clinical practice.…”

“…At most 30% at 32N/cm (47) Compliance ( Figure 3C) The amount of displacement or deformation in response to a unit force Pore size ( Figure 3D) The area between mesh filaments Pores >75 µm allow macrophage infiltration, neovascularization and incorporation (74); pores >1 mm prevent granuloma bridging for polypropylene mesh (75,76) Effective pores ( Figure 3E Degradation Disappearance of the mesh material 6 months for scar tissue to reach its maximum strength; (23,88,135) for adhesion formation the timeframe is unclear (128)…”

“…In meshes that are degradable, the goal is to have the mesh last until scar or regenerative tissue replaces it and matures to maximum strength. From early experiences with Vicryl and Dexon, it is known that a three-month time frame for degradation would be inadequate (23)(24)(25). Recent data suggest a degradation time of six months could be successful, as evidenced by the studies that have demonstrated adequate outcomes with the Gore Bio-A mesh (23,28,29).…”

“…From early experiences with Vicryl and Dexon, it is known that a three-month time frame for degradation would be inadequate (23)(24)(25). Recent data suggest a degradation time of six months could be successful, as evidenced by the studies that have demonstrated adequate outcomes with the Gore Bio-A mesh (23,28,29). This is analogous to studies in skin wound healing, which suggest that wounds regain 80% of their original strength by six months (88).…”