Porcine Model Of Hernia Repair Research Articles

A novel self-gripping long-term resorbable mesh providing temporary support for open primary ventral and incisional hernia

A novel synthetic fully long-term resorbable self-gripping mesh has been recently developed to reinforce soft tissue where weakness exists during ventral hernia repair open procedures. This resorbable mesh is a macroporous, knitted, poly-L-lactide, poly-trimethylene carbonate copolymer monofilament mesh with the ProGrip™ technology, providing grips on one side of the mesh. A new poly-L-lactide, poly-trimethylene copolymer was developed to provide the required features for mechanical support during at least 20 weeks covering the critical healing period, including resistance to fatigue under cyclic loading conditions, as it occurs in patients. The yarns and mesh initial physical and biomechanical properties were characterized. Then, the mesh mechanical strength was evaluated over time. The mechanical properties of the proposed mesh were found to be above the generally recognized threshold value to mechanically support the repair site of a hernia over a 20-week period during in-vitro cyclic loading test. The mesh performance was evaluated in vivo using a published preclinical porcine model of hernia repair at 4-, 12- and 20-weeks post implantation. The burst strength of the hernia repair sites reinforced with the new mesh were higher at 4 & 12 weeks and comparable at 20 weeks to the one of the native abdominal walls. At all time points, the mesh was well tolerated with moderate inflammation and was fast integrated in the abdominal wall at 4 weeks. Particularly, the grips were nicely engulfed in the newly formed connective tissue. They must facilitate the anchoring of the mesh by their extension from the mesh and their mushroom shape. The preclinical data of the self-gripping resorbable mesh suggests that it has all the favorable characteristics for future clinical use during ventral hernia repair open procedures.Graphical

OC-070 A NOVEL SELF-GRIPPING LONG-TERM RESORBABLE MESH PROVIDING TEMPORARY SUPPORT FOR PRIMARY VENTRAL AND INCISIONAL HERNIA

Abstract Medtronic recently developed a novel synthetic fully long-term resorbable self-gripping mesh to reinforce soft tissue where weakness exists during ventral hernia repair procedures. This resorbable mesh is a macroporous, knitted, poly-L-lactide, poly-trimethylene carbonate copolymer monofilament mesh with the ProGrip™ technology. The biocompatibility profile of the mesh has been extensively established and documented. No systemic nor local adverse reactions have been observed from implantation to complete resorption and metabolization of the mesh in a subcutaneous implantation preclinical rabbit model. Its performance was evaluated at 20 weeks using a modified published preclinical porcine model of hernia repair (Martin, 2013; Deeken, 2013). Histologic examination of the implantation sites confirmed that this novel mesh was well tolerated and led to new extracellular collagen matrix formation. The burst strength of the hernia repair sites reinforced with the new mesh was statistically equivalent to the one of the native abdominal walls. Currently marketed ProGrip™ meshes have been clinically and successfully used with less mechanical fixation devices than non-self-gripping meshes (Chastan, 2009; Rangwani, 2021). The new self-gripping long-term resorbable mesh fixation performance was demonstrated to be statistically equivalent to the one of ProGrip™ Self-Gripping Polyester Mesh both in ex-vivo testing and in an in vivo porcine model. This should support the ease-of-use feature of the mesh with a limited need for additional mechanical fixation, which will likely be associated with a shorter surgical time. The preclinical tests of the self-gripping resorbable mesh are compelling enough to make it a new mesh candidate for future clinical use.

Mechanical and Histological Characteristics of Phasix™ ST Mesh in a Porcine Model of Hernia Repair

Purpose The objective of this study was to determine mechanical and histological properties of Phasix™ ST Mesh in various defect sizes and characterize the tissue replacing Phasix™ ST Mesh in a porcine model of ventral hernia repair. Methods Simulated hernia defects were surgically created in the midline of twenty-four (n = 24) Yucatan pigs. Treatment groups included 8 cm defect sutured closed (buttress) and unclosed 4 cm and 8 cm defect groups. Phasix™ ST Mesh (15 cm diameter circle) was implanted laparoscopically and fixated circumferentially with SorbaFix™ Absorbable Fixation System fasteners. The repair sites underwent mechanical, molecular weight, and histological evaluation at 48 and 72 weeks postimplantation. Results Mechanical testing of Phasix™ ST Mesh-repaired sites revealed similar strengths at both time points for all three repair types, p > 0.05 in all cases (48 weeks: 142.4 ± 6.0 N, 142.3 ± 16.5 N, and 168.8 ± 38.5 N; 72 weeks: 110.0 ± 18.3 N, 138.6 ± 42.2 N, and 160.6 ± 42.0 N for 4 cm defect, 8 cm defect, and 8 cm buttress, respectively. mean ± SEM) No significant differences were observed over time except at 72 weeks postimplantation when the 4 cm defect group exhibited significantly lower strength than the T0 strength of Phasix™ ST Mesh (204.6 ± 5.0 N, p < 0.05). The molecular weight of Phasix™ ST Mesh decreased over time, regardless of repair type. Histological analysis showed comparable mature collagen/fibrovascular tissue around and within the Phasix™ ST Mesh interstices, including the segment of mesh overlying the defect. Conclusion Phasix™ ST Mesh-repaired sites exhibited similar mechanical strengths and histological properties across all defect sizes in this porcine model.

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

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.