COMPARING THE BIOLOGICAL RESPONSE OF CONVENTIONAL STATIC MESHES AND DYNAMIC RESPONSIVE IMPLANTS

Introduction: Inguinal hernia repair represent one of the most performed surgical procedure in the world. Notwithstanding the progress in prosthetic material and surgical procedures, the rate of complications remains high. Actually, chronic pain and discomfort are often source of debate among herniologists. Poor quality of tissue incorporation, such as stiff scar plaque leading to mesh shrinkage, is the typical results of conventional static implants that may lead to these adverse events. Recently, a new type of prosthesis, a 3D dynamic responsive implant, was introduced to the market. This device, designed to be positioned fixation-free, seems to induce the development of viable and more structured tissue instead of regressive fibrotic scarring. To highlight the differences in the biologic response between the conventional static meshes and this newly designed 3D dynamic responsive implant, a histological comparison was carried out. The scope of the study is to determine the quality of tissue incorporation in both types of implants, removed or biopsied after short, medium, and long term post implantation. Methods: The histological comparison has been carried out by in conventional flat meshes and 3D dynamic responsive implants used 'f) Springer Hernia (2015) (SuppI2):S3-S194 for inguinal hernia repair. The quality of tissue incorporation in the short-term (after 3-6 weeks), mid-term (3-4 months) and long-term (6-8 months) after placement was the highpoint of the investigation. Were examined 15 biopsies from conventional 'light weight - large porous' prostheses and biopsy specimen removed from fifteen 3D dynamic implants. All biopsy samples have been excised during recurrent hernia repair or other groin surgeries Results: Oreat differences of biologic response between the two types of implants were identified. Histologically, the 3D dynamic prosthesis showed the incorporation of tissue elements more similar to the tissue components of the abdominal wall. Negligible or absent inflammatory response, slack and well-hydrated connective ingrowth, great amount of elastic fibers, mature and abundant vascular structures and well-formed nervous structures were evidenced among the 3D structure of this implant. On the contrary, these features were completely absent within the conventional static meshes. These implants showed the ingrowth of thin and hardened fibrotic scar unanimously considered source of mesh shrinkage. In addition, these findings were associated to noteworthy chronic inflammatory infiltration evident also long term after placement. Conclusion: The main scope ofthe investigation is addressing a significant question: can an implant for inguinal hernia repair promote good quality biological ingrowth, addressing tissue regeneration instead of simply scar formation? The results of the study appears to expand our knowledge concerning the process of tissue incorporation in hernia prosthetics. These outcomes show that shape and attitude of the implant are important to induce an improved biologic response. From the results, it is clear that prosthetic compliance to cyclical load is essential to induce better quality response, ensuring that the new developed tissue works in in synchrony with the surrounding groin structures. In the 3D dynamic implants, the biologic response resembles much more closely the natural structures of the abdominal wall. All these features were absolutely lacking in the conventional static meshes, where a long acting inflammatory reaction together with the ingrowth of hardened, avascular, and dehydrated fibrotic tissue, embodies the typical result of a regressive process. Latest literature demonstrates that hernia is a degenerative disease. Therefore, by considering the pathogenesis of hernia disease, the objective of the surgical repair should be the regeneration of the abdominal wall components. The comparative evaluation between the two types of implants seems to confirm that, thanks to its dynamic compliance, the 3D dynamic implant stimulates the regeneration of the groin structures. Thus addressing the pathogenesis of hernia disease