Early imaging of integration response to polypropylene mesh in abdominal wall by environmental scanning electron microscopy: Comparison of two placement techniques and correlation with tensiometric studies

The repair of incisional hernias has taken advantage of the strength provid ed by prosthetic mesh grafts, but the best position for inserting the mater ials has not been conclusively established. Environmental scanning electron microscopy (ESEM) provides imaging of biologic samples with minimal manipu lation. We used ESEM for early imaging of the integration response to polyp ropylene meshes placed in two anatomic positions in the abdominal wall and correlated results with tensiometric studies. Two macroporous polypropylene prostheses were implanted in a rat model-one on the abdominal aponeurotic layer and one on the peritoneal surface-without creating a wall defect. Stu dies were performed over implantation intervals of 7, 15, and 30 days in st rips obtained from the polypropylene fiber-receptor repair tissue interface . Microscopic appearance, tensile strength, percent elongation, and stiffne ss were evaluated. Meshes implanted on the abdominal aponeurotic layer show ed better early tissue incorporation (higher collagen deposition, capillary density, cell accumulation) and increased tensile strength, reflecting tig hter anchorage to the abdominal wall. The percent elongation increased from day 7 to day 30 after implantation, mainly in the deep stratum. The ESEM i mages correlated well with biomechanical results, indicating the potential of this technique as a powerful, effective tool fur use in wound-healing st udies.