The tissue integration and the formation of adhesions in the repair of abdominal wall defects are principally led to the topology and the mechanical properties of implanted prosthesis. In this study we analyzed the influence of the topology of the meshes for abdominal wall repair, made of polypropylene (PP), evaluating its ability to prevent and to minimize the formation of adhesions, and to promote tissue ingrowth. Two series of in vivo studies were performed. In the first, two types of PP meshes, a lightweight macroporous mesh (LWM) and a heavyweight microporous mesh (HWM) were compared with determine the optimal porosity for tissue integration. In the second, a composite mesh, Clear Mesh Composite (CMC), made of a LWM sewn on a PP planar smooth film, was compared with a PP planar film, to demonstrate how two different topologies of same material are able to induce different tissue integration with the abdominal wall and different adhesion with internal organs. In both studies, the prostheses were implanted in Wistar rats and histological analysis and mechanical characterization of tissue coupled with the implants were performed. LWM showed better host tissue ingrowth in comparison to HWM. CMC prosthesis showed no adhesions to the viscera and no strong foreign body reaction, moreover its elasticity and anisotropy index were more similar to that of natural tissue. These results demonstrated that the surface morphology of PP surgical meshes allowed to modulate their repair ability. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1220-1228, 2016.

We describe the laparoscopic management of diaphragmatic hernia (DH) caused by vertebral pedicle screw displacement. A 58-year-old woman underwent surgery for scoliosis and underwent posterior pedicle screw fixation. In the first postoperative (PO)day, she developed mild dyspnea. An anteroposterior chest radiograph revealed bilateral pleural effusion, which was more pronounced on the left side. A thoracoabdominal computed tomography (CT) scan, performed in the second PO day, revealed a solid mass in the pleural cavity that was associated with screw displacement, which had also entered into the peritoneal cavity without apparent other lesion of hollow and solid viscous. In the third PO day, after the screw was removed, explorative laparoscopy was carried out. We observed herniation of the omentum through a small diaphragmatic tear. Once the absence of visceral injury was confirmed, we reduced the omentum into the abdomen. Then, we repaired the hernia by applying a dual layer polypropylene mesh over the defect with a 3-cm overlap. The remainder of the postoperative period was uneventful. Iatrogenic DH due to a pedicle screw displacement has never been described before. In cases of pleural effusion following spinal surgery, rapid assessment and treatment are crucial. We conclude that a laparoscopic approach to iatrogenic DH could be feasible and effective in a hemodynamically stable patient with negative CT findings because it enables the completion of the diagnostic cascade and the repair of the tear, providing excellent visualization of the abdominal viscera and diaphragmatic tears.

Hernias are generally repaired using synthetic prostheses. Infection may already be present or develop during implantation. Based on the increasing resistance to antibiotics, and the well-known antimicrobial properties of silver (Ag), the possibility of coating hernia prostheses with a nanostructured layer containing Ag was explored. Prostheses (Clear Mesh Composite [CMC]) made up of two polypropylene layers (macroporous light mesh and thin transparent film) were tested with human mesothelial cells from omentum biopsies. Mesotheliocytes modulate abdominal wall healing producing cytokines, growth factors, and adhesion molecules. Evaluating the growth of these cells on CMC or film alone showed that cell numbers on CMC increased over time, and were higher than those on film alone. Vimentin immunostaining confirmed the cells to be mesotheliocytes. Subsequently, the biocompatibility of mesh layer, coated or not with a thin layer of Ag/SiO2 -nanoclusters, was analyzed, showing no difference in absence or presence of Ag/SiO2 . Differently, TGF-β2 production, involved in tissue repair and fibrosis, increased in the presence of Ag/SiO2 . Moreover, Ag/SiO2 -coated mesh showed antibacterial properties. In conclusion, the mesh layer coated with Ag/SiO2 afforded cell growth, and showed antibacterial activity. Coating only the mesh layer did not decrease film transparency, and did not favor the formation of adhesions on the visceral side. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1586-1593, 2017.