RESUMO
BACKGROUND: Laparoscopic ventral hernia repair is becoming a popular technique with good results and fast postoperative recovery. The mesh is placed directly under the peritoneum and anchored with transabdominal sutures and tacks. However, the ideal size of the mesh covering the hernia orifice is know, nor the ideal type or amount of tacks has to be described. METHODS: To assess the forces acting on a single tack, a mathematical model of the ventral hernia was created. The force was described in reference to the surface of the hernia orifice and the pressure in the abdominal cavity. The following different types of mesh were examined in vitro: Proceed (knitted mesh), Dual Mesh (expanded polytetrafluoroethylene [ePTFE] flat mesh), and Shelhigh (biologic flat mesh). The following different tacks also were examined: Protac, Anchor, and EMS. A pig model was used to measure the forces needed to destroy the connection between mesh and tissue and to describe the place of destruction (mesh, tissue, or tack) and the force needed. RESULTS: The force acting on a single tack proportionally depends on the surface of the hernia orifice and the pressure in the abdominal cavity. The force needed to disconnect the tissue and mesh reached 8.97 +/- 0.11 N for ProTac, 2.67 +/- 0.22 N for Anchor, and 6.67 +/- 1.32 N for EMS. These values do not allow the mesh to be held in the right position when the orifice exceeds 10 cm for Protac and EMS. The disconnection of the EMS and Protac junction damages the tissue. Anchor tacks are insufficient to hold the mesh and stay in the tissue CONCLUSIONS: In the case of small hernias (diameter<10 cm) EMS or ProTac used alone are not enough to hold the mesh. Anchor is not recommended alone in any hernia.
