title: Biomechanical analyses of overlap and mesh dislocation in an incisional hernia model in vitro.
abstract: BACKGROUND
  Incisional hernia repair is one of the most common surgical complications. Despite the introduction of mesh techniques of repair, recurrences are still prevalent. The aim of the current study was to evaluate the dependence of mesh dislocation on defect size, facial overlap, mesh-position, and orientation of the mesh in cases of anisotropic stretchability.
  
  
  METHODS
  An in vitro incisional hernia model was used, which consisted of a pressure chamber, an elastic silicone pad representing the peritoneal sac, and a silicone mat with bovine muscle tissue representing the abdominal wall. Intrinsic pressure (up to 200 mm Hg) was generated within the pressure chamber by continuous inflation with CO(2). A slit-like or flap-like defect was created in the silicone mat to simulate small or large hernia defects, respectively. The implanted mesh was arranged in both onlay and sublay configurations. A large pore polypropylene mesh with significant anisotropic stretchability was investigated, whereas overlaps of 2, 3, and 4 cm were applied.
  
  
  RESULTS
  Despite the application of pressures up to 200 mm Hg, no mesh ruptures occurred. In the slit-like defect model, the minimal overlap required to prevent dislocation at 200 mm Hg was 3 cm using the sublay technique provided that the mesh was positioned with its most stretchable axis parallel to the largest slit dehiscence. Perpendicular rotation of the mesh resulted in dislocation at 160 mm Hg, despite using an overlap of 3 cm. Mesh reinforcement showed less stability in both the onlay position and the flap-like defect.
  
  
  CONCLUSIONS
  An overlap of 3 cm is sufficient to prevent early mesh dislocation. Meshes with anisotropic stretchability should be orientated with the most stretchable axis in the direction of least overlap.
authors.affiliation: Department of Surgery, RWTH Aachen University Hospital, Aachen, Germany. mbinneboesei@ukaachen.de
authors.forename: Marcel
authors.initials: M
authors.lastname: Binnebösel
authors.forename: Raphael
authors.initials: R
authors.lastname: Rosch
authors.forename: Karsten
authors.initials: K
authors.lastname: Junge
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Flanagan
authors.forename: Robert
authors.initials: R
authors.lastname: Schwab
authors.forename: Volker
authors.initials: V
authors.lastname: Schumpelick
authors.forename: Uwe
authors.initials: U
authors.lastname: Klinge
mesh_terms: D034861:Abdominal Wall / Q000601:surgery; D000818:Animals; D001696:Biomechanical Phenomena; D002417:Cattle; D059685:Herniorrhaphy; D066298:In Vitro Techniques; D008954:Models, Biological; D011183:Postoperative Complications / Q000209:etiology / Q000601:surgery; D011312:Pressure; D011475:Prosthesis Failure; D013526:Surgical Mesh; D013536:Suture Techniques / Q000009:adverse effects*