Improving the reinforcement of parastomal tissues with Marlex mesh: laboratory study identifying solutions to stomal aperture distortion.

Purpose: Parastomal hernia formation commonly complicates permanent stomas and represents a significant and frequently recurrent management problem, regardless of the method of repair. Prosthetic material reinforcement of parastomal tissues offers the best results. However, problems with unravelling of mesh fibers along cut margins leading to aperture enlargement and hernia recurrence may occur. Raised intra-abdominal pressure in the early postoperative period before incorporation of the mesh into surrounding tissues may result in hernia formation if the aperture size in the mesh increases.
Methods: Assessment of the physical properties of Marlex mesh was performed in a materials testing laboratory, using standardized tests to simulate the stresses imposed on in situ mesh.
Results: Holes cut in Marlex mesh were found to enlarge and distort at loads simulating intra-abdominal pressure changes. Reinforcement with a polypropylene pursestring suture was found to stabilize the periaperture mesh fibers and maintain the original area throughout tensions at least double maximal intra-abdominal pressures. Distensibility of intact sheets of mesh was found to vary by up to 100 percent, depending on the direction of the applied tension, and thus, mesh orientation in hernia repair has major implications.
Conclusion: We propose that if mesh is used to reinforce abdominal wall tissues and is cut or fashioned to size, then the cut margins must be reinforced if the intended dimensions and functional integrity of the mesh are to be maintained.