Mechanical stability of new meshes for M3 inguinal hernia repair

Abstract

<h4>Introduction</h4>The necessity of mesh fixation in laparoendoscopic repair of large medial (classified by the European Hernia Society as M3) inguinal hernias (IHs) remains debated. Recent data, including the MEFISTO randomized controlled trial, suggest that rigid, anatomically contoured meshes may provide sufficient stability of hernia repair without mesh fixation, potentially reducing fixation-related complications. However, biomechanical performance of newly introduced anatomical meshes has not been thoroughly evaluated.<h4>Aim</h4>This study aimed to assess the mechanical stability of 2 newly introduced anatomically shaped meshes-SWING-Mesh and 3DMax MID Anatomical Mesh-in a validated pressure chamber model simulating M3 IH defects.<h4>Materials and methods</h4>A rigid 3-dimensionally (3D) printed groin model with a 4-cm medial defect was mounted in a sealed pressure chamber capable of generating intra-abdominal pressures of up to 70 kPa. Two meshes were tested: SWING-Mesh (lightweight polypropylene; 55 g/m²; 16 cm × 12 cm) and 3DMax MID Anatomical Mesh (medium-weight polypropylene; 78 g/m²; 17 cm × 12 cm). Both were positioned with an at least 3-cm overlap beyond the defect margins without fixation. Initial testing was performed at 36 kPa. If displacement occurred, lower pressures were applied; if stability was maintained, higher overload pressures were used. Each experiment was repeated 3 times, with outcomes documented on photo and video material. The primary end point was mesh displacement into the defect.<h4>Results</h4>SWING-Mesh consistently displaced into the defect at 36 kPa in all trials. Supplementary tests showed migration as early as at 10 kPa. In contrast, 3DMax MID Anatomical Mesh remained stable at 36 kPa in all repetitions. Overload testing confirmed its resistance at 53, 60, and 70 kPa-the maximum achievable pressure in the chamber-without measurable displacement.<h4>Conclusions</h4>SWING-Mesh failed to provide stability even under moderate intra-abdominal pressures, which questions its suitability for nonfixed repair of M3 hernias. 3DMax MID Anatomical Mesh demonstrated complete stability under both physiologic and supraphysiologic conditions, confirming the mechanical advantage of medium-weight 3D meshes. Implant design, weight, and stiffness appear more decisive for stability than fixation, supporting the selective use of nonfixation techniques when rigid meshes are applied.