Biomechanical principles of a permanently durable abdominal wall reconstruction: current status and potential future development

The article reviews the biomechanical principles of durable abdominal wall reconstructions. The aim is to provide insights and conclusions for future research in this area. Incisional hernia repair implies the creation of a compound made of tissue, textile, and fixation elements. A pulse load bench test for incisional hernia repair has been available since 2014, and its influences are evaluated in three different versions of the test stand. Based on these evaluations, a biomechanical concept for long-term durable reconstructions was determined. To apply the concept to individual patients, computed tomography of the abdomen at rest and during the Valsalva maneuver was used. A load limit can be given for every patient based on the hernia defect area (CRIP- critical resistance to impacts related to pressure). By considering the mesh to defect area ratio, the retention strength of a planned reconstruction can be calculated (GRIP-gained resistance to impacts related to pressure). The gripping coefficients for tissues vary significantly, up to 18 fold. About half of the patients have overall tissue distensions up to 350% or more, with potential high regional variations. The surface retention forces for hernia meshes and for different sutures, tacks, and adhesives span a wide range of 14fold. Suturing a defect strengthens the reconstruction up to 3fold. Furthermore, recalculating data taken from multicentric randomized studies on primary sutures reveals that improved GRIP values are associated with reduced rates of incisional hernia. Repairing consecutive incisional hernias according to the GRIP concept results in no recurrence and low pain levels after one year. A future policy for market access of repair materials should include cyclic load bench testing. Moreover, a tailored approach to incisional hernia repair should take into account the biomechanical aspects involved.