Development of a dynamic model for ventral hernia mesh repair

Abstract

IntroductionThe adequate way of mesh fixation in laparoscopic ventral hernia repair is still subject to debate. So far, simulation has only been carried out in a static way, thereby omitting dynamic effects of coughing or vomiting. We developed a dynamic model of the anterior abdominal wall.Materials and methodsAn aluminium cylinder was equipped with a pressure controlled, fluid-filled plastic bag, simulating the abdominal viscera. A computer-controlled system allowed the control of influx and efflux, thus creating pressure peaks of up to 200 mmHg to simulate coughing and 290 mmHg to simulate vomiting. We tested fixation with tacks (Absorbatack, Covidien Deutschland, Neustadt a. D., Germany). The model was controlled for the friction coefficient of the tissue against the mesh and the physiologic elasticity of the abdominal wall surrogate.ResultsThe model was able to create pressure peaks equivalent to physiologic coughs or vomiting. Physiologic elasticity was thereby maintained. We could show that the friction coefficient is crucial to achieve a physiologic situation.The meshes showed a tendency to dislocate with an increasing number of coughs (Fig. 4). Nevertheless, when applied in a plain manner, the meshes withstood more cough cycles than when applied with a bulge as in laparoscopic surgery.ConclusionsThe dynamic movement of the abdominal wall, the friction between tissue and mesh and the way of mesh application are crucial factors that have to be controlled for in simulation of ventral abdominal hernia closure. We could demonstrate that patient specific factors such as the frequency of coughing as well as the application technique influence the long term stability of the mesh.

Assessing the GRIP of Ventral Hernia Repair: How to Securely Fasten DIS Classified Meshes

“…A tissue model was used for the application of dynamic intermittent strain (DIS). The ex vivo model hydraulically pushes a plastic containment in an aluminum cylinder ( 8 ). The new version of the model permits control of the length of the pressure plateau during the descent from the peak flow ( 11 ).…”

“…The threshold of a force parallel to the surface characterizing a distinct ventral hernia repair can be examined with dynamic intermittent strain ( 8 – 10 ). Delivering dynamic intermittent strain (DIS) up to 250 mmHg repeatedly in an ex vivo model can test the impact of repeated strain similar to jumping, coughing, or vomiting on the stability of ventral hernia repair ( 8 ). First results demonstrated a rapid deterioration of ventral hernia repair in the majority of applications tested upon repeated impacts ( 9 ).…”

Increasing hernia size requires higher GRIP values for a biomechanically stable ventral hernia repair

“…In patients, up to 400 coughs were observed within 24 h which can reach intraabdominal pressures well above 200 mmHg [ 12 , 13 ]. Using a self-built device delivering dynamic impact strain (DIS) simulating coughing actions, repeated impacts can rapidly impair ventral hernia repair [ 5 , 6 ]. The grip calculation can give the threshold for a repair to survive more than 400 DIS strains [ 7 , 8 ].…”

“…The DIS test has been described previously [ [5] , [6] , [7] , [8] ]. In brief, the test bench consists of a water-filled aluminium cylinder coated with a thin polyethylene foil and covered with tissues derived from pig bellies.…”

“…The high recurrence rates demand new ways to develop more stable ventral hernia repair procedures [ 4 ]. Coughs seem to rapidly impair ventral hernia repair [ 5 ]. A new bench test permits the analysis of biomechanical stability upon dynamic intermittent strain (DIS) which simulates coughing actions [ 6 ].…”