A Physic Tensile Forces Experiment to Possible Explain the Reason of Failing Ventral Hernia Repair

Abstract

IntroductionVentral Hernia Repair (VHR) has been a challenging surgery during years. Matters moved to mobilizing muscle and closing the abdominal wall. Component Separation Repair (CSR), which required dissection of the fascia of the rectus muscle and closure of the midline linea alba [1]. The goal of ventral hernia repair is to restore abdominal muscle strength and abdominal wall function [2,3]. The muscle component of the ventral hernia is one of many variables affecting the abdominal wall to contribute to ventral hernia. In this paper we focus on that issue understanding the complexity of the pathology. We hypothesized that evaluating the maximal stress on a set of artificial tensile structures, rubber bands, might open a different view on the effects of daily forces affecting the strength of varied abdominal walls. Materials and MethodsFour sets of six rubber bands were evaluated (Table 1).In the first comparison, we matched rubber band based on their thickness of 0.1x0.35 cm: A) short (4.2 cm), high strength rubber bands (red bands) (modeled the young person with much muscle strength and flexibility, B) long (7 cm), high strength rubber bands of longer length (white bands) modeled abdominal walls with fully stretched muscle, but with similar strength, such as occurs after pregnancy or with obesity. In the second comparison, we match the length (4.2 cm) and change the thickness: A) thick (0.1x0.35 cm), rubber bands (red bands) as above and C) thin (0.1x0.1 cm), rubber bands (yellow bands) modeled elderly or protein deficit patients, obese patient who had experienced an operation. We then use for final comparison a D) thin and short band (0.1x0.1x2 cm).Thickness, width and length of the bands were measured using a vernier caliper. The four bands were then stressed with progressively increasing weights at 20 g increments. Weight at the time of failure was recorded for each of six trials of each band type (Table 1).The Tensile strength was measured in force per cross-sectional area. All the data is reported and compared in table 1. The units of force were derived by multiplying mass (kg) by the acceleration of gravity (9.81 m/sec 2 ) per Newton's second law of motion (F=m x a). This results in a force unit of Newton. The tensile strength was measured by taking the weight (Newton) and dividing it by the cross-sectional area (cm 2 ). Tension and shear forces were summarized to create the condition to apply the log regression (Tables 2 and 3). Ventral hernia repair, a challenging procedure. We consider rubber bands, evaluating the strength of bands of differing length and thickness to see how changes in these parameters affect the elastic materials to try to mimic how abdominal muscle get affected by tensile forces.

Component Separation or Mesh Repair for Ventral Hernia Repair - The Role of Mesh in Covering all the Abdominal Wall in the Component Repair

“…These observations, were emphasized by our tensile experiments, where we showed that a thicker elastic material holds more weight than a thinner one despite similar length (P<0.0001) [27]. This gives us a way to compare different materials based upon the same cross-sectional area.…”