RESUMEN
Introduction: Suture tension has a direct influence on the sutured tissue. For abdominal wall closure, suture tension should be optimal without causing tissue necrosis, which can result in surgical site infection or incisional hernia. The purpose of the present study is to evaluate a device that can measure suture tension in-situ and in real-time. Materials and methods: A cheap, commercially available analog-to-digital converter was used, in conjunction with a force sensing resistor. A sensor probe housing was designed and 3D-printed. In order to test the sensor, a mechanical, computer controlled human abdominal wall model called the AbdoMAN was used. Results: An implantable suture tension sensor was developed, keeping cost-effectiveness in mind. This sensor can translate tension in the suture into a downward force, applied to the force sensing resistor. The sensor's raw readout was characterized using a set of weights, from which a formula correlating the readout to a specific force, was derived. Preliminary validation was successfully performed using the AbdoMANmodel, which showed a progressive rise in suture tension when the intra-abdominal pressure was artificially increased over time. Conclusion: The implantable suture tension sensor appeared to be capable of recording real time changes in suture tension, and the. validation process of this sensor has been initiated. With the information from devices like this, a much better understanding of the issues at play in the development of incisional hernia can be gained.
RESUMEN
INTRODUCTION: Small bites for the closure of the abdominal wall after midline laparotomy result in significantly less incisional hernias in comparison with large bites. However, fundamental knowledge of underlying biomechanical phenomena remains sparse. The objective of this study was to develop a digital image correlation-based method to compare different suturing techniques in terms of strain pattern after closure of a midline laparotomy in a passive model just after the time of surgery. METHODS: A digital image correlation (DIC)-based method was used for the comparison of strain fields on the external surface of the myofascial abdominal wall (skin and subcutaneous fat removed) among six configurations, including an intact linea alba in five post mortem human specimens. The second configuration comprised primary mass closure with small bites (five mm between two consecutive stitches and five mm distance from the incision, 5x5 mm). The third configuration was primary mass closure with large bites (ten mm by ten mm, 10x10 mm). The fourth, fifth and sixth configuration comprised primary mass closure with large bites and the placement of a mesh in onlay position with two different overlaps and the use of glue to simulate the integration of the mesh within the soft tissue. RESULTS: No visible difference was observed between 5x5 and 10x10 mm closure configurations. However, the use of mesh as suture line reinforcement highlighted a stiffer behavior of the midline area for similar intra-abdominal pressure, which was amplified when a larger mesh overlap was used. However, the whole abdominal wall showed quite similar shapes for the various configurations, except for the configuration with mesh reinforcement and the use of glue. CONCLUSION: Mesh reinforcement incited lower opening tension profiles in the midline area of the abdominal wall. following closure of the linea alba in median laparotomy. The next step should be to investigate the impact of mesh location (e.g. retromuscular) and different time points after surgery.
