Development of an adhesive grasper for Minimally Invasive Surgery

Abstract

Laparoscopic graspers require a high pinch force to generate sufficient friction force (grip) for tissue manipulation. Excessive or insufficient pinch forces distributed along the small contact area of laparoscopic graspers can cause damage and are one of the reasons why the risk of intraoperative complications during Minimally Invasive Surgery (MIS) procedures in the abdomen is 2-4 % higher compared to open surgery. The goal of this research was to develop and evaluate an 5 mm laparoscopic grasper, which has the same functionality (generated friction force, grasping time) as a conventional grasper for use on the intestine but which requires lower pinch force due to the use of adhesives. To lower the pinch force the adhesive component of the friction force was enlarged by introducing a muco-adhesive between tissue and grasper. To lower (local) high pressures a flat surface was used. Two experiments were conducted to find out in which direction the friction force generated by the adhesive film was the largest and to find the minimum required area of adhesive film to generate a force of 5 N. Next, a design for the tip and a design for the adhesive film feed mechanism was made. To evaluate the design a prototype was created, which was used to investigate whether the proposed tip design was able to generate a friction force of 5 N using a pinch force lower than 3 N. The prototype of the adhesive grasper was able to generate a friction force of 3.12 ± 0.58 N, while using a pinch force of 2.5 N. The generated friction force did not meet the goal of 5 N, but the concept of lowering the pinch force by introducing an adhesive layer is promising; the pinch force needed by the proposed tip is lower compared to existing graspers and the friction force was independent of the generated pinch force. The friction force can be increased further by developing a new adhesive film or by increasing the contact area.