Development of a medical Bernoulli gripper

Abstract

When performing minimally invasive interventions, surgeons use grippers to grip and manipulate tissue. These grippers generally rely on their toothed profile and require pinching of the tissue for sufficient grip, entailing a risk of tissue damage. An solution should be found for this risk of damage. An alternative could be to manipulate the tissue without pinching or even touching it. Contactless gripping exists in the industrial field by using the principle of Bernoulli. This study explores the possibility of applying Bernoulli gripping for tissue manipulation during minimally invasive surgery. A medical gripper using the principle of Bernoulli was developed. Increasing the air flow, the radius of the gripper face and the radius of the nozzle has a positive effect on the lifting force. In order to prevent tissue damage, different variants are tested that change the direction of the air flow. In an exploring experiment, a deflector was selected out of seven variants as best solution to prevent damage from the air flow. The Bernoulli gripper was made expandable and collapsible for insertion in the body of the patient with a system of living hinges. The effect of Venturi channels and the position of a membrane for an airtight surface on the lifting force were tested. The lifting force generated on the object during gripping was measured using a tensile-strength tester. Bernoulli’s theory was compared to the results of the experiments and a discrepancy was found between theory and results. This study shows that a Bernoulli gripper is feasible to lift flexible tissue.