An instrumented laparoscopic grasper to examine the forces used during laparoscopic surgery

Background: Excessive force application by instruments can result in damage in laparoscopic surgery. Quantification of forces used and their duration during laparoscopic tasks is the initial step to identifying excessive force application.We aimed to measure the grasp time and tool tip force used to run the smallbowel. Methods: An instrumented short fenestrated laparoscopic grasper was designed to measure grasping force and duration. Running the bowel was performed five times (with five manipulations in each) in an anaesthetised 40kg pig. Maximum force (F {max}) and root mean squared force (F {rms}) was measured in Newtons. Jaw close time (T {close}) and grasp time (T {hold}) was measured in seconds. Results: For all 25 manipulations, mean F {max} was 20·5N (range 10·2–35·2)and F {rms} was 13·7N (6·04–26·8). Mean T {close} was 0·52s (0·18–0·72) and mean T {hold} was 3·87s (2·2–7·6). Mean results for individual tasks are tabulated. Conclusions: This is the first time grasping forces have been measured in a live animal model. The data demonstrates the variability of force and duration used to perform a simple laparoscopic task and serves as a baseline for quantitative assessment of histological tissue damage.