Effect of Handle Design and Target Location on Wrist Posture during Aiming with a Laparoscopic Tool

Abstract

Laparoscopic surgery is a rapidly increasing field in healthcare today. However, current laparoscopic tools have inadequate handle designs and have been directly linked to post-surgery pain among surgeons. This study recruited forty subjects (20 male, 20 female) to evaluate the effect of handle design as well as target location on accuracy, precision, and wrist posture during an aiming task. Two laparoscopic tools were used for this study: a commercially available scissor-grip tool and a custom-designed ergo-grip tool. Each subject was asked to aim through a trocar at the center of one of five targets using one of the tools. The target was viewed by a laparoscopic camera and presented on a television. The results of this study showed that accuracy and precision were affected by both target position and tool; however, the differences were small (< 2 mm). Wrist flexion and ulnar deviation angles were affected by both target position and tool. Differences due to target position were expected given different hand locations are required to hit each target. Flexion angle was significantly smaller for the ergo-grip tool as opposed to the scissor-grip tool. Ulnar deviation angle was significantly smaller for the scissor-grip tool than for the ergo-grip tool. All but one subject preferred the ergo-grip tool when performing the task, suggesting that wrist flexion is a stronger predictor of comfort than ulnar deviation though both should be considered when designing ergonomic hand tools.