Separating Vision and Instrument Motion Improves Performance of Endoscopic Surgery

Abstract

Introduction: In performing therapeutic procedures using a flexible endoscope, the vision (endoscopic view) and instrument motion (surgical manipulations) are combined. This causes difficulties in surgical intervention while maintaining a steady view of the surgical field. A new type of endoscopic operating system (Direct Drive Endoscopic System (DDES), Boston Scientific Inc.) is under development to address these problems. The DDES consists of three main elements; 1) a flexible guide tube with three channels, a 6 mm visualization channel and two 4 mm instrument channels, 2) a set of 4 mm instruments and 3) a rail platform. When in place, the distal portion of the DDES guide tube moves similar to an endoscope with up down and left right control. The proximate portion of the DDES guide tube is fixed on a stable rail platform. The instruments have control handles that glide on individual rails. The control handles transmit hand motion to the instrument tips with 5 degrees of freedom without disturbing the visual perspective. We conducted this human factors study to evaluate the DDES in performing endoscopic tasks on a bench model. We hypothesize that, with separated vision and instrument motion, the DDES will improve surgical performance compared to using a conventional endoscope. Methods: We created an endoscopic task which required each participant to track down 4 dots located around a central point on the inner surface of a 5-inch diameter sphere and touch the dots in a predefined order using an endoscopic grasper. Participants completed the trial using a single channel endoscope (SCE) and the DDES uni-manually for alternating hands. Eight participants performed the task using the DDES system and 9 participants performed the task using the SCE. Participants' endoscopic experience varied. Task performance was evaluated based on time. Results: Task performance with the DDES system was significantly faster than performance with the SCE (p < .001). Average time to complete the task with the DDES, using the left hand was 23.6 ± 10.1 s, and with the right hand was 25.7 ± 9.2 s. Average time to complete the task with the SCE was 61.7 ± 27.7 s. Discussion:Results demonstrate clearly that when movement of surgical instruments does not depend on changing the view of the surgical site, surgical performance will increase. Additionally, the added degrees of freedom provided by the DDES system with an intuitive handle design has been proved to facilitate surgical performance. Results from this study provide insight for developing the operating system for the next generation of image-guided surgery such as endoluminal excision or NOTES.