Laparoscopic Overhead Illumination System Induces Three-Dimensionality

Akihiro Takai, MD, Yasutsugu Takada, MD, Satoshi Teramukai, MD, Hideki Motomura. Department of Surgery, Ehime University, Japan, Translational Research Center, Kyoto University Hospital, Japan, Faculty of Ehgineering, Ehime University, Japan

INTRODUCTION: Of the many mechanisms used by the visual system to recover the third dimension, the ability to exploit shading is probably the most primitive. The present study evaluated the impact of attached shadow cues on laparoscopic images for improving performance of laparoscopic tasks. We developed a novel laparoscopic illumination system (NLIS) using a flat-panel light that induced attached- and less casting-shadows on structures during laparoscopic tasks, and compared the results with those using a conventional laparoscopic illumination system (CLIS) with light at the tip that produces a shadowless image.

METHODS AND PROCEDURES: We installed a square, diffusion-type LED light on the ceiling of a training box as the NLIS. The square light (154 mm2), consisting of 324 LEDs, had a color temperature of 4700 K (cool white) and an illuminance of 1200 lux/m. Forty-two medical students, with no laparoscopic experience, and 23 surgeons (all but one with laparoscopic-surgery experience) participated in the study. All participants performed a peg transfer task (task 1: mid-range task, 12-cm target-to-endoscope distance; transferring pegs on a pegboard pattern using both hands within 2 min). The medical students also performed a suture removal task (task 2: close-range task, 3-cm target-to-endoscope distance; cut and removal of five ligated threads from 9-mm-diameter rubber tubes as fast as possible). Tasks were attempted 12 times (six times for each illumination system) and use of either the NLIS or CLIS was randomized for each attempt. End points were; (1) total number of successful peg transfers, (2) the percentage of dropping errors per peg transfer during task 1, and (3) total execution time (seconds) for suture removal in task 2. Each of the participants also filled out a subjective questionnaire on their performance of the tasks and their preference for a particular illumination system at the end of the study. A paired t-test was used for analysis and statistical significance was defined as P < 0.05.

RESULTS: The total number of peg transfers was greater when using the NLIS compared to when using the CLIS for both medical students and surgeons (mean, 75.1 vs. 71.7; p < 0.001, 113.9 vs. 109.5; p = 0.005, respectively). The percentage of dropping errors for surgeons was significantly lower when using the NLIS (mean, 2.86 vs. 4.35; p = 0.012). Total execution time for suture removal was significantly shorter when using the NLIS (mean, 414.3 vs. 433.6; p = 0.010). There was no significant difference in the rate of dropping errors for medical students. However, sequential mean scores of all attempts using the NLIS were equal to or greater than those using the CLIS in both tasks. Of the 65 participants, 28 medical students and 17 surgeons (70% in total) evaluated the NLIS as making the performance of their tasks more efficient.

CONCLUSION: The NLIS significantly improves the performance of laparoscopic tasks. Results of the present study indicate that attached shadow cues generated using overhead, diffusion-type flat-panel light improve performance of laparoscopic tasks regardless of laparoscopic experience or target-to-endoscope distance.

Session: Poster
Program Number: P422
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