What are the reasons for a longer operation time in robotic gastrectomy than in laparoscopic gastrectomy for stomach cancer?

BACKGROUND: Many studies have shown that robotic gastrectomy requires a longer operation time than laparoscopic gastrectomy. However, no study has analyzed the exact reason for this difference in detail. We therefore investigated the reasons why more time is needed in robotic gastrectomy. METHODS: Ten consecutive cases of robotic distal gastrectomy (RDG) performed in our institution were selected to measure the operation time in detail. Ten cases of laparoscopic distal gastrectomy (LDG) performed during the same period were chosen for comparison. The operation videos and electronic medical records of these 20 patients were retrospectively reviewed. The overall operation time, operation time in each step, and time required for instrument changes were measured. The number of intraoperative instrument changes and camera cleanings were also counted. RESULTS: The overall operation time (including effective time and junk time) was 56.8 min longer for RDG than LDG (273.7 vs. 216.9 min, respectively; p = 0.000). The effective time was only 15.3 min longer for RDG than LDG (145.9 vs. 130.6 min, respectively; p = 0.094). The time needed for the six technical steps was also not significantly different between the two groups. However, the junk time (instrument setup and docking or positioning of surgical arms) was 41.5 min longer for RDG than LDG (127.8 vs. 86.2 min, respectively; p = 0.001). The number of instrument changes was not different between RDG and LDG (p = 0.277), but the time required for each was longer for RDG than LDG (p = 0.000). The number of camera cleanings was lower for RDG than LDG (10.7 vs. 15.5 times, respectively; p = 0.005). CONCLUSIONS: To reduce the operation time in RDG, a smarter and simpler system for setup should be developed to reduce the junk time. Additionally, a system for swifter instrument changes and more sophisticated energy devices are warranted to reduce the effective time.