Considering the development of gastric cancer surgery using da Vinci Robotic Surgical System, the development of educational program needs to be achieved in Korea and this institute. Moreover, because of the large number of gastrectomy including robotic surgery for gastric cancer treatment, the investigators can provide high quality of educational program using da Vinci System. Therefore, the investigators wanted to create an innovative real-time training module, which can provide an intraoperative step-by-step guide to robotic surgical procedures. This technological project was named as Advanced Robotic Multi-display Educational System (ARMES).

Considering the development of gastric cancer surgery using da Vinci Robotic Surgical System, the development of educational program needs to be achieved in Korea and this institute. Moreover, because of the large number of gastrectomy including robotic surgery for gastric cancer treatment, the investigators can provide high quality of educational program using da Vinci System. Therefore, the investigators wanted to create an innovative real-time training module, which can provide an intraoperative step-by-step guide to robotic surgical procedures. This technological project was named as Advanced Robotic Multi-display Educational System (ARMES).

The four-stages of ARMES development are as follows:

1. Standardization of the key steps of the selected procedure;
2. Preparation of well edited short video clips for each of the previously determined steps using our extensive library of videos of over 350 high quality robotic gastrectomies;
3. Production of a 3D animation of the key surgical steps;
4. Integration of the video segments into the da Vinci Robot system using TileproTM.

Through predetermined standardized segments of short operation video clips and 3D animation, the investigators are developing a versatile intra-operative on-screen audiovisual mentoring system using TileproTM program, which will improve surgeons' capabilities to perform complex robotic operations achieving quicker operation specific competency. It will help surgeons at initial state of robotic surgery in technical as well as oncological aspect for cancer surgery in detail and step-by-step. Finally this program can be applied to other robotic surgery and progressed to be a standard education program.

Inclusion Criteria:

• Robotic surgery for primary early gastric cancer
• Distal gastrectomy with Billroth II anastomosis
• Age: 20~80 years old

Exclusion Criteria:

• Other malignancy and inflammatory diseases
• Disease associated with bleeding tendency
• Previous major abdominal surgery
• Pregnancy

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