Research of performing surgery in the isotonic water had started since May 2007 at our center. The concept of WaFLES is to establish novel therapeutic modality using characteristics of irrigant such as wet condition, water pressure, temperature, buoyancy and acoustic property of liquid. Besides, reperfusion of irrigant makes the system a closed circuit including abdominal cavity. Advantages of the setting are pointes out in suppressing venous bleeding, avoiding thermal injury to the tissue adjacent to coagulating area, soft handling of organs, and developing novel navigation system. The first hurdle of interruption of laparoscopic view by dispersion of blood was solved by controlling flow of irrigant, affording the continuous observation of bleeding point (fig. 1, 2). No harmful effect of storing large amount of irrigant in cardiopulmonary function, serum electrolyte and blood gas to date. However, several problems have been remaining yet including difficulty in expanding operative space, finding trajectory for introducing forceps, and holding floating organs, especially parenchymal organs. At the same time, irrigating pump should be designed as handy as possible to be used in routine clinical practice. We are making progress in variable direction, and will be present the update of the research in this conference
