Saline-Filled Laparoscopic Surgery: A Basic Study on Partial Hepatectomy in Rabbit Model Short Title: Saline-filled laparoscopic surgery

Background There is still a poor understanding of the effects of pneumoperitoneum with insufflation of carbon dioxide gas (CO2) on malignant cells, and pneumoperitoneum has a negative impact on cardiopulmonary responses. A novel saline-filled laparoscopic surgery (SAFLS) is proposed, and the technical feasibility of performing saline-filled laparoscopic partial hepatectomy (LPH) was evaluated in a rabbit model. Methods Twelve LPH were performed in rabbits, with 6 procedures performed using an ultrasonic device with CO2 pneumoperitoneum (CO2 group) and 6 procedures performed using a bipolar resectoscope (RS) in a saline-filled environment (Saline group). Resection time, CO2 and saline consumption, vital signs, blood gas analysis, complications, interleukin-1 beta (IL-1β) and C-reactive protein (CRP) levels were measured. The effectiveness of the resections was evaluated by the pathological findings. Results LPH was successfully performed with clear observation by irrigation and good control of bleeding by coagulation with RS. There were no significant differences in all perioperative values, IL-1βand CRP levels between the two groups. All pathological specimens of the Saline group showed that the resected lesions were coagulated and regenerated as well as in the CO2 group. Conclusions SAFLS provides a good surgical view with irrigation and identification of bleeding sites with the feasibility.