Surgery under endoscopic vision has advantages such as lower invasiveness, less bleeding, and less pain for patients, providing expanded vision for precise operation compared with open abdominal surgery. To improve preservation of normal tissue and flexible utilization of ultrasound imaging, water-filled laparoendoscopic surgery (WaFLES) has been actively researched. In WaFLES, the abdominal cavity is filled with saline instead of insufflated with carbon dioxide gas. The circulating irrigating solution maintains desirable moisture and temperature for organs as well as provides a clear endoscopic view. By buoyancy effect, the organs are floating and easy to move during surgery, but organs around the surgical field often affect the surgeon's view. We propose a novel surgical spacer for WaFLES based on reversible structural alteration between two- and three-dimensional shapes, which is designed to be inserted through a single small incision and expanded in the abdominal cavity independently. We designed and fabricated prototypes of the proposed spacer made of polyvinyl chloride and polyethylene terephthalate, and tested their structural strengths. The prototypes demonstrated the required strength to withstand the forces loaded from organs around the treated area under WaFLES conditions.
