A new, safer, controllable field-of-view endoscope avoiding movement inside body cavities

One of the greatest difficulties in endoscopic surgery is the limited field-of-view (FOV) of endoscopes. During endoscopic manipulation in body cavities to expand the FOV, there is the risk of inadvertent damage to body tissues, nerves, and internal organs. The risk increases especially in surgery that is performed inside a very small cavity, or in which body tissues are very fragile. To overcome these issues, we developed a novel endoscope that can provide various FOVs without moving or bending the endoscope itself inside the body cavity and investigated the feasibility of using the new endoscope in vivo. A beam splitter was used to visualize both forward and side views, and two polarization plates and observation windows were used to avoid overlap of the two views. An endoscope having a 7-mm diameter was fabricated through which both views were clearly visualized in vivo. It took only 0.7s to change the FOV with high repeatability, with a maximum distance error of 2.8%. The new endoscope can provide forward and panoramic views without moving the endoscope; therefore, the risk of inadvertent damage to fragile body tissues can be significantly decreased.