Compact forceps manipulator with a spherical-coordinate linear and circular telescopic rail mechanism for endoscopic surgery

Purpose By integrating locally operated small surgical robots in a sterilized area, a surgeon can perform safe and accurate robotically assisted laparoscopic surgery. At present, there is no locally operated compact forceps robot that can operate within a small space while providing a wide working area on the abdominal wall. In the present study, a new spherical-coordinate manipulator with a linear telescopic rail and two circular telescopic rails that can act as a third arm for the surgeon has been developed. Methods A compact locally operated detachable end-effector manipulator (LODEM) was developed. This manipulator uses circular telescopic rails with linkage mechanisms for the yaw and pitch axes, and a linear telescopic rail for the insertion/extraction axis is attached to forceps. The dimensions of the manipulator are 180 mm × 100 mm × 90 mm when contracted and 230 mm × 130 mm × 120 mm when expanded. The positional accuracy, mechanical deflection, and backlash of the prototype were evaluated while performing simulated in vivo laparoscopic surgery. Results The positional accuracy, deflection, and backlash of the telescopic rail mechanism were 2.1, 1.8, and 5.1 mm, respectively. The manipulator could successfully handle the target and maintain stability, while the arms of the endoscope specialist were free from collisions with the manipulator during an in vivo laparoscopic surgery. Conclusions A compact LODEM was designed to facilitate minimally invasive, robotically assisted laparoscopic surgery by a doctor working near the patient. This device could be used for such applications.