A minimally invasive surgical instrument of hand-held with self-locking

At present, minimally invasive surgery (MIS) is mostly conducted by surgeons with surgical instruments because of the limitation of popularity of robots. The instruments are mainly hand-held minimally invasive surgical instruments, whose end effector with low operating flexibility only possesses opening and closing motion. In order to improve the flexibility of the surgical instruments, this paper employs a wrist-like structure for designing a new type of hand-held surgery instrument based on wire-driven. There are three degrees of freedom (DOFs) of rotation, yaw, opening and closing. Furthermore, we also realize no coupling motion for each DOF by laying out wires reasonably. Moreover, motion self-locking kept by specific mechanical structure of each joint contributes to sustain the posture of joints under the action of external force. It has conducted a statics analysis for end effector by using ANSYS software. The analysis results show that the structural strength of proposed instrument meets the requirements of MIS. Finally, the operational performance and reliability of the surgical instrument were tested. The experimental results showed that the motion space of all DOFs and operating force of the surgical instruments meet the requirement of the MIS.