Robotic assistance in microsurgery.

The purpose of this study was to introduce a new robotic system for microsurgical procedures of the eye, ear, brain, face, and hand. The design and main features of the Robot Assisted MicroSurgery (RAMS) work station are described. In addition, compatibility with the operating-room table is assessed. The engineering components of the RAMS work station consist of a laptop computer, a joystick, a mouse, slave robot, VME and amplifier chassis, and safety control box. The mechanical part of the RAMS, the slave robot, is designed to simulate movements of the human upper extremity, which has five joints and six degrees of motion. The robot has a zero backlash in five joints, and can sustain full extension of loads over three pounds. The arm measures 2.5 cm in diameter, and it is 34.6 cm long from its base to its tip. The arm and its base weigh 2.5 kg. Motors and encoders on the robot are easily removable, allowing for the arm to be sterilized in an autoclave. Assessment of robotic positioning, time for setup, relative precision, and possible problems in the operating field are compared with human-assisted microsurgical procedures. Robotic arm positioning on the operating-room table differs for each type of procedure. For those involving the hand and upper extremity, the robotic arm base occupies 35 percent of the operating table; this is only 10 to 15 percent for human-assisted procedures. The setup time for robot-assisted procedures is longer than for human-assisted surgery. However, microsurgical manipulations with the RAMS are more rapid than the surgeon's motions. Therefore, depending on the type of procedure, the total operating time is comparable to human-assisted procedures. The movement of the RAMS was found to be more precise, in attempting to perform vascular and neural anastomoses. The authors conclude that concurrent use of the remote-controlled RAMS as a microsurgical assistant is applicable in microsurgery, with the advantages of greater precision and more rapid microsurgical manipulation. However, the long-term cost effectiveness of using this system as an assistant in microsurgery warrants further investigation.