Method and apparatus for performing minimally invasive cardiac procedures

Abstract

A system for performing minimally invasive cardiac procedures. The system includes a pair of surgical instruments that are coupled to a pair of robotic arms. The instruments have end effectors that can be manipulated to hold and suture tissue. The robotic arms are coupled to a pair of master handles by a controller. The handles can be moved by the surgeon to produce a corresponding movement of the end effectors. The movement of the handles is scaled so that the end effectors have a corresponding movement that is different, typically smaller, than the movement performed by the hands of the surgeon. The scale factor is adjustable so that the surgeon can control the resolution of the end effector movement. The movement of the end effector can be controlled by an input button, so that the end effector only moves when the button is depressed by the surgeon. The input button allows the surgeon to adjust the position of the handles without moving the end effector, so that the handles can be moved to a more comfortable position. The system may also have a robotically controlled endoscope which allows the surgeon to remotely view the surgical site. A cardiac procedure can be performed by making small incisions in the patient's skin and inserting the instruments and endoscope into the patient. The surgeon manipulates the handles and moves the end effectors to perform a cardiac procedure such as a coronary artery bypass graft.

1 - 15 . (canceled) 
     
     
         16 . A medical robotic system comprising:
 a robotic arm;   a surgical instrument detachably coupled to the robotic arm, the surgical instrument having an end effector;   a force sensor coupled to the end effector for sensing forces acting against the end effector;   a master input device having an actuator coupled to the force sensor to apply an applied force on the master input device that corresponds to a sensed force that is sensed by the force sensor; and   a controller coupled to the master input device, the robotic arm, and the surgical instrument so as to translate movement of the master input device into corresponding movement of the surgical instrument according to a master-slave relationship.   
     
     
         17 . The medical robotic system according to  claim 16 , further comprising a coupler for detachably coupling the surgical instrument to the robotic arm. 
     
     
         18 . The medical robotic system according to  claim 17 , wherein the surgical instrument has an outer sleeve and the coupler has a spring biased fastener which cooperates with the outer sleeve to hold the surgical instrument and allow manual disconnection. 
     
     
         19 . The medical robotic system according to  claim 17 , wherein a proximal end of the coupler has a slot and a distal end of the robotic arm has a pin adapted to be inserted into the slot when holding the coupler to the robotic arm. 
     
     
         20 . The medical robotic system according to  claim 19 , wherein the robotic arm has a release lever for releasing the pin from the slot so as to disengage the coupler from the robotic arm. 
     
     
         21 . The medical robotic system according to  claim 16 , further comprising:
 a sheath having a hollow core, a mechanical element, and a mechanism for driving the mechanical element,   the sheath coupled to the robotic arm so as to be insertable within a patient during a minimally invasive surgical procedure, and   the surgical instrument having a tool end and a mechanism for manipulating the tool end, so that the mechanical element engages the tool end manipulating mechanism when the surgical instrument is inserted within the hollow core of the sheath so that the mechanism for driving the mechanical element drives the mechanism for manipulating the tool end.   
     
     
         22 . The medical robotic system according to  claim 21 , wherein the mechanical element is a leaf and the mechanism for manipulating the tool end is a lever. 
     
     
         23 . The medical robotic system according to  claim 16 , wherein the surgical instrument comprises an elongate member, a tool, and a universal joint coupling the tool to the elongate member. 
     
     
         24 . The medical robotic system according to  claim 23 , wherein the surgical instrument further includes a plurality of leads extending through the elongate member and coupled to a portion of the universal joint so as to control pivotal movement of the tool relative to the elongate member. 
     
     
         25 . The medical robotic system according to  claim 24 , wherein the surgical instrument further includes at least one lead extending through the elongate member and coupled to the tool so as to control operation of the tool. 
     
     
         26 . The medical robotic system according to  claim 16 , wherein the surgical instrument has an end effector, and the controller causes the end effector to move a scaled movement relative to movement of the master input device. 
     
     
         27 . The medical robotic system according to  claim 16 , wherein the applied force is a scaled increment of the sensed force. 
     
     
         28 . A medical robotic system comprising:
 a robotic arm;   an end effector coupled to the robotic arm and having a force sensor for sensing forces being asserted against the end effector;   a master input device having an actuator; and   a controller coupled to the master input device, the robotic arm, end effector, and the force sensor so as to translate movement of the master input device into corresponding movement of the end effector according to a master-slave relationship while providing an input to the actuator so that the actuator applies an applied force on the master input device that corresponds to a sensed force that is sensed by the force sensor.   
     
     
         29 . The medical robotic system according to  claim 28 , wherein the applied force is a scaled increment of the sensed force. 
     
     
         30 . A medical robotic system comprising:
 a tool driver having a force sensor;   a surgical instrument having a pair of fingers;   a coupler for detachably coupling the surgical instrument to the tool driver so that the tool driver drives opening and closing of the pair of fingers and the force sensor senses a reactive force provided by the object being grasped by the pair of fingers;   a master input device having an actuator; and   a controller configured to command the tool driver to open and close the pair of fingers in response to movement of the master input device and command the actuator to apply a feedback force on the master input device that corresponds to the reactive force sensed by the force sensor.   
     
     
         31 . The medical robotic system according to  claim 30 , wherein the surgical instrument has an outer sleeve and a distal end of the coupler has a spring biased fastener which cooperates with the outer sleeve to hold the surgical instrument and allow manual disconnection. 
     
     
         32 . The medical robotic system according to  claim 30 , wherein a proximal end of the coupler has a slot and a distal end of the tool driver has a pin adapted to be inserted into the slot when holding the coupler to the tool driver. 
     
     
         33 . The medical robotic system according to  claim 32 , wherein the tool driver has a release lever for releasing the pin from the slot so as to disengage the coupler from the tool driver. 
     
     
         34 . The medical robotic system according to  claim 30 , wherein the surgical instrument has a tool rod coupled to one of the pair of fingers, the coupler has a piston, and the tool driver has a load cell and a motor, wherein the motor is responsive to the controller to move the load cell so as to drive the piston which in turn moves the tool rod so as to open and close the pair of fingers, and wherein the force sensor comprises the load cell. 
     
     
         35 . The medical robotic system according to  claim 30 , further comprising a robotic arm having a holder and a motor, wherein the coupler has a collar that removably attaches to the holder so that the motor moves the collar in response to movement of the master input device and movement of the collar in turn results in movement of the surgical instrument attached to the coupler when the collar is attached to the holder. 
     
     
         36 . The medical robotic system according to  claim 35 , further comprising a first sterile drape covering the tool driver and a second sterile drape covering the robotic arm while leaving the coupler and the surgical instrument exposed.