Surgical tool having electrocautery energy supply conductor with inhibited current leakage

A surgical instrument for use with a robotic surgical system, the instrument comprising:

• an elongate shaft having a proximal end and a distal end and defining an internal longitudinally extending passage, the distal end of the shaft being configured to permit insertion through a minimally invasive incision in a body of a patient;
• an electrocautery end effector disposed at the distal end of the shaft;
• an interface disposed at the proximal end of the shaft, the interface removably connectable to the robotic surgical system;
• a conductor extending from the interface and electrically communicating with at least a portion of the end effector so as to deliver electrical energy to tissue engaged by the end effector;
• an insulative sleeve disposed over the conductor;
• an insulation tube extending within the passage and over the insulated conductor, wherein a separation is maintained between the sealed insulation tube and the insulated conductor;
• and at least two o-rings disposed within the insulation tube so as to seal the insulation tube at each of its ends while centering the conductor within the insulation tube, wherein an interior of the insulation tube between the seated ends is filled with a filler material down to the conductor so as to inhibit capacitive coupling between the shaft and a surgical patient.

An electrosurgical instrument, the instrument comprising:

• an elongate shaft having a proximal end and a distal end and defining an internal longitudinally extending passage;
• an electrocautery end effector disposed at the distal end of the shaft, wherein at least the end effector and distal end of the shaft are configured to be insertable through a minimally invasive surgical incision;
• a user-controllable interface disposed at the proximal end of the shaft;
• a conductor extending from the interface to the end effector so as to deliver electrical energy to tissue engaged by the end effector;
• an insulation tube extending within the passage and over the conductor;
• and at least two o-rings disposed within the insulation tube so as to seal the insulation tube at each of its ends while centering the conductor within the insulation tube, wherein an interior of the insulation tube between the sealed ends is filled with a filler material down to the conductor so as to inhibit capacitive coupling between the shaft and surgical patient.