Hydraulic instrument drive system for minimally invasive surgery

A robotic-assisted surgical system comprising:

• a base comprising a cart;
• an arm extending from the base;
• a surgical instrument removably mountable to the arm, the surgical instrument having
• an end effector configured for at least a first motion type, and
• an instrument end effector output system (IEEOS);
• an input pressure system (IPS) including a reservoir and pump disposed in the base;
• and
• a mechanical transfer system (MTS);
• the IPS, MTS and IEEOS arranged such that the MTS receives fluid or mechanical input from an output of the IPS and delivers corresponding fluid or mechanical input to an input of the IEEOS to cause movement of the end effector;
• wherein at least one of the IPS and the IEEOS is operable using a fluid system;
• and
• a user input device, wherein the IPS and IEEOS are operable in response to user input to the user input device to cause motion of the end effector.