A robotic surgical system for performing minimally invasive medical procedures includes a robot manipulator for robotically assisted handling of a laparoscopic instrument having a manipulator arm, a manipulator wrist supported by the arm and an effector unit supported by the wrist, wherein the manipulator arm provides three degrees-of-freedom by means of a first joint, a second joint and a third joint, each having an associated actuator, for robotically positioning the wrist, the wrist providing two degrees-of-freedom by means of a fourth joint and a fifth revolute joint having an associated actuator, for robotically setting the yaw angle and the pitch angle of the effector unit respectively; the effector unit includes a laparoscopic instrument actuator and provides one degree-of-freedom by means of a revolute sixth joint having an associated actuator for robotically setting the roll angle of the LIAs which includes a seat with an associated coupling mechanism for mounting an instrument stem adaptor to the effector unit, and an actuation mechanisms cooperating with the instrument stem adaptor for actuating a laparoscopic instrument connected to the adaptor. The effector unit is configured such that the rotation axis of the revolute sixth joint coincides with the longitudinal axis of a laparoscopic instrument mounted to the effector unit and the effector unit includes a sensor assembly having a 6 degree-of-freedom (DOF) force/torque sensor and a 6 DOF accelerometer. The sensor assembly connects the LIA to the sixth revolute joint.