Patent ID: 7867242

Claim:
An apparatus for advancing an instrument into a body comprising: a base, wherein the base defines a trajectory; a first stage moveably coupled to the base, wherein the first stage is moveable along the trajectory; a second stage moveably coupled to the first stage along a guide rail extending between the first and second stages, wherein the second stage is moveable relative to the first stage on or parallel to the trajectory and operable to move an instrument coupled thereto with respect to the base and the first stage; a plurality of rollers having corresponding axles positioned at different angles to one another around the guide rail; and a hydraulic system including: a hydraulic cylinder coupled to the first stage; a hydraulic piston coupled to the second stage; and a hydraulic actuator in fluid communication with the hydraulic cylinder and hydraulic piston, wherein the hydraulic actuator is operable to advance the hydraulic piston with respect to the hydraulic cylinder and move the second stage relative to the first stage.