Multi-stage dilator and cannula system and method

A system for performing robotically-assisted image guided surgery comprising:

• a motion tracking system operable to track one or more objects in a surgical area;
• and
• a robotic arm;
• and
• a dilator assembly comprising a first elongated member and a second elongated member, each of the first elongated member and the second elongated member include a longitudinal axis, the first elongated member including a first projection extending transverse to the longitudinal axis at a head end of the first elongated member, and the second elongated member including a second projection extending transverse to the longitudinal axis at a head end of the second elongated member, the first elongated member is configured to be received by the second elongated member in a nested arrangement, and the first projection of the first elongated member abuts and is restrained from axial movement in one direction by the second projection of the second elongated member when the first elongated member is advanced relative to the second elongated member in a first direction, the first elongated member is slidable relative to the second elongated member;
• wherein the robotic arm is configured to hold and move the dilator assembly to one or more predetermined positions over a body of a patient using tracking data from the motion tracking system;
• and
• wherein the first elongated member is connected with a tracking device, the tracking device configured to be tracked by the motion tracking system.