SURGICAL INSTRUMENT INCLUDING HOUSING, A CUTTING ACCESSORY THAT EXTENDS FROM THE HOUSING AND ACTUATORS THAT ESTABLISH THE POSITION OF THE CUTTING ACCESSORY RELATIVE TO THE HOUSING
An instrument for treating tissue during a medical procedure includes a hand-held portion and a working portion. The hand-held portion is manually supported and moved by a user and the working portion is movably coupled to the hand-held portion. A tracking device is attached to the hand-held portion for tracking the instrument. The tracking device is in communication with a control system, which is used to keep the working portion within or outside of a boundary. A plurality of actuators are operatively coupled to the working portion. The control system instructs the actuators to move the working portion relative to the hand-held portion during the medical procedure in order to maintain a desired relationship between the working portion and the boundary.