Cannula

A fastening system comprising:

• a cannula defined by an elongate shaft having a hollow portion therein;
• means positioned at a first end of said cannula for receiving a tool for advancing and retrieving the cannula during bone stabilization;
• drilling means positioned at a second end of the cannula, distal from the first end thereof;
• a plurality of threads positioned on the cannula intermediate the receiving means and the drilling means, a first group of said threads being characterized by a non-circular circumference, and
• at least one slotted flute traversing a portion of the cannula so as to intersect a plurality of threads, said slotted flute comprising a cutting surface, a tangential surface, positioned adjacent to and substantially orthogonally to said cutting surface, and an elongate opening which traverses a portion of said slotted flute and extends inwardly through the cannula into the hollow portion thereof.

A fastening system comprising:

• a cannula defined by an elongate shaft having a drilling means positioned at a first end thereof;
• a plurality of self-tapping threads integral with the cannula, a first group of threads having a non-circular circumference;
• a transition zone separating the drilling means and the plurality of self-tapping threads, the transition zone being defined by a short segment of featureless cylindrical shaft, and
• at least one slotted flute traversing a portion of the cannula so as to intersect a plurality of threads.

A method for fastening segmented elements, said method comprising the steps of:

• inserting a portion of a guide pin into the segment elements, said guide pin having a shaft partially defined by a non-circular circumference;
• sliding a cannula over the guide pin, said cannula defined by an elongate shaft having a hollow portion therein;
• receiving a tool at a first end of said cannula for advancing and retrieving the cannula during element fastening;
• drilling the segmented elements with a second end of the cannula to form an opening in the segmented elements;
• generating a plurality of first element chips proximate to the second end of the cannula;
• directing the first element chips into the hollow portion thereof;
• tapping the opening in the elements with a plurality of self-tapping threads positioned on the cannula;
• generating a plurality of second element chips proximate to the self-tapping threads;
• directing a portion of the second element chips through at least one slotted flute which traverses a portion of the cannula so as to intersect a plurality of threads;
• directing a portion of the second element chips into an elongate slot which traverses a portion of the slotted flute and extends inwardly through a wall of the cannula;
• directing a portion of the first and second element chips into an interior space defined by the non-circular shaft of the guide pin and an interior annular surface of the hollow portion of the cannula so that the first and second element chips exit away from the opening in the bone.

A method for fastening segmented elements, said method comprising the steps of:

• placing a cannula at a designated location on the segmented elements;
• receiving a tool at a first end of said cannula for advancing and retrieving the cannula during element fastening;
• drilling the segmented elements with a second end of the cannula to form an opening in the elements;
• generating a plurality of element chips proximate to the second end of the cannula;
• tapping the opening in the segmented elements with a plurality of self-tapping threads positioned on the cannula;
• directing a portion of the element chips away from the second end of the cannula through at least one slotted flute which traverses a portion of the cannula so as to intersect a plurality of threads;
• directing a portion of the element chips into an elongate slot which traverses a portion of the slotted flute and extends inwardly through a wall of the cannula;
• directing a portion of the element chips into an interior space defined by an interior annular surface of the cannula so that the element chips exit away from the opening in the element.