A puncture instrument for forming, in a vertebral pedicle, a pilot hole for embedding a pedicle screw the puncture instrument comprising:
- a puncture needle for forming the pilot hole;
- a reference bar attached to the puncture needle for guiding the puncture needle to a desired position at a desired angle with respect to the vertebral pedicle;
- and
- auxiliary parts for use in making the reference bar coincide with a predetermined reference location of the vertebral pedicle;
- wherein the puncture needle is longitudinally elongated so as to have a longitudinal axis;
- wherein the puncture needle has a puncture needle proximal end, and a puncture needle distal end remote from the puncture needle proximal end;
- wherein the puncture needle has an operation section at the puncture needle proximal end;
- wherein the puncture needle has a needle point at the puncture needle distal end;
- wherein the reference bar has first and second opposite extreme ends and is a straight bar from said first extreme end to said second extreme end;
- wherein one of the first and second extreme ends of the reference bar constitutes a reference bar proximal end, and the other of the first and second extreme ends constitutes a reference bar distal end remote from the reference bar proximal end;
- wherein the reference bar proximal end is fixed to the puncture needle at a location of the puncture needle intermediate the puncture needle proximal end and the puncture needle distal end;
- wherein the reference bar is fixed to the puncture needle so as to form a predetermined fixed angle between the longitudinal axis of the puncture needle and a longitudinal axis of the straight bar constituting the reference bar;
- wherein the predetermined fixed angle is in a range of 30 degrees to 60 degrees;
- and
- wherein the reference bar has a length such that the reference bar is disposed perpendicular to a line intersecting both the needle point of the puncture needle and said one of the first and second extreme ends of the reference bar that constitutes the reference bar distal end;
- wherein the auxiliary parts comprise a first auxiliary bar and a second auxiliary bar, respectively;
- wherein the first auxiliary bar is fixed to and projects away from the reference bar distal end, and the second auxiliary bar is fixed to and projects away from the reference bar proximal end;
- and
- wherein the first and second auxiliary bars are both perpendicular to the straight bar constituting the reference bar.