Instrument for attaching to a bone anchor and instrument for use in distraction and/or retraction, in particular for orthopedic surgery or neurosurgery, more specifically for spinal surgery

1. An instrument configured to attach to a bone anchoring element during surgery, the instrument comprising:

an elongate portion; and

an end portion having a first side and an opposite second side, wherein the elongate portion extends away from the first side, and wherein an opening is defined at the second side to accommodate at least a portion of a head of the bone anchoring element;

wherein the opening of the end portion has a first section with a first width that permits insertion and removal of the head through the second side of the end portion, and a second section forming a seat with a width that is smaller than the first width to prevent removal of the head from the second side when the head is held in the seat; and

wherein a region of the opening between the first section and the second section remains unobstructed by other portions of the instrument to facilitate unhindered movement of the head from the second section towards the first section.

2. The instrument of claim 1 , wherein a longitudinal axis extends substantially through a center of the seat, and wherein the first section is arranged laterally to the second section relative to the longitudinal axis, such that the instrument is movable relative to the head in a direction transverse to the longitudinal axis to move the head between the first and second sections of the opening.

3. The instrument of claim 1 , further comprising a spring portion configured to urge the head from the first section of the opening towards the second section of the opening.

4. A tool for distraction and/or retraction comprising:

the instrument of claim 1 forming a first retractor blade;

a second retractor blade;

a frame;

a first arm for coupling the first retractor blade to the frame; and

a second arm for coupling the second retractor blade to the frame.

5. The tool of claim 4 , wherein each of the first and second retractor blades and/or each of the first and second arms comprises a coupling portion respectively configured to couple the first and second retractor blades to the first and second arms, such that blade portions of the first and second retractor blades assume a predefined orientation with respect to each other.

6. The tool of claim 5 , wherein the blade portions of the first and second retractor blades form an angle of about 90° with one another in the predefined orientation.

7. The tool of claim 4 , wherein the first and second retractor blades are pivotably connectable to the first and second arms, respectively, such that each of the first and second retractor blades can pivot only in a single plane.

8. The tool of claim 4 , wherein each of the first and second arms comprises a first arm portion and a second arm portion that are movable relative to one another.

9. The tool of claim 8 , wherein the first and second arm portions of each of the first and second arms are configured to assume a first configuration where the first and second arm portions are aligned with each other, and a second configuration where the first and the second arm portions are angled with respect to each other.

10. The tool of claim 8 , wherein the first and second arm portions of each of the first and second arms are rotatable relative to one another.

11. The tool of claim 8 , wherein the first and second arm portions of each of the first and second arms are lockable relative to each other.

12. The tool of claim 4 , wherein the first and second arms are movable relative to each other on the frame.

13. The tool of claim 12 , wherein the first arm is movably mounted to the frame and the second arm is fixedly mounted to the frame.

14. The tool of claim 12 , wherein the frame comprises a positioning rod along which the first arm is incrementally and/or continuously movable.

15. The tool of claim 4 , further comprising a third retractor blade mountable to the frame, wherein the third retractor blade comprises a blade portion that is arranged opposite to blade portions of the first and second retractor blades and is movable in a direction perpendicular to a direction of displacement between the first arm and the second arm on the frame.

16. An instrument configured to attach to a bone anchoring element during surgery, the instrument comprising:

an elongate portion;

an end portion located at an end of the elongate portion, the end portion defining an opening having a first section sized to permit insertion and removal of a head of the bone anchoring element therethrough, and a second section forming a seat that defines at least part of a circular profile sized to prevent removal of the head through the opening when the head is held in the seat; and

a spring portion configured to urge the head from the first section of the opening towards the second section of the opening, wherein the spring portion remains spaced apart from the circular profile defined by the seat and from the head when the head is held in the seat.

17. The instrument of claim 16 , wherein the spring portion comprises a leaf spring attachable to the elongate portion.