Instruments and methods for bone anchor engagement and spinal rod reduction
An instrument for engaging a bone anchor may include a first implant engaging member having a proximal end and a distal end and a second implant engaging member having a proximal end and a distal end. The second implant engaging member may be pivotally connected to the first implant engaging member about a pivot point located proximate the distal ends of the first and second implant engaging members. Manipulation of the proximal ends of the first and second implant engaging member can cause each of the distal ends to rotate about the pivot point to engage at least a portion of a bone anchor. A rod adjusting tool may be connectable to the bone anchor engaging tool and may be axially adjustable relative to the bone anchor tool to adjust a spinal rod relative to the bone anchor.
1. An instrument for engaging an implant comprising:
a first implant engaging member having a proximal end, a distal end, an arcuate section between the proximal end and the distal end, and an inner surface;
and a second implant engaging member having a proximal end, a distal end, an arcuate section between the proximal end and the distal end, and an inner surface, the second implant engaging member being pivotally connected to the first implant engaging member about at least one pivot point located proximate the distal ends of the first and second implant engaging members, manipulation of the proximal ends of the first and second implant engaging member causing each of the distal ends to rotate about the at least one pivot point to engage at least a portion of an implant, the arcuate section of the first implant engaging member and the arcuate section of the second implant engaging member connecting to define an annular collar between the first implant engaging member and the second implant engaging member at the pivot point, the annular collar being sized to facilitate the delivery of at least one of an implant or a second instrument therethrough; and
an adjustment mechanism to facilitate the connection and adjustment of a second instrument relative to the instrument, the adjustment mechanism comprising a thread formed on the inner surface of the first implant engagement member and a thread formed on the inner surface of the second implant engagement member.
2. The instrument of claim 1 , wherein the distal ends of the first implant engaging member and the second implant engaging member are rotatable between an approximately closed position in which the distal ends are proximate one another and an open position in which the distal ends are displaced from one another.
3. The instrument of claim 2 , further comprising a biasing mechanism coupled to the first implant engaging member and the second implant engaging member to bias the distal ends to the closed position.
4. The instrument of claim 3 , wherein the biasing mechanism comprises at least one spring positioned between the first implant engaging member and the second implant engaging member.
5. The instrument of claim 2 , wherein the distal ends when in the closed position are separated a distance that is approximately equal to or less than a width or a diameter of the portion of the implant.
6. The instrument of claim 1 , wherein at least one of the distal end of the first implant engagement member and the distal end of the second implant engagement member includes an implant engagement mechanism.
7. The instrument of claim 6 , wherein the implant engagement mechanism comprises a projection extending from an interior surface of the distal end at least one of the first implant engaging member and the second implant engaging member.
8. The instrument of claim 7 , wherein the projection is a cylindrically shaped pin.
9. The instrument of claim 7 , wherein the projection is an arcuate rim.
10. The instrument of claim 6 , wherein the implant engagement mechanism comprises a plurality of ridges provided on an interior surface of the distal end at least one of the first implant engaging member and the second implant engaging member.
11. An instrument for engaging a bone anchor comprising,
a first implant engaging member having a proximal end, a distal end having an implant engagement mechanism, an arcuate section between the proximal end and the distal end, and an inner surface;
a second implant engaging member having a proximal end, a distal end having an implant engagement mechanism, an arcuate section between the proximal end and the distal end, and an inner surface, the second implant engaging member being pivotally connected to the first implant engaging member about a pair of pivot points aligned along a pivot axis located proximate the distal ends of the first and second implant engaging members such that manipulation of the proximal ends of the first and second implant engaging member causes each of the distal ends to rotate about the pivot axis between an approximately closed position in which the distal ends are proximate one another and an open position in which the distal ends are displaced from one another, the arcuate section of the first implant engaging member and the arcuate section of the second implant engaging member connecting to define an annular collar therebetween proximate the pivot axis, the annular collar being sized and shaped to facilitate the delivery of a second instrument through the collar; and
an adjustment mechanism to facilitate the adjustment of at least a portion of the second instrument through the opening, the adjustment mechanism comprising a thread formed on the inner surface of the first implant engagement member and a thread formed on the inner surface of the second implant engagement member.
12. The instrument of claim 11 , further comprising a biasing mechanism coupled to the first implant engaging member and the second implant engaging member to bias distal ends to the closed position.
13. The instrument of claim 12 , wherein the biasing mechanism comprises at least one spring positioned between the first implant engaging member and the second implant engaging member.
14. The instrument of claim 11 , wherein the distal ends when in the closed position are separated by a distance that is approximately equal to or less than a diameter of the portion of the bone anchor.
15. The instrument of claim 11 , wherein the implant engagement mechanisms of the first implant engaging member and the second implant engaging member each comprise a projection extending from an interior surface of the distal ends of the first implant engaging member and the second implant engaging member, respectively.
16. The instrument of claim 15 , wherein the projection is a cylindrically shaped pin.
17. The instrument of claim 16 , wherein the projection is an arcuate rim.
18. The instrument of claim 11 , wherein the implant engagement mechanisms of the first implant engaging member and the second implant engaging member each comprise a plurality of ridges provided on an interior surface of the distal ends of the first implant engaging member and the second implant engaging member.