Instruments and methods for manipulating a spinal fixation element

Abstract

An instrument for manipulating a spinal fixation element relative to a bone anchor includes a bone anchor grasping mechanism, a first adjustment mechanism, and a second adjustment mechanism. The bone anchor grasping mechanism includes a first arm having a distal end configured to engage an opening provided in the bone anchor. The first adjustment mechanism includes a second arm pivotally connected to the first arm. The second arm has a distal end configured to engage an opening provided in the bone anchor and is operable to adjust a spinal fixation element in a first direction upon pivoting relative to the first arm. The second adjustment mechanism is coupled to the bone anchor grasping mechanism or the first adjustment mechanism and is movable relative to the bone anchor grasping mechanism to adjust the spinal fixation element in a second direction, perpendicular to the first direction, relative to the bone anchor.

1 . An instrument for manipulating a spinal fixation element relative to a bone anchor, the instrument comprising: 
 a bone anchor grasping mechanism including a first arm having a distal end configured to engage an opening provided in the bone anchor,    a first adjustment mechanism including a second arm pivotally connected to the first arm, the second arm having a distal end configured to engage an opening provided in the bone anchor, the second arm being operable to adjust a spinal fixation element in a first direction upon pivoting relative to the first arm, and    a second adjustment mechanism coupled to at least one of the bone anchor grasping mechanism and the first adjustment mechanism, the second adjustment mechanism being movable relative to the bone anchor grasping mechanism to adjust the spinal fixation element in a second direction, perpendicular to the first direction, relative to the bone anchor.    
   
   
       2 . The instrument of  claim 1 , wherein the first arm is directly pivotally connected to the second arm, the first arm and second arm pivoting about a pivot axis that intersects the first and second arm.  
   
   
       3 . The instrument of  claim 1 , further comprising a coupling mechanism positioned between and connected to the first arm and the second arm, the coupling mechanism being configured to receive the second adjustment mechanism and permit motion of the second adjustment mechanism relative to the first arm.  
   
   
       4 . The instrument of  claim 3 , wherein the coupling mechanism is an internally threaded nut for engaging external threads provided on the second adjustment mechanism.  
   
   
       5 . The instrument of  claim 4 , wherein the first arm and second arm pivot about a pivot axis that intersects the first arm and second arm and the pivot axis intersects the coupling mechanism.  
   
   
       6 . The instrument of  claim 4 , wherein the coupling mechanism includes a thread section that is movable between a first position in which the thread section engages the external threads on the second adjustment mechanism and a second position in which the thread section disengages the external threads on the second adjustment mechanism to permit axial motion of the second adjustment mechanism relative to the first arm.  
   
   
       7 . The instrument of  claim 1 , wherein the distal end of the first arm includes a projection sized and shaped to releaseably engage the opening in the bone anchor.  
   
   
       8 . The instrument of  claim 7 , wherein the projection is generally arcuate in shape having a curvature approximate to a curvature of the opening in the bone anchor.  
   
   
       9 . The instrument of  claim 8 , wherein the projection has a distal surface, a proximal surface, and a connecting surface extending between the distal surface and the proximal surface.  
   
   
       10 . The instrument of  claim 9 , wherein the proximal surface is oriented at an angle other than perpendicular to a longitudinal axis of the instrument.  
   
   
       11 . The instrument of  claim 1 , further comprising an activation mechanism coupled to the bone anchor grasping mechanism and to the first adjustment mechanism to effect motion of the first arm relative to the second arm.  
   
   
       12 . The instrument of  claim 11 , wherein the activation mechanism comprises a first handle connected to the first arm and a second handle connected to the second arm.  
   
   
       13 . The instrument of  claim 12 , wherein the first handle and the second handle are oriented generally in a direction parallel to the longitudinal axis of the instrument.  
   
   
       14 . The instrument of  claim 12 , wherein at least one of the first handle and the second handle is oriented lateral to the longitudinal axis of the instrument.  
   
   
       15 . The instrument of  claim 1 , wherein the second adjustment mechanism is tubular in shape having a lumen extending therethrough.  
   
   
       16 . The instrument of  claim 15 , further comprising a delivery instrument for delivering a closure mechanism to the bone anchor, the delivery instrument being positionable through the second adjustment mechanism to deliver a closure mechanism to the bone anchor.  
   
   
       17 . An instrument for manipulating a spinal fixation element relative to a bone anchor, the instrument comprising: 
 a first arm having a distal end having an arcuate projection for engaging a first arcuate groove provided in the bone anchor,    a second arm pivotally connected to the first arm, the second arm having a distal end having an arcuate projection for engaging a second arcuate groove provided in the bone anchor, the first arm and second arm being pivotable about a pivot axis that intersects the first arm and second arm, the second arm being operable to adjust a spinal fixation element in a first direction upon pivoting relative to the first arm, and    an adjustment mechanism coupled to first arm and the second arm, the adjustment mechanism being movable relative to the bone anchor grasping mechanism to adjust the spinal fixation element in a second direction, perpendicular to the first direction, relative to the bone anchor.    
   
   
       18 . The instrument of  claim 17 , further comprising a coupling mechanism positioned between and connected to the first arm and the second arm, the coupling mechanism being configured to receive the adjustment mechanism and permit motion of the adjustment mechanism relative to the first arm and the second arm.  
   
   
       19 . The instrument of  claim 18 , wherein the pivot axis intersects the coupling mechanism.  
   
   
       20 . An instrument for manipulating a spinal fixation element relative to a bone anchor, the instrument comprising: 
 a first arm having a distal end having a projection for engaging a first opening provided in the bone anchor,    a second arm pivotally connected to the first arm, the second arm having a distal end having a projection for engaging a second opening provided in the bone anchor, the first arm and second arm being pivotable about a pivot axis that intersects the first arm and second arm, the second arm being operable to adjust a spinal fixation element in a first direction upon pivoting relative to the first arm,    an adjustment mechanism coupled to first arm and the second arm, the adjustment mechanism being movable relative to the bone anchor grasping mechanism to adjust the spinal fixation element in a second direction, perpendicular to the first direction, relative to the bone anchor, and    a coupling mechanism connected to the first arm and the second arm and positioned between the first arm and the second arm such that the pivot axis intersects the coupling mechanism, the coupling mechanism being configured to receive the adjustment mechanism and permit motion of the adjustment mechanism relative to the first arm and the second arm.