Abstract:
An instrument may be used to move a rod attached to vertebrae to an opening of a fixation device. Positioning the rod in the opening may properly align the vertebrae with respect to the vertebra attached to the fixation element. A fixation holder may be coupled to the fixation element. The holder may include a protrusion. The protrusion may engage a guide of the instrument during use. The protrusion and the guide may ensure that the rod is properly positioned within the opening in the connector. The instrument and holder may automatically align the rod to the opening without requiring manual manipulation of the rod or the fixation element. The fixation element may include a connector. The connector may be positioned within the fixation element so that removal of the connector from the fixation element is inhibited.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to spinal fixation systems for correction of spinal deformities or injuries, and embodiments of the invention relate to an instrument for moving a vertebra or vertebrae to a desired position. 
     2. Description of Related Art 
     Spinal disorders, degenerative conditions, or trauma may result in a need to correct or stabilize the spine of a patient. A variety of spinal fixation systems may be used to correct and/or stabilize a spine. A spinal fixation system may be classified as an anterior, lateral, or posterior system according to a position of the system relative to the spine. Anterior and lateral spinal fixation systems usually include short structures that support only a few adjacent vertebral bodies of a spine. Several anterior and lateral spinal fixation systems may be coupled to vertebral bodies to correct and/or stabilize a large portion of the spine. Posterior stabilization systems often include pairs of vertically aligned rods for stabilizing both short and long segments of a spine. 
     A posterior spinal fixation system may include a pair of bendable rods that are contoured and longitudinally disposed adjacent to vertebral bodies of a spine. Rods used in a fixation system are typically circular in cross section, although rods having non-circular cross sections may also be used. The rods may be attached to vertebral bodies of the spine by a plurality of fixation elements. The fixation elements may be hooks and/or bone screws. Transverse connectors may be used to join the pair of spinal rods together. Transverse connectors may stabilize and provide rigidity to a spinal fixation system. 
     A fixation element may include a connector that attaches the fixation element to a spinal rod. One type of connector includes an opening that snaps onto a spinal rod. When a spinal rod is positioned in the opening of a connector, a fastener, such as a bolt or a locking plate, may securely attach the connector to the fixation element. The fastener may inhibit motion of the spinal rod relative to the fixation element. U.S. Pat. No. 6,132,430 issued to Wagner, which is incorporated by reference as if fully set forth herein, describes fixation elements wherein fixation element connectors are configured to snap onto spinal rods. Other types of fixation elements may also be used in a spinal fixation system. Fixation elements may include, but are not limited to, the fixation elements shown and described in U.S. Pat. Nos. 4,763,644; 4,805,602; 4,887,596; 4,950,269; 5,129,388; 5,961,518; 5,989,250; 5,997,539; and 6,063,089; each of these patents being incorporated by reference as if fully set forth herein. 
     A spinal rod may be attached to one or more vertebrae during a posterior spinal fixation procedure. A vertebra or vertebrae that are not in desired positions may be moved during a spinal fixation procedure. A fixation element may be attached to a vertebra that needs to be moved. A translation instrument may be used to draw the fixation element and the spinal rod together. A fastener may then be attached to the fixation element to join the rod and the element together. 
     A translation device that may be used to join a fixation element and a spinal rod together is the Universal Spinal System Rod Introduction Pliers from Synthes Spine (Paoli, Pa.). One of the jaws of the pliers has a hollow barrel. The other jaw is a rod contactor. The pliers are used with a holder that threadably attaches to a fixation element. After attaching the holder to the fixation element, the holder is inserted into the hollow barrel. Grips of the pliers are squeezed together by a user to cause the rod contactor to rotate and contact a spinal rod. Continued squeezing of the grips forces the rod and the fixation element together so that the rod may be positioned within an opening of the fixation element. A user of the translation device must adjust the position of the holder within the barrel to ensure that the rod is positioned within the fixation element when the grips of the translation device are closed together. Proper alignment of the translation device may be difficult to achieve during use of the translation instrument. A user may have to manually adjust the vertical position of the fixation element while simultaneously translating the fixation element and the rod together. 
     U.S. Pat. No. 5,020,519 to Hayes et al., which is incorporated by reference as if fully set forth herein, describes a device that may be used to introduce a rod into an opening in a spinal implant. The system includes a one-piece tool that clamps a spinal implant and aligns a rod with an opening in the spinal implant. The device may be used to reduce the vertical offset between the rod and the implant. The spinal implant must be maintained in the correct position in the translation device while threading the rod into place between the jaws. 
     SUMMARY OF THE INVENTION 
     A translation instrument may be used to move a vertebra or vertebrae to a desired position. A spinal rod may be attached to vertebral bodies by fixation elements. An adjacent fixation element may be attached to an out-of-position vertebra. It may be desirable to move the spinal rod and the adjacent fixation element together so that the vertebra is placed in a desired position relative to adjacent vertebrae. Securing the fixation element to the spinal rod may allow for proper alignment of vertebral bodies of a spinal column. 
     A translation instrument may be used to move the spinal rod and the adjacent fixation element together. The translation instrument may simultaneously translate the fixation element towards the rod and adjust the vertical height of the fixation element relative to the rod so that the rod is positioned within a rod opening of the fixation element. A guide of the translation instrument may engage the fixation element or an extension member coupled to the fixation element. The guide may ensure that the spinal rod is properly positioned relative to a fixation element when the translation instrument is used. 
     A fixation element may be coupled to a vertebral body whose position is to be adjusted. A fixation element may be, but is not limited to, a bone screw or a hook. A holder may be coupled to the fixation element. The holder may include an attachment mechanism, a shaft, and a guide. The attachment mechanism may securely attach the holder to the fixation element. The shaft may allow the holder to be coupled to a positioner of a translation instrument. The holder guide may be a protrusion that extends from a side of the shaft. 
     A translation instrument may include a positioner, an arm, and an actuator. A positioner may couple a fixation element holder to the translation instrument. In an embodiment, the positioner may allow the holder to move axially relative to the translation instrument. 
     An arm of a translation instrument may be pivotally coupled to an actuator of the translation instrument. The actuator may be a pair of lever arms or grips that are pivotally coupled together. When the grips are grasped and moved towards each other, the arm may move towards a holder placed within a positioner of the translation instrument. The arm may include a guide configured to mate with a guide of the holder. The arm may also include a rod engager. In an embodiment, the rod engager may be an indentation or groove in a body of the arm that contacts and holds a rod. The arm guide contacts the holder guide during use to adjust a position of the translation instrument relative to a fixation element. Grasping and moving the grips towards each other may rotate the arm so that the rod engager contacts a rod. Moving the grips closer together may bring the rod and the fixation element together. The holder guide may interact with the arm guide as the grips are moved towards each other. Contact of the holder guide with the arm guide may adjust a position of the translation instrument relative to the fixation element so that the rod and a rod opening of the fixation element may be brought together. After the rod is placed within the rod opening, the fixation element may be attached to the rod. 
     A guide of a fixation element holder and a guide of a translation instrument may interact to allow a rod held by the arm to be positioned in a rod opening of a fixation element. Using the holder guide and the translation instrument guide to adjust a position of the translation instrument relative to the fixation element may eliminate the need to manually guide a rod to a rod opening while simultaneously translating a vertebra or vertebrae to an adjusted position. 
     A translation instrument may include bias or spring members that influence a separation distance between grips of the instrument. The bias members may force the grips apart when a user does not apply a compressive force to the grips. When the grips are positioned fully apart from each other, the translation instrument is in an initial position. When the translation instrument is in the initial position, an arm of the translation instrument is in a position rotated away from a holder that is coupled to a positioner of the translation instrument. As the grips are moved together, the arm rotates towards the holder. If a user releases the grips, the biasing members may return the grips to the initial position. 
     A translation instrument may include a position retainer that resists forces applied to the grips by the bias members. In an embodiment, the position retainer may include a serrated member that is pivotally coupled to a first grip. The serrations may be configured to engage a portion of a second grip. The engaging portion of the second grip may be an end of the grip. The serrations are oriented to allow the grips to be moved towards each other, but resist movement of the grips away from each other. During use, a user may rotate the serrated member so that the member contacts the engaging portion of the second grip. The user may then move the first grip towards the second grip to rotate an arm towards a holder that is coupled to a positioner of the translation instrument. The user may stop the movement of the grips towards each other. If the user stops movement of the grips towards each other, the position retainer may allow the position of the arm to remain fixed relative to the holder. If the user desires to rotate the arm towards an initial position, the user may rotate the serrated member away from the engaging portion. Force applied to the grips may be removed to allow the bias members to return the grips, and the arm, towards the initial position. 
     In an embodiment, a position retainer of a translation instrument may be located at an end of the translation instrument. The location of the position retainer at the end of the translation instrument may allow a user convenient access to the position retainer during use with a hand that is not grasping the instrument. The location may also allow convenient access to the position retainer by a member of a surgical team who is not grasping the translation instrument. 
     A position retainer may also include a locking mechanism. The locking mechanism may be used to fix a position of a serrated member so that grips of the translation instrument are fixed relative to each other. Fixing the position of the grips relative to each other may inhibit accidental release of the position retainer. In an embodiment, the locking mechanism may be a hook that is pivotally attached to a second grip near an engaging portion of the second grip. When the hook is rotated so that the hook contacts the serrated member, movement of the grips towards or away from each other may be inhibited. When the hook is rotated away from the serrated member, the grips may be moved towards each other, or the serrated member may be rotated away from the engaging portion so that the grips may be moved away from each other. 
     An advantage of using a translation instrument to position a vertebra or vertebrae is that the translation instrument may simultaneously translate and vertically adjust the position of the vertebra or vertebrae. A position of a rod opening of a fixation element that may be coupled to an out-of-position vertebra may be adjusted relative to a position of a rod when the translation instrument is used. The translation instrument may ensure that the rod is placed within the rod opening during use. The fixation element may then be coupled to the rod. The translation instrument may eliminate the need to manually adjust a vertical position of the rod opening relative to the rod while simultaneously adjusting the lateral position of the rod opening relative to the rod. 
     A further advantage of a translation instrument may be that the translation instrument includes bias members that return the translation instrument to an initial position when grips of the instrument are released. The bias members may eliminate the need to manually close the grips and manually open the grips during use. 
     Another advantage of a translation instrument may be that the translation instrument includes a retention mechanism that inhibits grips of the translation instrument from returning to an initial position during use. The translation instrument may also advantageously include a locking member that fixes the position of the grips relative to each other and prevents accidental release or adjustment of the translation instrument. 
     Further advantages of a translation instrument may be that the translation instrument is sturdy, durable, lightweight, safe, simple, efficient, reliable and inexpensive; yet the translation instrument may also be easy to manufacture and use. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further advantages of the disclosed device and method will become apparent to those skilled in the art with the benefit of the following detailed description of the preferred embodiments and upon reference to the accompanying drawings in which: 
     FIG. 1 depicts a front view of an embodiment of a translation instrument that is coupled to a holder and fixation element when the translation instrument is in an initial position. 
     FIG. 2 depicts a back view of an embodiment of a translation instrument that is coupled to a holder and fixation element when the translation instrument is in an initial position. 
     FIG. 3 depicts a front view of an embodiment of a translation instrument that is coupled to a holder and fixation element when the translation instrument is in a closed position. 
     FIG. 4 depicts a back view of an embodiment of a translation instrument that is coupled to a holder and fixation element when the translation instrument is in a closed position. 
     FIG. 5 depicts a schematic view of an embodiment of a spinal fixation system positioned adjacent to vertebrae. 
     FIG. 6 depicts a front view of an embodiment of a fixation element coupled to a spinal rod. 
     FIG. 7 depicts a side view of an embodiment of a fixation element coupled to a spinal rod. 
     FIG. 8 depicts a side view of an embodiment of a fixation element connector. 
     FIG. 9 depicts a front view of an embodiment of a fixation element clip. 
     FIG. 10 depicts a cross-sectional view of a portion of an embodiment of a fixation element. 
     FIG. 11 depicts a partial cross sectional view of a holder that is coupled to a fixation element, wherein a shaft of the holder is not shown in cross section. 
     While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. The drawings may not be to scale. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring to the drawings, and more particularly to FIGS. 1-4, a translation instrument is indicated generally as  100 . A translation instrument  100  may be used during a spinal fusion procedure to move a vertebra to a desired position relative to a spinal fixation system. A fixation element may be coupled to the vertebra. The fixation element may include a connector. A spinal fixation system may include a spinal rod that is coupled to two or more vertebrae. The translation instrument  100  may allow the connector to be snapped on the spinal rod so that the vertebra is moved to a desired position relative to the two or more vertebrae that are coupled to the spinal rod. The translation instrument  100  may simultaneously adjust a vertical position and lateral position of the connector relative to the spinal rod so that the spinal rod is snapped into an opening in the connector when the translation instrument is used. 
     FIG. 5 shows a portion of a spinal fixation system  10  placed in relation to representations of vertebral bodies  12 . A spinal fixation system  10  may include rods  14 , fixation elements  16 , and transverse connectors  18 . A pair of rods  14  (only one shown in FIG. 5) may be coupled on opposite sides of vertebral bodies  12  of a spine by fixation elements  16 . Fixation elements  16  may include, but are not limited to, threaded fasteners and hooks. The fixation elements  16  may be, but are not limited to, bone screws and/or hooks. Transverse connectors  18  may be coupled across the spine to the pair of rods  14 . A transverse connector may provide rigidity and stability to the spinal fixation system  10 . 
     During a spinal fixation procedure, a fixation element  16  may be attached to an out of position vertebra. The fixation element  16  may be, but is not limited to a bone screw or hook. FIG.  6  and FIG. 7 show front and side views, respectively, of an embodiment of a fixation element  16  attached to a spinal rod. The fixation element  16  may include body  20 , connector  22  and clip  24 . FIG. 8 depicts an embodiment of a connector. A connector  22  may include two arms  26 , slot  28 , textured surfaces  30  and end  32 . A spinal rod  14  may be positioned in opening  34  between the two arms  26 . The slot  28  between the arms may extend to end  32 . The slot  28  may allow the arms  26  to deflect so that a spinal rod  14  may be snapped into the opening  34  between the two arms. When the connector  22  is positioned in the body  20 , the connector arms  26  may be compressed towards each other by tapering inner surfaces of the body so that a spinal rod  14  positioned between the arms is secured to the connector and to the fixation element  16 . 
     FIG. 9 shows an embodiment of a clip  24 . The clip  24  may be positioned between a body  20  of a fixation element and an end  32  of a connector  22  to secure a rod  14  to the connector, and the connector to the body. Textured surfaces  36  of the clip  24  may engage textured surfaces  30  of the connector  22  to form a secure connection. Texturing on the clip  24  and the connector  22  may be serrations, scoring, peening, or other roughening that enhances frictional or interlocking engagement between the clip and the connector. Texturing on the clip  24  may be a different type of texturing than texturing on the connector  22 . In an embodiment, the connector may include threading and the clip may be a nut that mates to the threading of the connector, although a small working space in which the clip may be rotated may tend to weigh against the use of a threaded connection between the connector and the clip. 
     FIG. 10 shows an embodiment of a portion of a fixation element  16 . A connector  22  of the fixation element  16  may include raised portion  38  that allows the connector to be attached to a body  20  of the fixation element such that removal of the connector from the body is inhibited. Attaching the body  20  and the connector  22  together may allow for insertion of the connector and fixation element  16  into a patient as a single unit instead of in two separate pieces. To attach the connector  22  to the body  20 , arms  26  of the connector may be compressed and the connector may be inserted into the of the fixation element  16 . Expansion of the arms  26  back to an initial position may inhibit removal of the connector  22  from the body in an opposite direction to the direction of insertion. The raised portion  38  may be placed in recess  40  of the body  20 . The raised portion  38  may contact the body  20  to inhibit the connector  22  from being removed from the body in the direction of insertion of the connector into the body. The recess  40  may have a width that limits rotation of the connector  22  to a range that the fixation element  16  may be skewed to relative to a rod  14 . In embodiments of fixation elements, the range of rotation of the connector  22  in the body  20  is limited to about ±350, to about ±25°, or to about ±15°. In other fixation element embodiments, the range of rotation of the connector in the body is limited to less than +15°, 
     FIG. 11 shows a cross sectional view of a holder coupled to a body of a fixation element. A body  20  of a fixation element  16  may include grooves  42  and indention  44 . The grooves  42  and indention  44  may allow the fixation element to be coupled to holder  46 . 
     A holder  46  may include head  48 , hollow shaft  50 , shaft  52  and guide  54 . The head  48  may include wall  56  (shown in FIG. 1) that limits an insertion depth of a fixation element body  20  into the holder  46 . The wall  56  may also apply force to the fixation element  16  during a spinal fusion procedure. The force applied by the wall  56  may allow a rod of a spinal fixation system to be placed in a connector of the fixation element to properly align a vertebra to which the fixation element is attached with respect to the rod and the vertebrae to which the rod is attached. The head  48  may include end tips  58  that fit within grooves  42  of the fixation element  16 . The head  48  may include an internal threading  60  that engages threading  62  of the shaft  52 . The shaft  52  may be positioned in the hollow shaft  50 . Rotating in a clockwise direction end  64  of the shaft  52  may advance the shaft relative into the head  48 . Second end  64  of the shaft  52  may include knurling or other type of texturing that allows a user to easily grip and rotate the shaft  52 . Guide  54  may be an arm extending from a side of the hollow shaft  50 . The hollow shaft may be placed in positioners of a translation instrument  100 . 
     Grooves  42  of a fixation element  16  may slide on end tips  58  of a holder  46  until the fixation element contacts an internal surface of holder wall  56 . A shaft  52  of the holder  46  may be rotated in a first direction, typically in a clockwise direction, to advance the shaft relative into a head  48  of the holder. End  62  of the shaft  52  may contact a surface of the indentation  44  in the fixation element  16 . Contact of the shaft  52  with the fixation element  16  may provide a force against the fixation element that securely attaches the fixation element to the holder  46 . Rotating the shaft  52  in an opposite direction, typically counter-clockwise, allows the holder  46  to be removed from the fixation element  16 . 
     FIGS. 1-4 show embodiments of translation instruments  100 . A translation instrument  100  may include positioners  102 , arm  104 , and grips  106 . The translation instrument  100  may be used to place a spinal rod that is coupled to two or more vertebrae in a connector of a fixation element that is coupled to an out of position vertebra. A fixation element holder  46  may be placed within positioners  102  of the translation instrument  100 . Positioners  102 , arm  104 , and grips  106  of the translation instrument  100  may be pivotally coupled together. Pivotal connections  108  joining the grips  106  to the arm  104  may allow the arm to rotate when the grips are moved towards each other. The pivotal connections  108  allow the grips  106  to move towards or away from each other. The arm  104  of the translation instrument  100  may rotate towards a fixation element holder  46  that is placed within the positioners  102  when the grips  106  are moved towards each other. 
     A first positioner  102 ′ may be pivotally coupled to grips  106  of a translation instrument  100  (shown in in FIG.  4 ). A second positioner  102 ″ may be pivotally coupled to linking arm  109  and to arm  104 . The positioners may include pins  111  that limit a range of rotational motion of the positioners relative to the grips  106 . Limiting a rotational range of motion of the positioners  102  may facilitate placement of a holder  46  in the positioners. 
     Positioners  102  of a translation instrument  100  may retain a fixation element holder  46 . The positioners  102  may allow axial movement of holder shaft  52  relative to the translation instrument  100 . The positioners  102  may inhibit lateral and rotational motion of the holder  46  relative to the translation instrument  100 . 
     Arm  104  of a translation instrument  100  may include rod engager  110  and guide  112 . The rod engager  110  may contact a rod  14  during use. The rod engager  110  may be an indentation or groove in the arm  104  that contacts the rod  14  and secures the rod to the translation instrument  100  during use. 
     A guide  112  of a translation instrument arm  104  may contact a holder guide  54 . The translation instrument guide  112  may be a channel between a first surface  114  and a second surface  116 . Contact of the first surface  114  and/or the second surface  116  against a guide  54  of a fixation element holder  46  may adjust the position of holder  46  relative to the translation instrument  100 . First surface  114  may contact the holder guide  54  when hollow shaft  50  is placed in positioners  102  and the translation instrument is moved towards the holder guide  54 . Position adjustment of the fixation element holder  46  relative to the translation instrument  100  allows a rod  14 , which is engaged by the translation instrument arm  104 , to be positioned within rod opening  34  of a fixation element connector  22  when grips  106  of the translation instrument are squeezed together. 
     Spring members  118  may be coupled to grips  106  of a translation instrument  100 . The spring members  118  may apply forces to the grips  106  that tend to separate the grips. When the grips  106  are fully separated, the translation instrument  100  is in an initial position. FIG.  1  and FIG. 2 show translation instruments  100  in initial positions. When the translation instrument  100  is in the initial position, the arm  104  may be rotated away from a fixation element holder  46  that is placed within positioners  102  of the translation instrument. In an embodiment, the first guide surface  114  may contact fixation element holder guide  54  if a translation instrument in an initial position is moved towards a fixation element  16  attached to the holder  46 . Contact of the first surface  114  of the guide  112  against the fixation element holder guide  54  may limit insertion depth of the translation instrument  100  relative to the fixation element  16 . The grips  106  may be squeezed together to place the translation instrument in a closed position. FIG.  3  and FIG. 4 show translation instruments  100  in closed positions. 
     Retainer  120  may be rotationally coupled to a first grip  106 ′ of the translation instrument. The retainer  120  may be rotated towards or away from a second grip  106 ″. The retainer  120  may contact retainer stop  122 . The retainer stop  122  may interact with the retainer  120  to inhibit separation of the grips  106  from each other if a user releases the grips. The retainer  120  may be rotationally coupled near an end of first grip  106 ′, and retainer stop  122  may be an end of second grip  106 ″ of the translation instrument  100 . A retainer  120  and a retainer stop  122  may be positioned at other locations along lengths of the grips  106 . A retainer  120  may include serrations  124 . The retainer stop  122  may engage the serrations  124 . Interaction of the serrations  124  with the retainer stop  122  may allow the grips  106  to move towards each other if a user grasps the grips and forces the grips towards each other. Interaction of the serrations  124  with the retainer stop  122  may inhibit the grips  106  from separating if a user releases the grips. The interaction of the retainer stop  122  and the serrations  124  may inhibit spring members  118  from returning a translation instrument  100  to an initial position. 
     Lock  126  may be used to inhibit undesired rotation of the retainer  120  away from a second grip  106 ″. The lock  126  may be a hook that is pivotally coupled to the second grip  106 ″. When the lock  126  is rotated to engage the retainer  120 , as shown in FIG. 4, the lock may inhibit movement of the grips  106  towards or away from each other. The lock  126  may be used to inhibit unintentional release of the retainer  120  during a surgical procedure. 
     A translation instrument  100  may be used to move an out-of-position vertebra or vertebrae  12  and a rod  14  of a spinal stabilization system  10  together. Fixation elements  16  may be used to couple rods  14  to vertebrae to form the stabilization system  10 . Transverse connectors  18  may be coupled to the rods  14  to provide rigidity and stability to the stabilization system  10 . A fixation element  16  may be coupled to an out-of-position vertebrae. In an embodiment, the fixation element  16  may be a bone screw that is threaded into the out-of-position vertebra. 
     A fixation element holder  46  may be coupled to the fixation element  16 . The fixation element  16  may have a connector  22  positioned within a body  20  of the fixation element. Grooves  42  of the fixation element  16  may slide along end tips  58  of the holder  46  until the fixation element contacts inner surface of wall  56  of the holder. Holder shaft  52  may be rotated to couple the holder  46  and the fixation element body  20  together. The fixation element holder  46  may be placed within positioners  102  of the translation instrument  100 . The translation instrument  100  may be moved towards the fixation element  16  until a first surface  114  of the guide  112  contacts holder guide  54 . A rod  14  of a spinal stabilization system  10  that is coupled to two or more vertebrae may be positioned in rod engager  110 . Grips  106  of the translation instrument  100  may be grasped and moved towards each other so that the arm  104  moves towards the rod to the connector. As the grips  106  are forced together, the guide  112  of the translation instrument  100  and the holder guide  54  adjust the position of the rod  14  relative to the connector so that the rod  14  and the rod opening  34  of the fixation element  16  are brought together such that the rod snaps into the connector. The translation instrument  100  may be removed from the holder  46  and the holder may be removed from the fixation element  16 . A clip  24  may be placed between a connector end  32  and the fixation body  20  to secure the fixation element  16 , connector  22  and rod  14  together. 
     During a translation maneuver, movement of an out-of-position vertebra  12  relative to a spinal rod may be achieved and the application of increasing force to the grips  106  of the translation instrument  100 . A retainer  120  may be used during a translation maneuver to inhibit unintentional movement of an arm  104  of the translation instrument  100  away from a fixation element holder  46 . The retainer  120  may be rotated to a position where serrations  124  of the retainer engage a retainer stop  122 . If the position of the grips  106  relative to each other will not be changed for a period of time, a lock  126  of the translation instrument  100  may rotated so that the lock  126  engages the retainer  120  and holds the grips of the translation instrument at a fixed separation distance. Use of the lock  126  may inhibit the grips  106  from being moved towards or away from each other. When the position of the arm  104  of the translation instrument  100  needs to be adjusted again, the lock  126  may be disengaged from the retainer  120  and the grips  106  may be moved towards each other. If it is desired to move the arm  104  away from the fixation instrument holder  46  during a translation maneuver, a user may rotate the retainer  120  away from the retainer stop  122  and apply less force to the grips so that the separation between the grips  106  increases. Increasing the separation distance between the grips  106  allows the arm  104  to move away from the fixation element holder  46 . 
     Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the invention. It is to be understood that the forms of the invention shown and described herein are to be taken as examples of embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the invention. Changes may be made in the elements described herein without departing from the spirit and scope of the invention as described in the following claims.