Patent Publication Number: US-2023149051-A1

Title: Crosslink locking mechanism

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 63/280,985 filed Nov. 18, 2021, which is incorporated herein by reference. 
    
    
     FIELD 
     The present invention relates generally to the field of surgery, and more specifically, to crosslink locking mechanism for use with reducers in spinal fusion surgery. 
     BACKGROUND 
     The spine is a series of individual bones called vertebrae. A normal spine has no side-to-side curve but does have a series of front-to-back curves, giving it a gentle “S” shape. Many people have an abnormal curvature of the spine and it may be necessary to straighten or adjust the spine into a proper curvature and alignment. 
     Spinal surgical procedures have been developed to correct the abnormal curvature of the spine. One procedure involves placing multiple pedicle screws into the vertebrae of the curved region and coupling spinal fixation rods to the screw heads. The rods are shaped to mimic the normal curvature and force the spine into proper alignment once positioned within the screw head. The rods are then secured or locked to the screws maintain the curvature. 
     The Spinal surgical procedures can require complex movement and manipulation of the vertebrae to restore normal curvature to the patient. The manipulation may include a rotational force applied on pedicle screws in the coronal plane (medial-laterally) is referred to as “derotation”. This is usually done by applying compression and/or distraction forces of a derotation instrument to vertebrae via the screw extenders. 
     Typically there is a derotation instrument on each side of the spine that are connected with a crosslink between them. Current crosslink either do not lock rotational freedom or require the turning of a knob or bolt. Traditional crosslink locking mechanisms often require a knob, bolt, or screw to lock or tighten the rotational/hinge freedom of the device. These crosslink locking mechanisms are slow due to the requirement of turning of a knob or bolt, and some require the surgeon to tighten the device either by hand or with a secondary instrument. 
     The speed of this operation is of high importance A faster, more convenient method of locking rotational motion is needed. 
     Accordingly, there remains a need for instruments and methods that provide solutions to the problems of current systems. The present invention is directed toward meeting these needs. 
     SUMMARY 
     The present invention is directed to a crosslink mechanism features a locking clip with interlocking teeth. When being deployed, the surgeon will compress the spring loaded clips, freeing rotation on both sides of the mechanism. Once clipped onto the sequential reducers, the surgeon releases the clips allowing the spring to lock the teeth and therefore lock rotational freedom out of the mechanism. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS.  1 A and  1 B  show a side view and top view of one embodiment of a crosslink that is configured to rigidly couple with spinal screw reducers or extenders. 
         FIGS.  2 A and  2 B  show a left locking system configured to lock the left connector to the left end of the connecting member. 
         FIGS.  3 A and  3    show a right locking system configured to lock the right connector to the right end of the connecting member. 
         FIGS.  4 ,  5  and  6    show the left and right connectors being deployed in various orientations. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to the present embodiments of the technology, examples of which are illustrated in the accompanying drawings. Similar reference numbers may be used to refer to similar components. However, the description is not intended to limit the present disclosure to particular embodiments, and it should be construed as including various modifications, equivalents, and/or alternatives of the embodiments described herein. 
     It will be understood that the words “comprising” (and any form of comprising, such as “comprise” and “comprises”), “having” (and any form of having, such as “have” and “has”), “including” (and any form of including, such as “includes” and “include”) or “containing” (and any form of containing, such as “contains” and “contain”) when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     It will be further understood that, although the terms first, second, third etc. may be used herein to describe various limitations, elements, components, regions, layers and/or sections, these limitations, elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one limitation, element, component, region, layer or section from another limitation, element, component, region, layer or section. Thus, a first limitation, element, component, region, layer or section discussed below could be termed a second limitation, element, component, region, layer or section without departing from the teachings of the present application. 
     The expression “configured (or set) to” used in the present disclosure may be used interchangeably with, for example, the expressions “suitable for”, “having the capacity to”, “designed to”, “adapted to”, “made to” and “capable of” according to a situation. The expression “configured (or set) to” does not mean only “specifically designed to” in hardware. Alternatively, in some situations, the expression “a device configured to” may mean that the device “can” operate together with another device or component. 
     It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination. For example, it will be appreciated that all features set out in any of the claims (whether independent or dependent) can be combined in any given way. 
     It is to be understood that at least some of the figures and descriptions of the invention have been simplified to focus on elements that are relevant for a clear understanding of the invention, while eliminating, for purposes of clarity, other elements that those of ordinary skill in the art will appreciate may also comprise a portion of the invention. However, because such elements are well known in the art, and because they do not necessarily facilitate a better understanding of the invention, a description of such elements is not provided herein. 
       FIGS.  1 A and  1 B  show a side view and top view of one embodiment of a crosslink  100  that is configured to rigidly couple with spinal screw reducers or extenders  102 , such as sequential screw reducers, to correct a rotation deformity of the spine by turning or rotating the deformed spine structure toward a normal position. The crosslink  100  includes a left connector  104 , a right connector  106 , and a connecting member  108 . The crosslink  100  can be adjusted to many different orientations. The left and right connectors  104 ,  106  are configured to rotate with respect to the connecting member  108 . Connecting member  108  may also be shortened or extended are needed. The connecting member  108  includes a center locking mechanism that rigidly locks the length between the two locking clips. It is important that this length is locked down for the locking clips to function 
     For rotation, the left connector  104  includes a left connector hinge  110  that is rotatably coupled to a left connector hinge  112  of the connecting member  108  by a left hinge pin  114 . A left locking system  200  is configured to lock the left connector  104  to the left end of the connecting member  108 . The right connector  106  includes a right connector hinge  116  that is rotatably coupled to a right connector hinge  118  of the connecting member  108  by a right hinge pin  120 . A right locking system  300  is configured to lock the right connector  106  to the right end of the connecting member  108 . 
       FIGS.  2 A and  2 B  show an innovative left locking system  200  configured to lock the left connector  104  to the left end of the connecting member  108  that does not require secondary tightening, which allows for fast and high strength application of the crosslink  100  during surgery. The left locking system  200  includes a spring-loaded locking clip  202  positioned within a side recess or pocket  105  of the left connector  104 . The spring-loaded locking clip  202  is coupled to the left connector  104  in a rocking or teeter-totter fashion with a pin  204 . A first end  202   a  of the locking clip  202  includes a clip button  206  configured to be pushed, and a second end  202   b  includes radially engaging, interlocking teeth  208  configured to engage radially engaging, interlocking teeth  210  on the left connector hinge  112 . The locking system  200  further includes a spring coupled to the locking clip  202  configured to position the locking clip  202  in a normally closed position. In the normally closed or locked position, the interlocking teeth  208  of the locking clip  202  are engaged with the interlocking teeth  210  of the left connector hinge  112 , which locks the left connector  104  to the connecting member  108 , preventing rotation of the left connector  104 . 
     To unlock the locking system  200 , the clip button  206  is compressed or pushed inward  212  toward the left connector  104 , rocking  214  the locking clip  202 , which moves the interlocking teeth  212  outward  216 , disengaging the locking interlocking teeth  208  from the connecting member interlocking teeth  210 . 
     To re-lock the left connector  104  with the connecting member  108 , the clip button  206  is released, which moves the interlocking teeth  208  inward to reengage the connecting member interlocking teeth  210 . 
       FIGS.  3 A and  3 B  show a right locking system  300  configured to lock the right connector  106  to the right end of the connecting member  108 . Locking system  300  is similar to locking system  200  discussed above. The locking system  300  includes a spring-loaded locking clip  302  positioned within a side recess or pocket  107  of the right connector  106 . The spring-loaded locking clip  302  is coupled to the right connector  106  in a rocking or teeter-totter fashion with a pin  304 . A first end  302   a  of the locking clip includes a clip button  306  configured to be pushed, and a second end  302   b  includes radially engaging, interlocking teeth  308  configured to engage radially engaging, interlocking teeth  310  on the right connector hinge  116 . The locking system  300  further includes a spring coupled to the locking clip  302  configured to position the locking clip  302  in a normally closed or locked position. In the normally closed position, the interlocking teeth  308  of the locking clip  302  are engaged with the interlocking teeth  310  of the left connector hinge  112 , which locks the right connector  106  to the connecting member  108 , preventing rotation of the right connector  106 . 
     To unlock the locking system  300 , the clip button  306  is compressed or pushed inward  312  toward the right connector  106 , rocking  314  the locking clip  302 , which moves the interlocking teeth  308  outward  316 , disengaging the locking interlocking teeth  308  from the connecting member interlocking teeth  310 . 
     To re-lock the left connector  104  with the connecting member  108 , the clip button  306  is released, which moves the interlocking teeth  308  inward to reengage the connecting member interlocking teeth  310 . 
     The crosslink connection with reducers or extenders is rigid but not limited to clips as shown in the pictures. 
       FIGS.  4 ,  5  and  6    show the left and right connectors  104 ,  106  being deployed in various orientations. 
       FIG.  4    shows a configuration for crosslink  100  in which both the left and right connector  104 ,  106  clipped onto the left and right sequential reducers  102   a,    102   b  in a straight orientation with respect to the connecting member  108 . 
       FIG.  5    shows a configuration for the crosslink  100  in which the left connector  104  are rotated  400  to a downward orientation with respect to the connecting member  108 . To accomplish this rotation, the clip button  206  is pressed or compressed downward  212 , which rocks the spring-loaded clip  202  and lifts the clip interlocking teeth  208  outward  216 , disengaging the locking interlocking teeth  208  from the connecting member interlocking teeth  210  and unlocking the left connector  104 . Once disconnected, the left connector  104  is free to rotate in a downward direction  400 . The left connector  104  is then positioned in the desired orientation it is clipped onto the sequential reducer  102   a.  The clip button  206  is then released, allowing the spring to rock the spring-loaded clip  202  back into normal position with the interlocking teeth  208  lowering and coupling with the connecting member interlocking teeth  210 , and therefore locking rotational freedom out of the mechanism. 
       FIG.  6    shows a configuration for the crosslink  100  in which the left and right connectors  104 ,  106  are rotated  400  to a downward orientation with respect to the connecting member  108 . To accomplish this rotation for the left connector  104 , the clip button  206  is pressed or compressed downward  212 , which rocks the spring-loaded clip  202  and lifts the clip interlocking teeth  208  outward  216 , disengaging the locking interlocking teeth  208  from the connecting member interlocking teeth  210  and unlocking the left connector  104 . To accomplish this rotation for the right connector  106 , the clip button  306  is pressed or compressed downward  312 , which rocks the spring-loaded clip  302  and lifts the clip interlocking teeth  308  outward  316 , disengaging the locking interlocking teeth  308  from the connecting member interlocking teeth  310  and unlocking the right connector  106 . 
     Once disconnected, the left and right connectors  104 ,  106  are free to rotate in a downward direction  400 . The left connector  104  is positioned in the desired orientation it is clipped onto the sequential reducer  102   a.  The clip button  206  is then released, allowing the spring to rock the spring-loaded clip  202  back into normal position with the interlocking teeth  208  lowering and coupling with the connecting member interlocking teeth  210  to lock the left connector  104 . The right connector  106  is positioned in the desired orientation it is clipped onto the sequential reducer  102   b.  The clip button  306  is then released, allowing the spring to rock the spring-loaded clip  302  back into normal position with the interlocking teeth  308  lowering and coupling with the connecting member interlocking teeth  310  to lock the right connector  106 . 
     In use, the reducers or extenders  102   a,    102   b,  the left and right connectors  104 ,  106 , and connecting member  108  are manipulated to desired or optimal position, then the locking systems  200 ,  300  are configured to lock the left and right connectors  104 ,  106 , in the desired position with the connecting member  108  to hold the reducers or extenders  102   a,    102   b  in a rigid structure or construct. Once locked, the crosslink  100  and reducers  102   a,    102   b  may be rotated or moved as one body to correct a deformity. 
     Example embodiments of the methods and systems of the present invention have been described herein. As noted elsewhere, these example embodiments have been described for illustrative purposes only and are not limiting. Other embodiments are possible and are covered by the invention. Such embodiments will be apparent to persons skilled in the relevant art(s) based on the teachings contained herein. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments but should be defined only in accordance with the following claims and their equivalents.