Abstract:
A spinal fixation system including an interconnection device is provided. The interconnection device comprises a connector element including a passage structured to receive a component of the spinal fixation system therein. The passage is at least partially bound by a first wall portion and a second wall portion, wherein the first wall portion is movable between a first position to receive the component and a second position to restrain the component in the passage. The device further includes a retainer element which holds the first wall portion in the second position in order to lock the component in the passage.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to the field of orthopedic devices, and more particularly, but not exclusively, relates to a device for the interconnection of components in a spinal implant assembly. 
     BACKGROUND 
     The present invention relates to a prosthetic device and a manner of using the same, and more particularly, but not exclusively, relates to the interconnection of components to assemble an orthopedic construct for treatment of a spinal deformity. 
     The use of prosthetic implants to address orthopedic injuries and ailments has become commonplace. In this arena, it is often desired to decrease the invasiveness of the procedures, improve implant integrity, and provide more positive patient outcomes. Some of these implants depend on interconnection between various system components. Unfortunately, current interconnection devices can be limiting in certain applications. 
     Thus, there remains a need for an improved device for the interconnection of components in a spinal implant assembly. The present invention satisfies this need and provides other benefits and advantages in a novel and unobvious manner. 
     SUMMARY 
     The present invention relates generally to the field of orthopedic devices, and more particularly relates to a device for the interconnection of components in a spinal implant assembly. While the actual nature of the invention covered herein can only be determined with reference to the claims appended hereto, certain forms of the invention that are characteristic of the preferred embodiments disclosed herein are described briefly as follows. 
     In one form of the present invention, a device is provided that interconnects components of a spinal implant system. The device contains a connector element with a passage structured to receive a portion of the component of the spinal implant system. A first wall portion and a second wall portion partially surround the passage with the first wall portion being capable of transitioning between a first configuration to receive the portion of the component and a second configuration to secure the portion of the component in the passage. The device further includes a retainer element which cooperates with the connector element to maintain the first wall portion in a particular configuration. In one embodiment of the present application the first wall is maintained in the second configuration to secure the portion of the component in the passage. 
     In a further form of the present invention, a device is provided for interconnecting components of a spinal implant system. The device includes an elongated body comprising a first end which defines a first connector and a second end which defines a second connector. Each of the first connector and the second connector are integrally formed with the elongated body and each includes a passage therethrough. Each passage is integrally formed from a respective connector and is further defined as being sized to receive a portion of a component of the spinal implant system. A flexibly deformable wall encloses the passage but for one section including an opening. The wall is capable of transitioning from a first configuration arranged to transversely receive the portion of the component and a second configuration arranged to lock the portion of the component in the passage. A pair of retainer elements is further provided to cooperate with the connector elements to influence and retain the wall in the second configuration. When the wall is retained in the second configuration the portion of the component in the passage is secured therein. 
     In another form of the present invention, a device for interconnecting various components of a spinal implant system is provided. The device includes a connector element including a component seating portion formed by at least a first and second wall. The component seating portion is in communication with an opening between the first and second walls and is structured to receive a portion of the component therein. The first wall is further capable of movement in a first direction to a first position which expands the component seating portion at the opening to receive the portion of the component. A second direction of movement of the first wall is further provided to contract the component seating portion to a second position in order to capture the portion of the component therein. The device also includes a retainer element for selectively maintaining the first wail in the second position to secure the portion of the component in the component seating portion. 
     In yet a further form of the present invention, a device is provided for interconnecting components of a spinal fixation system. This device includes an elongated body wherein one or more of its ends define a connector element including a passage. The passage is defined by a first wall, a second wall, and a closed end which is formed by part of the connector element. Opposite the closed end is an open end situated between the first and second walls. The first wall is capable of moving in a direction which expands the opening to a first configuration to receive a portion of the component. Another direction of movement is provided for the first wall such that it moves to contract the passage and opening at a second configuration to capture the portion of the component in the passage. A retainer element which cooperates with the connector element selectively maintains the first wall in the second configuration to secure the portion of the component in the passage. 
     It is one object of the present invention to provide an improved device for the interconnection of components in a spinal implant assembly. Further objects, features, advantages, benefits, and aspects of the present invention will become apparent from the drawings and description contained herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a posterior view of the spinal column illustrating a spinal fixation system. 
         FIG. 2  is a side elevational view of an interconnection device according to one form of the present invention. 
         FIG. 3  is a top plan view of the interconnection device shown in  FIG. 2 . 
         FIG. 4  is a side elevational view of an end portion of the interconnection device shown in  FIG. 2 , as positioned for engagement with a spinal rod. 
         FIG. 5  is a side elevational view of the end portion of the interconnection device shown in  FIG. 4 , as provisionally engaged to the spinal rod. 
         FIG. 6  is a side elevational view of the end portion of the interconnection device shown in  FIG. 4 , as securely engaged to the spinal rod. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is hereby intended, and that alterations and further modifications to the illustrated devices and/or further applications of the principles of the invention as illustrated herein are contemplated as would normally occur to one skilled in the art to which the invention relates. 
     Referring to  FIG. 1 , there is shown therein posterior spinal fixation system  20  of one embodiment of the application located at a desired skeletal location of a patient. More specifically, as depicted in  FIG. 1 , system  20  is affixed to bones B of the spinal column  21  from a posterior approach. Bones B include the sacrum S and several vertebrae V. System  20  generally includes several bone attachment devices  22  and rods  23  structured to selectively interconnect with bone attachment devices  22 . In system  20 , bone attachment devices  22  are affixed to various locations of the spinal column  21  and interconnected with rods  23 . Various components of system  20 , including rods  23  and bone attachment devices  22 , may be interconnected by an interconnection device  24  to provide a stable construct for treating spinal disorders. Posterior fixation system  20  may be used for, but is not limited to, treatment of degenerative spondylolisthesis, fracture, dislocation, scoliosis, kyphosis, spinal tumor, and/or a failed previous fusion. 
     Bone attachment devices  22  may be, but are not limited to, multi-axial, poly-axial, uni-axial, or uni-planar bone screws having a threaded stem portion opposite a head portion including a rod receiving portion, where the threaded stem and the head portion are movable relative to one another. The threaded stem of these bone screws is structured to threadingly engage a passageway prepared in one or more bones or bony structures in a standard manner, and can be provided with cutting flutes or other structure for self-tapping and/or self-drilling capabilities. The threaded stem can also be cannulated to receive a guidewire to facilitate placement and may further include fenestrations or other openings for placement of bone growth material. In one movable form, the threaded stem and the head portion are engaged together with a “ball and joint” or swivel type of coupling that permits relative movement therebetween during at least some stages of assembly. In yet another form, bone attachment devices  22  may include one or more hooks to engage an adjacent bony structure such as a pedicle, lamina, spinous process, transverse process, or other bony structure suitably engaged with a spinal hook. For instance, a multi-axial laminar hook form of device  22  can be used in place of a bone screw. In still other embodiments, device  22  can include a bone attachment structure in the form of a staple, bone plate, interbody fusion device, interbody spacer, spinal anchor, intravertebral fusion device, bone clamp, or other anchor. In one form bone attachment devices  22  are made of medical grade stainless steel but other embodiments may be composed of, but are not limited to, titanium, a titanium alloy or other metallic alloy, and/or a nonmetallic composition 
     In addition, rod  23  may be solid or hollow along some or all of its length and/or may be of homogenous or heterogeneous composition. Rod  23  can be rigid, or be flexible or include one or more flexible portions to permit at least limited spinal motion. Rod  23  may be substituted with any suitable spinal stabilization element positionable along the spinal column, including plates, tethers, wires, cables, cords, inflatable devices, expandable devices, and formed in place devices, for example. 
       FIG. 2  is a side elevational view of interconnection device  24  according to one form of the present application, wherein like numerals refer to like features previously described. Interconnection device  24  includes an elongated body  26  extending along longitudinal axis L. Elongated body  26  includes a first end  28  opposite a second end  30  with each further defining a first connector  32  and a second connector  34 , respectively. In alternative embodiments not shown, first end  28  or second end  30  include either first connector  32  or second connector  34  as illustrated in  FIG. 2 , while the opposing end includes an alternatively structured connector not shown. Each of first connector  32  and second connector  34  includes an engagement portion  36  structured to receive a component of system  20 , wherein each engagement portion  36  is disposed on the same side of connectors  32 ,  34 . Engagement portion  36  is generally formed by a first wall  37  and a second wall  40 , wherein each of first wall  37  and second wall  40  individually extend from first connector  32  and second connector  34 . In the embodiment illustrated, each of first wall  37  and second wall  40  is integrally formed from first connector  32  and second connector  34 . However, in alternative embodiments not shown, it is contemplated that all or part of first wall  37  and second wall  40  may be formed from a material different than that of first connector  32  and second connector  34 . 
     Further defining engagement portion  36  is a closed end  42 . While closed end  42  is illustrated as being formed by a section of connectors  32  and  34 , it should be understood that closed end  42  may be formed as a continuation of first wall  37  and second wall  40 , such that closed end  42  is not in direct contact with connectors  32  and  34 . In deed, in one form closed end  42  may be in the form of a third wall which extends between first wall  37  and second wall  40 . In any of these forms, closed end  42  may be in direct contact with connector  32  or  34 , or spaced apart therefrom in order to achieve a desirable height of interconnection device  24  relative to components of system  20 . As shown, engagement portion  36  is substantially circular in sectional profile, structured to receive for example, rod  23  of system  20  when rod  23  has a circular sectional profile. It should be understood however that the section profile of rod  23  may change, and as the sectional profile of rod  23  changes, the shape and structure of engagement portion  36  also changes. In deed, in alternative embodiments not shown, engagement portion  36  may even be structured to receive alternative components of system  20  not shown. 
     As illustrated, first wall  37  includes an enlarged end portion  37   a  opposite a smaller section  38  which is located near a relief section  44  including surfaces  44   a  and  44   b . Relief section  44  is provided so that first wall  37  is moveable in two directions, as indicated by directional arrows A and B. It should be understood that each of directional arrows A and B do not correspond to directions generally. Arrow A corresponds to a direction of movement of first wall  37  toward second wall  40  while arrow B corresponds to a direction of movement of first wall  37  away from second wall  40 . As force is applied from one direction first wall  37  moves toward second wall  40  in the direction of arrow A, closing opening  43  and contracting engagement portion  36 . As movement occurs in direction A, surface  44   a  moves away from surface  44   b  in relief section  44 . Additionally, as force is applied from an alternative direction first wall  37  moves away from second wall  40  in the direction of arrow B, stretching opening  43  and expanding engagement portion  36 . As movement occurs in direction B, surface  44   a  moves toward surface  44   b  in relief section  44 . Relief section  44  may be larger or smaller than as depicted and it should be appreciated that its size will alter in relation to the amount of movement desired in either direction A or B. For example, if a greater range of motion is desired in direction B, the distance between surfaces  44   a  and  44   b  of relief section  44  will be greater. 
     In addition to relief section  44 , all or part of first wall  37  may be formed of a flexible material to aid in the movement of first wall  37  for expanding and contracting engagement portion  36 . For example, the material comprising section  38  may be flexible while the material comprising end portion  37   a  remains rigid and inflexible. In alternative embodiments not shown, one or both of first connector  32  and second connector  34  may not include relief section  44 . In these embodiments, first wall  37  is flexibly deformable to allow for expansion and contraction of engagement portion  36 . In these alternative embodiments, only a section of first wall  37  may be flexible or the entire portion of first wall  37  may be flexible. In some embodiments, first wall  37  may be made flexible upon some or all of its length by adding relief notches or holes thereto. Other manners known to those skilled in the art for providing flexibility to first wall  37  are further included in this application. 
     Interconnection device  24  further includes an aperture  46  extending transversely through each of first connector  32  and second connector  34 . Aperture  46  further includes internal threading  48  as most clearly seen in first connector  32  in  FIG. 2 . Further included in interconnection device  24  is a retainer element  50  shown in the form of threaded fastener  51 . Threaded fastener  51  includes an elongated threaded stem  52  opposite an enlarged head portion  54 , wherein head portion  54  includes a tool engagement portion  56 . Threaded stem  52  is structured to threadingly engage internal threading  48  such that as threaded fastener  51  is rotated, it moves transversely to second connector  34 . While threaded fastener  51  is only shown in second connector  34 , it should be understood that it is structured to engage aperture  46  of first connector  32  as well, and has only been omitted therefrom to enhance clarity of certain structural features. As illustrated, aperture  46  is adjacent relief section  44 , but will vary in alternative embodiments. In one form aperture  46  can be placed at any position which will facilitate extension of threaded fastener  51  through aperture  46  to contact first wall  37 . For example, as shown aperture  46  is arranged substantially perpendicular to longitudinal axis L, but in alternative embodiments may intersect longitudinal axis L at a number of angular variations. In one of these embodiments aperture  46  extends from where elongated body  26  joins connectors  32  and  34  to a position near first wall  37 , so long as threaded fastener  51  is capable of extending through aperture  46  and contacting first wall  37 . 
     Referring to  FIG. 3 , wherein like numerals refer to like features previously described, interconnection device  24  is shown in top plan view. As shown, each of threaded fasteners  51  is engaged with apertures  46  and includes tool engagement portion  56  in a hex or allen shape. In alternative embodiments tool engagement portion  56  may be square, phillips, slotted, or of any other form known to those skilled in the art. It should be further understood that as illustrated in both  FIGS. 2 and 3 , first connector  32  and second connector  34  are formed integral with elongated body  26 . In these embodiments, each of elongated body  26 , first connector  32 , second connector  34 , and engagement portion  36  are integrally formed. In alternative embodiments one or both of connectors  32 ,  34  may be connected to elongate body  26  in a different manner, including but not limited to threading, pinning, compression, welding, and/or adhesion. 
     Additionally, the length of interconnection device  24 , as indicated by reference arrow C, is generally sized to span a distance between two components of system  20 . In one embodiment the length of interconnection device  24  is sized to span and connect rods  23 . In alternative embodiments not shown, interconnection device  24  may be formed of two members and include a linking/interconnection device that allows alteration of length as indicated by arrow C to appropriately span a desired distance between components. In still another alternative embodiment, the interconnection device provides for alterations of the angular orientation between the two members to provide adjustability in the positioning of interconnection device  24  between two components. It should be further understood that either first connector  32  or second connector  34  may be rotated relative to the other about longitudinal axis L. For example, while one connector is engaging a spinal rod extending longitudinal to spinal column  21  the other connector may be engaging a component extending transversely from spinal column  21 , for instance, a bone screw having a stem or stud extending therefrom. 
     Referring now to  FIGS. 4 ,  5 , and  6 , where like numerals refer to like features previously described, there is illustrated the manner in which interconnection device  24  engages with a component of spinal system  20 , wherein the component is in the form of spinal rod  23 . It should be understood that in each of  FIGS. 4 ,  5 , and  6  second connector  34  is illustrated, but that the description directed to second connector  34  is similarly applicable to first connector  32 . In specific regard to  FIG. 4 , there is shown a side elevational view of second connector  34  as positioned for engagement with spinal rod  23 . As illustrated, rod  23  has a circular sectional profile including a diameter indicated by reference arrow D. Diameter D of rod  23  is larger than opening  43  between first wall  37  and second wall  40  in  FIG. 4 . As connector  34  is engaged with rod  23 , the outer surface  23   a  of rod  23  contacts point  39  of first wall  37  and point  40   a  of second wall  40 . As further pressure is applied, outer surface  23   a  begins to move first wall  37  away from second wall  40  at opening  43  in direction B. While first wall  37  moves in direction B surface  44   a  of relief section  44  simultaneously moves toward surface  44   b . As this happens, opening  43  becomes larger such that engagement portion  36  may receive rod  23  therein. In this embodiment relief section  44  provides the flexibility necessary in order for first wall  37  to move enough to allow rod  23  to pass entirely through opening  43  and into engagement portion  36  as is illustrated in  FIG. 5 . However, if increased flexibility of first wall  37  is desired then relief section  44  may be altered or part of first wall  37  may be flexible, as herein already described. Once rod  23  has sufficiently passed point  39  and point  40 , first wall  37  correspondingly moves in direction A until rod  23  is entirely seated in engagement portion  36  and opening  43  is back to its original position, as also shown in  FIG. 5 . As first wall  37  moves back to its original position, surface  44   a  moves away from surface  44   b  in relief section  44 . 
     Once rod  23  is completely received in engagement portion  36  a space remains between outer surface  23   a  of rod  23  and first wall  37  and second wall  40 , as indicated by reference numerals  41  and  41   a  respectively, as shown in  FIG. 5 . In this form interconnection device  24  may be freely moved along rod  23  to a desired location without removing second connector  34  from rod  23 . In order to eliminate spaces  41  and  41   a  and to restrict movement of interconnection device  24  along rod  23 , threaded fastener  51  may be engaged with aperture  46  and extended therethrough to influence first wall  37  toward second wall  40  at opening  43 . As illustrated in  FIG. 6  threaded fastener  51  is further defined at its tip  60  by a flat section  62  and a tapered section  64 . First wall  37  includes a tapered retainer contact area  58  which corresponds to tapered section  64 . As threaded fastener  51  is rotated in aperture  46  it moves toward contact area  58  such that tapered section  64  communicates with contact area  58 . Further engagement of threaded fastener  51  moves tapered section  64  further down contact area  58  bearing against first wall  37  and forcing it toward second wall  40  in direction A while surface  44   a  moves further away from surface  44   b  in relief section  44 . As this occurs, point  39  influences rod  23  toward point  40   a  until rod  23  is securely retained in engagement portion  36  and spaces  41  and  41   a  are eliminated. When fully engaged, head  54  of threaded fastener  51  is in contact with connector  34  and connector  34  and rod  23  are secured in a rigid construct. 
     While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiments have been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.