Patent Publication Number: US-2022218398-A1

Title: Spine plate implant with cam lock bone screw retention

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This U.S. non-provisional patent application is a continuation of U.S. application Ser. No. 16/293,429 filed on Mar. 5, 2019, which is a continuation of U.S. application Ser. No. 15/422,447 filed on Feb. 1, 2017, which claims the benefit of and/or priority under 35 U.S.C. § 119(e) to U.S. provisional patent Application No. 62/290,027 filed Feb. 2, 2016, the entire contents of each are specifically hereby incorporated herein by reference. 
    
    
     FIELD 
     The present invention relates to orthopedic implants such as plates and screws for the spine and, more particularly to spine plate implants having screw retention features. 
     BACKGROUND 
     People contend with spine issues as a result of age, disease, trauma, and congenital and acquired complications and conditions. While some of these issues can be alleviated without surgery, other issues respond better to surgery. In some cases, surgery may include installing an orthopedic implant. 
     One type of orthopedic implant for the spine is a plate or plate construct along with bone screws for attaching the plate/plate construct to vertebrae of the spine. Various spine plates have been developed over the years for general, particular and specific use. However, with most, if not all of the spine plates there is an issue known as back out where one or more of the bone screws unscrews (backs out) from the plate. This compromises the integrity of the orthopedic implant and its ability to perform its intended function. 
     While numerous spine plate implants have been designed over the years to combat bone screw back out, they are deficient in many respects. It is therefore an object of the present invention to provide an orthopedic plate implant that overcomes the deficiencies of the prior art. 
     SUMMARY 
     The present invention is a spine plate implant that utilizes cam lock setscrews to retain bone screws that are received in the spine plate. Each cam lock setscrew is situated adjacent a configured bone screw bore of the spine plate and is configured to allow a bone screw to pass by the cam lock setscrew and be received in the spine plate when in one rotational position (an unlocked, open, or neutral position), and to retain the bone screw received in the spine plate when in another rotational position (a locked, closed, or engaged position). 
     The present spine plate implant includes a spine plate, a plurality of cam lock setscrews, and a plurality of bone screws. The spine plate has a plurality of bone screw bores each one configured to receive a bone screw and a pocket adjacent each bone screw bore, each pocket configured to receive a cam lock setscrew. The bone screw is configured to allow engagement with the cam lock setscrew when the cam lock setscrew is rotated into a locked position. Once the cam lock setscrew is in the locked position, the bone screw is inhibited from backing out of the bone screw bore. When the cam lock setscrew is in an unlocked position, the bone screw may be backed out of the bone screw bore. 
     Each cam lock setscrew has external threads that engage with threading in the setscrew pocket to provide rotational stability, engagement, and positioning of the cam lock setscrew with the setscrew pocket. External teeth are provided about a portion of the outer diameter of each cam lock setscrew for engagement with the bone screw when the cam lock setscrew is rotated into the locked position. An external flat is provided about a portion of the external teeth of the cam lock setscrew that allows the bone screw to be received in the spine plate when the cam lock setscrew is rotated into the unlocked position. 
     The bone screw includes one or more tangs, flanges, or the like about an upper area of the bone screw that provide engagement with the external teeth of the cam lock setscrew when the cam lock setscrew is in the locked position. When the cam lock setscrew is in the unlocked position, the external flat is adjacent a tang, flange, or the like of the bone screw permitting the bone screw to pass by the cam lock setscrew for removal of the bone screw from the bone screw bore. 
     Further aspects of the present invention will become apparent from consideration of the drawings and the following description of a form of the invention. A person skilled in the art will realize that other forms of the invention are possible and that the details of the invention can be modified in a number of respects without departing from the inventive concept. The following drawings and description are to be regarded as illustrative in nature and not restrictive. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features of the invention will be better understood by reference to the accompanying drawings which illustrate a form of the present invention, wherein: 
         FIG. 1  is an exploded isometric view of an exemplary cervical plate implant fashioned in accordance with the present principles; 
         FIG. 2  is an isometric view of the cervical plate implant of  FIG. 1 , assembled, with the cam lock setscrews thereof situated in the plate thereof; 
         FIG. 3  is an isometric view of the plate of the cervical plate implant of  FIG. 1 ; 
         FIG. 4  is an enlarged isometric view of one side of the cam lock setscrew of the cervical plate implant of  FIG. 1 ; 
         FIG. 5  is an enlarged isometric view of another side of the cam lock setscrew of  FIG. 4 ; 
         FIG. 6  is an enlarged side view of the cam lock setscrew of  FIG. 4 ; 
         FIG. 7  is an enlarged side view of the cam lock setscrew of  FIG. 4 ; 
         FIG. 8  is an enlarged top view of the cam lock setscrew of  FIG. 4 ; 
         FIG. 9  is an isometric view of the cervical plate implant of  FIG. 1  with the cam lock setscrews situated in the plate along with several bone screws received in the plate with two bone screws thereof awaiting insertion into the plate, the cam lock setscrews all in an unlocked or neutral position; 
         FIG. 10  is a sectional view of the cervical plate implant as shown in  FIG. 9  with bone screws received in the plate and the cam lock setscrews in the unlocked position; 
         FIG. 11  is an enlarged sectional view of an end screw cavity of the plate of the cervical plate implant with a bone screw and cam lock setscrew received therein, the cam lock setscrew in an unlocked position; 
         FIG. 12  is an enlarged sectional view of the end screw cavity of the plate of the cervical plate implant with a bone screw and cam lock setscrew received therein of  FIG. 11 , the cam lock setscrew in a locked position; and 
         FIG. 13  is an enlarged top view of the end screw cavity of the plate of the cervical plate implant with a bone screw and cam lock setscrew received therein of  FIG. 11 , the cam lock setscrew and bone screw in a locked position. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the figures, there is depicted an exemplary form of a spine plate implant, generally designated  10 . The spine plate implant  10  is made from a biocompatible material such as, but not limited to, titanium, stainless steel, an alloy of titanium or stainless steel, or other. The spine plate implant  10  is characterized by a spine plate  12 , a plurality of cam lock setscrews  14 , and a plurality of bone screws  60 . While the spine plate implant  10  is particularly for the cervical portion of the spine, it can be used for other portions of the spine. 
       FIG. 3  depicts the spine plate  12 . The spine plate  12  is characterized by an elongated body  13  having a generally planar upper surface  16  and a generally planar lower surface  17 . The body  13  defines a first end  18 , a second end  19 , and a middle  20 , with the nomenclature first and second being arbitrary. The first end  18  has a first boss  22  at one side thereof, and a second boss  23  at another side thereof opposite to the first boss  22 , the nomenclature first and second again being arbitrary. A notch  26  is provided in the periphery of the first end  18  between the first boss  22  and the second boss  23 . A first configured cavity  30  is provided at the first boss  22  while a second configured cavity  31  is provided at the second boss  23 , the nomenclature first and second again being arbitrary. The first configured cavity  30  includes a bore  32  that is structured to receive a bone screw  60 , and a pocket  33  adjacent the bore  32  that is structured to receive a cam lock setscrew  14 . Particularly, the bone screw bore  32  is structured to angle a received bone screw  60  outwardly from the bottom of the body  13  as best seen in  FIG. 10 , while the cam lock setscrew pocket  33  includes screw threads  64  about its inner lower periphery. The second configured cavity  31  includes a bore  34  that is structured to receive a bone screw  60 , and a pocket  35  adjacent the bore  34  that is structured to receive a cam lock setscrew  14 . Particularly, the bone screw bore  34  is structured to angle a received bone screw  60  outwardly from the bottom of the body  13  in like manner as received bone screw  60  from the bone screw bore  32 , while the cam lock setscrew pocket  35  includes screw threads  65  about its inner lower periphery. 
     The second end  19  has a first boss  24  at one side thereof, and a second boss  25  at another side thereof opposite to the first boss  24 , the nomenclature first and second again being arbitrary. A notch  27  is provided in the periphery of the second end  19  between the first boss  24  and the second boss  25 . A first configured cavity  36  is provided at the first boss  24  while a second configured cavity  37  is provided at the second boss  25 , the nomenclature first and second again being arbitrary. The first configured cavity  36  includes a bore  38  that is structured to receive a bone screw  60 , and a pocket  39  adjacent the bore  38  that is structured to receive a cam lock setscrew  14 . Particularly, the bone screw bore  38  is structured to angle a received bone screw  60  outwardly from the bottom of the body  13  as best seen in  FIG. 10 , while the cam lock setscrew pocket  39  includes screw threads  68  about its inner lower periphery. The second configured cavity  37  includes a bore  40  that is structured to receive a bone screw  60 , and a pocket  41  adjacent the bore  40  that is structured to receive a cam lock setscrew  14 . Particularly, the bone screw bore  41  is structured to angle a received bone screw  60  outwardly from the bottom of the body  13  in like manner as the bone screw  60  from the bone screw bore  34  of the first end  18 , while the cam lock setscrew pocket  41  includes screw threads  69  about its inner lower periphery. 
     The middle  20  of the body  13  has a first configured cavity  42  at a first side of the middle  20  while a second configured cavity  43  is provided at a second side of the middle  20 , the nomenclature first and second again being arbitrary. The first configured cavity  42  includes a bore  44  that is structured to receive a bone screw  60 , and a pocket  45  adjacent the bore  44  that is structured to receive a cam lock setscrew  14 . Particularly, the bone screw bore  44  is structured to project a bone screw  60  downwardly from the bottom of the body  13  as best seen in  FIG. 10 , while the cam lock setscrew pocket  45  includes screw threads  66  about its inner lower periphery. The second configured cavity  43  includes a bore  46  that is structured to receive a bone screw  60 , and a pocket  47  adjacent the bore  46  that is structured to receive a cam lock setscrew  14 . Particularly, the bone screw bore  46  is structured to project a received bone screw  60  downwardly from the bottom of the body  13  in like manner as the received bone screw  60  from the bone screw bore  44  of the first side of the middle  20 , while the cam lock setscrew pocket  47  includes screw threads  67  about its inner lower periphery. 
     The body  13  also includes a first window or opening  28  situated between the middle  20  of the body  13  and the first end  18 , and a second window or opening  29  situated between the middle  20  and the second end  19 , the nomenclature first and second, again being arbitrary. The first and second windows  28 ,  29  have generally the same shape, but may be different if desired. As well, the particular shape of the first and second windows  28 ,  29  may be changed as desired. 
     The bone screw  60  of the present spine plate implant  10  is depicted in various figures. The bone screw  60  is characterized by an externally threaded shank  61  having a distal tip  62  and a proximal head  63 , the shank threading configured for reception in spinal bone. As best seen in  FIGS. 11 and 12 , the underside  70  of the head  63  is rounded to allow reception of the bone screw head  63  in the bone screw opening of the spine plate  12 . The bone screw  60  has a socket  71  in the top of the head  63  for receipt of a driving tool (not shown). While the socket is shown as hexagonally configured, the socket may have other configurations. An annular wall  72  extends from the upper surface  75  of the head  63  and about the socket  71 . A first tang, flange or the like  73  extends from one side of the annular wall  72 , while a second tang, flange or the like  74  extends from another side of the annular wall  72 , preferably, but not necessarily, opposite to the first tang  73 , the nomenclature first and second being arbitrary. While two tangs are shown, the bone screw may have more tangs or in the alternative, have a single annular tang extending from the annular wall. 
     Referring now to  FIGS. 4-8 , the cam lock setscrew  14  is shown. The cam lock setscrew  14  is characterized by a generally cylindrical body  50  having a neck  57  and a head  51 . The head  51  has a generally planar upper surface  52  with a socket  53  situated therein. The socket  53  is configured as a geometric shape for receiving a like shaped tool or instrument (not shown) in order to install the cam lock setscrew  14  into a setscrew pocket of the spine plate, and to lock the cam lock setscrew  14  once a bone screw  60  has been installed onto the spine plate. The neck  57  of the cam lock setscrew  14  has external threading  54  that is sized for reception by the threading of a setscrew pocket of the spine plate. In accordance with an aspect of the present invention, the body  50  has external teeth or the like  55  about a portion of its periphery underneath the head  51  and above the neck threading  54 . As best seen in  FIGS. 7, 11 and 12 , the head  51  has a lip  58  situated generally above the teeth  55 . The teeth  55  and lip  58  of the cam lock setscrew  14  cooperate to retain a bone screw  60  as/when the cam lock setscrew  14  is rotated in/into the locked position. The head  51  further has a flat or the like  56  that is generally situated opposite the lip  58 . The flat  56  extends through the teeth  55  and allows a bone screw  60  to pass by the cam lock setscrew  14  situated in a setscrew pocket of the spine plate  12  as the bone screw  60  is being received in the adjacent bone screw bore (i.e. the cam lock setscrew is in the open, unlocked, or neutral position). Rotation of the flat  56  away from the bone screw  60  rotates the teeth  55  into the underside  70  of the head  63  of the bone screw  60  engaging the teeth  55  with the bone screw head  63  and positioning the lip  58  over the bone screw head  63  and preferably over a tang  73 ,  74  (see, e.g.  FIGS. 12,13 ) to lock the teeth  55  of the cam lock setscrew  14  into the bone screw  60  holding the bone screw  60  in place (the closed, locked, or engaged position). 
       FIG. 1  shows a plurality of cam lock setscrews  14  being inserted in respective cam lock setscrew pockets of the spine plate  12 . The cam lock setscrews  14  are threadedly received in the respective cam lock setscrew pockets.  FIG. 2  shows the plurality of cam lock setscrews  14  received in their respective cam lock setscrew pockets, with each cam lock setscrew  14  in the unlocked position ready to accept a bone screw.  FIGS. 10-11  show bone screws  60  received in the spine plate  12  with the associated cam lock setscrews in the unlocked position.  FIGS. 12-13  show a bone screw  60  received and retained in the spine plate  12  with the associated cam lock setscrew in the locked position. 
     The cam lock setscrews  14  are initially in the neutral or open position to allow a bone screw  60  to pass through and into the associated bone screw opening. Once the bone screw is fully seated into the bone screw opening the cam lock setscrew is turned clockwise until it abuts against the head of the bone screw, thus locking the bone screw in place and preventing the bone screw from backing out. 
     It should be appreciated that dimensions of the components, structures, and/or features of the present spine plate implant may be altered as desired within the scope of the present disclosure.