Abstract:
An occipital plate for use in an occipitocervical fixation procedure to stabilize the base of a patient&#39;s skull with respect to the patient&#39;s neck. The occipital plate of the invention is made up of a middle portion having left and right sides, and left and right hinged legs extending outward in opposite directions from the left and right sides of the middle portion. Each of the left and right hinged legs uses a hinge mechanism to secure a spinal rod to the occipital plate.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    Not Applicable. 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not Applicable. 
       FIELD OF THE INVENTION 
       [0003]    This invention relates to medical devices. More specifically, the invention is directed to an occipital plate. 
       BACKGROUND OF THE INVENTION 
       [0004]    As noted in U.S. Pat. No. 7,695,500 issued to Markworth, there are many occipital plate implants on the market today. Some implants have through-holes and must be preloaded on the rod. Others have top loading sockets similar to polyaxial screws which allow bent rods to be anchored to the plate. The most simple, but generally most difficult, to use form is that of a rod that smoothly tapers to an occipital plate that must be bent and contoured to match highly varied anatomy. All of these iterations have at most one to two degrees of freedom and typically require long preparation time to ensure a proper bend. This makes the implants both difficult to connect to the longitudinal rod member and the occipital plateau without putting stress on the atlantoaxial joint. 
         [0005]    Accordingly, there remains a need for an improved occipital plate. 
       SUMMARY OF THE INVENTION 
       [0006]    An occipital plate for use in an occipitocervical fixation procedure to stabilize the base of a patient&#39;s skull with respect to the patient&#39;s neck. The occipital plate of the invention is made up of a middle portion having left and right sides, and left and right hinged legs extending outward in opposite directions from the left and right sides of the middle portion. Each of the left and right hinged legs uses a hinge mechanism to secure a spinal rod to the occipital plate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is an environmental perspective view of an occipital plate, according to the present invention. 
           [0008]      FIG. 2  shows a front view of the occipital plate of  FIG. 1  but with left and right hinged legs in an open configuration. 
           [0009]      FIG. 3  shows a front view of the occipital plate of  FIG. 1  but with left hinged leg in a closed configuration and a right hinged leg in a partially closed configuration. 
           [0010]      FIG. 4  shows a front view of the occipital plate of  FIG. 1  but with left and right hinged legs in a closed configuration. 
           [0011]      FIG. 5  shows a rear view of the occipital plate of  FIG. 4 . 
           [0012]      FIG. 6  shows a top side view of the occipital plate of  FIG. 4 . 
           [0013]      FIG. 7  shows a bottom side view of the occipital plate of  FIG. 4 . 
           [0014]      FIG. 8  shows a front view of an occipital plate with first and second hinged legs comprising high friction front surfaces, according to the invention. 
           [0015]      FIG. 9  shows an exploded view of the occipital plate of  FIG. 1 , according to the invention. 
           [0016]      FIGS. 10 through 15  show various views of an occipital plate according to the invention. 
           [0017]      FIG. 16  shows a table (Table 1) listing part numbers. 
       
    
    
       [0018]    The remaining Figures show further views of an occipital plate according to the invention. 
         [0019]    Similar reference characters denote corresponding features consistently throughout the attached drawings. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0020]    This invention relates to medical devices. More specifically, the invention is directed to an occipital plate  100  for use in an occipitocervical fixation procedure. The occipital plate  100  and its parts can be made out of any suitable material such as, but not limited to, titanium, tungsten, and stainless steel, alone or in combination. Part numbers are listed in Table 1 (shown in  FIG. 16 ). 
         [0021]    The occipital plate  100  comprises a middle portion  120 , a left hinged leg  140 , and a right hinged leg  160 . The occipital plate  100  defines a central axis line  130 . While not necessary it is preferred that the occipital plate  100  exhibits 2-fold symmetry about central axis line  130 . The middle portion  120  defines front  180  and rear  200  surfaces, and left  220  and right  240  opposite sides. Holes  244  extend from the front surface  180  through to the rear surface  200  of the middle portion  120  are provided for receiving bone fasteners  225  for fixation of occipital plate  100  to the occiput Oc, i.e., the posterior (back) portion of a patient&#39;s head (see  FIG. 1 ). The holes  244  can be in the form of countersunk screw holes. The occipital plate  100  can be curved for facilitating attachment to the lower posterior curve of the skull known as the occipital region (labeled as “ Oc ” in  FIG. 1 ). 
         [0022]    Left and right hinged legs  140  and  160  respectively extend outward from left  220  and right  240  opposite sides of the middle portion  120 . The left hinged leg  140  comprises a left stationary leg portion  300 , a left rotatable leg portion  320 , and a left hinge joint  340 . The left stationary leg portion  300  defines proximal end  360  and distal end  380  thereof. Left rotatable leg portion  320  defines proximal end  400  and distal end  420  thereof. The distal end  420  defines through-hole  430 , which can be a countersunk screw hole. The terms “proximal” and “distal” are used with respect to the middle portion  120  when the hinged legs of occipital plate  100  are in an open configuration as shown in  FIG. 2 . The left hinge joint  340  can take any suitable form. In one embodiment the left hinge joint  340  comprises tubular hinge components  350   a  and  350   b  and left hinge pin  485 . 
         [0023]    The left stationary leg portion  300  and left rotatable leg portion  320  are connected via the left hinge joint  340 . More specifically, the distal end  380  of left stationary leg portion  300  and the proximal end  400  of left rotatable leg portion  320  are each connected to hinge joint  340 . As shown, for example, in  FIG. 2  the proximal end  360  of the left stationary leg portion  300  is integral with the left opposite side  220  of the middle portion  120  whereas the distal end  380  of the left stationary leg is operatively connected to the left hinge joint  340 . The left rotatable leg portion  320  pivots about left hinge joint  340 . The amount of rotation is sufficient to allow the securement of a spinal rod (represented by first spinal rod shown as “SR 1 ” in  FIG. 8 ) to the left hinged leg  140 . 
         [0024]    The term “front surface” refers to the surface which during and post surgery is opposed to the one (the rear surface) that faces the bone of a patient&#39;s occipital region. The term “rear surface” refers to the surface which during and post surgery faces the bone of a patient&#39;s occipital region. The left stationary leg portion  300  and left rotatable leg portion  320  respectively define front surfaces  344  and  346 . The front surfaces  344  and  346  can be machined to provide high friction surfaces as shown in  FIG. 8 ; such surfaces are preferably knurled, in order to bite into the surface of a spinal rod. 
         [0025]    In one embodiment the left rotatable leg portion  320  of the left hinged leg  140  is of sufficient length to allow its distal end  420  to be directly fastened to the middle portion  120  of occipital plate  100  (see, e.g.,  FIGS. 2 through 7 ). In this embodiment the middle portion  120  defines a complementary left fastener receiving hole  460 . During surgery the left rotatable leg portion  320  is rotated about the hinge joint  340  until the through hole  430  of distal end  420  is aligned over the complementary left fastener receiving hole  460  whereupon a fastener, such as a locking screw, is affixed into hole  460  via through hole  430  to secure the left rotatable leg portion  320  to the middle portion  120 . Fasteners are shown in  FIG. 1 . 
         [0026]    The purpose of securing the distal end  420  of the left hinged leg  140  to the middle portion  120  is to clamp a spinal rod (represented by alpha-numeric label SR 1  in, e.g.  FIGS. 1 and 2 ) to the occipital plate  100 . This procedure provides flexibility to the surgeon who is not limited to the specific location of a prior art seat as typically found on a prior art occipital plates. Moreover, rods can be secured at various angles to the left hinged leg  140  as shown in  FIG. 2 . 
         [0027]    In another embodiment, the proximal end  360  of left stationary leg portion  300  defines a left fastener receiving hole  440  (see  FIG. 10 ). The fastener receiving hole  440  may be a threaded blind hole. In this embodiment a fastener, such as a locking screw, is used to fasten the distal end  420  of the left rotatable leg portion  320  to the proximal end  360  of stationary leg portion  300 . 
         [0028]    The right hinged leg  160  comprises a right stationary leg portion  500 , a right rotatable leg portion  520 , and a right hinge joint  540 . The right stationary leg portion  500  defines proximal end  560  and distal end  580  thereof. Right rotatable leg portion  520  defines proximal end  600  and distal end  620  thereof. The proximal end  600  defines through-hole  630 , which can be a countersunk screw hole. The terms “proximal” and “distal” are used with respect to the middle portion  120  when the hinged legs of occipital plate  100  are in an open configuration as shown in  FIG. 2 . The right hinge joint  540  can take any suitable form. In one embodiment the right hinge joint  540  comprises tubular hinge components  550   a  and  550   b  and right hinge pin  685 . 
         [0029]    The right stationary leg portion  500  and right rotatable leg portion  520  are connected via the right hinge joint  540 . More specifically, the distal end  580  of right stationary leg portion  500  and the proximal end  600  of right rotatable leg portion  520  are each connected to hinge joint  540 . As shown, for example, in  FIG. 2  the proximal end  560  of the right stationary leg portion  500  is integral with the right opposite side  220  of the middle portion  120  whereas the distal end  580  of the right stationary leg is operatively connected to the right hinge joint  540 . The right rotatable leg portion  520  pivots about right hinge joint  540 . The amount of rotation is sufficient to allow the securement of a spinal rod (represented by second spinal rod shown as “SR 2 ” in  FIG. 8 ) to the right hinged leg  160 . 
         [0030]    In one embodiment the right rotatable leg portion  520  of the right hinged leg  160  is of sufficient length to allow its distal end  620  to be directly fastened to the middle portion  120  of occipital plate  100  (see, e.g.,  FIGS. 2 through 7 ). In this embodiment the middle portion  120  defines a complementary right fastener receiving hole  660 . During surgery the right rotatable leg portion  520  is rotated about the hinge joint  540  until the through hole  630  of distal end  620  is aligned over the complementary fastener receiving hole  660  whereupon a fastener, such as a locking screw, is affixed into hole  660  via through hole  630  to secure the right rotatable leg portion  520  to the middle portion  120 . 
         [0031]    The purpose of securing the distal end  620  of the right hinged leg  160  to the middle portion  120  is to clamp a spinal rod (represented by alpha-numeric label SR 2  in, e.g.,  FIGS. 1 and 2 ) to the occipital plate  100 . This procedure provides flexibility to the surgeon who is not limited to the specific location of a prior art seat as typically found on a prior art occipital plates. Moreover, rods can be secured at various angles to the right hinged leg  160 . 
         [0032]    In one embodiment, the proximal end  560  of right stationary leg portion  500  defines a right fastener receiving hole  640  (see  FIG. 10 ). The fastener receiving hole  640  may be a threaded blind hole. In this embodiment a fastener, such as a locking screw, is used to fasten the distal end  620  of the right rotatable leg portion  320  to the proximal end  560  of stationary leg portion  500 . 
         [0033]    The right stationary leg portion  500  and right rotatable leg portion  520  respectively define front surfaces  544  and  546 . The front surfaces  544  and  546  can be machined to provide high friction surfaces as shown in  FIG. 8 ; such surfaces are preferably knurled in order to bite into the surface of a spinal rod (represented by alpha-numeric label “SR 2 ” in  FIG. 8 ). 
         [0034]    Referring now to the Figures with regard to which the meaning of labels and numbers shown in the Figures are summarized in Table 1 (see  FIG. 16 ). 
         [0035]      FIG. 1  is an environmental perspective view of an occipital plate, according to the present invention. The occipital plate  100  of the invention is shown attached by fasteners  225  to the lower posterior curve of the skull known as the occipital region Oc. 
         [0036]      FIGS. 2 ,  3  and  4  respectively show a front view of the occipital plate  100  of  FIG. 1  but with left and right hinged legs  140  and  160  deployed in an open, a partially closed, and a closed configuration. In this embodiment the left and right fastener receiving holes  460  and  660  are located in the middle portion  120  of occipital plate  100 . 
         [0037]      FIGS. 5 ,  6 , and  7  respectively show rear, top side and bottom side views of the occipital plate  100  shown in closed configuration. The holes  430  and  460  are shown aligned, and likewise holes  630  and  660  are aligned and each pair of holes are able to receive a fastener to secure spinal rods SR 1  and SR 2  (not shown) to the right and left hinged legs  140  and  160 , respectively. 
         [0038]      FIG. 8  shows a front view of an occipital plate with first and second hinged legs  140  and  160  with high friction front surfaces. Specifically, surfaces  344 ,  346 ,  544  and  546  are machined to offer high friction surfaces to secure rods SR 1  and SR 2  (not shown). 
         [0039]      FIG. 9  shows an exploded view of the occipital plate  100  of  FIG. 1 , according to the invention. Left and right hinge pins  485  and  685  are shown. It should be understood that any suitable hinge mechanism can be used and is not limited to that shown in  FIG. 9 . 
         [0040]      FIG. 10  shows a occipital plate  100  according to the invention wherein the proximal end  360  of left stationary leg portion  300  defines a left fastener receiving hole  440 , and the proximal end  560  of right stationary leg portion  500  defines a right fastener receiving hole  640 . The fastener receiving holes  440  and  640  can be threaded blind holes. In this embodiment a fastener, such as a locking screw (not shown), is used to fasten the distal end  420  of the left rotatable leg portion  320  to the proximal end  360  of stationary leg portion  300 ; and a fastener, such as a locking screw (not shown), is used to fasten the distal end  620  of the right rotatable leg portion  320  to the proximal end  560  of stationary leg portion  500 . 
         [0041]      FIGS. 11 through 15  show various views of the occipital plate  100  shown in  FIG. 10  according to the invention.  FIG. 16  shows a table (Table 1), which comprises a list of part numbers. 
         [0042]    In one embodiment the occipital plate  100  includes at least one curved perimeter portion  800  (e.g. see  FIG. 17  where the at least one curved perimeter portion  800  is represented by alpha-numeric labels  800   a  and  800   b ); more specifically, the occipital plate  100  defines a perimeter  820 , which further defines said at least one curved perimeter portion  800 . The at least one curved perimeter portion  800  serves to help smooth selected edges of the occipital plate  100 . During actual use of this embodiment of the occipital plate  100  the at least one curved perimeter portion  800  helps avoid snagging of a patient&#39;s tissue, such as muscle tissue, on the occipital plate  100 . 
         [0043]    The invention being thus described, it will be evident that the same may be varies in many ways by a routineer in the applicable arts. Such variations are not to be regarded as a departure from the spirit and scope of the invention.