BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a spine fixing apparatus capable of suitably fixing an unstable spine caused by a fracture or disease by adjusting angle and width between rods of the apparatus according to a curvature shape of the spine, and simplifying assembly process thereof so as to reduce overall assembly time. 
     2. Description of the Related Art 
     Generally, when a spine is fractured or diseased, the spine must be fixed. As such, a number of methods for fixing unstable spine have been developed. Among them is to place the spine as it were and fix it with a spine-fixing device. Typically, the spine-fixing device has two rods arranged along the spine so as to be fixed with screws thereon and connectors bridging the rods for fixing each other such that the spine is supported by the rods. 
     In the conventional spine fixing device, however, the screws are coupled to the spine integral with the rods and the two rods are fixedly coupled each other using the connectors such that the connector cannot be adjusted in a lateral and vertical directions thereby failing to fix the spine in the suitable position. 
     Furthermore, since the connector has a fixed length, the connector cannot bridge the two rods when the distance or angle between the rods are changed. 
     SUMMARY OF THE INVENTION 
     The present invention has been made in an effort to solve the above problems. 
     It is an object of the invention to provide a spine-fixing apparatus capable of reliably fixing the unstable spine, caused by a fracture or disease, by adjusting distance and angle between rods, which arranged along the spine, of the fixing-apparatus according to a shape of the spine. 
     It is another object of the present invention to provide a spine fixing-apparatus which enables each fixing nut to correctly fastened with the upper end of each spine screw member thereby preventing any erroneous coupling therebetween. 
     It is further another object of the present invention to provide a spine-fixing apparatus capable of simplifying installation process and reducing overall installation time as well as reliable installation by integrally forming a screw portion of a spine screw member, a supporting member for supporting a rod, and a cover for the supporting member of the spine-fixing apparatus. 
     To achieve the above objects, a spine-fixing apparatus of the present comprises a plurality of spine screw members fixed to a spine in a predetermined interval, a pair of rods coupled to the spine screw members for supporting the spine, a plurality of fixing nuts coupled to the spine screw members, and a plurality of pressing pieces interposed between the fixing nuts and the spine screw members for pressing and fixing the rods. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention, and together with the description, serve to explain the principles of the invention. 
     FIG. 1 is a front elevation view of a spine-fixing apparatus installed on a spine according to a first embodiment of the invention; 
     FIG. 2 is a perspective view of the spine-fixing apparatus of FIG. 1; 
     FIG. 3 is an exploded perspective view of a pressing portion of the spine-fixing apparatus of FIG. 1; 
     FIG. 4 is an assembled perspective view of the pressing portion of the spine-fixing apparatus according to a first embodiment of the present invention; 
     FIG. 5 is a top view of a bridge member of the spine-fixing apparatus of FIG. 1; 
     FIG. 6 is a perspective view of the spine-fixing apparatus for illustrating an operation of the bridge member of the spine-fixing apparatus; 
     FIG. 7 is an exploded perspective view of a pressing portion of the spine-fixing apparatus according to a second embodiment of the invention; 
     FIG. 8 is an assembled perspective view of the pressing portion of FIG. 7; 
     FIG. 9 is a front elevation view of a spine-fixing apparatus installed on spine according to a third embodiment of the invention; 
     FIG. 10 is a perspective view of the spine-fixing apparatus of FIG. 9; 
     FIG. 11 is an exploded perspective view of a spine screw member of the spine-fixing apparatus of FIG. 9; and 
     FIG. 12 is a perspective view of the spine-fixing apparatus for illustrating an operation of the bridge member of the spine-fixing apparatus according to the third embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A preferred embodiment of the present invention will be described hereinafter with reference to the accompanying drawings. 
     FIG.  1  and FIG. 2 are respective front elevation view perspective view of the spine-fixing apparatus according to a first preferred embodiment of the present invention. 
     Generally, when the spine  1  is unstable caused by a fracture or disease, a fixing apparatus is used to stably fix the spine  1 . 
     Referring to FIG.  1  and FIG. 2, spine screw members  10  are coupled to certain portions of each of the spine  1  in a predetermined interval. The spine screw members  10  are continuously arranged in two rows along the spine  1 . The spine screw members  10  fixed to the spine  1  are connected by a pair of rods  5 , which support the spine  1  in the longitudinal direction through the spine screw members  10 . On the spine screw members  10  are separatively installed pressing members  30  to press the rods  5  toward the spine screw members  10 . 
     As shown in FIG.  3  and FIG. 4, each of the pressing member  30  comprises a pressing piece  32  inserted into an opening formed at the upper end of the spine screw member  10  for pressing the upper surface of the first or second rod and a fixing nut  31  for being coupled with the spine screw member  10  at the upper periphery while surrounding the pressing piece  32 . 
     The pressing piece  32  comprises a pressing protrusion  32   a  inserted into the opening at the upper end of the spine screw member  10 , a catch plate  32   b  stepped on the top of the pressing protrusion  32   a  for being caught by the upper end of the spine screw member  10 , and a guide protrusion  32   d  on the top of the catch plate  32   b  for guiding the fixing nut  31 . 
     The pressing protrusion  32   a  has a shape of a short cylinder so as to be easily inserted into the opening at the upper end of the spine screw member  10 , and an end surface of the cylinder is formed having a grid pattern so as to prevent the rod  5  from sliding to and fro after the fixing nut  31  is screwed down. Also, the guide protrusion  32   d  has the shape of a cylinder such that the fixing nut  31  can be guided along the guide protrusion  32   d  in order for the fixing nut  5  to be accurately coupled with the spine screw member  10 , and a neck  32   c  is formed around the guide protrusion at its lower end connected to the catch plate  32   b  such that the guide protrusion  32   d  can be removed after fastening the fixing nut  31  to the spine screw member  10 . 
     The rods  5  arranged along the spine  1  are mutually connected by the bridge member  100  in such a way that a distance between the two rods  5  can be by the bridge member  100 . 
     FIG. 5 shows the bridge member  100  of the spine fixing apparatus according to the invention. 
     Referring to FIG. 5, the bridge member  100  is comprises a first and second bridge members  110  and  120 . The first bridge member  110  is bent inward at its distal end so as to partially grip the rod  5  and is provided with extended portion at its proximal end toward the other rod  5 . It is preferred that the distal end of the bridge member  110  is bent as much as 180° enough so as to prevent the rod  5  from being separated therefrom. 
     Further, the first bridge member  110  has a screw hole at its distal end portion such that a fixing screw  112  is penetrated and contacted the rod  5  to fix the rod  5 . It is preferred that the fixing screw  112  is slightly inclined toward the rod  5 , and more preferably, inclined at about 5°. Further, the fixing screw  112  has a curved end  114  corresponding to a round surface of the rod so as to enlarge the friction surface therebetween, resulting in more reliable fixation. 
     The distal end of the first bridge member  110  is tapered while extending around the rod  5 . Here, it is structurally preferable that the end of the first bridge member  110  is roundly finished while surrounding the rod  5  for easy coupling with the rod  5 . 
     The first bridge member  110  has an extension  116  with a slot  118  formed along the longitudinal direction of the extension  116  (see FIG.  6 ). The slot  118  is long as much as one third of the length of the extension  116  and rounded at both ends thereof. Furthermore, uneven portions  116   a  are formed on an upper and lower surfaces of the extension  116  around the slot  118 . so as to enhance friction force. 
     The second bridge member  120  is substantially arranged in the opposite direction to the first bridge member  110  and has a screw hole at its distal end such that a fixing screw  122  is penetrated and contacted the other rod  5  to fix the rod. The fixing screw  122  of the second bridge  120  is longer than the first fixing screw  112  corresponding to the thickness of the second bridge member  120 . Also, the fixing screw  122  of the second connector  120  preferably has curved end corresponding to a round surface of the rod so as to enlarge the friction surface therebetween, resulting in more reliable fixation. 
     The second bridge member  120  has a upper and lower extensions  126  and  128  extended toward the rod  5  coupled with the first bridge member  110 . The upper and lower extensions  126  and  128  are formed with a predetermined distance therebetween such that the extension  116  of the first bridge member  110  is placed between the upper and lower extensions  126  and  128 . It is preferred that the extension  116  of the first bridge member  110  and the upper and lower extensions  126  and  128  of the second bridge member  120  preferably have the same thickness. 
     The upper and lower extensions  126  and  128  of the second bridge member  120  have holes at the same positions thereof such that an adjustment screw  130  penetrates through the hole of the upper extension  126  of the second bridge member  120 , the slot  118  of the extension of the first bridge member  110 , and hole of the lower extension  128  of the second bridge member  120  in order. The hole of the lower extension  128  is threaded on its inner wall such that the adjustment screw  130  is screwed into the lower extension  128 . Accordingly, when the adjustment screw  130  is screwed down, the upper and lower extensions  126  and  128  of the second bridge member  120  are fixedly coupled with the extension  116  of the first bridge member  110 . It is preferred that the hole of the upper extension  126  has the diameter slightly larger than that of the lower extension  128 . 
     Since the slot of the first bridge member  110  is elongated in longitudinal direction of the extension  116 , it is possible to adjust the distance between the rods  5  by sliding the adjustment screw  130  along the slot  118  while the adjustment screw is loosed. 
     Also, the first bridge member and the second bridge member is pivotally connected on the axis of the adjustment screw  130  such that the first and second bridge members can be adjusted according to the shape of the spinebefore being fixed. The upper and lower surfaces of the first bridge member around the slot  118  have the uneven portions  116   a  so that the first bridge member and the second bridge member can be tightly coupled to each other. 
     FIG.  7  and FIG. 8 are respective the exploded perspective view and assembled perspective view of the spine-fixing apparatus according to a second embodiment of the invention. 
     As shown in FIG.  7  and FIG. 8, the spine-fixing apparatus according to the second embodiment of the invention comprises spine screw members  10  fixedly coupled to the spine in a predetermined interval, a first and second rods  5  coupled to the spine screw members  10  for supporting the spine, and pressing members  40  for respectively pressing the first and second rods  5  toward the spine screw members. 
     Each of the pressing members  40  comprises a fixing nut  41  and a pressing piece  42  inserted into an opening formed at a head of each of the spine screw members  10  so as to press the upper surface of each of the first and second rods  5 . 
     Each of the spine screw members  10  has a guide portion  10   a  upwardly extended for guiding the fixing nut  41 . The fixing nut  41  has an inner diameter slightly greater than that of the guide portion  10   a  so that the guide portion  10   a  of the spine screw member  10  can be inserted into the fixing nut  41 . 
     The pressing piece  42  is provided with a pressing plate  42   c  for pressing the upper surface of the rod  5 , and a cylindrical supporting portion  42   b  formed on an upper surface of the pressing plate  42   c  for being guided along the inner surface of the spine screw member  10 . 
     Also, the pressing plate  42   c  and the supporting portion  42   b  of the pressing piece  42  is provided with a through hole  42   a  formed at the center thereof such that an internal fixing screw  43  is screwed therein for fixing the rods  5 . 
     The guide portion  10   a  of the each spine screw member  10  allows the fixing nut  41  to be guided onto the upper end of the spine screw member  10 . After the fixing nut  41  is fastened, the guide portion  10   a  can be removed from the spine screw member  10  after the installation of the spine-fixing apparatus because a grooved neck is formed between the guide portion  10   a  and the spine screw member  10 . Further, the rod  5  can be further pressed by the internal fixing screw  43  being inserted into a central hole of the pressing piece  42 . 
     FIG.  9  and FIG. 10 are respective front elevation and perspective views of the spine-fixing apparatus according to a third embodiment of the invention, FIG. 11 is an exploded perspective view of a spine screw member of the spine-fixing apparatus according to the third embodiment of the invention, and FIG. 12 is a perspective view of the of the spine fixing apparatus for illustrating an operation of the bridge member of the spine-fixing apparatus according to the third embodiment of the invention. 
     Referring to FIG. 9 to FIG. 12, each of spine screw members  20  comprises a screw portion  11  to be inserted into the spine  1  in a predetermined depth, a supporting portion  13  formed on top of the screw portion  11  for receiving and supporting rod  5 ( 6 ), and a cover  15  pivotally mounted on top of the supporting portion  13  for fixing the rod  5 ( 6 ) received in a groove which divides the supporting portion  13  into two branches. 
     The supporting portion  13  has a recess  13   a  at upper end of one branch thereof and the cover  15  has a coupling protrusion  15   a  at one end corresponding to the recess  13   a  such that the coupling protrusion  15   a  of the  15  and the recess  13   a  of the supporting portion  13  are engaged each other and pivotally connected by means of a hinge pin  14 . Also, in order to fasten the other side of the cover  15  to the supporting portion  13 , the supporting portion  13  has a fastening hole  13   b  at upper end of other branch thereof, the cover  15  has a threaded hole  15   b  formed at an opposite end portion of the coupling protrusion  15   a  corresponding to the threaded hole  15   b  such that the cover  15  is fixed to the supporting portion  13  by a fastening screw  16  being screwed into the threaded hole  15   b  and the fastening hole  13   b.    
     The cover  15  has another threaded hole  15   c  formed at a center thereof in parallel with the thread hole  15   b  such that another internal fixing screw  17  is screwed down into the threaded hole  15   c  in order to fixedly press the upper surface of the rod  5 ( 6 ). 
     The operation of the above structured spine-fixing apparatus will be described hereinafter. 
     Firstly, the screw portions  11  of the spine screw members  20  are fixedly screwed into the spine  1  to be supported. The first and second rods  5  and  6  are received in the U-shaped grooves  13   c  formed on the supporting portions  13  such that the rods  5  and  6  are settled on the bottom of the U-shaped grooves  13   c.    
     After the first and second rods  5  and  6  are arranged in the grooves  13   c , the covers  15  on the top of the spine screw members are pivoted so as to cover the upper ends of the spine screw members  20 . 
     Next, the fastening screw  16  is screwed down through the threaded hole  15   b  of the cover and the screw hole  13   b  of the supporting portion  13  so as to fix the cover  15  to the supporting portion  13 . After the cover  15  is fixed to the supporting portion  13 , the internal fixing screw  17  is screwed down through the screw hole  15   c  of the cover of the spine screw member  20  so as to fixing the rod  5 ( 6 ) by the lower end of the internal fixing screw pressing the upper surface of the fixing rod( 6 ). 
     After the spine screw members  20  are completely assembled like this, as shown in FIG. 12, the distance and angle between the first and second rods  5  and  6  are adjusted using a bridge  100  so that the spine  1  can be reliably supported in the optimum conditions. 
     The present invention described hereinbefore is not limited to the foregoing description of the embodiments, whereas various variations and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention defined by the appended claims. 
     As described above, in the spine-fixing apparatus of the present invention the distance and angle between the rods can be adjusted such that the spine-fixing apparatus can be installed in optimal formation according to the shape of the spine. 
     Also, since the spine-fixing apparatus of the present invention is provided with a guide member at the upper end of the spine screw member, the fixing nut can be guided such that the spine-fixing apparatus provide reliable fixation of the spine. 
     Furthermore, the screw portion of the screw member, supporting member for supporting the rod, and the cover for fixing the rod to the supporting member of the spine-fixing apparatus are integrally formed, the installation process of the spine-fixing apparatus is simplified, resulting in reducing overall installation time.
A spine-fixing apparatus includes a plurality of spine screw members fixed to a spine in a predetermined interval, a pair of rods coupled to the spine screw members for supporting the spine, a plurality of fixing nuts coupled to the spine screw members, and a plurality of pressing pieces interposed between the fixing nuts and the spine screw members for pressing and fixing the rods.