Patent Document

FIELD OF INVENTION 
       [0001]    The embodiments disclosed herein relate to bone strengthening and reinforcing and, more particularly, to internal bone fixation devices and methods of using such devices for repairing a weakened or fractured bone. 
       BACKGROUND 
       [0002]    Bone is a living tissue and plays a structural role in the body. Unfortunately, over millions of patients in the world are diagnosed with bone damage because of various reasons. Bone defects caused by osteonecrosis, bone tumor resection, or osteoporotic fracture are often treated by a bone grafting procedure. Whether utilizing autogenic, allogenic, or synthetic grafts, the processes of creeping substitution and remodeling are essential for the healing of the bone defects. It is, however, mechanically undesirable during the remodeling stage, because the grafts will lose their supporting strength gradually. Without adequate mechanical support, the bone defects might collapse or deform and could not sustain the physical loading in daily activities. Fracture repair is required to restore a damaged or weakened bone structure in order to endure the applied strength or stress to a body. Several different treatment methods have been developed in the past few decades in order to facilitate or expedite the recovery process. More particularly, a surgical approach adopted by a lot of physicians is to provide an external treatment. Implantation of bone void fillers, such as bone cement in a fractured bone, is less invasive and is being increasingly applied during surgical procedures. The device or apparatus utilized by an operator during implantation is required to be more user-friendly and feasible. A reinforcement with an empty chamber to be filled by the bone reinforcing mixture such as cement may be inserted into the damaged area. A typical device for bone cement injection has a tube-like shaped body, which delivers a cartridge containing bone cement into the reinforcement. Usually the reinforcement is left in the body to support bone strength. Ideally, the stiffness of the reinforcement must be enough to resist stress in order to maintain a desired shape either during the surgery or being left out from the body after treatment. Unfortunately, to prevent undesired deformation of the implanted reinforcement is still a major challenge. 
       SUMMARY OF THE INVENTION 
       [0003]    Devices and methods for reinforcing a weakened or damaged bone are disclosed herein. According to one aspect illustrated herein, provided is a device including a rigid tube encased by a barrel that can be expanded to a desired shape by an externally applied force through a gear. The tube has a tapered end distal to the cap, an aperture proximal to the cap, and a threaded inner wall proximal to the tapered end, which allows the barrel to be desirably positioned on the tube. The barrel has a securing part and an adjustable part. The device has a lumen that can be operated as a cannulated device by minimally invasive methods. The device has multiple apertures for delivering bone reinforcing mixtures to a bone. 
         [0004]    According to one aspect illustrated herein, provided is an apparatus for reinforcing a bone including a cap, and a substantially rigid tube adjacent to the cap. The tube has a tapered end distal to the cap, an aperture proximal to the cap, and a threaded inner wall proximal to the tapered end to allow the apparatus to be securely handled. The apparatus further includes a barrel which is designed to encase the tube, and the barrel has a securing portion which is allowed to be moved toward the cap in response to an external force and to be fixed at a desired position proximal to the tapered end of the tube. According to another aspect illustrated herein, provided is a system for reinforcing a bone including an expandable barrel with a rigid tube which has a tapered end distal to the cap, an aperture proximal to the cap, and a threaded inner wall proximal to the tapered end to allow the apparatus to be securely handled. The apparatus further includes a barrel which is designed to encase the tube, and the barrel has a securing portion which is allowed to be moved toward the cap in response to an external force and to be fixed at a desired position proximal to the tapered end of the tube. The system is operated by a gear with a mechanism to exert an external force to the barrel. One end of the gear is designed to be locked with the threaded inner wall of the tube. 
         [0005]    Various embodiments provide certain advantages. Not all embodiments of the invention share the same advantages, and those that do may not share them under all circumstances. Further features and advantages of the embodiments are described in detail below with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    The presently disclosed embodiments will be further explained with reference to the attached drawings, wherein like structures are denoted as the accompany drawings. The drawings shown are not necessarily to scale, with emphasis instead generally being placed upon illustrating the principles of the presently disclosed embodiments. 
           [0007]      FIGS. 1A-1B  show expanded views of a rigid tube component of a device for reinforcing a bone according to an illustrative embodiment of the present invention; 
           [0008]      FIG. 2  shows an expanded view of an apparatus including a barrel component and a rigid tube component for reinforcing a bone according to an illustrative embodiment of the present invention; 
           [0009]      FIG. 3  shows an expanded view of a barrel component of an apparatus for reinforcing a bone according to an illustrative embodiment of the present invention; 
           [0010]      FIG. 4A  shows an expanded view of a barrel for reinforcing a bone according to an illustrative embodiment of the present invention; 
           [0011]      FIG. 4B  shows an expanded view of an apparatus for reinforcing a bone being expanded to a desired geometry according to an illustrative embodiment of the present invention; 
           [0012]      FIG. 5  shows the assembling of two components of an apparatus for reinforcing a bone according to an illustrative embodiment of the present invention; 
           [0013]      FIG. 6  shows a three-dimensional perspective view of an apparatus for reinforcing a bone (including an expanding apparatus) according to an illustrative embodiment of the present invention; 
           [0014]      FIG. 7  shows a section view of an apparatus for reinforcing a bone (including an expanding apparatus) according to an illustrative embodiment of the present invention; 
           [0015]      FIG. 8  shows a three-dimensional perspective view of an injector apparatus according to an illustrative embodiment of the present invention; 
           [0016]      FIG. 9  shows a section view of the injector apparatus of the present invention; 
           [0017]      FIG. 10  is a schematic diagram showing the use state of an example of the present invention (implant unexpanded); 
           [0018]      FIG. 11  is a schematic diagram showing the use state of an example of the present invention (implant expanded); 
           [0019]      FIG. 12  is a schematic diagram showing the use state of an example of the present invention (injection with bone cement); and 
           [0020]      FIG. 13  is a schematic diagram of an example of the present invention showing the binding of an implant with bone cement in a vertebra. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0021]    The embodiments of the present invention are described more fully hereinafter with reference to the accompanying drawings, which form a part hereof, and which show, by way of illustration, specific exemplary embodiments by which the invention may be practiced. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. As used herein, the term “or” is an inclusive “or” operator, and is equivalent to the term “and/or,” unless the context clearly dictates otherwise. In addition, throughout the specification, the meaning of “a”, “an” and “the” include plural references. The term “coupled” implies that the elements may be directly connected together or may be coupled through one or more intervening elements. 
         [0022]    Main components of an embodiment of a device for fixing an apparatus for reinforcing a weakened or fractured bone are shown in  FIG. 1A  and  FIG. 1B . The device  100  includes a cap  110  which is at one end of the device. The device  100  further includes a tube  120  with an elongated shape. The cap  110  is at one end of the tube  120 . In an embodiment, the cap  110  and the tube  120  are formed from the same rod or bulk in order to possess a better rigidity or stiffness, and the cap  110  may have a through hole  115  at the center. The cap  110  may be composed of two annuli  1101  and  1102  as shown in  FIG. 1A . The annulus  1101  with a larger diameter is disposed farther away from a tapered, tube end  121  of the tube  120  compared to the annulus  1102 . The tube  120  is preferably made with a material such as metal or its alloy. In some embodiments, titanium or its alloy may be selected. In other embodiments, the tube  120  can be either constructed from a single metal, such as stainless steel, and gold or from composite materials such as fiber reinforced metal. Preferably, the tube  120  is rigid or substantially rigid in order to resist or minimize deformation under any applied external force. Moreover, the tube  120  further includes a lumen. The lumen may extend through the cap  110  to form a tunnel which opens at both ends of the device  100 . In an embodiment, the tapered, tube end  121  distal to the cap  110  is preferably designed as a tapered shape as shown in  FIG. 1A . The tapered angle can be between 0 to 45 degrees. Preferably, it can be between 0 to 30 degrees. In some embodiments according to the present disclosure, the angle is designed to be between 2 to 15 degrees. One of the purposes of introducing a tapered end design is to facilitate the tube  120  sliding into a press-fitting outer barrel  200  which may have an inner diameter designed to be interlocked with the outer diameter of the tube  120 . The tube  120  can further include at least one aperture  122  which is disposed proximally to the cap  110 . The aperture  122  can be formed of various shapes such as a circle, slot, and triangle, and the aperture  122  allows materials to pass into and out of the tube  120 . In an embodiment, the inner wall of the tube  120  proximal to the tapered, tube end  121  can be threaded. With a threaded inner wall  125 , the device  100  can be easily fastened with a gear (not shown) which is designed to accurately dispose or implant the device  100  at a desired fracture or weakened bone position. 
         [0023]    Those skilled in the art should recognize that the term “bone” used herein can be referred to vertebrae, tibia, fibula, humerus, ulna, radius and other bones and still be within the scope and spirit of the disclosed embodiments. 
         [0024]    The present disclosure further discloses an apparatus  10  for reinforcing a weakened or fractured bone as shown in  FIG. 2 . The apparatus  10  includes a device  100  and a barrel  200 . The device  100  can be the same as the aforementioned device  100  or can be slightly modified to fit in the apparatus  10 . The elongated barrel  200  includes a securing part  201  at one end. The barrel  200  further includes an adjustable part  202  adjacent to the securing part  201 . In an embodiment, the securing part  201  is connected with the adjustable part  202 , and the term “connected” used herein may refer to any connecting ways and should not be limited to such as jointed, welded, mounted, integrated, or as an integral unit. In an embodiment, the securing part  201  and the adjustable part  202  are formed/machined from the same piece of rod or bulk in order to possess a better rigidity or stiffness. The materials selected for the barrel  200  can be metal or its alloy. In an embodiment, the material selected for the barrel is the same as that of the device  100 . In some embodiments, titanium or its alloy may be selected. In other embodiments, the tube  120  can be constructed of a single metal, such as stainless steel, and gold, or be constructed of a composite material such as fiber reinforced metal. The barrel  200  may have a lumen inside. In other words, both the securing part  201  and the adjustable part  202  are hollow in order to be assembled with the device  100 . The inner diameter (if the hollowed-out pattern is circular) of the securing part  201  can be designed to be press fitted with the adjustable part  202 . The outer rim of the securing part  201  can be trimmed to different shapes such as circular or polygonal. In an embodiment, the securing part  201  is hexagonal-shaped or a shape of the combination of rectangle and circle. In an embodiment, the securing part  201  is a bolt head with a through hole as shown in  FIG. 2 . 
         [0025]      FIG. 2  depicts a tubular adjustable part  202 . Those skilled in the art should recognize that the adjustable part is not limited to a tube or a cannula. In an embodiment, a part of the adjustable part  202  is carved out to form at least one slotted or patterned hole in the wall of the adjustable part  202 . In another embodiment, a part of the adjustable part  202  is carved out to form a meshed pattern. The slotted or patterned hole(s) of the adjustable part  202  allows the tubular adjustable part  202  to deform easily when an external force is applied on the barrel  200  along the axial direction of the tubular barrel  200 . The hollowed patterns also allow reinforcing materials to flow into and out of the barrel  200 . In an embodiment, the adjustable part  202  can expand from a first geometry to a larger volume second geometry, for example, from a tubular shape to a cage, crown, or lantern-like object. 
         [0026]    The outer surface of the adjustable part  202  may be other than straight, and it can be machined to have a curved or bowed outer surface for the purpose of stress distribution. Therefore, the adjustable part  202  may have a straight, convex, or concave outer surface or the combination thereof. In an embodiment, the thickness of the adjustable part  202  is designed to be non-uniform. The thickness variation may help the adjustable part  202  expand to a desired geometry. The barrel  200  of an embodiment as illustrated in  FIG. 3  includes an adjustable part  202  with a thickest portion at the intermediate part  2021  which is between two thinner portions  2022  and  2023 . The location of the thickest portion may affect the stress distribution when the barrel  200  is under an external force. Therefore, the stress distribution can be modified by changing the expansion geometry of the adjustable part  202 .  FIG. 4A  illustrates an embodiment with an adjustable part  202  with a thickest portion at the center of the intermediate part  2021 , allowing the adjustable part  202  to expand to a desired geometry, such as a symmetric or asymmetric cage, as shown in  FIG. 4B . In another embodiment, the adjustable part  202  has a thickest portion at the intermediate part  2021  but closer to the securing part  201 , allowing the adjustable part  202  to expand to a crown-shaped object. Those skilled in the art should realize that the arrangement of the thickest portion on the adjustable part  202  is not limited to the aforementioned embodiments. Any non-uniform thickness design for the adjustable part is within the scope of the present disclosure, and although the aforementioned embodiments use a slotted pattern for illustration, a meshed design is also included. In another embodiment, the barrel  200  with a mesh-patterned hole adjustable part  202  may expand like a balloon or a lantern. 
         [0027]    Referring to  FIG. 5 , an example of integration of the apparatus  10  is further described. In the apparatus  10 , the barrel  200  is designed to encase, enclose or envelope the device  100 . In an embodiment, the inner diameter of the securing part  201  is defined to be the same as or substantially the same as the outer diameter of the tube  120 . The outer diameter of the annulus  1101  is greater than the inner diameter of the adjustable part  202 . The device  100  is inserted or slid into the portion  2022  distal to the securing part  201  with the tapered, tube end  121  inserted first. The device  100  can be placed inside the barrel  200  until the portion  2022  hits the annulus  1101 . The tapered, tube end  121  with an outer diameter smaller than the inner diameter of the securing part  201  can move into the securing part  201  with less resistance. Since the inner wall proximal to the tapered, tube end  121  is threaded, a handling gear (not shown here) with a threaded end can be screwed into the apparatus  10  from the securing part  201  of the barrel  200 . With the gear engaged, the apparatus  10  can be disposed to any desired location of a fractured or weakened bone during treatment. Those skilled in the art should recognize that the handling gear can be any device or apparatus which is designed for the operator to screw into the apparatus  10 , and any variation or modification is within the scope and spirit of the disclosed embodiments. 
         [0028]      FIGS. 6-13  illustrate an embodiment of an expanding apparatus  30  according to the present invention and also refer to  FIGS. 1-4  for the following description. The expanding apparatus  30  includes an outer tube  400 , which has a through hole  402  with a connection portion  403 . The connection portion  403  is corresponding to the securing part  201 , i.e. the securing part  201  can be inserted and fit into the connection portion  403 . At the other end, a base  405  is attached to the outer tube  400  with a hole in connection with the through hole  402 . The base  405  further includes a first pressing surface  406 . 
         [0029]    As described above, the apparatus of the present invention, as an implant, can be expanded with the expanding apparatus  30 , comprising an outer tube  400 , an inner coupling member or a packing  900 , a hollow body  500 , and a handle  600 . The outer tube  400  has the through hole  402  axially set within the outer tube  400 . The connection portion  403  is set at one end of the outer tube  400  and corresponding to the securing part  201  with a polygonal shape and chamfered at the edge thereof, and the securing part  201  can be inserted and fit into the connection portion  403 . The base  405  is attached to the other side of the outer tube  400  and includes the first pressing surface  406 . 
         [0030]    One end of the packing  900  forms a second pressing surface  901  against the first pressing surface  406 , and a recess  902  is set at the other end of the packing  900 . A third pressing surface  903  is formed at the both sides of the recess  902 . Further, a first fitting hole  904  (in an axial direction), an outer rim  905  (at the peripheral) and a fitting portion  906  are set on the packing  900 . 
         [0031]    A second fitting hole  501  and a third fitting hole  502  are sequentially set at one end within the hollow body  500 , and a second inner thread  503  is set at the other end. An inner tube  510  is set at the third fitting hole  502 , a tunnel  511  is axially set within the inner tube  510 , a lock  512  is set at one side of the inner tube  510 , and a first external threaded portion  513  is set at the other side of the inner tube  510 . The first external threaded portion  513  is linked to the first threaded inner wall  125  of the apparatus (implant)  10 , and the inner tube  510  is sequentially fit into the first fitting hole  904  and the through hole  402  to fit the fitting portion  906  into the third fitting hole  502 , to fit the outer rim  905  into the second fitting hole  501 , and to embed the lock  512  into the recess  902 , to restrict the shift of the packing  900  only in the axial direction and not over the outer rim  905  on the hollow body  500 . 
         [0032]    A second external thread  601  is set outside the handle  600 . A steering portion  610 , a bearing or a component with similar mechanism, is connected to one side of the handle  600 , and a twisting portion  602  is set at the other side of the handle  600  in a wing shape, which is easy for twisting to the user. The second external thread  601  is connected to the second inner thread  503 , and the steering portion  610  forms a fourth pressing surface  611 . 
         [0033]    The method to use the expanding apparatus  30  can be summarized in the following steps:
       a) connecting the connection portion  403  of the outer tube  400  to the securing part  201 ,   b) rotating the hollow body  500  to thread the first external threaded portion  513  into the threaded inner wall  125 ;   c) adding an outer tube  710  as shown in  FIG. 10  and implanting the apparatus  10  into a part of damaged bone (such as spine)  700 ;   d) rotating the twisting portion  602  of the handle  600  while holding the hollow body  500 , making the fourth pressing surface  611  of the steering portion  610  press the third pressing surface  903  of the packing  900 , and also enabling the second pressing surface  901  of the packing  900  to push the first pressing surface  406  of the outer tube  400 ; and   e) continuingly twisting the twisting portion  602  of the handle  600  and pushing the apparatus  10  by the outer tube  400 , deforming the adjustable part  202  by the torque from the twisting portion  602  and making a press fit between the hole of the securing part  2011  and the tapered, tube end  121 .       
 
         [0039]    In the above description, the adjustable part  202  can form a curve with different gradients in the axial direction after expansion. 
         [0040]    In the above description, the handle  600  of the expanding apparatus  30  can be replaced by a container  800  for bone cement and an injecting handle  1000  to form an injector apparatus  60 . The container  800  includes a piston  810  and a shell  820 , and the piston  810  is movable in the axial direction and set within the shell  820 . An exit  821  is formed at one side of the shell  820 , and a room  822  is set within the shell  820  and connected to the exit  821 . The room  822  is useful for accommodating a material  830 , which is a mixture for reinforcing bone (e.g., bone cement). A second external thread  1001  is formed outside the injecting handle  1000 , a chamber  1002  is set within one side of the injecting handle  1000 , and a twisting part  1003  is formed at the other side in a wing shape for twisting. The second external thread  1001  is linked to the second inner thread  503 . The container  800  is set at the chamber  1002  when the piston  810  is against the bottom of the chamber  1002 , and the exit  821  is connected to the tunnel  511 . 
         [0041]    The method to inject the material by using the aforesaid injector apparatus can be done by the following steps:
       a) holding the hollow body  500  and twisting the twisting part  1003  or the injecting handle  1000 , making the bottom of the chamber  1002  to push the piston  810  and enable the material  830  in the room  822  sequentially delivered out the exit  821 , the tunnel  511 , the device  100 , the aperture  122 , the barrel  200  and the window of the barrel, and into the damaged bone  700  to-be-treated; and   b) relieving the injecting handle  1000 , holding the base  405  of the outer tube  400 , simultaneously twisting in a reverse direction of the hollow body  500 , and ejecting the injection module.       
 
         [0044]    While the invention has been described above with references to specific embodiments thereof, it can be seen that many changes, modifications and variations in the materials, arrangements of parts and steps can be made without departing from the inventive concept disclosed herein. Accordingly, the spirit and broad scope of the appended claims are intended to embrace all such changes, modifications and variations that may occur to one having skill in the art upon a reading of the disclosure.

Technology Category: a