Patent Publication Number: US-2021186707-A1

Title: Supporting member and supporting member assembly for implantation into or between subjects bones, and template plug and tamper corresponding to the same

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention relates to a supporting member and a supporting member assembly to be implanted into or between a subject&#39;s bones, and a template plug and a tamper corresponding to the supporting member. More particularly, the invention relates to a supporting member that can be connected with at least one supporting member of the same structure as its own in a bone or between two connected bones, a supporting member assembly composed of such supporting members, and a template plug and a tamper corresponding to such supporting members. 
     2. Description of Related Art 
     The societies many of us live in are aging or aged, which raises concerns about health issues of the elderly. A senior citizen tends to suffer from osteoporosis and is therefore prone to bone fractures or even vertebral compression fractures. While vertebral compression fractures in most patients can heal within months, the recovery period is anything but easy. For example, persistent pain in the lower back or nerve compression may inconvenience a patient&#39;s daily life to such an extent that the patient ends up bedridden, whose complications include bedsores, pneumonia, and urinary infection, among others. Some patients&#39; vertebral compression fractures do not heal at all and hence give rise to permanent pain, if not compromising the stability of the entire vertebral column or leading to a hunchback, in the latter case of which the vertebrae adjacent to the fractured one(s) may suffer from compression fracture too, as in a domino effect. Besides, patients with such related diseases as degenerative disc disease, herniation of intervertebral disc, spondylolisthesis, spondylolysis, spinal canal stenosis, or pseudoarthrosis may experience back pain, sciatica, claudication, or weakness in the legs. 
     Treatment for vertebral compression fracture can be carried out in many ways. “Open posterior spinal fixation” and “bone fusion surgery” involve driving pedicle screws into fractured vertebrae in order to secure and support the vertebrae. “Minimally invasive percutaneous vertebroplasty” is an X-ray image-guided procedure in which a bone puncture needle injects bone cement into a collapsed fractured vertebra through a tiny incision and a pedicle of the vertebra in order to fill the vertebra with bone cement and thereby relieve pain, but this procedure cannot correct a deformed vertebra. “Minimally invasive percutaneous balloon kyphoplasty” uses an inflatable balloon to restore the height of a collapsed vertebra and, after removal of the balloon, injects bone cement into the cavity formed by the inflated balloon in order to correct the deformation of the collapsed vertebra to a certain degree. This procedure, however, is not very effective in correcting a deformed vertebra and requires bone cement, too. Other treatments include implanting a high-precision medical device (e.g., one designed on the mechanical principle of a jack or tripod) into a fractured vertebra for support, and yet such medical devices are disadvantaged by their complicated mechanical structures, limited supporting effect, and the necessity of filling with bone cement on a supplementary basis. 
     Another method for treating a vertebral compression fracture entails placing an implant into the fractured vertebra. However, an overly large implant may rupture the pedicle through which it passes during implantation, causing damage to the nearby nerves, and an implant that is not large enough for the intended collapsed vertebra can only expand the vertebra to a limited extent and therefore fails to support the vertebra adequately. 
     As to treatment between a subject&#39;s bones, or interosseous treatment, it is common practice nowadays to incorporate “intervertebral fusion” with “posterior spinal instrumentation” to enhance the effect of rigid fixation. 
     Intervertebral fusion can be divided by its approach into: anterior lumbar interbody fusion (ALIF), lateral/oblique lumbar interbody fusion (LLIF/OLIF), and posterolateral/transforaminal lumbar interbody fusion (PLIF/TLIF). ALIF is the golden rule in the art, allowing the largest possible support element to be implanted, but is disadvantageous in that it is performed by way of the abdominal cavity, requires a relatively large incision, and may injure the intestinal tract, the abdominal aorta, or the ureters, if not resulting in hernia or retrograde ejaculation at the same time. Technically, therefore, ALIF is highly demanding on both orthopedic and neurological surgeons. LLIF/OLIF reduces the disadvantages of ALIF but necessitates special equipment. PLIF/TLIF is clinically the most widely used, and yet the limited window attributable to obstruction by the spinal cord and the spinal nerves makes it difficult to use an adequately sized support element. 
     Currently, intervertebral fusion can be assisted by placing an implant between the vertebrae to be fused. However, an exceedingly large implant may injure the surrounding nerves, blood vessels, or other important tissues during implantation, and an implant whose size is smaller than required may result in overly small areas of contact with the adjacent vertebrae, causing problems associated with undue concentration of pressure. 
     BRIEF SUMMARY OF THE INVENTION 
     With regard to implantation into a subject&#39;s bones, the conventional open posterior spinal fixation and bone fusion procedure when performed on a patient with osteoporosis may require a relatively large incision and use a relatively large number of screws to secure a relatively large number of vertebrae in order to prevent the screws from getting loose. Nevertheless, an extensive spinal fixation operation not only is time-consuming and prone to massive blood loss, but also may lead to the development of multiple complications (e.g., stiffness in the back, cardiopulmonary failure, and infection) in elderly patients. As to minimally invasive percutaneous vertebroplasty or kyphoplasty, the bone cement used in the operation may leak from the vertebra(e) in question, and a serious leak into blood vessels may result in arterial thrombosis, venous thrombosis, or stroke. If a lot of bone cement leaks to the spinal cord or the nerve roots and subsequently cures (the curing process generates high heat), the surrounding nerves will be severely compressed and damaged. Moreover, when bone cement exists permanently as the filler in a fractured vertebra, the low bone-compatibility and extremely high hardness of bone cement may give rise to bone resorption, hinder the healing of the fracture, or even fracture a neighboring vertebra. 
     As for implantation between a subject&#39;s bones, the conventional devices for intervertebral fusion are the intervertebral cages, which can be roughly divided into those of a unitary structure and those of a composite structure. Common unitary-structure cages are in the shape of a disc, straight bullet, or banana and have a simple structural design that requires the use of a complicated tool during implantation in order to prevent nerve and blood vessel injuries. Clinically, therefore, a unitary-structure intervertebral cage often falls short of its required dimensions such that the areas of contact between the cage and the adjacent vertebrae are not large enough to avoid pressure concentration (which may cause subsidence or extrusion of the intervertebral cage into or from the vertebrae) or promote intervertebral fusion (the failure of which may lead to the formation of a false joint, i.e., pseudoarthrosis). Composite-structure intervertebral cages either incorporate a screw or have an expandable structure. The screw-type cages, though featuring enhanced fixation, add to the difficulty of surgical operation and are applicable only in ALIF. The expandable-structure intervertebral cages can be further divided into the medial-lateral expansion type and the caudal-cranial expansion type, both of which enable relatively large areas of contact and increased fixation but have rather intricate mechanical structures, including, for example, a large number of articulations and points of stress concentration. These complex structures not only limit the amount of bone graft that can be packaged in each cage, but also increase the chances of long-term fatigue failure and false joint formation between vertebrae. 
     As is well known in the art, a bone implant must not be a complicated mechanical assembly, which tends to fatigue, disintegrate, or fail after persistent use in the human body. In addition, a bone implant is preferably highly bone-compatible or even conducive to the healing of bone fracture and therefore must not include materials that are rarely used, or not allowed to be used, in the human body. Regarding the treatment of bone fracture, therefore, many issues remain to be addressed by medical experts and scientific researchers. 
     In view of this, in order to solve the above problems, the primary objective of the present invention is to provide a supporting member for implantation into or between a subject&#39;s bones, comprising: a main body having two opposite sides defined respectively as an upper side and a lower side; a first connecting portion formed at the upper side of the main body and shaped as a male or female part of a dovetail joint; a second connecting portion formed at the lower side of the main body and corresponding in shape to the first connecting portion; and a guiding structure formed at a side of the main body and configured to mate with an external template plug; wherein the first connecting portion of the supporting member is connectable with the second connecting portion of another said supporting member to form a said dovetail joint. 
     In a preferred embodiment, the first connecting portion is a dovetail block and the second connecting portion is a dovetail groove in order to prevent two vertically connected said supporting members from separating from each other after connecting in a sliding manner. 
     In a preferred embodiment, a front side of the first connecting portion further includes a first positioning portion, a front side of the second connecting portion further includes a second positioning portion, and the second positioning portion corresponds in shape and position to the first positioning portion; wherein, the first positioning portion is a positioning block and the second positioning portion is a positioning hole so that the supporting members with such structures are able to position and fasten to each other. 
     In a preferred embodiment, a front side of the main body has a U-shaped groove structure that can be compressed or deformed to facilitate fastening between supporting members and return to an original shape elastically to prevent the supporting members from separating from each other. 
     In a preferred embodiment, the guiding structure includes a plurality of guiding holes and/or buffer grooves. 
     In a preferred embodiment, the guiding holes and the buffer grooves have various designs with progressive deviation or difference in terms of angle, position, size, or shape. 
     In a preferred embodiment, the main body is one or a plurality of reticulated structures. 
     In a preferred embodiment, the reticulated structure can be filled with a bone-filling material or bone cement. 
     In a preferred embodiment, the bone is a vertebra. 
     In a preferred embodiment, a material of the supporting member includes metal, plastic, or a mixture thereof. 
     Another objective of the present invention is to provide a template plug configured to guide the aforementioned supporting member into or between a subject&#39;s bones, which includes a plurality of connecting pins, an extension portion, and a grip portion, wherein the extension portion has one end connected to the plural connecting pins and an opposite end connected to the grip portion, and the extension portion and/or the grip portion has: a third connecting portion, which is formed on an upper side of the extension portion and/or the grip portion, and is a dovetail projection; a fourth connecting portion, which is formed on a lower side of the extension portion and/or the grip portion, and corresponds to the third connecting portion; wherein, the plural connecting pins can be correspondingly engaged with the guiding structure of the supporting member. 
     In a preferred embodiment, the template plug further includes a plurality of connecting pins and buffer bases. 
     In a preferred embodiment, the template plug has two connecting pins that correspond in design to but are slightly different from the guiding structure in terms of angle, position, shape, or size. 
     In a preferred embodiment, the third connecting portion of the template plug can correspond to the second connecting portion of the supporting member and the fourth connecting portion can correspond to the first connecting portion of the supporting member so that the template plug can be pushed along and coupled with the supporting member in a sliding manner. 
     Still another objective of the present invention is to provide a tamper, which can correspondingly match the aforementioned supporting member or template plug, the tamper includes a slender shaft and a grip portion connected to the slender shaft; wherein, an upper side of the slender shaft and/or the grip portion further includes a fifth connecting portion corresponding to the second connecting portion, and a lower side of the slender shaft and/or the grip portion further includes a sixth connecting portion corresponding to the first connecting portion. 
     Yet another objective of the present invention is to provide a supporting member assembly to be implanted into or between a subject&#39;s bones, which includes a plurality of aforementioned supporting members, wherein the first connecting portion of each supporting member forms a dovetail joint with the second connecting portion of another said supporting member in order to connect the plural supporting members sequentially. 
     The present invention has the following advantages: 
     1. The present invention provides a supporting member that is configured as a micro-unit and whose small size allows not only implantation into a bone or between two connected bones, but also connection with other such members in the bone or between the connected bones so as to form a supporting member assembly, making possible a minimally invasive, small-incision surgical operation. 
     2. The present invention also provides a tamper for restoring a fractured bone and pushing/pressing an implanted supporting member, and a template plug for introducing a supporting member into a bone or between two connected bones, connecting the supporting member to a previously implanted supporting member in a sliding manner, and thereby fastening the two supporting members together vertically, before the template plug is removed from the supporting members. 
     3. The present invention further provides a supporting member assembly that is formed by sequentially implanting and connecting a plurality of supporting members into a bone or between two connected bones so as to push outward the end plate(s) to be treated and thereby expand the collapsed fractured bone(s). This supporting member assembly is an improvement over the one-size implants used in the conventional implantation techniques on the grounds that an existing one-size implant cannot “be a single micro-unit before implantation into or between a subject&#39;s bones and connect with other similar micro-units sequentially implanted into or between the bones to form a larger yet complete block”. In addition, unlike the traditional one-size implants, the supporting member assembly of the invention will not rupture the affected bone structure (e.g., a pedicle) or injure the surrounding nerves (e.g., the spinal cord or spinal nerves), blood vessels (e.g., the abdominal aorta or the vertebral arteries), or other important tissues (e.g., the ureters) during implantation, or provide inadequate support due to an expediently smaller-than-required size. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIGS. 1 ( a ) and ( b )  show perspective views of the supporting member according to embodiment 1 of the present invention. 
         FIGS. 2 ( a ) and ( b )  show perspective views of the supporting member according to embodiment 2 of the present invention. 
         FIGS. 3 ( a ) and ( b )  show perspective views of the supporting member according to embodiment 3 of the present invention. 
         FIG. 4  is a perspective view of the supporting member according to embodiment 4 of the present invention. 
         FIG. 5  is a sectional view of the supporting member assembly according to a preferred embodiment of the present invention. 
         FIG. 6  is a perspective view of the supporting member assembly according to embodiment 5 of the present invention. 
         FIG. 7  is a schematic diagram illustrating a preferred embodiment of the implantation system of the present invention. 
         FIGS. 8 ( a ) and ( b )  show perspective views of the template plug according to embodiment 6 of the present invention. 
         FIGS. 9 ( a ) and ( b )  show perspective views of the template plug according to embodiment 7 of the present invention. 
         FIGS. 10 ( a ) and ( b )  show perspective views of the tamper according to embodiment 8 of the present invention. 
         FIG. 11  shows schematic views of an implantation system according to a preferred embodiment of the present invention applied to a vertebra in (a) an axial view and (b) a left side view. 
         FIG. 12  shows (a) an axial view and (b) a left side view of a supporting member assembly according to a preferred embodiment of the present invention applied to a vertebra. 
         FIG. 13  shows (a) an axial view and (b) a left side view of a supporting member assembly according to a preferred embodiment of the present invention applied to a vertebra. 
         FIG. 14  shows (a) an axial view and (b) a left side view of a supporting member assembly according to a preferred embodiment of the present invention applied between connected vertebrae. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The details and technical solution of the present invention are hereunder described with reference to accompanying drawings. For illustrative sake, the accompanying drawings are not drawn to scale. The accompanying drawings and the scale thereof are not restrictive of the present invention. 
     The use of “comprise/include” means not excluding the presence or addition of one or more other components, steps, operations, and/or elements to the described components, steps, operations, and/or elements. As used herein and in the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context dictates otherwise. 
     Hereinafter, the present invention will be further described with detailed descriptions and embodiments. However, it should be understood that these embodiments are only used to help understand the invention more easily, not to limit the scope of the invention. 
     The present invention is designed not only for implantation into or between human bones, but also for use in other vertebrates such as amphibians, reptiles, birds, and mammals. Furthermore, the invention can be used in or between any suitable bones, preferably but not limited to vertebrae. In one preferred embodiment, the bone to which the invention is applied is a vertebra. 
     Generally speaking, a conventional bone implant cannot be minimally invasive and adequately supportive at the same time. To solve the clinical problems associated with bone fracture effectively, the present invention aims to provide a supporting member, a supporting member assembly, a template plug for guiding the supporting member into a subject&#39;s bone or between two connected bones, and a tamper for assisting the required implantation operation. A detailed description of some embodiments of the invention is given below. 
     [Embodiments 1 to 4]—Supporting Member 
     Please refer to  FIG. 1  to  FIG. 4  for perspective views of four supporting members  100  according respectively to embodiments 1 to 4 of the present invention. 
     The supporting members  100  according to embodiments 1 to 4 are configured to be implanted into or between a subject&#39;s bones and each include a main body  11 , a first connecting portion  12 , a second connecting portion  13 , and a guiding structure  14 . The main body  11  has an upper side and a lower side, which is the opposite side of the upper side. In embodiment 3, referring to  FIG. 3 , the main body  11  is preferably one or a plurality of reticulated structures. This embodiment is advantageous in that the at least one reticulated structure can be filled with a bone-filling material (e.g., bone cement), provides space for the proliferation of osteoblasts, allows passage of nutrients, produces a supporting effect similar to that of trabeculae, and facilitates fusion between the main body of the supporting member (or the filler therein) and the surrounding ossein, thereby assisting in the healing of a bone fracture. In embodiment 2, referring to  FIG. 2 , the main body  11  has one or a plurality of holes (e.g., through holes with a diameter ranging from about 0.3 mm to about 5 mm), wherein the at least one hole is intended to provide space that can be filled with a bone-filling material, promote the proliferation of osteoblasts and the delivery of nutrients, enhance filler (e.g., bone cement) attachment, and reduce the weight and Young&#39;s modulus (also known as the modulus of elasticity) of the implant. 
     The first connecting portion  12  is formed on the upper side of the main body  11  and is shaped as the male part of a dovetail joint. The second connecting portion  13  is formed in the lower side of the main body  11  and corresponds in shape to the first connecting portion  12 . The first connecting portion  12  of a supporting member  100  can be connected to the second connecting portion  13  of another supporting member  100  to form a dovetail joint. As used herein, the term “male (or female) part of a dovetail joint” refers to a trapezoidal structure protruding from (or sunken into) the main body  11 , and the term “dovetail joint” refers to a joint formed by such a protruding trapezoidal structure engaged with, fastened to, connected in a sliding manner to, or otherwise secured in a matching sunken trapezoidal structure. In one preferred embodiment, the first connecting portion is a dovetail block, the second connecting portion is a dovetail groove, and the first connecting portion of a supporting member with such connecting portions can form a dovetail joint with the second connecting portion of another such supporting member, as shown in  FIG. 5 . This structural feature aims to prevent two vertically connected supporting members from tilting sideways with respect to and separating vertically from each other after the trapezoidal dovetail groove of the upper supporting member is mated, in a sliding manner, to the “top rail” formed by the dovetail block of the lower supporting member; in short, the structural feature is intended to fasten or lock the supporting members together after the supporting members are implanted into a bone or between two connected bones. In some embodiments, the first connecting portion is a dovetail block whose width gradually increases from the front end toward the rear end, and the second connecting portion has a corresponding shape so that while the second connecting portion of a supporting member with such connecting portions is being mated, in a sliding manner, to the dovetail block of another such supporting member, the former supporting member can only be moved forward but not rearward. 
     In some embodiments, the first connecting portion further includes a first positioning portion, and the second connecting portion further includes a second positioning portion corresponding in shape and position to the first positioning portion. For example, the first positioning portion may be a protruding structure while the second positioning portion is a recessed structure corresponding in shape to the protruding structure, or the first positioning portion may be a recessed structure while the second positioning portion is a protruding structure corresponding in shape to the recessed structure. The foregoing designs of the positioning portions are advantageous in that the first positioning portion and the second positioning portion can be fastened to each other to prevent two connected supporting members from getting loose with respect to each other. In one preferred embodiment, the first positioning portion is a projection, and the second positioning portion is a recess. In embodiment 3 as well as embodiment 1, the front side of the first connecting portion  12  of the supporting member  100  is provided with a terminal positioning bump (i.e., the first positioning portion  121 ), and the bump can enter, in a sliding manner, a positioning hole (i.e., the second positioning portion  131 ) of the next implanted supporting member  100  to prevent the two supporting members  100  from sliding with respect to and separating from each other in either the forward or the rearward direction. In embodiment 4 as well as embodiment 2, the front side of the first connecting portion  12  of the supporting member  100  is provided with a terminal positioning block (i.e., the first positioning portion  121 ), and the block can enter, in a sliding manner, a positioning groove (i.e., the second positioning portion  131 ) of the next implanted supporting member  100  to prevent the two supporting members  100  from sliding with respect to and separating from each other in either the forward or the rearward direction. In one preferred embodiment, the main body  11  has a U-shaped groove structure  151  as shown in  FIG. 2  and  FIG. 4  so that when a supporting member with such a structure is brought into engagement with another such supporting member in a sliding manner, and before their positioning portions (e.g., a positioning bump and a positioning hole) are fastened to each other, the U-shaped groove structures  151  of the two supporting members can be elastically compressed or deformed to facilitate fastening between the positioning bump and the positioning hole, and that after the positioning portions are fastened together, the U-shaped groove structures  151  will return to their original shapes elastically to ensure that the positioning bump is securely fastened to the positioning hole to prevent the supporting members from separating from each other. 
     The guiding structure  14  is formed at one side of the main body  11  and is configured to mate with an external template plug. The guiding structure  14  may be, for example but not limited to, the guiding holes  141  shown in  FIG. 1  to  FIG. 4 . In one preferred embodiment, the guiding structure  14  includes a plurality of guiding holes (such as but not limited to two, three, four, or five guiding holes), and there is no limitation on the shapes of the guiding holes (e.g., the guiding holes may be circular holes, rectangular holes, triangular holes, other polygonal holes, or holes of irregular shapes). In each of embodiments 1 to 3, the main body  11  is formed at one side with two guiding holes  141  for mating with an external template plug. In embodiment 4, referring to  FIG. 4 , there are also two guiding holes  141 , but the guiding holes  141  are connected by a gradually deepened buffer groove  142  that is relatively wide at a shallow depth and turns pointed as the depth increases. These two guiding holes  141  and the buffer groove  142  between them are also designed to mate with an external template plug. The guiding structure  14  aims to connect with the “connecting pins” at the front end of an external template plug (as detailed further below). The two guiding holes  141  and the buffer groove  142  in embodiment 4 may have various designs in terms of angle (e.g., they may diverge or converge in the forward direction), position (e.g., they may be shifted laterally outward or inward with respect to one another), size (e.g., they may be tapered in the forward or rearward direction), or shape (e.g., they may be conical or columnar). 
     In one preferred embodiment, the material of the supporting member of the present invention includes a biocompatible material such as a biocompatible metal, a biocompatible plastic, or a mixture thereof. Suitable metals include but are not limited to magnesium alloys, tantalum alloys (e.g., TaC and TaN), titanium alloys (e.g., GUMMETAL®), nickel-titanium alloys, nickel-titanium-copper alloys, cobalt-chromium alloys (e.g., Elgiloy®, a non-magnetic cobalt-based hardenable cobalt-chromium-nickel superalloy), cobalt-chromium-nickel alloys (e.g., Phynox®), chromium-tungsten-nickel alloys (e.g., L605), cobalt-chromium-vanadium alloys, cobalt-nickel-chromium-molybdenum alloys (e.g., MP35N and MP20N), stainless steel (e.g., 316, 316L, and 304), and metallic glass. Suitable plastics include polymers, copolymers, composite materials, and mixtures of the above, such as but not limited to styrene-based elastomers, olefinic elastomers, polyolefinic elastomers, polyurethane-based thermoplastic elastomers, polyamides, polybutadienes, polyisobutylene, poly(styrene-butadiene-styrene), poly(2-chloro-1,3-butadiene), silicones, thermoplastic polyurethanes (TPU), polyurethanes (PU), polysiloxanes (e.g., polydimethylsiloxane (PDMS) and hard polydimethylsiloxane (h-PDMS)), poly(methyl methacrylate) (PMMA), polyetheretherketone (PEEK), ultra-high-molecular-weight polyethylenes (UHMWPE), and silicon rubber. In a more preferred embodiment, the material of the supporting member of the invention includes a titanium alloy. The foregoing embodiments are advantageous in that a plurality of supporting members may, depending on their material properties, be sequentially implanted into a bone or between two connected bones, fastened together, and vertically or horizontally stacked until the resulting supporting member assembly has the desired height/width and supporting strength. 
     The dimensions of the supporting member of the present invention are preferably determined according to the size of the space of the target implantation site and the size of the incision to be made for the implantation operation. For example, if the target implantation site is in a vertebra, the supporting member may have a relatively slender design to minimize the hole drilled into the vertebra and thereby protect the surrounding nerves and blood vessels from injury. That is to say, the supporting member of the invention can be adjusted and modified as needed. The invention imposes no limitation on the dimensions of the supporting member. 
     [Embodiment 5]—Supporting Member Assembly 
     Please refer to  FIG. 5  and  FIG. 6  respectively for a sectional view and a perspective view of the supporting member assembly  200  according to embodiment 5 of the present invention. The supporting members in the supporting member assembly  200  are sequentially identified in a bottom-up order as the first supporting member  21 , the second supporting member  22 , the third supporting member  23 , the fourth supporting member  24 , and the fifth supporting member  25 . As the supporting members are implanted in the same direction, their guiding structures  213  face the same direction. 
     The supporting member assembly  200  according to embodiment 5 is configured to be implanted into or between a subject&#39;s bones and includes the plural supporting members stated above, with the first connecting portion of each supporting member (except for the uppermost supporting member  25 ) forming a dovetail joint with the second connecting portion of the adjacent supporting member. As shown in  FIG. 5 , the plural supporting members are sequentially connected in such a way that the first connecting portion (i.e., the connecting portion  211 ) of each supporting member (except for the uppermost supporting member  25 ) forms a dovetail joint with the second connecting portion of the next implanted supporting member. During the process, the first positioning portion (i.e., the positioning portion  212 ) of each supporting member (except for the uppermost supporting member  25 ) is slid into the second positioning portion of the next implanted supporting member to prevent each two adjacent supporting members from sliding with respect to each other in the forward or rearward direction. 
     In one preferred embodiment, the supporting member assembly includes two to seven supporting members. In a more preferred embodiment, the supporting member assembly includes three to five supporting members. In the embodiment shown in  FIG. 5  and  FIG. 6 , the supporting member assembly  200  is an assembly of five supporting members, in which, as shown in  FIG. 6 , the first supporting member  21  and the fifth supporting member  25  are reticulated structures to provide the space needed for the proliferation of osteoblasts and allow passage of nutrients, and in which the second to the fourth supporting members  22 ,  23  and  24  are solid structures to be stacked up to increase the height of the space created by the assembly as well as the strength of the assembly, with a view to, for example, pushing two adjacent vertebrae further apart from each other vertically. It can also be seen in  FIG. 5  and  FIG. 6  that the first supporting member  21 , which only has to connect with the second supporting member  22 , may have only the first connecting portion, and that the fifth supporting member  25 , which only has to connect with the fourth supporting member  24 , may have only the second connecting portion. 
     A plurality of supporting members of the present invention can be fastened together in a modular manner while being implanted into a bone or between two connected bones so as to form a vertical or horizontal stack of the desired height or width and with the desired supporting strength. The resulting supporting member assembly can push outward the end plate(s) to be treated, thereby expanding a fractured bone or providing interosseous fixation. The invention allows a plurality of supporting members to be connected in the tiny limited space in a bone or between two connected bones in order to stabilize the bone or firmly secure the connected bones. The number of the supporting members required to be implanted depends on the height of the bone to be restored or the distance between the two connected bones to be secured. Theoretically, the supporting member assembly can be made larger by adding as many supporting members as needed, until the bone to be restored or the space between the two connected bones to be secured is completely filled by the assembly. Thus, the invention overcomes the aforementioned drawback of the conventional one-size implants, i.e., failure to “be a single micro-unit before implantation into or between a subject&#39;s bones and connect with other similar micro-units sequentially implanted into or between the bones to form a larger yet complete block”. The invention also solves such problems of the conventional one-size implants as the likelihood of their rupturing the affected bone structure (e.g., a pedicle) or injuring the surrounding nerves (e.g., the spinal cord or spinal nerves), blood vessels (e.g., the abdominal aorta or the vertebral arteries), or other important tissues (e.g., the ureters) during implantation, and of their providing inadequate support due to an expediently smaller-than-required size. 
     To put together a plurality of supporting members of the present invention, two template plugs according to the invention can be sequentially mated to the guiding structures of the supporting members in order to guide each supporting member into a subject&#39;s bone or between two connected bones, connect each two successively implanted supporting members in a sliding manner, and fasten each two successively implanted supporting members together vertically. During the process, each template plug is removed from the supporting member it is mated to, after the other template plug has put the next supporting member in place. The implantation and connection process are detailed below with reference to  FIG. 7 . 
     The supporting members  311  of the present invention are configured to work with a working assembly in order to be implanted. The supporting members  311  and the working assembly are herein referred to collectively as an implantation system  300 . 
     The working assembly matches the supporting members  311  and is configured to implant the supporting members  311  into or between a subject&#39;s bones. The working assembly includes one or a combination of devices selected from the group consisting of an introducer (not shown), a reamer (not shown), a working cannula  33 , a tamper (not shown), and a template plug  32 . 
     The introducer includes an introducing portion, an extension portion, and a grip portion. The extension portion has one end connected to the introducing portion and the opposite end connected to the grip portion. The end of the introducing portion that is not connected to the extension portion is pointed and sharp. In one preferred embodiment, the introducing portion and the extension portion of the introducer may be solid or hollow. The introducer is configured to make a hole into a vertebra and gradually enlarge the hole so that the working cannula can be put into the hole. In fact, the introducer refers to any one of a series of solid or hollow introducers that have a needle-shaped introducing portion and vary in size so as to drill and enlarge a hole in a vertebra in a successive and gradual manner, lest a large hole drilled into the vertebra in one go injure the surrounding nerves or blood vessels. 
     The reamer includes a reaming portion, an extension portion, and a grip portion. The extension portion has one end connected to the reaming portion and the opposite end connected to the grip portion. The reaming portion is a sharp spiral structure with which the reamer can move or pull out bone debris. The sharp spiral structure of the reamer can be driven to a specific position in a bone and ream out bone debris for physiological examination. 
     The working cannula  33  includes a hollow tube and a grip portion. The hollow tube allows insertion by the introducing portion and the extension portion of the introducer, the slender shaft of the tamper, and the two connecting pins and the extension portion of the template plug  32 . The hollow tubular structure of the working cannula  33  not only can accommodate the largest of the introducers used to gradually enlarge the hole drilled into a vertebra, but also serves as a passage for the reamer, the tamper, the template plug  32 , and the supporting members  311  to be implanted, thereby limiting the working position of the implantation system  300 . 
     Some examples of the tamper and of the template plug  32  will be detailed below with reference to embodiments 6 to 8.  FIG. 7  shows how the supporting members  311  are put together using two template plugs  32  and how the connecting pins  321  of each template plug  32  are mated to the guiding structure of the corresponding supporting member  311 . It is feasible to implant only one supporting member  311  into a bone or between two connected bones, or sequentially introduce and connect two or more supporting members  311  into a bone or between two connected bones to form a supporting member assembly  31  with adequate supporting strength. 
     [Embodiments 6 and 7]—Template Plug 
     Please refer to  FIG. 8  and  FIG. 9  for perspective views of two template plugs  400  according respectively to embodiments 6 and 7 of the present invention. 
     The template plugs  400  according to embodiments 6 and 7 are both configured to guide the supporting member of the present invention into or between a subject&#39;s bones. Each template plug  400  includes a connecting pin  41 , an extension portion  42 , and a grip portion  43 , wherein the extension portion  42  has one end connected to the connecting pin  41  and the opposite end connected to the grip portion  43 . 
     The connecting pin  41  serves to mate with the guiding structure of a supporting member of the present invention and is therefore configured to match the guiding structure in, for example, position, structure, and/or number. As stated above, the guiding structure of a supporting member of the invention may include guiding holes and a buffer groove, both formed in one side of the main body of the supporting member, wherein the number of the guiding holes may be two, three, four, five, etc. It is therefore preferable that there are as many connecting pins as the guiding holes, i.e., two, three, four, or five connecting pins corresponding to two, three, four, or five guiding holes respectively. Take embodiments 1 to 4 for example. The supporting member in each of embodiments 1 to 4 has two guiding holes, and in order to mate with the two guiding holes, the template plug  400  in each of embodiments 6 and 7 has two connecting pins  41 . In embodiment 7, referring to  FIG. 9 , the two connecting pins  41  are connected by a gradually raised buffer base  45  that is relatively wide at the rear end and turns pointed toward the front end, and that is intended to correspond to a gradually deepened buffer groove that is relatively wide at a shallow depth and turns pointed as the depth increases. In one preferred embodiment, the two connecting pins correspond in design to but are slightly different from the intended guiding structure in terms of angle (e.g., diverging or converging in the forward direction in the same way as the guiding holes of the guiding structure but to a slightly different degree), position (e.g., shifted laterally outward or inward to a small degree with respect to the guiding holes of the guiding structure), shape (e.g., being conical or columnar in a slightly different way from the guiding holes of the guiding structure), or size (e.g., tapered in the forward or rearward direction to a slightly different degree from the guiding holes of the guiding structure). This structural feature, i.e., the slight structural difference between the connecting pins and the intended guiding structure, aims to enable temporary fastening, and thus temporarily prevent separation, between the template plug and each supporting member having the intended guiding structure. 
     To prevent a plurality of template plugs  400  that are used together from shifting in position during supporting member implantation, each template plug  400  may further include a coupling and positioning structure  44 , i.e., a third connecting portion  441  and a fourth connecting portion  442 . The third connecting portion  441  is located at an upper side of the extension portion  42  and the grip portion  43 , while the fourth connecting portion  442  is located at a lower side of the extension portion  42  and the grip portion  43 . For example, the third connecting portion  441  is a dovetail projection corresponding to the dovetail recess, or second connecting portion, of a supporting member of the present invention and can therefore be pushed into, advanced, and coupled with the dovetail recess of the supporting member in a sliding manner, and the fourth connecting portion  442  is a dovetail recess corresponding to the dovetail projection, or first connecting portion, of the supporting member and can therefore be pushed along, advanced, and coupled with the dovetail projection of the supporting member in a sliding manner. As another example, a template plug of the invention may have the same upper connecting portion (e.g., dovetail block) and lower connecting portion (e.g., dovetail groove) as a supporting member of the invention so as to connect with another template plug of the same configuration. 
     Referring to  FIG. 9 , a “first” (with reference to the order of a sequence) template plug  400  has its connecting pins  41  and buffer base  45  mated respectively with the guiding holes  141  and the buffer groove  142  of a “first” (with reference to the order of a sequence) supporting member such that the “first” supporting member is held by the “first” template plug  400 . After the “first” template plug  400  puts the “first” supporting member securely into a bone or between two connected bones, the third connecting portion  441  of the “first” template plug  400  is coupled to the dovetail recess, or second connecting portion  13 , of a “second” (with reference to the order of a sequence) supporting member and to the dovetail recess, or fourth connecting portion  442 , of the “second” (with reference to the order of a sequence) template plug  400  holding the “second” supporting member. When the “second” template plug  400  has fastened the dovetail recess, or second connecting portion  13 , of the “second” supporting member to the dovetail projection, or first connecting portion  12 , of the “first” supporting member, the “first” template plug  400  (or more particularly its connecting pins  41  and buffer base  45 ) can be removed from the guiding holes  141  and the buffer groove  142  of the “first” supporting member, and by doing so, the third connecting portion  441  of the “first” template plug  400  can also be removed from the dovetail recess, or fourth connecting portion  442 , of the “second” template plug  400 . 
     In short, after the “second” template plug holding the “second” supporting member is moved along the “first” template plug and fastens the “second” supporting member to the “first” supporting member, the “first” template plug can be removed from the “second” template plug. By the same token, more than two supporting members can be sequentially introduced into and connected in a bone or between two connected bones. 
     [Embodiment 8]—Tamper 
     Please refer to  FIG. 10  for perspective views of the tamper  500  according to embodiment 8 of the present invention. 
     The tamper  500  is configured to match the supporting member of the present invention and includes a slender shaft  51  and a grip portion  52  connected to the slender shaft  51 . The tamper  500  serves to restore a fractured bone and press down a supporting member that has just been implanted. 
     As shown in the enlarged views of  FIG. 10( a )  and  FIG. 10( b ) , the tamper  500  further includes a coupling and positioning structure  53  so as not to be shifted in position during operation. In this embodiment, the coupling and positioning structure  53  includes a fifth connecting portion  531  and a sixth connecting portion  532 . The fifth connecting portion  531  is located at an upper side of the slender shaft  51  and/or the grip portion  52  and corresponds in shape to the second connecting portion of the supporting member of the present invention, and the sixth connecting portion  532  is located at a lower side of the slender shaft  51  and/or the grip portion  52  and corresponds in shape to the first connecting portion of the supporting member. As the third connecting portion and the fourth connecting portion of the template plug of the invention also correspond in shape to the second connecting portion and the first connecting portion of the supporting member of the invention respectively, the fifth connecting portion  531  of the tamper  500  can connect with the fourth connecting portion of the template plug of the invention in a sliding manner, and the sixth connecting portion  532  of the tamper  500  can connect with the third connecting portion of the template plug in a sliding manner. In one preferred embodiment, the connecting portions of the tamper of the invention have the same structures as the connecting portions of the supporting member of the invention (e.g., the upper connecting portion being a dovetail block, and the lower connecting portion being a dovetail groove) in order for the tamper to connect with the template plug. 
     The structure of the slender shaft  51  is preferably similar to but flatter than that of the supporting member of the present invention, and the dimensions of the slender shaft  51  may vary to meet practical needs. In fact, a plurality of tampers  500  whose slender shafts  51  vary in size may be used sequentially, in an ascending order of the shaft sizes, to either gradually push upward the top side of a collapsed fractured vertebra in order to restore the height of the vertebra, or press down a supporting member that has just been implanted so as to make room for the next supporting member to be implanted. 
     Please refer to  FIG. 11  to  FIG. 14  for schematic drawings showing how an implantation system  600  of the present invention is operated to implant a plurality of supporting members of the invention into a vertebra V or between two connected vertebrae V. 
     As shown in  FIG. 11 , the operation of implanting a plurality of supporting members of the present invention into a vertebra V begins by drilling a hole into the collapsed fractured vertebra V through one of its pedicles P and enlarging the hole using a series of introducers whose sizes are gradually increased. Once the hole is large enough, the working cannula  63  is placed into the hole, and the reamer is inserted through the working cannula  63  to remove the bone debris. Then, the tamper is used to restore the collapsed fractured vertebra V, and a supporting member  611  is subsequently introduced into the vertebra V (or between two connected vertebrae V if that is the case) by a template plug  62 . After that, the tamper is used again to restore the collapsed fractured vertebra V and press down the supporting member  611 , and another template plug  62  is used to introduce the next supporting member into the vertebra V (or between the two connected vertebrae V), connect this supporting member to the previous supporting member  611  in a sliding manner, and fasten the two supporting members together vertically. 
     The present invention allows the supporting member  611  to be implanted into a subject&#39;s bone or between two connected bones, followed sequentially by more supporting members, which are connected to the supporting member  611  and to one another right in the bone or between the connected bones to form a supporting member assembly  61  (see  FIG. 12 ). Depending on the extent of bone fracture and the supporting strength needed, two supporting member assemblies  61  may be implanted in a bilateral manner (see  FIG. 13  and  FIG. 14 ) to overcome such drawbacks of the conventional one-size implants as potential injury to the surrounding nerves and inadequate support. 
     In summary of the above, the present invention provides a supporting member that is configured as a micro-unit and whose small size allows not only implantation into a bone or between two connected bones, but also connection with other such members in the bone or between the connected bones so as to form a supporting member assembly, making possible a minimally invasive, small-incision surgical operation. In addition, the invention provides an introducer that can make and gradually enlarge a hole into a bone to enable the placement of a working cannula into the hole; a reamer for moving or pulling out bone debris; a tamper for restoring a fractured bone and pushing a previously implanted supporting member; and a template plug that can be used to introduce a supporting member into a bone or between two connected bones, connect this supporting member to its immediate predecessor in a sliding manner, and fasten the two supporting members together vertically, before the template plug is removed from the supporting members. The invention further provides a supporting member assembly that is formed by sequentially implanting and connecting a plurality of supporting members into a bone or between two connected bones so as to push outward the end plate(s) to be treated and thereby expand the fractured collapsed bone(s). This supporting member assembly is an improvement over the one-size implants used in the conventional implantation techniques on the grounds that an existing one-size implant cannot “be a single micro-unit before implantation into or between a subject&#39;s bones and connect with other similar micro-units sequentially implanted into or between the bones to form a larger yet complete block”. Furthermore, unlike the traditional one-size implants, the supporting member assembly of the invention will not rupture the affected bone structure (e.g., a pedicle) or injure the surrounding nerves (e.g., the spinal cord or spinal nerves), blood vessels (e.g., the abdominal aorta or the vertebral arteries), or other important tissues (e.g., the ureters) during implantation, or provide inadequate support due to an expediently smaller-than-required size. 
     The above is the detailed description of the present invention. However, the above is merely the preferred embodiment of the present invention and cannot be the limitation to the implement scope of the present invention, which means the variation and modification according to the present invention may still fall into the scope of the invention.