Polyaxial pedicle screw assembly

This application applies to U.S. Provisional Patent Application No. 60 / 548,543 filed on February 27, 2004, U.S. Provisional Patent Application No. 60 / 565,658 filed on April 2, 2004, and January 28, 2005. It claims priority under US Patent Application No. 11 / 045,908 filed in, the entire description of which is incorporated herein by reference.

Embodiments of the invention generally relate to medical devices and assemblies, and more specifically to orthopedic implant assemblies used in the field of surgical treatment of the cervical, thoracic, and lumbar spine.

Surgical procedures to treat spinal injuries are one of the most complex and challenging surgeries for both patients and surgeons. If there are various deformities, traumas, or vertebral fractures, the surgeon attaches a threaded device to the stalk of the spine and uses a semi-rigid rod to several (typically two or more). Attempts to "fuse" them with each other by connecting the vertebrae. However, due to the complexity of the human tissue, most surgeons are not aligned and have two or different heights in order to properly secure the stalk assembly to the patient's body. When placing the rods in more stalk-joining screws, they must be bent (notches are created, which reduces fatigue strength). However, this bending creates a notch, reduces fatigue strength, and wastes valuable surgical time before the surgeon can insert the rod.

Depending on the purpose, indication, and patient size of the spinal surgery, the surgeon must choose from different spinal devices with different sized rods before the surgery, which is more appropriate before the surgery. Waiting for the device to be sterilized often causes a delay in surgery. Some surgeons prefer uniaxial screws for rigidity, while others sacrifice rigidity for surgical freedom when placing screws. Therefore, there is a need for a device that accepts both theories. For example, during scoliosis surgery, prior art multi-axis devices typically fit in the required positions to convince the spinal column to the required reduction shape before the assembly is finally assembled. Can't.

Most prior art top-mounted multi-axis spine screws do not adequately address damage to assembly components due to the cantilever structure. Also, most multi-shaft screws generally do not provide sufficient freedom because the rods are supported very close to the top of the center of rotation of the osteosynthesis screw. Moreover, most top-mounted threading devices generally do not accept rods of different sizes. Therefore, a new, new that can overcome the limitations of traditional designs, thus improving the degree of freedom during surgery for surgeons and improving the prognosis for better, complete rehabilitation for patients. Further, an improved screw assembly for handle joining is required.

In view of the above circumstances, embodiments of the present invention include a screw head having a spherical end, a fixing component adapted to accept the spherical end of the screw head, a pin mounted on the screw head, and a screw head. Provided is an assembly having a blocker adapted to engage with. The screw head has a groove adapted to receive a vertical member. The fixing component has a concave socket adapted to accept the spherical end of the screw head. In one embodiment, the fixing component has a threaded portion formed to attach to the bone on the opposite side of the concave socket. Preferably, the pin engages the fixing part with the bottom of the vertical member. The blocker preferably fixes the top of the vertical member.

Preferably, the pin has an upper saddle portion and a lower tip portion. Further, according to one embodiment, the pin has a multi-part assembly. The pins may be formed as a single piece of coating or as two parts (top and bottom) using different materials, with the lower part having mechanical hardness on top. Higher materials are used. The first material is used for the screw head and the fixing part, and the lower tip of the pin is made of a material having higher material hardness and compressive strength than the first material. There is. The assembly further has a wear resistant ceramic coating on the surface of the screw head and the fixing part.

Preferably, the screw head is further separated by a groove and further has two upright ends arranged opposite each other, each of the opposing upright ends has an inner wall and an outer wall, the inner wall being a wall screw. In addition, the outer wall has a dent. Preferably, the blocker has a blocker thread formed on the outer peripheral surface of the blocker, and the blocker thread is sized to fit the wall screw and is formed to fit. The saddle above the pin has one or more grooves. The spherical end of the screw head may have a plurality of grooves terminating at the open portion of the tip of the spherical end. Further, the spherical end of the screw head preferably has a gap formed so as to receive the pin. The concave socket of the fixing component has an inner portion adapted to accept the spherical end of the screw head and an outer portion preferably formed with a recess or other shape. Preferably, the fixing part has either an osteosynthesis screw or a hook.

Another aspect of the present invention relates to a screw head having a male spherical end, a bone fixing part having a female recessed hemispherical socket for receiving the screw head, and a screw head and a bone fixing part. Provided is a handle fixing assembly having a fixing pin with a saddle adapted to be fitted and a blocker for engaging a screw head to fix a vertical member.

Yet another aspect of the present invention is to attach the screw head to the bone fixing part, to fix the bone fixing part to the bone, to fix the fixing pin to the screw head, and to engage the fixing pin with the bone fixing part. Includes fitting, inserting a vertical member into the screw head, and inserting a blocker into the screw head, the screw head has a male spherical end, and the bone fixation part receives the screw head. Provided is a method of assembling a handle fixing assembly having a female recessed hemispherical socket for acceptance. Preferably, the method further comprises applying a wear resistant ceramic coating to the screw head and the bone fixation component. The fixing component may be formed on either an osteosynthesis screw or a hook.

Embodiments of the present invention provide an implant device that includes a threaded assembly for stalk joints, which may be used anteriorly or posteriorly, and anterior lumbar intravertebral fusion, posterior lumbar intervertebral fusion. , Lateral lumbar fusion, corrective degenerative disc disease, adult / pediatric scoliosis as a fixation device, and can be used in surgery to achieve posterior cervical fusion.

Embodiments of the present invention provide a multiaxial spinal junction screw that, when required during surgery, can be stiffened as well as a uniaxial joint screw. Embodiments of the present invention also allow the surgeon to make a larger range of lateral movement than the prior art product by utilizing the space below the screw head to form a larger arc of rotation. In addition, the pin component with saddle gives you the freedom to use different ranges of spinal rods instead of fixed size rods.

These and other aspects of the embodiments of the present invention will be better appreciated and understood by consideration with the following description and accompanying drawings. However, although the following description shows preferred embodiments of the present invention and a number of specific details relating thereto, it is to be understood that they have been made by way of example, not to limit them. Within the scope of the embodiments of the present invention, it may be possible to make numerous changes and modifications without departing from its spirit, but the embodiments of the present invention include all such modifications.

Embodiments of the present invention will be better understood by the following detailed description made with reference to the drawings.

Details of embodiments and various features and advantages thereof of the present invention are illustrated in the accompanying drawings and more fully described with reference to the unrestricted embodiments described in detail below. .. It should be noted that the illustrated shapes are not necessarily drawn to the correct dimensions. Descriptions of well-known components and treatment techniques have been omitted to avoid unnecessarily obscuring embodiments of the present invention. The examples used herein are merely intended to facilitate understanding of the methods for carrying out embodiments of the present invention and to allow those skilled in the art to implement embodiments of the present invention. Therefore, the examples should not be construed as limiting the scope of embodiments of the present invention.

As mentioned above, overcoming the limitations of traditional designs, thus improving the degree of freedom during surgery for surgeons and improving the prognosis for better, complete rehabilitation for patients. There is a need for new and improved handle assembly threads that can be made. Embodiments of the present invention meet this requirement by providing an improved multiaxial spine joining threading device and method of assembly that can accept rods of varying diameters and withstand high fatigue strength. I will respond. Here, a preferred embodiment of the present invention is shown with reference to the figures, in particular FIGS. 1 to 16 in which similar reference numerals are made to consistently indicate corresponding shapes throughout the figure.

1 to 6 are an exploded view of the handle joining screw assembly 1 according to the first embodiment of the present invention. The screw assembly 1 engages with and accepts an osteosynthesis screw (fixing part) 10 having a thread portion 11 for engaging with a bone (not shown) and a screw head 20. It has a recessed female socket-like end 12.

At the time of implementation, the screw head 20 is first fitted into the osteosynthesis screw 10 as shown in FIG. The saddle pin 30 then fits into the base 25 below the screw head 20 that includes the groove 26 for receiving the saddle pin 30 (Figure 7 is most obvious), as shown in FIG. Will be done. When the pin 30 with saddle is fitted in its mounting position during the manufacturing process, the screw assembly 1 is ready for ultrasonic cleaning to remove all impurities, after which this manufacturing mode ( The pin 30 with saddle is shipped in the form of being connected to the screw head 20 connected to the osteosynthesis screw 10).

FIG. 7 shows an undercut 7 in which the female spherical pocket 12 of the osteosynthesis screw 10 makes the screw head 20 pivotal, but prevents the pin 30 with the expansion saddle from falling off once it is inserted. Indicates that it has. The thread portion 11 of the osteosynthesis screw 10 is a multi-threaded screw for speeding up insertion into the bone. The thread portion 11 has a taper in the diameter of the valley, but the outer diameter is cylindrical, and even in the case of spongy bone, a new "bite" is provided for each rotation, and the bone The depth of the screw when measured to the lower end of the joining screw 10 can be increased.

After the osteosynthesis screw 10 is inserted into the bone, the vertical member 50 and the blocker 40, which are implemented as rods, rods, etc., are inserted into the screw assembly 1 as shown in FIG. The screw head 20 can accept 5.5 mm rods as well as 6.0 mm rods, which is an advantage over prior art screw assemblies that are restricted to accepting only rods of a certain size. .. FIG. 5 shows the assembled state of the screw assembly 1 assembled in the straight uniaxial direction. The thread portion 11 of the osteosynthesis thread 10 is a double thread, which allows wide contact with the bone, but advances 4 mm per revolution. FIG. 6 shows a screw assembly 1 in which the axis of rotation is in an inclined position. The maximum tilt angle is 25 ° in one direction, but the central axis correction / movement distance of the vertical member 50 is 3.8 mm in one direction, which is large enough for most prior art screws. It's almost double.

FIG. 7 shows the fixing mechanism of the screw assembly 1. A two-stage fixing mechanism is shown here. The first position extends the screw head 20 into the osteosynthesis screw 10, and the second position is multi-axial by using a pin 30 with a saddle to secure the assembly 1. Permanently convert screw assembly 1 to single shaft screw assembly 1. As shown in FIG. 8, the screw assembly 1 is provided by simply feeding the longitudinal member 50 to the "home" or by using a tool (not shown) to secure the assembly 1 at the required angle. It can be permanently fixed in all required positions (within the 25 ° tolerance).

FIG. 9A shows the overall structure of the screw head 20. FIG. 9B is a front view of the screw head 20. FIG. 9 (C) is a cross-sectional view taken along the cutting line CC of FIG. 9 (D). FIG. 9 (E) is a cross-sectional view taken along the cutting line BB of FIG. 9 (F), and FIG. 9 (G) is a cross-sectional view taken along the cutting line AA of FIG. 9 (F). is there. Further, FIG. 9 (H) is an enlarged detailed view of the circled region A of FIG. 9 (G) showing the threaded inner portion 23 in more detail. As shown in FIGS. 9 (A) to 9 (H), the screw head 20 includes a male bulbous (spherical) end 21 for engaging the recessed female socket 12 of the osteosynthesis screw. The screw head 20 also has a pair of upright ends 22 opposite the male spherical end 21, where the upright end 22 has a threaded inner portion 23 for engaging the blocker 40. Have. Further, the screw head 20 includes a substantially U-shaped open interior 24 for receiving a pin 30 with a saddle and a vertical member 50. The male end 21 of the screw head 20 includes a plurality of (eg, four or more) grooves 6, which allow the male end 21 after the saddle pin 30 has penetrated. Expand into the female spherical pocket 12 of the osteosynthesis screw 10 at all angles.

Assemblies 1 impose an early limitation on the range of tilt angles of the screw head 20 by the bone or human body because the screw head 20 pivots within the female socket-like end 12 of the osteosynthesis screw 10. It can be inserted deep into the bone without receiving it. The screw head 20 further includes an external profile or notch 29 to aid in the use of surgical equipment during operation and assembly during surgery. These notches 29 allow the screw head 20 to be firmly and securely held and operated on one or both sides of the screw head 20 using a variety of instruments (not shown).

FIG. 10A is a perspective view of the bone fixing assembly according to the second embodiment of the present invention, and the bone fixing component is formed as a hook 60. The hook 60 is also illustrated further in FIG. 10 (B). The hook 60 includes a concave socket 12 having an inner portion 9 adapted to receive the spherical end 21 of the screw head 20 and an outer portion 8 provided with a recess. The hook 60 further includes a pair of arms 61, 62 connected by a connecting arm 64. The gap 63 separates the arms 61 and 62 from each other. The arms 61, 62 are formed to accept another member (not shown) for subsequent attachment to the bone.

Several embodiments of the saddle-mounted pin 30 are shown in FIGS. 11 (A) to 14. The pin 30 with saddle allows the proper seating area to be used for the vertical member 50 to avoid notching in a typical titanium vertical member 50 (titanium is very sensitive to notches). Let me. In addition, the pin 30 with saddle allows the use of vertical members 50 of multiple sizes in the same threaded assembly system 1, which is due to the notch generation factors mentioned above in systems using titanium. It's the first time. The saddle-mounted pin 30 is formed with a groove 32 passing through the center so that the upper portion (head) 131 of the saddle-mounted pin 30 can be expanded. The bottom surface 35 of the saddle-pin head 131 is tilted to accommodate the saddle-pin 30 when expanded to accommodate the larger size vertical member 50. The pin 30 with saddle first expands the male sphere 21 of the screw head 20 into the female spherical socket 12 of the osteosynthesis screw 10 to secure or begin to secure the screw assembly device 1 (ie). (Make sure that the male sphere 21 of the screw head 20 is fixed in the female spherical socket 12 of the osteosynthesis screw 10). The saddle pin 30 then generates a secondary anchoring force by "biting" into the female spherical socket 12 of the osteosynthesis screw 10 to avoid bending damage to the assembly 1.

11 (A) and 11 (B) show a first embodiment of the saddle-mounted pin 30. The saddle-mounted pin 30 as a whole has an upper 131 and a lower 132. The upper portion has a groove 32 formed from the lowermost region 33 of the upper 131 of the saddle-mounted pin 30 to the upper region 34 of the lower 132. A secondary fixing mechanism 36 may be formed at the bottom 132 of the saddle pin to achieve a more secure fixation of the saddle pin 30 when inserted into the screw head 20. The lower 132 of the saddle pin 30 is terminated with a tip 37 so that it can bite into the female socket 12 of the osteosynthesis screw 10. 12 (A) and 12 (B) show a second embodiment of the saddle-mounted pin 30. The difference between the first and second embodiments of the saddle-mounted pin 30 is that the saddle-mounted pin 131 of the second embodiment fits more snugly into the shape of the screw head 20 and the vertical member 50. To have two opposed, approximately flat upper ends 38 for such purposes.

13 and 14 show a third embodiment of the saddle-mounted pin 30. In particular, in the third embodiment, the saddle-attached pin 30 has two portions, preferably an upper 131 containing titanium and preferably a lower 132 ceramic. According to a third embodiment, the material of the lower 132 of the saddle pin 30 is preferably ceramic, which is the material used in the manufacture of the screw head 20 and the osteosynthesis screw 10.₆Al₄It has a hardness higher than the hardness of V and the compression resistance and the compression resistance.

As shown in FIG. 13, the upper 131 of the saddle-mounted pin 30 has a groove 32 of the seat portion 133 and a tapered inclined end portion 134. Preferably, the top 131 of the saddle pin 30 and the ceramic tip 132 are assembled last in the entire process. Specifically, the screw head 20 is fitted into the osteosynthesis screw 10. Next, the ceramic tip 132 is slid into the screw head 20, and finally the titanium saddle (top) 131 is press-fitted into the screw head 20, all placed in their respective positions and loosened. Placed in a dressed state.

Figure 14 is most obvious, where the lower 132 of the saddle pin terminates at a continuous, graduated wall 137,138 with an angle of inclination and also in the assembly of the screw head 20 and the osteosynthesis screw 10. It is terminated with a tip 37 for mounting. A characteristic of the material used for the tip 134 of the saddle pin is that the saddle pin 30 has a proper bending and penetration effect on the assembly of the screw head 20 and the osteosynthesis thread 10. It has characteristics that can prevent the attached pin 30 from being deformed. Examples of the types of materials used for the tip 37 of the saddle pin include Zyranox® and HIP Vitox®, both of which are Morgan Advanced in the United Kingdom. Sold by Morgan Advanced Ceramics.

The blocker 40 further shown in FIGS. 15 (A) to 15 (C) includes 41 buttress standard threads formed along the outer peripheral surface of the blocker 40. The blocker 40 helps secure the longitudinal member 50 within the screw head 40. The thread 41 of the blocker 40 is formed to engage the thread 23 of the thread head 20. Further, the blocker 40 helps prevent the screw head 20 from expanding by directing a larger reaction force in the vertical direction rather than the horizontal direction when torque is applied on the vertical member 50. The top 42 of the blocker 40 has a tightening shape 43, such as a hexagonal or square fixed shape, so that high torque can be applied when fixing the assembly 1. Also, the blocker 40 should have a rotatable saddle (not shown) to hold the vertical member 50 tangentially and help further prevent notches in the titanium alloy used to form the vertical member 50. It may be configured as. In addition, the blocker 40 measures the torque applied to the blocker 40 by being reliably and accurately associated with the blocker drive tool (not shown) to aid in the calculation of the twist and vertical positions of the blocker 40. May have a "synchronous" thread 41 to facilitate.

Another aspect of the invention is shown in the system diagram of FIG. 16, which includes the components related to the components shown in FIGS. 1-15 (C). FIG. 16 shows a method of assembling the handle joining screw assembly 1, in which the screw head 20 is attached to the bone fixing part 10 (200) and the bone fixing part 10 is attached to the bone (not shown). (210), Fix the pin 30 with saddle to the screw head 20 (220), engage the pin 30 with saddle with the bone fixing part 10 (230), and attach the vertical member 50 to the screw head 20. Includes inserting into the screw head 20 (240) and inserting the blocker 40 into the screw head 20 (250). As mentioned above, embodiments of the present invention allow the screw head to axially move up to 25 ° in all planes. Further, embodiments of the present invention allow for greater displacement of the longitudinal member 50 in the central axial direction (approximately 4 mm relative to prior art devices, which are generally limited to 2 mm).

Further, according to one aspect of the invention, the assembly 1 according to the invention can be used as a dynamic rod system for complementing an artificial intervertebral disc. According to this embodiment, the outer surface of the spherical connecting portion 21 of the screw head 20 and the spherical inner surface of the cup 12 of the osteosynthesis screw are coated with a wear-resistant ceramic coating. In this configuration, the saddle pin 30 does not bite into the osteosynthesis screw 10 and is in fact formed to be shorter than in some other embodiments. This system allows some movement instead of tight fixation, and by sharing the load with the artificial disc, it prevents excessive force from being applied to the artificial disc, thus extending the life of its function. .. For example, as used in embodiments of the present invention, this occurs as a result of ceramic coating. Therefore, the spherical connecting portion 21 of the screw head 20 and the spherical inner surface 12 of the bone fixing screw 10 have low friction and high wear resistance characteristics, thereby improving the overall characteristics of the screw assembly 1.

As shown in FIGS. 1 to 15 (C), the embodiment according to the present invention is formed so as to accept a screw head 20 having a spherical end portion 21 and a spherical end portion 21 of the screw head 20 as a whole. Provided is an assembly 1 having a fixing part 10, a pin 30 mounted on a screw head 20, and a blocker 40 adapted to engage the screw head 20. The screw head 20 has a groove 24 formed to receive the vertical member 50. The fixing component 10 has a recessed socket 12 formed to receive the spherical end 21 of the screw head 20. In a first embodiment, the fixing component 10 also has a threaded portion 11 that is located on the opposite side of the recessed socket 12 and is formed to attach to the bone. The pin 30 engages the fixing component 10 with the bottom 51 of the vertical member 50. The blocker 40 fixes the top 52 of the vertical member 50. The pin 30 has an upper saddle portion 131 and a lower tip portion 132.

Further, the pin 30 may have an assembly composed of a plurality of parts. The saddle 131 above the pin 30 has titanium and the tip 132 below the pin 30 has a ceramic material. Further, the lower tip portion 132 has a material having a higher mechanical hardness than the upper saddle portion 131. The screw head 20 and the fixing component 10 have a first material, and the lower tip 132 of the pin 30 has a material having a higher material hardness and compressive strength than the first material. Assembly 1 further has a wear-resistant ceramic coating (not shown) on the surfaces of the screw head 20 and the fixing component 10.

The screw head 20 further has two upright ends 22 separated by a groove 24 and placed opposite each other, each of which has an inner wall 27 and an outer wall 28, an inner wall 27. Has a wall screw 23, and the outer wall 28 has a recess (notch) 29. Blocker 40 has a blocker threads 41 formed on the outer peripheral surface 42 of the blocker 40, Bro Kka thread 41 is sized to mate the wall screw 23, and are to fit fits .. The saddle portion 131 above the pin 30 has a groove 32. The spherical end 21 of the thread 20 has a plurality of grooves 6 that terminate in the opening 4 of the tip 3 of the spherical end 21. Further, the spherical end 21 of the screw head 20 has a gap 19 formed so as to receive the pin 30. The recessed socket 12 of the fixing component 10 has an inner portion 9 adapted to receive the spherical end 21 of the screw head 20 and an outer portion 8 provided with a recess. The fixing part 10 is a threaded osteosynthesis thread 10 (as shown in FIGS. 1-8) or (FIGS. 10 (A) and 10 (B)) according to several embodiments of the present invention. Formed on any of the hooks 60 (as shown).

Embodiments of the present invention provide an implant device 1 comprising a stalk-joining screw assembly, which may be used anteriorly or posteriorly, anterior lumbar intraintra-fusion, posterior lumbar intra-lumbar fusion. It can be used for fusion, lateral lumbar fusion, orthodontic degenerative disc disease, adult / pediatric scoliosis as a fixation device, and surgery to achieve posterior cervical fusion.

In addition, embodiments of the present invention provide multiaxial spinal joint screws that, when required during surgery, can be stiffened as well as single shaft joint screws. Embodiments of the present invention also allow the surgeon to make a larger range of lateral movement than the prior art product by utilizing the space below the screw head to form a larger arc of rotation. In addition, the saddle-attached pin component 30 gives the freedom to use different ranges of spinal longitudinal members 50 rather than fixed-sized vertical members.

The above description of a particular embodiment discloses the overall features of the invention so completely that one can utilize current knowledge to ensure that it does not deviate from the inclusive concept. It is possible to readily modify and / or apply the various application methods of such particular embodiments, and therefore such applications and modifications are within the same meaning and scope as the disclosed embodiments. Should be and is intended to be included. The expressions and terms used herein are for explanatory purposes only and are not intended to be limiting. Therefore, although embodiments of the present invention have been described using preferred embodiments, those skilled in the art will appreciate that embodiments of the present invention can be modified and implemented within the spirit and scope of the appended claims. Will.

<figref num="1">It is an assembly exploded view of the screw assembly by embodiment of this invention.</figref><figref num="2">It is an assembly exploded view when the screw assembly by embodiment of this invention is in one stage of manufacturing.</figref><figref num="3">It is an assembly exploded view when the screw assembly by embodiment of this invention is in one stage of manufacturing.</figref><figref num="4">It is an assembly exploded view when the screw assembly by embodiment of this invention is in one stage of manufacturing.</figref><figref num="5">FIG. 5 is a perspective view when the screw assembly according to the embodiment of the present invention is completely assembled in a uniaxial position.</figref><figref num="6">It is a perspective view when the screw assembly by embodiment of this invention is completely assembled in a multi-axis position.</figref><figref num="7">It is a partial internal view when the screw assembly by embodiment of this invention is in a uniaxial position.</figref><figref num="8">It is a partial internal view when the screw assembly by embodiment of this invention is in a multi-axis position.</figref><figref num="9(A)">It is an independent view of the screw head by embodiment of this invention.</figref><figref num="9(B)">It is an independent view of the screw head by embodiment of this invention.</figref><figref num="9(C)">It is an independent view of the screw head by embodiment of this invention.</figref><figref num="9(D)">It is an independent view of the screw head by embodiment of this invention.</figref><figref num="9(E)">It is an independent view of the screw head by embodiment of this invention.</figref><figref num="9(F)">It is an independent view of the screw head by embodiment of this invention.</figref><figref num="9(G)">It is an independent view of the screw head by embodiment of this invention.</figref><figref num="9(H)">It is an independent view of the screw head by embodiment of this invention.</figref><figref num="10(A)">It is a perspective view of the assembly for bone fixation according to the 2nd Embodiment of this invention.</figref><figref num="10(B)">It is a detailed view of the hook of the bone fixation assembly shown in FIG. 10A according to the second embodiment of the present invention.</figref><figref num="11(A)">It is a detailed view of the pin with a saddle according to the 1st Embodiment of this invention.</figref><figref num="11(B)">It is a detailed view of the pin with a saddle according to the 1st Embodiment of this invention.</figref><figref num="12(A)">It is a detailed view of the pin with a saddle according to the 2nd Embodiment of this invention.</figref><figref num="12(B)">It is a detailed view of the pin with a saddle according to the 2nd Embodiment of this invention.</figref><figref num="13">It is a detailed view of the pin with a saddle according to the 3rd Embodiment of this invention.</figref><figref num="14">It is a detailed view of the pin with a saddle according to the 3rd Embodiment of this invention.</figref><figref num="15(A)">It is a detailed view of the blocker by one Embodiment of this invention.</figref><figref num="15(B)">It is a detailed view of the blocker by one Embodiment of this invention.</figref><figref num="15(C)">It is a detailed view of the blocker by one Embodiment of this invention.</figref><figref num="16">It is a flow chart which shows the preferable method by one Embodiment of this invention.</figref>