JP4024987B2 - Rod fixing tool - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides a nut guide that guides a nut that is screwed into the implant in order to fix the rod when the rod for bonding is fixed to an implant for a bone fastener that joins bones such as the thoracic vertebra and the lumbar vertebra. More particularly, the present invention relates to a nut guide that can accurately guide a nut with respect to a screw portion of an implant and can accurately hold the implant without rotating integrally with the nut.
[0002]
[Prior art]
For example, a pair of implants are screwed and embedded in separated vertebral bodies such as the thoracic vertebra and the lumbar vertebra, and both ends of the rod are engaged with U-shaped engagement grooves formed on the heads of the pair of implants. A screw member is screwed onto the head of each implant, and the rod is fastened and fixed to the implant by the screw member.
[0003]
When the screw member is screwed to the implant as described above, it is difficult to directly screw the screw member to the implant. Therefore, the lower end of the hollow tool is engaged with the head of the implant, and this tool is used. A screw member is dropped into the hollow portion, a tightening tool having a long shaft portion is inserted into the hollow portion of the tool, and the dropped screw member is screwed onto the top of the implant.
[0004]
[Problems to be solved by the invention]
As described above, in the conventional configuration in which the lower end portion of the hollow tool is engaged with the top portion of the implant and the screw member is dropped into the hollow portion of the tool to be positioned with respect to the screw portion formed on the top portion of the implant. Although the screw member is located at the top position of the implant, the axis of the screw part formed at the top of the implant and the axis of the screw member do not necessarily coincide with each other, and the axis is slightly inclined. There may be.
[0005]
When the screw member is tightened in such a state, a galling phenomenon may occur between the screw member and the screw portion, and the screw member may not be tightened smoothly. In some cases, the implant also rotates integrally when the screw member is tightened.
[0006]
[Means for Solving the Problems]
The present invention has been made in view of the above-described problems, and is a rod fixing tool used for a method of fixing a rod (5) to the head of an implant (1). A step (a) of engaging the tool engaging hole (7H) of the nut (7) with the small-diameter portion (31) of the shape and positioning the nut (7) on the column (29); A rod engaging recess (21) engageable with a rod (5) engaged with an engaging hole (19) capable of engaging the head and an engaging groove (1G) of the implant (1) at the distal end. And the shaft center of a nut guide (11) comprising a hollow shaft body (15) provided with a screw hole (23) into which the nut (7) can be screwed into the back of the engagement hole (19). The nut guide (11) is positioned so as to coincide with the axis of the support (29), and the screw hole 23) screwing and fixing the nut (7) into the nut (7), and the head of the implant (1) to engage the engagement hole (19) in the nut guide (11). The nut guide (11) is positioned, and the rod (5) engaged with the engagement groove (1G) of the implant (1) is engaged with the rod engagement recess (21) of the nut guide (11). And the step (c) of aligning the axial center of the implant (1) with the axial center of the nut guide (1), and from the base end side of the nut guide (11) to the nut guide (11) The shaft portion of the tool (33) is inserted into the provided through hole (13), and the engaging portion (35) formed at the tip of the shaft portion of the tool (33) is screwed into the screw hole (23). Engage with the fixed tool engaging hole (7H) of the nut (7). and d) rotating the tool (33) so as to tighten the nut (7) to move the nut (7) from the screw hole (23) to the internal thread of the implant (1), The column (29), the nut guide (11) and the tool for use in each step of the step (e) of tightening and fixing the rod (5) to the engagement groove (1G) of the implant (1) (33) .
[0008]
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIGS. 3 and 4, the implant 1 for osteosynthesis is used by being screwed and embedded in separated vertebral bodies 3 such as a thoracic vertebra and a lumbar vertebra, for example. Near the end of the connecting rod 5 is fixed to the top) by a nut 7.
[0009]
More specifically, the implant 1 includes a screw part 1S for screwing and embedding in the vertebral body 3, and a U-shaped engagement for holding and holding the rod 5 at the head (top). A mating groove 1G is provided, and an internal thread portion for screwing the nut 7 for tightening and fixing the rod 5 is provided inside the engaging groove 1G. The nut 7 has a configuration in which a male screw portion that is screwed into the female screw portion is formed on the outer peripheral surface, and a non-circular, for example, hexagonal tool engagement hole 7H is provided through the central portion.
[0010]
In the above configuration, a pair of implants 1 are screwed and embedded in the separated vertebral bodies 3, and the rods 5 are appropriately engaged with engagement grooves 1G formed in the heads of the pair of implants 1, and then the engagement grooves The rod 5 can be fastened and fixed to the engagement groove 1G of the implant 1 by screwing and tightening the nut 7 to the female thread portion formed in 1G.
[0011]
As described above, when the nut 7 is screwed into the female screw portion, the nut 7 is small and difficult to handle. Therefore, a nut guide that can easily screw the nut 7 into the female screw portion will be described. As shown in FIGS. 1 and 2, the nut guide 11 according to the present embodiment is composed of an elongated pipe-like hollow shaft body 15 having a through-hole 13, and the proximal end of the hollow shaft body 15 A grip portion 17 is provided on the part side.
[0012]
A distal end portion of the hollow shaft body 15 is provided with an engagement hole 19 capable of engaging the head of the implant 1, and the engagement hole 19 has a portion with respect to the hollow shaft body 15. An inverted U-shaped rod engaging recess 21 is formed which is engageable with the rod 5 being orthogonal. A screw hole 23 into which the nut 7 can be screwed and accommodated is formed at the back of the engagement hole 19, and the screw hole 23 is interposed between the screw hole 23 and the engagement hole 19. A nut guide hole 25 having a diameter substantially equal to the valley diameter is formed.
[0013]
In the configuration as described above, in order to screw the nut 7 into the female thread portion of the implant 1 using the nut guide 11, first, the nut 7 is screwed and fixed into the screw hole 23 of the nut guide 11. Thus, in order to screw and fix the nut 7 in the screw hole 23 of the nut guide 11, as shown in FIG. 1, for example, the nut 7 is attached to the non-circular small-diameter portion 31 of the support column 29 standing on the base 27. The nut 7 is positioned on the column 29 by engaging the tool engagement hole 7H. Then, the nut guide 11 is positioned so that the shaft center of the column 29 and the shaft center of the nut guide 11 coincide with each other, and the nut guide 11 is rotated so that the nut 7 is screwed and fixed into the screw hole 23 of the nut guide 11. To do. Alternatively, the non-circular engaging portion 35 provided at the tip of the shaft portion of the tool 33 for rotating the nut 7 is engaged with the tool engaging hole 7H of the nut 7, and the nut 7 is nut-guided using the tool 33. 11 screw holes 23.
[0014]
As described above, in a state where the nut 7 is screwed into the screw hole 23 of the nut guide 11, the head of the implant 1 is engaged in the engagement hole 19 in the nut guide 11 as indicated by an imaginary line in FIG. 3. When the nut guide 11 is positioned so that the rod 5 engages with the engagement groove 1G of the implant 1, the rod 5 engages with the rod engagement recess 21 of the nut guide 11. And the axial center of the implant 1 and the axial center of the nut guide 11 will be in the state which corresponds.
[0015]
When the shaft portion of the tool 33 is inserted into the through hole 13 from the base end side of the nut guide 11 in the state as described above, the engaging portion 35 formed at the tip of the shaft portion of the tool 33 is engaged with the tool of the nut 7. Engage with hole 7H. Therefore, when the tool 33 is rotated so as to tighten the nut 7, the nut 7 gradually comes out from the screw hole 23 of the nut guide 11, is guided by the nut guide hole 25, and is screwed into the female screw portion of the implant 1, thereby removing the rod 5. It is tightened and fixed in the engaging groove 1G.
[0016]
As described above, when the nut 7 is screwed into the female thread portion of the implant 1, the nut 7 is guided by the nut guide hole 25 and is screwed in such a state that the axis of the implant 1 and the axis of the nut 7 are aligned. Therefore, it can be smoothly screwed in without causing a galling phenomenon or the like. When the nut 7 is tightened, the rod 5 is engaged and held by the rod engaging recess 21 of the nut guide 11, so that the implant 1 does not rotate integrally and the nut 7 is securely and firmly attached. It can be tightened.
[0017]
【The invention's effect】
As will be understood from the above description, according to the present invention, when the nut is screwed into the female thread portion of the implant and the rod is pressed and fixed to the engagement groove of the implant, the screwing of the nut to the female screw portion is performed. It can be carried out smoothly without causing a galling phenomenon and the like, and the nut can be firmly tightened and fixed by holding the implant so as not to rotate integrally.
[Brief description of the drawings]
FIG. 1 is an explanatory front view of a nut guide according to an embodiment of the present invention.
FIG. 2 is an explanatory side view of the nut guide according to the embodiment of the present invention.
FIG. 3 is an explanatory view showing a state in which an implant is embedded in a vertebral body and connected by a rod, and a relationship between the implant and a nut guide.
FIG. 4 is an explanatory view showing a state in which an implant is embedded in a vertebral body and connected by a rod.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Implant 3 Vertebral body 5 Rod 7 Nut 11 Nut guide 15 Hollow shaft body 19 Engagement hole 21 Rod engagement recessed part 23 Screw hole 25 Nut guide hole

Claims (1)

A rod fixing tool used in a method of fixing the rod (5) to the head of the implant (1),
(A) The step of engaging the tool engagement hole (7H) of the nut (7) with the non-circular small diameter portion (31) of the support post (29) to position the nut (7) on the support post (29). ,
(B) Engageable rod engagement with the engagement hole (19) that can engage the head of the implant (1) and the rod (5) engaged with the engagement groove (1G) of the implant (1). A nut guide comprising a hollow shaft body (15) provided with a recess (21) at the tip and a screw hole (23) into which the nut (7) can be screwed into the back of the engagement hole (19). Positioning the nut guide (11) so that the axis of (11) coincides with the axis of the column (29), and screwing and fixing the nut (7) into the screw hole (23);
(C) positioning the nut guide (11) so that the head of the implant (1) is engaged in the engagement hole (19) in the nut guide (11), and engaging the implant (1); The rod (5) engaged with the groove (1G) is engaged with the rod engaging recess (21) of the nut guide (11), and the shaft center of the implant (1) and the nut guide (1) are engaged. The process of matching the axis of
(D) The shaft portion of the tool (33) is inserted into the through hole (13) provided in the nut guide (11) from the base end side of the nut guide (11), and the shaft portion of the tool (33) is inserted. Engaging the engagement portion (35) formed at the tip portion with the tool engagement hole (7H) of the nut (7) screwed and fixed into the screw hole (23);
(E) The tool (33) is rotated so as to tighten the nut (7), and the nut (7) is moved from the screw hole (23) to the female thread portion of the implant (1). 1) tightening and fixing the rod (5) in the engagement groove (1G);
A rod fixing tool comprising the support (29), the nut guide (11), and the tool (33) for use in each of the steps.

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