WO2006004367A1

WO2006004367A1 - Pedicle screw assembly and transconnector for coupling rods therein

Info

Publication number: WO2006004367A1
Application number: PCT/KR2005/002135
Authority: WO
Inventors: Min Sick Shin
Original assignee: G.S Medical Co., Ltd.
Priority date: 2004-07-07
Filing date: 2005-07-05
Publication date: 2006-01-12
Also published as: KR20060003653A; KR100612621B1

Abstract

The present invention relates to a pedicle screw assembly for more firmly fixing the bones, and to a transconnector for firmly coupling rods included in the assembly. The pedicle screw assembly is composed of a threaded fixing body 1, coupling member 2, an elongated rod 3, and a fixing screw 4. The threaded fixing body includes a screw portion 11 and a screw head 12 which are formed integrally with each other. The screw head is composed of a lower spherical portion 121, a straight cylindrical portion 122, an upper spherical portion 123, a recess 124, a recess upper portion 125, and a center portion 126.

Description

PEDICLE SCREW ASSEMBLY AND TRANSCONNECTOR FOR

COUPLING RODS THEREIN

Technical Field

[1] The present invention relates to an apparatus for fixing bones, such as the spine or the like, applicable to orthopedic subjects. More particularly, this invention relates to a pedicle screw assembly for more firmly fixing the bones, and to a transconnector for firmly coupling rods included in the assembly.

[2]

Background Art

[3] A pedicle screw assembly for fixing bones, such as the spine, etc., is widely applied for orthopedic subjects. The pedicle screw assembly is one of the orthopedic in¬ struments, in which a threaded fixing body is fixedly screwed at one end into the spine and securely fixed at the other end to the outside of the spine so as to recover the bent or deformed spine into its normal state.

[4] Much research is in progress on such an orthopedic pedicle screw assembly and various products have been developed.

[5] U.S. Patent No. 6,488,681B2 discloses such a pedicle screw assembly. Also, U.S.

Published Application No. 2002/0183748 Al based on the former Patent, discloses a method of recovering the spine using the pedicle screw assembly.

[6] In addition, Korean Patent Laid-Open No. 2002-73439 discloses a spine suturing assembly and a bone suturing system employing the assembly.

[7] This applicant has developed a bone fixation apparatus and has obtained a Korean

Utility Model Registration, whose registration number is 347155.

[8] Since the threaded fixing body of the pedicle screw assembly is inserted into the bone to recover the long-term deformed bone, the assembly must be firmly fixed. If, after the pedicle screw assembly has been applied to the subject, it is displaced due to a degradation of fixation, the deformed bone cannot be properly recovered. Therefore, the most important quality requirement for the pedicle screw assembly is the sufficient fixation. The present invention has been developed to meet this requirement, achieving the excellent fixability against the prior arts.

[9] Two or more pedicle screw assemblies are associatively used. When in use, rods included in the respective assemblies are interconnected to fix the deformed bones. In order to interconnect the rods, a device referred to as a transconnector is used.

[10] Korean Patent No. 307306 discloses an intra-spine fixation apparatus for fixing the respective rods in the pedicle screw assembly. [11] In addition, U.S. Patent 6,283,967Bl discloses a transconnector for coupling the rods in the pedicle screw assembly.

[12] A transconnector refers to a means for coupling the rods included in the pedicle screw assembly. However, the rods are not regularly arrayed at a given direction. Therefore, firmly coupling the rods having this positional deviation is one of the important requirements that the transconnector must meet. However, the disclosed prior arts only fix the rods by adjusting the distance between the rods in the state in which the rods are arrayed in parallel with each other. So, satisfactory coupling cannot be always expected. A transconnector according to the present invention has been developed to meet this requirement, which is capable of firmly coupling the rods even if there are insignificant deviations in the array of the rods.

[13]

Disclosure of Invention Technical Problem

[14] An object of the present invention is to provide a pedicle screw assembly which improves fixation for coupling between rods and a threaded fixing body inserted and fixed into the bones.

[15] Another object of the present invention is to provide a pedicle screw assembly which improves fixation for coupling, by making free the fixing position of a coupling member supporting a threaded fixing body inserted and fixed into the bones.

[16] Yet another object of the present invention is to provide a transconnector for firmly coupling the rods even if there are insignificant deviations in the array of the rods.

[17] Still another object of the present invention is to provide a transconnector in which a male member can freely rotate at the place where it is coupled with a female member, the male member freely rotating such that a straight condition formed with the female member can be deviated, and the male member or female member can adjust the distance between the rods individually.

[18] The above and other objects of the present invention can be achieved by the following descriptions.

[19]

Technical Solution

[20] An orthopedic pedicle screw assembly according to the present invention includes a threaded fixing body 1 having a screw portion 11 and a screw head 12 which are formed integrally with each other, a coupling member 2, an elongated rod 3, and a fixing screw 4. The inventive orthopedic pedicle screw assembly is characterized in that, the screw head includes a lower spherical portion 121, a straight cylindrical portion 122, an upper spherical portion 123, a recess 124 formed inwardly from the outer circumference of the upper end of the upper spherical portion, a recess upper portion 125, and a center portion 126, in that the lower spherical portion has a radius R around a center C distanced downward from a center point C, the upper spherical portion has a radius R around a center C distanced upward from the center point C, the recess upper portion 125 has centers C 3 , C 4 at the right and left sides of the center point C and radii R , R around the centers C , C , and the center portion has a radius R ^r 3 4 3 4 ^r 5 and a center C of which is identical to or positioned over the center point C, and in

5 that the centers C, C , C , C are located on a straight line, the centers C, C , C are also

1 2 5 3 4 located on a straight line, and the radii R , R , R , R are the same as one another. On the upper part of the screw head are formed three grooves 13 for a screwdriver.

[21] A transconnector 5 of the present invention is characterized in that it includes a female member 51, a male member 52, a bolt 53, and a nut 54, the female member having a clamping member 511 formed slantly at an angle of about 30° with respect to the female member for securely fixing the rod which is attached to the female member, and an oval hole 512 formed at one side of the female member, for receiving the bolt 53 therein to allow the bolt to move right and left, the male member having a clamping member 521 formed slantly at an angle of about 30° with respect to the male member for securely fixing the rod which is attached to the male member, and the bolt being formed with a through-hole 531 for inserting and fixing the male member thereto.

[22] In the transconnector, the bolt 53 can freely move within the limits of the longer diameter of the oval hole 512, the male member 52 can rotate in itself, and the male member and the female member can be cooperated with each other in such a manner as to be deformed at an arbitrary angle departed from a straight condition. Since the male member can be freely slid in the hole 531 of the bolt 53, the distance between the rods can be properly adjusted.

[23]

Advantageous Effects

[24] According to the pedicle screw assembly of the present invention, fixation for coupling is improved by making free the fixing position of a coupling member supporting a threaded fixing body inserted and fixed into the bones, and the inventive transconnector enables firm coupling of the rods even if there are insignificant deviations in the array of the rods.

[25]

Brief Description of the Drawings

[26] The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which: [27] FIG. 1 is a cross sectional view showing a pedicle screw assembly of the present invention;

[28] FIG. 2 is an exploded perspective view showing a pedicle screw assembly of the present invention;

[29] FIG. 3 is a plan view briefly showing a screw head 12 of a threaded fixing body 1;

[30] FIG. 4 is a cross sectional view briefly showing a screw head 12 of a threaded fixing body 1 ;

[31] FIG. 5 is a perspective view showing a transconnector for coupling rods associated in two pedicle screw assemblies;

[32] FIG. 6 is an exploded perspective view showing a transconnector of the present invention; and

[33] FIG. 7 is a cross sectional view showing a transconnector with the two rods coupled.

[34]

Mode for the Invention

[35] Hereinafter, the present invention will be described in detail with reference to the attached drawings.

[36] FIG. 1 is a cross section view briefly showing a pedicle screw assembly of the present invention, and FIG. 2 is an exploded perspective view briefly showing a pedicle screw assembly of the present invention.

[37] A pedicle screw assembly for orthopedics includes, as shown in FIGs. 1 and 2, a threaded fixing body 1, coupling member 2, a rod 3, and a fixing screw 4. The threaded fixing body is applied to a subject with it coupled to the coupling member. That is, the threaded fixing body is provided with a screw portion 11 and a screw head 12 which are formed integrally with each other, the screw head being assembled inside the coupling member to be able to freely swivel therein. Since the threaded fixing body swivels freely, after the threaded fixing body has been screwed and fixed to the subject's bone, the rod 3 can be fixed at a desired position. The threaded fixing body may be screwed in the subject's bone by means of a screwdriver. This is obvious to those who have ordinarily skills in the art to which the present invention pertains. After the threaded fixing body has been screwed and fixed to the bone, the rod 3 is penetrated through the coupling member such that it can be positioned over the screw head, and then the fixing screw 4 fixes the rod 3 from the upper inside of the coupling member.

[38] The present invention is directed to the threaded fixing body having the screw portion 11 and the screw head 12 which are formed integrally with each other. Of these, the present invention is especially related to the screw head. [39] FIG. 3 is a plan view briefly showing a screw head 12 of a threaded fixing body 1 in the pedicle screw assembly according to the present invention. On the upper part of the screw head are formed three grooves 13 for a screwdriver such that a screwdriver can screw the threaded fixing body into the bone or remove it from the bone. Of course, it is not necessary that the number of the grooves 13 is three. The number of the grooves 13 may be, for example, four to six.

[40] FIG. 4 is a cross section view briefly showing a screw head 12 of a threaded fixing body 1 according to the pedicle screw assembly.

[41] The screw head of the threaded fixing body is composed of a lower spherical portion 121, a straight cylindrical portion 122, an upper spherical portion 123, a recess

124 formed inwardly from the outer circumference of the upper end of the upper spherical portion 123, a recess upper portion 125, and a center portion 126. The lower spherical portion has a radius R around the center C distanced downward from a center point C, and the upper spherical portion has a radius R around the center C distanced upward from a center point C.

[42] The straight cylindrical portion 122 is formed between the lower spherical portion

121 and the upper spherical portion 123. It is preferable that a length (or height) of the straight cylindrical portion 122 is a little larger than the distance between the center C of the lower spherical portion 121 and the center C of the upper spherical portion 123. For example, supposing that the distance between the center C of the lower spherical portion 121 and the center C of the upper spherical portion 123 is about 0.33mm, it is preferable that the length of the straight cylindrical portion 122 is about 0.4mm. Of course, these numerical values may vary depending on the size of the threaded fixing body. This is easily done by those skilled in the art.

[43] The recess 124 is formed inwardly from the outer circumference of the upper end of the upper spherical portion 123 to have inwardly reduced radius. The recess upper portion 125 is an upper part of the recess 124. The recess upper portion 125 has centers C , C at the left and right sides of the center point C, respectively, and radii R , R

3 4 3 4 around the centers C 3 , C 4. It is preferable that, if the distance between the center C 1 of the lower spherical portion 121 and the center C of the upper spherical portion 123 is about 0.4mm, the distance between the centers C and C of the recess upper portion

125 is about 1.34mm. Of course, these numerical values may vary depending on the size of the threaded fixing body. This is easily done by those killed in the art.

[44] The center portion 126 is positioned over the recess upper portion 125. The center portion 126 has a radius R , and its center C is identical to or positioned over the center point C. Since the radius of the center portion 126 is decreased as the center C goes up, the curved surface of the center portion will become more convex.

[45] The centers C, C , C , C are located on a straight line along the vertical axis, and the centers C, C , C are also located in a straight line along the horizontal axis. The radii R , R , R , R are the same as one another, but the radius R is shorter than these radii R 1 , R 2 , R 3 , R 4.

[46] By providing the screw head of the threaded fixing body with the above structure, the coupling member can be more freely swivel around the screw head, so that the position of the coupling member is set freely. Further, since the fixation position of the coupling member can be freely selected, the fixability of the coupling member can be improved.

[47] The present invention also provides a transconnector for firmly coupling the rods employed in the pedicle screw assembly. The transconnector functions to couple the rods associated to the pedicle screw assembly. However, the rods are always not arrayed evenly in a given direction. Due to this array deviation, various difficulties have arisen.

[48] FIG. 5 is a perspective view showing a transconnector 5 for coupling the rods 3 associated in two pedicle screw assemblies 1, and FIG. 6 is an exploded perspective view showing a transconnector of the present invention.

[49] The transconnector includes a female member 51, a male member 52, a bolt 53, and a nut 54.

[50] The female member 51 has a clamping member 511 formed slantly at an angle of about 15° with respect to the female member for securely fixing the rod which is attached to the female member. Also, the female member 51 has an oval hole 512 formed at one side of the female member, for receiving the bolt 53 therein to allow the bolt to move right and left.

[51] The male member 52 has a clamping member 521 formed slantly at an angle of about 30° with respect to the male member for securely fixing the rod which is attached to the male member 52. The bolt is formed with a through-hole 531 for inserting and fixing the male member thereto. The male member is inserted into the through-hole 531 of the bolt 53, and then the bolt is inserted into the oval hole 512, and finally the nut 54 is tightened up.

[52] In the transconnector, since the bolt 53 can freely move within the limits of the longer diameter of the oval hole 512 and the male member 52 can rotate in itself, the male member and the female member can be cooperated with each other in such a manner as to be deformed at an arbitrary angle departed from a straight condition. Since the male member can be freely slid in the through-hole 531, the distance between the rods can be properly adjusted. Because the distance between the male member and the female member can be freely adjusted, the transconnector of the present invention can be conveniently used regardless of the distance between the rods 3. In addition, since the male member can rotate in itself and swivel centering around the bolt 3, it can firmly couple the rods at any case including the case where the rods are not parallel with each other. [53] FIG. 7 is a cross section view showing a transconnector with the two rods coupled.

After the rod 3 has been put in the end portion of the respective male member and female member, the clamping members 511, 521 are tightened to firmly clamp the rods. [54] As explained above, the present invention provides a pedicle screw assembly which secures fixation between the rods and the threaded fixing body inserted in the bones, and, by making free the fixing position of the coupling member fixing the threaded fixing body inserted in the bones. [55] The variations or modifications may be easily achieved by those who ordinarily skilled in the art. Such variations or modifications in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. [56]

Claims

[1] An orthopedic pedicle screw assembly comprising a threaded fixing body 1 having a screw portion 11 and a screw head 12 which are formed integrally with each other, a coupling member 2, an elongated rod 3, and a fixing screw 4, wherein the screw head includes a lower spherical portion 121, a straight cylindrical portion 122, an upper spherical portion 123, a recess 124 formed inwardly from the outer circumference of the upper end of the upper spherical portion, a recess upper portion 125, and a center portion 126; wherein the lower spherical portion has a radius R around a center C distanced downward from a center point C, the upper spherical portion has a radius R 2 around a center C 2 distanced upward from the center point C, the recess upper portion 125 has centers C , C at the right and left sides of the center point C and

3 4 radii R 3 , R 4 around the centers C 3 , C 4 , and the center ^r portion has a radius R 5 and a center C of which is identical to or positioned over the center point C; and wherein the centers C, C , C , C are located on a straight line, the centers C, C , C are also located on a straight line, and the radii R , R , R , R are the same as one another. On the upper part of the screw head are formed three grooves 13 for a screwdriver.

[2] The orthopedic pedicle screw assembly as defined in claim 1, wherein the upper part of the screw head are formed three to six grooves 13 for a screwdriver.