KR100861395B1 - Double jaws with an elastic closing action for distraction-compression apparatus - Google Patents

Abstract

The present invention provides a device for removable clamping of fastening elements 12, 13 in a surgical fixation or positioning device, which device comprises: (A) longitudinal axis 2, first end 14, and second end; (15) a circular or prismatic rod having a terminating first rod segment 19 adjacent the first end 14 and a terminating second rod segment 20 adjacent the second end 15 ( 1) and (B) a first pair of clamping jaws 4 which can be displaced on the first rod segment 19 coaxially with the longitudinal axis 2 and (C) a second rod coaxially with the longitudinal axis 2. A second pair of clamping jaws 5 which can be displaced on the segment 20, (D) the two pairs 4, 5 respectively having an internal clamping jaw 6, 7 and an end 14, 15. With two clamping jaws 6, 7, 8, 9 of each pair of clamping jaws 4, 5 having an external clamping jaw 8, 9 directed towards one another. 30, 31, 32), and (E) each of which is directed towards each other At least one clamping means (10, 11) for removable rigid clamping of the fastening means (12, 13) of the surgical fixation or positioning device between the clamping faces (29, 30, 31, 32) of (F) An elastic means 40 is arranged between the inner and outer jaws 6, 7, 8, 9 joining the inner and outer clamping jaws 6, 7, 8, 9.

Surgical fixtures, positioning devices, fastening elements, clamping, rods, elastic means.

Description

DOUBLE JAWS WITH AN ELASTIC CLOSING ACTION FOR DISTRACTION-COMPRESSION APPARATUS}

The invention relates to a device for removable clamping of a fastening element in a surgical fixation or positioning device according to the preamble of claim 1.

Double jaw connections for elements of external fasteners are known from German Utility Model No. 295 12 917 (Jaquet). This known hinged connector includes a positioning device of two pairs of clamping jaws made of an upper outer clamping jaw and an upper inner clamping jaw, and a lower inner clamping jaw and a lower outer clamping jaw. The four clamping jaws are arranged on the central clamping shaft. The coil spring is inserted between the pair of clamping jaws, ie between the inner clamping jaws so that the coil spring allows both inner clamping jaws to be spaced apart from each other and pressed against the outer clamping jaw. The clamping jaws continue to be held against each other by the locking against the influence of the resilient means. Between each pair of clamping jaws, a groove is provided on the clamping surface, and each groove is formed transversely in the clamping shaft passage respectively for the insertion connector or fastening rod of the external fastener. This passage opens outwards and applies an pressure against the influence of the elastic means to allow the insertion connector or fastening rod to be inserted into the opening of the clamping jaw of the associated passage. After snapping the insertion connector or the fastening rod into the passage, the hinged connector is held firmly by the operation of the elastic means before the hinged connector is locked to a limited extent.

A disadvantage of this known arrangement is that a coil spring is provided between the pairs of clamping jaws and this makes it inaccessible. In addition, these known devices do not have a constant spring force because they depend on the position of the nut. As a result, the coil spring is subjected to high fatigue.

To this end, the present invention provides a solution. The object of the present invention,

(A) Equipped with elastic elements for each pair of clamping jaws, allowing independent operation of both pairs of clamping jaws,

(B) has fewer components compared to those mentioned in this technical field for simple operation and removal,

(C) having a constant spring force (also without nut / screw actuation),

It is to provide a device for removable clamping of fastening elements such as rods, retractors, rings or bone screws.

This object of the invention is achieved by a device for removable clamping of a fastening element in a surgical fixation or positioning device having the features of claim 1.

In a preferred embodiment, the clamping jaw passes through it and has a bore coaxial with the longitudinal axis. The purpose of this bore is to receive the rod in such a way that the clamping jaws are displaced axially on the rod. In the bore of at least one clamping jaw of each pair of clamping jaws, the rod has a radial gap such that at least one clamping jaw of each pair of clamping jaws can be inclined from a position coaxial with the longitudinal axis of the rod.

The gap is achieved in the axial region of the clamping jaw, the rod having a diameter d, and the bore of at least one clamping jaw of each pair of clamping jaws has a diameter D, where D> d. It may be desirable. The ratio of (D-d) / d may be between 0.01 and 0.10.

In another embodiment, the rod has at least one reduction in the axial region of the clamping jaw, and the rod has a minimum thickness b in the reduction. In addition, the bore of at least one clamping jaw of each pair of clamping jaws has a diameter D and b <D. The at least one recess can be made like an annular groove, for example.

In an embodiment where the recess is formed on the clamping surface, the recess lies on opposite opposite sides of the two clamping jaws belonging to the pair of clamping jaws. This recessed groove is formed to receive the rod-like fastening means. The recess extends transversely and eccentrically with respect to the longitudinal axis of the rod. Preferably, each groove has an axis perpendicular to the longitudinal axis of the rod and having a distance A therefrom.

In another embodiment, the resilient means is arranged on the side of the clamping jaw on the opposite side of the groove corresponding to the longitudinal axis. The elastic means preferably has a predetermined distance from the longitudinal axis of the rod, and the distance between the central axis of the elastic means and the longitudinal axis of the rod is B.

In another embodiment, the resilient means is performed as a rod-like element having a central axis parallel to the longitudinal axis of the rod.

Preferably, the resilient means is made and used from a material having a non-linear stress strain diagram. It is advantageous for the elastic means to be made of a memory metal alloy, preferably nitinol, without a clamping influence on the basis of which it will be a memory influence. For this reason, the memory metal alloy may have a transition temperature higher than 50 °, preferably higher than 80 °. The transition temperature is typically higher than 100 ° and preferably higher than 120 °. Pseudoelastic materials are also suitable.

In particular, the elastic means can be made of a nickel-titanium alloy, with 45% <Ni <55%, 45% <Ti <55% and x + y = 100%. Such materials are especially biocompatible and have high elasticity.

Unlike the metallic material, the elastic means may be made of synthetic material, preferably polyetheretherketone (PEEK) or carbon fiber reinforced PEEK.

In another embodiment, the at least one clamping means is implemented as a threaded joint and it is preferred that the nut can be threaded to the rod via a screw. Instead of a nut, a bolt may be screwed into the bore threaded inside.

The second clamping means may be a head rigidly joined with a rod or a second threaded joint.

In another embodiment, the annular disc is disposed between the inner clamping jaws of both pairs of clamping jaws. According to an embodiment, the disc may be displaced on the rod coaxial with the longitudinal axis or may be integral with the rod. By means of a disk firmly bonded to the rod, the pair of clamping jaws can achieve separation between the first and second rod segments, and this operation can be independent.

The grooves are preferably cylindrical or prismatic, whereby an increased clamping effect can be applied on the rod-like fastening means. This causes the groove to surround the rod-like fastening element at an angle α> 180 ° when viewed in a cross section perpendicular to the axis of the groove.

In the unfixed state of the device, the rod-like fastening element is snapped into the groove transversely to the longitudinal axis of the device and the ratio B / between the minimum widths B of the groove on the opening perpendicular to the axis of the groove. The LW is preferably between 70% and 90% on the lateral surface of the clamping jaw for the inner width LW of the same opening.

DETAILED DESCRIPTION OF THE INVENTION The present invention and its refinements are described in detail with reference to partial schematics of several embodiments.

1 is a longitudinal sectional view of an embodiment of a device according to the invention.

2 is a longitudinal sectional view of another embodiment of a device according to the invention.

3a is a side view of an embodiment of the device according to the invention shown in FIG. 2.

3b is a front view of an embodiment of the device according to the invention shown in FIGS. 2 and 3a.

1 shows a rod 1 having a longitudinal axis 2 and two rod segments 19, 20, and a pair that can be axially displaced on each rod segment 19, 20. Clamping jaws 4, 5. Each pair of clamping jaws 4, 5 comprises an inner clamping jaw 6, 7 and an outer clamping jaw 8, 9. The clamping jaws 6, 7, 8, 9 have bores 16, 17 coaxial with the longitudinal axis, each pair being axially displaced between one of the rod segments 19, 20. The inner clamping jaws 6, 7 are adjacent with respect to the end faces 22, 23 perpendicular to the longitudinal axis 2 in the annular disk 37 which is rigidly arranged between the rod segments 19, 20. The outer clamping jaws 8, 9 can be pressed against the inner clamping jaws 6, 7 by the clamping means 10, 11. The clamping means 10, 11 are nuts 18 which are screwed onto both rod segments 19, 20 via screws 24 provided at these ends. The clamping jaws 6, 8 of the first pair of clamping jaws 4 and the clamping jaws 7, 9 of the second pair of clamping jaws are perpendicular to the longitudinal axis 2 and oppose each other. 31, 32). Between each pair of clamping surfaces 29, 30, 31, 32 belonging to one of the pairs of clamping jaws 4, 5, the rod-like fastening means 12 can be pushed perpendicular to the longitudinal axis and the clamping means ( Tightening 10, 11 locks the inner and outer clamping jaws 6, 7, 8 and 9 respectively.

In addition, recesses 25 are provided on the two opposing clamping faces 29, 30, 31, 32. The recess 25 extends perpendicular to the longitudinal axis 2 and has a predetermined distance therefrom. The cross section of the recess 25 is circular in this case, but may have a triangular shape. Between the two clamping jaws 6, 7, 8, 9 of each pair of clamping jaws 4, 5, the recess 25 opens toward the transverse face 28 of the clamping jaw 6. The grooves 33 and 34 are formed and have groove axes 35 and 36 perpendicular to the longitudinal axis 2 at a predetermined distance.

As shown in FIG. 2, the cross section perpendicular to the groove axes 35 and 36 has the shape of a one-sided flat circular surface with respect to both grooves 33 and 34, and the inner width LW of each groove 33 and 34. ) Is greater than the width B of the opening on the transverse face of the jaws 6, 7, 8, 9 located perpendicular to the associated groove axes 35, 36 of the corresponding grooves 33, 34.

By constituting the rod-like fastening means 12, 13, one pushes into the transverse grooves 33, 34 on the longitudinal axis 2 to prevent slippage from the grooves 33, 34 in the transverse direction on the longitudinal axis 2. Can be.

In addition, each pair of clamping jaws 4, 5 has elastic means in which both clamping jaws 6, 7, 8, 9 belonging to the pair of clamping jaws 4, 5 are thereby held at a predetermined axial distance from each other. And 40. The distance between the two clamping jaws 6, 7, 8, 9 belonging to the pair of clamping jaws 4, 5 is such that each pair of rod-like fastening means 12, 13 is transverse to the longitudinal axis 2. It is dimensioned to allow manual pushing between the adjacent clamping faces 29, 30, 31, 32 of the clamping jaws 4, 5. The rod-like fastening means 12, 13 are pushed in this manner, the clamping means 10, 11 are loosened, and then firmly between the clamping faces 29, 30, 31, 32 by the elastic means 40. Can be displaced parallel to the central axes 26, 27.

As the elastic means 40, two nitinol rods 41 have a predetermined distance from the rod 1 between the two clamping jaws 6, 7, 8, 9 of each pair of clamping jaws 4, 5. Is inserted from Nitinol rod 41 has a central axis 42 and is pressed into bore 43. In order to introduce the rod-like fastening means 12, 13 into the grooves 33, 34, the two clamping jaws 6, 7, 8, 9 of each pair of clamping jaws 4, 5 are recessed 25. ), The two clamping jaws (6, 7, 8, 9) of each pair of clamping jaws (4, 5) have elastic means (40) and the nitinol rod (41) Are pressed against each other on the side that is sexually deformed When the two clamping jaws 6, 7, 8, 9 of each pair of clamping jaws 4, 5 perform a deployable movement, each outer clamping jaw 8, 9 is coaxial with the longitudinal axis 2. It has a bore 17 whose diameter D is larger than the diameter d of the rod 1 in the axial region.

2, 3A and 3B illustrate an embodiment in which the following points are different from the embodiment shown in FIG. 1.

(a) only the first clamping means 10 is implemented as a threaded joint with a nut 18 which can be screwed onto the first end 14 of the rod 1 via the screw 24 and the second clamping The means 11 comprise a rigid head 60 on the second end 15 of the rod. As a result, the outer clamping jaw 9 of the second pair of clamping jaws 5 is axially seated on the head 60.

(b) No disc 37 is provided between the inner clamping jaws 6, 7 of the two pairs of clamping jaws 4, 5 (FIG. 1).

(c) The possibility of deploying the external clamping jaws 8, 9 of each pair of clamping jaws 4, 5 during the insertion of the rod-like fastening means 12, 13 is the axis of each clamping jaw 8, 9. By a reduction 50 on the rod 1 in the form of an annular groove in the directional region. The diameter d of the reduction part 50 is smaller than the diameter D of the bores 17 in the outer clamping jaws 8, 9.

By tightening the first clamping means 10, both pairs of clamping jaws 4, 5 can be pressed against the head 6 and the clamping jaws 6, 7 of each pair of clamping jaws 4, 5. The rod-like fastening means 12, 13 located between 8, 9 can be firmly fastened to the grooves 33, 34.

The rod-like fastening element 12 is also displaced into the groove 33 transversely to the longitudinal axis 2, with both clamping jaws 6, 8 adjacent the groove 33 having a maximum deployment of approximately 2 ° to 3 °. It develops at an angle β.

Claims (23)

A device for removable clamping of fastening means (12, 13) in a surgical fixation or positioning device, (A) Closed to the longitudinal axis 2, the first end 14, the second end 15, the first end rod segment 19, adjacent the first end 14, the second end 15. A cylindrical or prismatic rod 1 having a terminating second rod segment 20, (B) a first pair of clamping jaws 4 which can be displaced on the first rod segment 19 coaxially with the longitudinal axis 2, (C) a second pair of clamping jaws 5 which can be displaced on the second rod segment 20 coaxially with the longitudinal axis 2, (D) The first pair of clamping jaws 4 and the second pair of clamping jaws 5 respectively have an external clamping jaw 8 directed towards the inner clamping jaws 6, 7 and the ends 14, 15. 9, the inner clamping jaws 6 and 7 and the outer clamping jaws 8 and 9 for each of the first pair of clamping jaws 4 and the second pair of clamping jaws 5 Has two pairs of clamping faces 29, 30, 31, 32 oriented relative to each other, (E) at least one for removable rigid clamping of the fastening means 12, 13 of the surgical fixation or positioning device between two pairs of clamping faces 29, 30, 31, 32 each oriented with respect to each other; And clamping means (10, 11) of (F) An elastic means is arranged between the inner clamping jaws 6, 7 and the outer clamping jaws 8, 9 so as to connect the inner clamping jaws 6, 7 and the outer clamping jaws 8, 9. Connect, (G) The elasticity of the resilient means 40 is provided when the clamping means 10, 11 are loosened, so that each of the first pair of clamping jaws 4 and the second pair of clamping jaws 5 The rod-shaped fastening means 12, 13 inserted between the clamping surfaces 29 between the inner clamping jaws 6, 7 and the outer clamping jaws 8, 9 by the elasticity of the elastic means 40. , 30, 31, 32. 2. The inner clamping jaw (6, 7) and the outer clamping jaw (8, 9) are formed coaxially with the longitudinal axis (2) in order to pass therethrough and to accommodate the axial displacement of the rod (1). Having bores 16, 17, the rod 1 having the inner clamping jaws 6, 7 and the outer clamping of the first pair of clamping jaws 4 and the second pair of clamping jaws 5. And a radial gap in at least one of the bores (16, 17) formed in the jaw (8, 9). The clamping jaw of claim 1, wherein the rod 1 has a diameter d in the axial region of the inner clamping jaws 6, 7 and the outer clamping jaws 8, 9. And at least one of the bores 16, 17 formed in the inner clamping jaws 6, 7 and the outer clamping jaws 8, 9 of the second pair of clamping jaws 5. D), wherein the radial gap is due to the point D> d. 3. The rod (1) according to claim 2, wherein the rod (1) has at least one reduction part (50) in the axial region of the inner clamping jaws (6, 7) and the outer clamping jaws (8, 9). 1) has a thickness b in the reduction part 50, the inner clamping jaws 6, 7 and the first pair of clamping jaws 4 and the second pair of clamping jaws 5; At least one of said bores (16, 17) formed in the outer clamping jaw (8, 9) has a diameter (D), and the radial gap is b <D. 5. The clamping face according to claim 1, wherein the clamping faces 29, 30, 31, 32 of the inner clamping jaws 6, 7 and the outer clamping jaws 8, 9 have an inner clamping. Grooves in the first pair of clamping jaws 4 and the second pair of clamping jaws 5, with recesses 25 formed between the jaws 6, 7 and the outer clamping jaws 8, 9. (33, 34) characterized in that the transverse direction and eccentrically pass through the longitudinal axis (2) for receiving the rod-like fastening means (12, 13). 6. Device according to claim 5, characterized in that both grooves (33, 34) each have groove axes (35, 36) extending perpendicularly to the longitudinal axis (2) of the rod (1) and at a distance (A). . The inner clamping jaw (6, 7) and the outer clamping jaw (8) according to claim 5, wherein the resilient means (40) is on the side that corresponds to the longitudinal axis (2) and faces the grooves (33, 34). 9) arranged on the device. 5. The device according to claim 1, wherein the elastic means is a rod-like element parallel to the longitudinal axis. 6. 5. The device according to claim 1, wherein the resilient means is made of a material having a nonlinear stress-strain diagram. 6. 5. The device according to claim 1, wherein the resilient means is made of a memory metal alloy. 6. The elastic means 40 according to any one of the preceding claims, wherein the elastic means 40 is made of a nickel-titanium alloy, and 45% <Ni <55%, 45% <Ti <55% and x + y = 100% Device characterized in that. The apparatus of claim 10, wherein the memory metal alloy has a transition temperature of greater than 50 °. 13. The apparatus of claim 12, wherein the transition temperature is higher than 100 degrees. 5. The device according to claim 1, wherein the elastic means is made of synthetic material. 6. 5. The device according to claim 1, wherein the at least one clamping means comprises a screw connection. 6. Device according to claim 15, characterized in that the threaded connection comprises an outer screw (24) on the rod (1) and a nut (18) which is screwable to the outer screw (24). 5. The method according to claim 1, arranged between the first pair of clamping jaws 4 and the second pair of clamping jaws 5, between the inner clamping jaws 6, 7. Apparatus characterized in that it further comprises an annular disk (37) for separating. 18. The device according to claim 17, wherein the annular disk (37) can be axially displaced on the rod (1). 18. The device according to claim 17, wherein the annular disk (37) is arranged integrally with the rod (1) between the first rod segment (19) and the second rod segment (20). 6. Device according to claim 5, characterized in that the groove (33, 34) is prismatic. 6. The grooves (5) according to claim 5, wherein each groove (33, 34) has an inner width (LW) on the opening perpendicular to the groove axes (35, 36), the inner clamping jaws (6, 7) and the outer clamping jaws (8). 9) having a width B between them, wherein the ratio of B / LW is between 70% and 90%. 5. Apparatus according to any one of the preceding claims, characterized in that the elastic means (40) are made of pseudoelastic material. 4. The device of claim 3, wherein the ratio of (D-d) / d is between 0.01 and 0.10.

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