WO2019073046A1

WO2019073046A1 - Instrument for connecting a correction rod to a bone screw

Info

Publication number: WO2019073046A1
Application number: PCT/EP2018/077908
Authority: WO
Inventors: Frank Heuer
Original assignee: Silony Medical International AG
Priority date: 2017-10-13
Filing date: 2018-10-12
Publication date: 2019-04-18
Also published as: DE102017123906A1; WO2019073048A1; DE102017123907A1; DE102017123906B4

Abstract

The invention relates to an instrument (2) for connecting a correction rod (4) to a bone screw (6), particularly a pedicle screw, comprising an outer first housing part (18) having an approximately half-shell-shaped section (20), forming a first staple leg (22), and an approximately half-shell-shaped outer second housing part (24) forming a second staple leg (26) which is connected to the first staple leg (22) in an articulated manner by means of a pivot joint (28) such that it can pivot about a pivoting axis (58) extending orthogonally to the axial longitudinal direction (A), said instrument also comprising an adjusting part (30) and a rod pressure part (32). The second staple leg (26) can be actuated by finger pressure on the proximal end (70) thereof by the operating surgeon in a release position, and the pivot joint (28) is formed such that the two staple legs (22, 26) comprise joint regions (38, 40) that engage in each other in the form of a puzzle.

Description

Title: Instrument for connecting a correction rod to a bone screw

description

The invention relates to an instrument for connecting a correction rod with a bone screw, in particular a pedicle screw, with an axial longitudinal direction, a radial direction and a circumferential direction, with an outer first housing part, which has an approximately half-shell-shaped portion forming a first clip leg, and with an approximately half-shell-shaped outer second housing part, which forms a second clip leg, which extends on the first clip leg via a pivot joint about an orthogonal to the axial longitudinal direction Swivel axis is pivotally hinged, and with a the outer housing parts axially passing through and thus inner adjustment part, wherein a proximal end of the adjustment of the outside of the housing parts is manually actuated, and with a rod pressure member which is axially applied against the correction rod and with the

Setting member is axially coupled, but is rotatable relative to the adjusting member about the axial longitudinal direction, so that rotational movements of the adjusting member not on the

Bar pressure member are transmitted, and wherein the

Clamp legs surround the rod pressure member shell-shaped and receive longitudinally displaceable and each having a distal end portion, with which they engage the bone screw, and wherein the second clip leg through

Finger pressure on its proximal end by the using surgeon in the release position is actuated.

Such an instrument is typically referred to as

Reduction Instrument referred, since hereby a

Correction rod, which should usually connect several bone screws, especially pedicle screws, with respect to a respective bone screw in the vom

Surgeons intended manner and positioned at the

Bone screw is fixed. The bone screw has a shaft which can be introduced into the bone and a so-called fork head, which generally has two limbs, which forms a groove for receiving the correction rod. In the clevis then a fastener, in particular a grub screw, and optionally other components, in particular a pressure piece is inserted to the correction rod to fix after positioning against the clevis or the bone screw. Usually, the clevis is brought into a desired orientation with respect to the shaft, before the components finally

permanently fixed against each other.

An instrument mentioned at the outset is known, for example, from EP 2 792 325 A1. The present invention is based on the object, the pivot joint, which the first and the second

Clamp leg pivotally interconnects,

to further form that available space transverse to the axial direction can be used even better.

This object is achieved according to the invention in an instrument of the type mentioned by the fact that the pivot joint is formed by the fact that the two clip legs have puzzle-like intermeshing joint areas. - The interlocking hinge areas are therefore not by two in the direction of the pivot axis together

bordering joint plates with a connecting these

Pivot pin formed, but the interlocking hinge portions extend in a plane. The

interlocking hinge areas have this

on the one hand, a tongue-shaped projection and, on the other hand, a recess substantially complementary thereto for receiving the tongue-shaped projection. It is, as in interlocking puzzle pieces, a in the Extension plane acting rear handle formed so that the interlocking joint areas do not accidentally solve. In this way, the extension of the pivot joint in the direction of the pivot axis of the at least double wall thickness of the joint areas can be reduced in known instruments except for

Wall thickness of one of the joint areas, which represents a significant gain of usable space that can be used elsewhere.

In the instrument in question is transmitted by the axial coupling between the adjusting part and rod pressure part an axial adjusting movement of the setting on the bar pressure member, which then the correction rod and the bone screw in their relative to each other

intended mounting position forces. To adjust the setting part for this, various mechanical mechanisms could be used. It proves to be advantageous if for this purpose in the first housing part proximal to the approximately half-shell-shaped portion, a female threaded portion is provided and the adjusting part has a male thread at a portion and thus in the female threaded portion at the outer first housing part can be screwed. In this embodiment, therefore, the female threaded portion of the first

Housing part formed, which is in this area

preferably not only bowl-shaped, but in

Continuous circumferential direction, that is sleeve-shaped. The puzzle-like interlocking hinge areas are preferably of wall areas of the respective

Clamp legs formed. So it's the one

Clamp leg a tongue-shaped projection formed by a wall portion of the staple leg, and on the other staple leg to this projection is substantially complementary recess bounded by a wall portion of this staple leg. It should be noted that the orientation of the projection and the recess preferably but not necessarily in the

Oriented circumferential direction of the instrument. The

The projection and the complementary recess may also be inclined in the distal or proximal direction. The orientation of the inventively designed

Swivel joint is not mandatory. The

Pivot axis may in this case in the direction of receiving the bone screw for the correction rod, ie in the direction of the correction rod, or orthogonal thereto, as in WO 2016/150920 AI.

As already indicated above, can by the

inventive design of the pivot joint a

Reduction of space can be achieved. It proves to be advantageous if a radial wall thickness or radial extent of the pivot joint is less than the sum of wall thicknesses of the puzzle-like interlocking joint regions of the clip legs. In particular, it proves to be particularly advantageous if the radial wall thickness or radial extent of the pivot joint at most is great as the wall thickness of one of the puzzle-like interlocking joint areas of the clip legs.

The projection in question and the complementary recess of the interlocking joint areas could by additional approaches or components in the

Be formed staples legs. In contrast, it proves to be advantageous if a tongue-shaped projection of a wall portion of the

Staple leg is formed and if on the other

Clamp leg a to the projection substantially complementary recess of a wall portion of the

Clamp leg is limited. This opens up a simple manufacture and reliability of the staple legs or the pivot joint between the staple legs.

For constructive production of the respective recess in the one clip leg, it proves to be advantageous if this recess is formed or delimited by two web portions projecting from one edge of the one clip leg and to be strung together, which then surround the tongue-shaped projection when the pivot joint is formed.

It also proves to be particularly advantageous if one of the land areas or both land areas one

Stop limit for the pivoting of the two

Clamp legs against each other form. According to a preferred embodiment of the invention it is further provided that the puzzle-like

interlocking joint areas of the two

Staple leg in the direction of the pivot axis of the

Staple legs are inserted into each other. This means that the clip legs are each made separately from each other and then their joint areas in

Direction of the pivot axis are joined together, as a puzzle piece is used orthogonal to the other puzzle piece in this section.

In development of this idea, it proves to be advantageous that the puzzle-like interlocking joint areas by a securing element in this

Mounting situation against detachment are secured. This fuse element is in an advantageous manner

Spring element. It can continue in an advantageous manner

be formed part-ring or U-shaped and be pushed or clipped on the clip legs transversely to the axial longitudinal direction. This can at a

Partial ring training this partial ring shape in

Circumferential direction an angle of more than 180 °,

preferably of at least 190 °, in particular of

at least 200 ° and more preferably at least 240 °.

Next, it proves to be advantageous if the

Securing element in turn is held captive in a securing position on the staple legs, which can be achieved by the above measures. In a further embodiment of the above thoughts, it proves to be advantageous if the securing element in a substantially circumferentially extending recess or groove on the one or both clip legs

is included.

In a further preferred embodiment, it proves to be advantageous if the securing element still performs a more extensive function. It is then proposed that the securing element is a spring element and

at the same time biases the two clip legs such that their distal end areas pivot toward one another. One between the two mutually pivotable

Clamping legs acting restoring force is exercised by the aforementioned spring element according to this further proposal. This has the advantage that no further additional spring element between the two clip legs must be provided.

For this purpose, it proves to be further advantageous if the securing element at least in the axial longitudinal direction play in the securing position to the

Staple legs is kept captive.

The basic inventive concept of the present

Registration, namely the formation of a pivot joint through puzzle-like interlocking joint areas, can prove to be advantageous in other than Repositionsinstrumenteen. The subject of the invention is therefore also considered an instrument for forming a Access channel to a bone anchor, in particular a bone screw, having an axial longitudinal direction, a radial direction and a circumferential direction, with an outer first housing part, which has an approximately half-shell-shaped portion which forms a first staple leg, and with an approximately

half-shell-shaped outer second housing part, which forms a second clip leg, which runs on the first clip leg via a pivot joint about an orthogonal to the axial longitudinal direction

Swivel axis is hinged pivotally, and wherein the

Clip legs each have a distal end portion

with which they engage the bone anchor, and wherein the second staple leg by finger pressure on its proximal end by the using surgeon in

Release position is actuated, and wherein the

Swivel joint is formed by the two

Staple legs puzzle-like interlocking

Have joint areas. Such an instrument can be used, for example, in minimally invasive surgery,

especially spinal surgery, find use.

Further details, features and advantages of the invention will become apparent from the appended claims and from the drawings and the following

Description of a preferred embodiment of the

Invention. In the drawing shows:

Figure 1 is a perspective view of

Instrument according to the invention in the fortified Condition on a bone screw with indicated correction rod in a first operating position;

Figure 2 is a perspective view of

Instrument according to the invention in the fortified

Condition on a bone screw with indicated correction rod in a second operating position;

Figure 3 is a perspective view of

inventive instrument and the

Bone screw according to FIG

not yet coupled state;

Figure 4 components of the invention

Instruments comprising i.a. a first and second clip legs;

Figure 5a is a side view of the components of Figure 4 in the joined state;

Figure 5b, a pivot joint of the clip legs as

Detail of Figure 5a;

Figure 6a is another perspective view of the

inventive instrument of Figure 1;

FIG. 6b shows internal components of the instrument

Figure 6a, namely an adjustment and a

Bar pressure part; FIG. 6c shows the instrument according to FIG. 6a without setting part and bar pressure part;

FIGS. 7

a) to c) is a longitudinal sectional view, a plan view and a detailed view of the instrument of Figure 1 to illustrate the drive connection

between setting part and outside

Housing part in an intervention situation of the

External thread of the adjusting part;

FIGS. 8

between setting part and outside

Housing part in a non-engagement situation of the external thread of the adjustment and

Figures 9

a) to c) different views of another

Embodiment of an instrument according to the invention.

Figures 1-8 show a plurality of views of a first embodiment of an instrument 2 according to the invention for connecting a correction rod 4 with a

Bone screw 6. The bone screw 6 is an example of a so-called pedicle screw for spinal surgery, with a threaded shaft 8, the has at its proximal end a head 10, which in turn in the case exemplified polyaxially pivotable in a two leg 12 having

Clevis 14 is added. The legs 12 of the

Clevis 14 have radially outwardly reachable areas 16 for gripping the clevis by means of the instrument 2. FIG. 4 illustrates an axial longitudinal direction A, a radial direction R and a circumferential direction U for this purpose. The instrument according to the invention is a so-called reduction instrument for

Positioning the correction rod 4 in the clevis 14 of the bone screw 6. The instrument 2 according to the invention comprises a first outer housing part 18, which has a first approximately half-shell-shaped portion 20 which forms a first staple leg 22, and a second outer housing part 24, the second staple leg 26 forms. The first and the second clip legs 22, 26 are pivotally connected to each other via a pivot joint 28 in a manner to be described in more detail. Furthermore, the instrument 2 comprises an adjusting part 30 shown separately in FIGS

cooperating bar pressure part 32.

The setting part 30 has, in the example and preferred illustrated case, an external thread 34 with which it can be screwed in relation to the first outer housing part 18 in a manner still to be described in detail. This results in an axial adjustment of the adjusting member 30 relative to the outer housing parts 18 and 24 at the same time. The adjusting member 30 is connected to the bar pressure member 32nd axially coupled, but rotatable relative thereto, so that a longitudinal adjustment of the adjusting member 30 on the

Rod member 32 is transmitted, so that the rod pressure member 32 with distal end portions 36, the correction rod 4 in its intended mounting position on the

Bone screw 6 can bring. The rod pressure member 32 is longitudinally displaceable between the two housing parts 18, 24 and staple legs 22, 26, however, rotationally fixed

recorded.

Subsequently, the preferred trained rotary joint 28 between the first outer housing part 18 and

first clip leg 22 and second outer housing part 24 and second clip leg 26 described, with reference to Figures 4, 5a, 5b reference will be made. The pivot joint 28 is preferably formed in that the two clip legs 22, 26 have puzzle-like articulated areas 38, 40. They are formed by respective wall regions 42, 44 of the clip legs 22, 26. The hinge portions 38, 40 include a

tongue-shaped projection 46, for example in the first clip leg 22, and a complementary thereto

Recess 48 in the other clip leg 26. In the example shown, the recess 48 of two projecting from an edge 50 of the second clip leg 26 and the projection 46 around each striving web portions 51, 52 is limited. The free ends of these web portions 51, 52 at the same time form a

Stop limit 54, 56 for the pivotability of the clip legs 22, 26 to each other. The two clip legs 22, 26 are preferably prefabricated and then joined together by the

respective projection 46 and the respective complementary recess 48 in the direction of a pivot axis 58 of the

Swivel joint 28 are positioned side by side and then inserted into each other in the direction of the pivot axis 58 like puzzle pieces. To the clip legs 22, 26 around a securing element 60 is provided in the form of a spring element 62, which is clipped onto the joined clip legs. The securing element 60 itself is part-ring-shaped and held captive in the mounting situation illustrated in FIGS. 5a, 5b. For this purpose, the clip legs 22, 26 has a circumferentially extending groove 64 which is wider in the axial direction A than the securing element 60. In addition, the securing element 60 has a radially inwardly projecting projection 66 which in a recess 68 in the clip leg 26th intervenes. Due to the game lag in the axial

When the clip legs 22, 26 are pivoted by finger pressure onto a proximal section 70 of the second clip leg 26 into the position shown in FIG. 3, the distal end sections 72 open, longitudinal direction A as shown in FIG. 74, the staple leg at the same time by the securing element 60 or

Spring element 62 a restoring force between the

Staple legs 22, 26 is generated, which tries to pivot the distal end portions 72, 74 toward each other again. But it would also be possible for the Provision of separate spring means can be used. By the above-described operation, the instrument 2 is opened and can be releasably fixed to the hintergreifbaren areas 16 of the clevis 14 of the bone screw 6.

Due to the preferred design of the pivot joint 28, the radial space of the pivot joint on the radial wall thickness of the wall portions 42, 44 are limited, which is a significant advantage of the preferred embodiment

is seen.

The coupling of the setting part 30 and the bar pressure part 32 shown in FIG. 6b are designed in accordance with DE 10 2015 205 362 A, so that reference is hereby made to this.

The following is the preferred functional connection

between the adjusting part 30 and the outside

Housing component of the instrument 2 described with reference to Figures 4, 7 and 8.

In the first housing part 18, an internally threaded portion 90 is provided proximal to the approximately half-shell-shaped portion 20, which is not formed directly by the first housing part 18, but on a transversely adjustable to the axial longitudinal support body 92nd

is trained. The internal thread portion 90 is also not continuous in the circumferential direction U, but it is only in a relatively small circumferential angle segment

educated. The carrier body 92 is preferably formed sleeve-shaped and further included in the exemplary and preferred case in a guide body 94. In the case illustrated by way of example, this guide body 94 is designed such that it is arranged radially outside the first housing part 18. It can be set with respect to the first housing part 18 immovable. He has in the example shown two spaced apart and in the circumferential direction U

extended flange portions 96 which extend around the first housing part 18 around. Between these

Flange portions 96 is formed in the axial longitudinal direction extending bearing portion 98. Between the inside of the bearing portion 98 and an outer side 100 of the support body 92 are exemplified two

Compression spring 102 supported, which press the carrier body 92 radially inward in the position shown in the figures and in particular in Figure 7. As can be seen in detail from FIGS. 7 a and c, the carrier body 92 projects with its internally threaded portion 90 into the clear opening 104 of the first housing part 18. The adjusting member 30 is in this position with its external thread 34 in the

Internal thread section 90 can be screwed. It also rotates with respect to the non-rotatably received between the housing parts bar pressure member 32 and moves it in the distal direction or in the opposite proximal direction.

It can best be seen from FIG. 4 that the first

Housing body 18 in the region of the support body 92 and the guide body 94 is not formed closed in the circumferential direction U, but is designed to be open, that the carrier body 92 with its internal thread portion 90 can pass radially inward into engagement with the external thread 34 of the setting part 30. The carrier body 92 has, diametrically opposite the female threaded portion 90, a manual operating portion 108 in the form of a key having an ergonomically shaped depressor trough 110. By finger pressure on this actuation region 108, the entire carrier body 92 together with the internally threaded portion 90 against the bias of the compression spring means 102 in the direction of arrow 112 in the in Figures 8a to c

displaced shown further operating position. It can be seen from FIG. 8c that the internally threaded portion 90 of the carrier body 92 projects outwardly of the clear opening 104 and thus out of engagement with the external thread 34 of the housing

Setting part 30 passes, so that the adjusting member 30 in the axial longitudinal direction A with respect to the housing parts 18, 24 is displaceable. As a result, a quick release function can be realized. A significant advantage of this

The above-described embodiment further consists in the fact that also through this radial space can be saved. It can best be seen from FIG. 8c that in this way the nominal diameter of the external thread 34 of the adjusting part 30 can be extended to the inside diameter of the clear cross-sectional opening 104 of the housing part. This in turn allows a large inner diameter Di of the

Adjustment part 30, for the supply of more

Instruments, especially screwdrivers, is available. With reference to Figures 6b and 7 preferred dimensions are explained below. It proves to be advantageous that a nominal diameter (Dnenn) of the external thread 34 of the adjusting member 30 corresponds to almost an inner diameter (Di) of the first outer housing part 18.

It also proves to be advantageous that a

Outer diameter (Dal) of a rotational coupling portion between the rod pressing member 32 and the adjusting member 30 is larger than an outer diameter (Da2) of one proximal thereto

subsequent portion of the adjusting member and larger than a core diameter (core) of the external thread 34 of the adjusting member 30. Furthermore, it proves to be advantageous that a

Outside diameter (Dal) of a rotational coupling portion between the rod pressing member 32 and the adjusting member 30 is between 0.95 and 1.05 times the nominal diameter of the external thread of the adjusting member.

Finally, FIGS. 9a to c show another one

Embodiment relating only to the quick release mechanism of the previous embodiment

different. Instead of an additional guide body for the support body 92 for the internal thread 90 here forms the first housing part 18 at the same time a guide body 94 'for the transversely displaceable support body 92nd

Claims

claims

Instrument (2) for connecting a correction rod (4) with a bone screw (6), in particular a pedicle screw, with an axial longitudinal direction (A), a radial direction (R) and a circumferential direction

(U), with an outer first housing part (18), which has an approximately half-shell-shaped portion

(20) forming a first clip leg (22) and having an approximately half shell outer second housing part (24) forming a second clip leg (26) which pivots about the first clip leg (22) via a pivot joint (28) an orthogonal to the axial longitudinal direction (A) extending pivot axis (58) is pivotally articulated, and with a the outer housing parts

(18,24) axially penetrating and thus inner adjusting part (30), wherein a proximal end of the

Adjustment (30) from outside the housing parts (18, 24) is manually operable, and with a

Stabdruckteil (32), which against the correction rod

(4) is axially applied and with the adjusting member (30) is axially coupled, but with respect to the adjusting part

(30) is rotatable about the axial longitudinal direction (A) so that rotational movements of the adjustment member (30) are not transmitted to the rod pressing member (32), and wherein the staple legs (22, 26) surround the rod pressing member (32) in a cup shape and longitudinally slidably receive and a respective distal end region (72, 74)

with which they attach to the bone screw (6) and wherein the second staple leg (26) is finger pressure on its proximal end (70) by the using surgeon in the release position

is actuated, characterized in that the pivot joint (28) is formed by the fact that the two clip legs (22, 26) like a puzzle

have interlocking hinge portions (38, 40)

Instrument according to claim 1, characterized in that in the first housing part (18) proximal to the approximately half-shell-shaped portion (20) a

Inside threaded portion (90) is provided, and that the adjusting member (30) at a portion

External thread (34) and thus in the

Internal threaded portion (90) in the outer first housing part (18) can be screwed.

Instrument according to claim 1 or 2, characterized

marked that the puzzle-like

interlocking hinge portions (38, 40) of wall portions (42, 44) of the respective clip legs (22, 26) are formed or limited.

Instrument according to claim 1, 2 or 3, characterized

characterized in that a radial wall thickness or radial extension of the pivot joint (28) is less than the sum of wall thicknesses of the puzzle-like interlocking hinge portions (38, 40) of the clip legs (22, 26).

5. Instrument according to claim 4, characterized in that the radial wall thickness or radial extension of the pivot joint (28) is at most as large as the wall thickness of one of the puzzle-like interlocking hinge portions (38, 40) of the clip legs (22, 26).

6. Instrument according to one or more of the preceding claims, characterized in that on the one clip leg (22) a tongue-shaped projection (46) by a wall portion (44) of the clip leg is formed and that on the other clip legs (26) one to the Projection (46) substantially complementary recess (48) of a wall portion (42) of the clip leg (26) is limited.

7. Instrument according to claim 6, characterized in that the recess (48) of two of an edge (50) of the one clip leg (26) projecting and to be pursued web portions (51, 52) is formed or limited, which then in training of the pivot joint (28) the tongue-shaped projection

(46) surrounded.

8. Instrument according to claim 7, characterized in that one of the web portions (51, 52) or both

Web areas a stop limit (54, 56) for the pivoting of the two clip legs (22, 26) against each other form.

9. Instrument according to one or more of the preceding claims, characterized in that the puzzle-like intermeshing hinge portions (38, 40) of the two clip legs (22, 26) in the direction of the pivot axis (58) of the clip legs are inserted into each other.

10. Instrument according to one or more of the preceding claims, characterized in that the

puzzle-like intermeshing hinge areas (38, 40) by a securing element (60) in this

Mounting situation against detachment are secured.

11. Instrument according to claim 10, characterized in that the securing element (60) is a spring element (62).

12. Instrument according to claim 10 or 11, characterized

characterized in that the securing element (60) is formed partially annular or U-shaped and transverse to the axial longitudinal direction of the staple legs (22, 26) can be pushed.

13. Instrument according to claim 10, 11 or 12, characterized

in that the securing element (60) is held captive in a securing position on the clip legs (22, 26).

14. Instrument according to claim 10, 11, 12 or 13, characterized in that the securing element (60) is received in a substantially circumferentially extending recess or groove (64) on the one or both clip legs.

15. Instrument according to one or more of claims 10-14, characterized in that the securing element (60) is a spring element (62) and at the same time biases the two clip legs (22,26) such that their distal end portions to pivot towards each other.

16. Instrument according to claim 15, characterized in that the securing element (60) at least in the axial longitudinal direction (A) play in a

Secured position on the staple legs (22, 26) is held captive.