ZA200601545B - Longitudinal support - Google Patents

Description

=~ 2005/01545

English translation of the specification of the Internatio nal Patent Application No.

PCT/CHO03/00605 “Longitudinal support” in the name of Mathys Medizinaltechnik

AG

Longi tudinal support 2022/PCT 4.9.2003

The invention concerns a longitudinal support element according to the preamble of patent claim 1, a longitudinal support to stabilise bones, particularly bodies of the vertebra according to patent claim 5 and a device to stabilise bones, particularly bodies of the vertebra, according to patent claim 14.

The current treatment of damaged or tumorous bodies of the vertebra comprises usually the implanting of a rigid longitudinal support, anchored on the bodies of the vertebra by bone anchoring means or a rigid b one plate. The purpose of these devices is to prevent, by means of the rigid implants, the movement of the bodies of the vertebra stabilised in this manner relative to one another and to promote the fusion of adjacent bodies of the vertebra.

A device to stabilise the bodies of the vertebra using a multi-segmented longi tudinal support that can be fixed in a desirable fo rm, is known from FR 2 796 828 Jammet. By using this, the longitudinal support, comprising a plurality of axial segments and intended for the stabilisation, can be joined with the head segments of the pedicle screws or pedicle hooks, which for the purpose of stab ilisation are screwed into the pedicle of the corresponding body of the vertebra, and can be adapted without using great force to suit the form specified by the positions of the pedicle screws. It is a disad vantage of this prior known devi ce, that the longitudinal support elements can bes fastened individually on the head segments of the pedicle screws or pedicle hooks and cannot be joined with one another, so that each longitudinal support ele ment has to be individually inse=rted and placed into the body of the patient, re presenting to the surgeon a tedious and time-consuming step of the operation.

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This is where the invention wants to provide reme dy. The object of the invention is to psroduce a longitudinal support element with an articulated socket, in the cavity of which a complementary articulated head of a further longitudinal support element can be elastically snapped in, so that a longitudinal support, comprising a plurality of longitudinal support elements, can be pre-assembled outside of the patient's body.

This objective is achieved by the invention with & longitudinal support element having the features of claim 1, with a longitudirmal support to stabilise bones, particu larly bodies of the vertebra, that has the features of claim 4 and with a device to stabilise bones, particularly bodies of the vertebra, that has the features of clairm 14.

The advantages achieved by the invention are basically that as a result of the longitu dinal support element according to the inverution + a lomgitudinal support, comprising a plurality of longitudinal support elements which can be joined with one another, can be pre-assembled, + the longitudinal support can be adapted in-situ to suit the desired geometry without using any force, + the intmplanting of the longitudinal support can be considerably simplified.

In the preferred embodiment the articulated socket can be made from a nickel- titaniurm alloy (Nitinol), wherein 45%<Ni<55%, 4526<Ti<55% and x + y = 100%.

Such aa material is biocompatible and highly elastic -

In another embodiment the articulated socket hass an external spherical convex construction, thus achieving the advantage of a polyaxially pivotable accom modation of the articulated socket in, for example, a bone anchoring means-= constructed as a tulip screw.

In yet another embodiment the first connectingg segment of the longitudinal support element comprises an outside thread.

The a dvantages of the longitudinal support ac=cording to the invention are basica lly that

. Co. 2 « a first longitudinal support element, having an articulated socket, can be polyaxially pivotably joined with a second longitu dinal support element having a complementary articulated head, and « the longitudinal support can be shaped to suit thes anatomy.

In a preferred embodiment the connection betwee n a first connecting segment of a first longitudinal support element and a first co nnecting segment of a second longitudinal support element can be axially lengt hened or shortened, so that a first longitudinal support element can be coaxially joined with a second longitudinal support element and the length of the longitudinal support segment formed by the two longitudinal support elements can be adjusted.

This longitudinally adjustable connection betwee-n the two longitudinal support elements can telescope or be realised as a screws joint. For this purpose the first connecting segment can be constructed as a coaxial shaft on the first longitudinal support element and the thread be constructed as an outside thread and the first connecting segment constructed as a sleeve on the second longitudinal support element, the sleeve comprising a central bore with an inside thread that complements the outside thread.

In a further embodiment the articulated head has a spherical convex design and the cavity of the articulated socket is complementary to it.

In another embodiment the articulated head and the articulated socket can be elastically snapped into one another. This will brimg the advantage, that a simple pre-assembly of a longitudinal support, compri sing a plurality of longitudinal support segments, is possible.

In yet another embodiment the longitudinal support comprises an end-piece with an articulated head that can be snapped into an articulated socket. This has the advantage that an articulated socket, provided at the end of the longitudinal support, will not be compressed when mounted in the receptacle on the head of a pedicle screw. The longitudinal support preferably comprises a second end-piece with an articulated socket.

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The device according to the invention to stabilise bodies of the vertebra essentially comprises a longitudinal support according to one of the above illustrated embodiment and

A) at least two bosne anchoring means each with a central axis, am anchoring segment each to fix the bone anchoring means on a bone, in particular on a body of the vertebra and a head segment each with means to accommodate the articulated socket, and

B) fixing means to fix the articulated sockets in the means to accommodate the articulated socket.

In a preferred embodiment the means to accommodate the articulated socket are constructed as a concave spherical recess, that complements the articulated socket.

In another embodi ment the fixing means comprise a tightening screw, that can be screwed into an inside thread in the head of the bone anchoring me=ans, so that an articulated socket can be secured in the bone anchoring meas using the fixing means.

In yet another em bodiment the fixing means comprise an elastically expandable clamp, that can be placed over the articulated socket and can be smapped onto the head segment of the bone fixing means, while after the assembly of the clamp the articulated socket is compressed by the clamp. This will bring with it the advantage, thmat due to the compressing of the second articulated part the articulation is locked between the two longitudinal support segments on the one hand and on the other hand the longitudinal support is fixed on this bone anchoring means.

The clamp has preferably a lug on each of its free end, that can be snapped onto the head segmen t of the bone anchoring means. For a better acceptance of the lugs notches, complementing the lugs, may be provided on the head segment.

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The invention and developments of the invention are explained below in detail based on the partly schematic illustrations of several embodiments. They show in:

Fig.1 - a side view of an embodiment of the longitudinal support aaccording to the invention, with type A and type B longitudinal support elesments provided alternating behind one another,

Fig.2a - a longitudinal section through an embodiment of the devi ce according to the invention,

Fig.2 b - a cross-section through the embodiment of the device according to the invention and illustrated in Fig.2a, and

Fig.3 - a cross-section through another embodiment of the devi ce according to the i nvention.

Fig.1 illustrates an embodiment of the longitudinal support 20 with type A and type B longitudinal support elements 7, 8 provided alternating bermind one another and with an end-piece 18, 21 at each end. The connecting segrments 9, 10, 12, 13 of both longitudinal support elements 7, 8 are so constructed, that a first connecting segment 9 of a first longitudinal support element 7 (tygpe A) forms with a second longitudinal support element 8 (type B) a coaxial conrmection, that can be adjusted only axially longitudinally, while a second connecting element 10 of a first longitudinal support element 7 (type A) with a second connecting element 13 of a second longitudinal support element 8 (type B) allows a polyaxially pivotable connection of the two longitudinal support elements 7, 8. In this case the first two connecting segments 9, 12 can be particularly joined by a threasd connection 42, in such a rmanner that the first longitudinal axis 23 of the lonagitudinal support element 7 (type A) and the second longitudinal axis 24 of the lormgitudinal support element 8 type B) are arranged coaxially. In this case the thread connection 42 is so constructed, that the first connecting segment 9 of the first longitudinal support element 7 (type A) comprises a shaft 31 with an outsicde thread 11 and the first connecting segment 12 of the second longitudinal swipport element 8

- 2005/0 1845 (type B) comprises a sleeve 32 with a central bosre 42 having an inside thread 34 that complements the outside thread 11. The construction of the threaded bore 42 could be constructed by interchanging the cornecting segments 9, 12.

The longitudinal support element 7 (type A) comprises two connecting segments 9, 10, which are coaxial with the first longitudinal axis 23 and are provided behind one another and at the ends a first and a secomd end 14, 15. In this conjunction the first connecting element 9 of the longitudin al support element 7 (type A) is constructed as a cylindrical shaft 31 with a thread 11. The second connecting segment 10 of the longitudinal support elerment 7 (type A) comprises an articulated socket 28 with a hollow spherical segment-like, coaxial cavity 30, said socket can be elastically deformed transversely to the first longitudinal axis 23, while said cavity at the second end 15 of the longitudinal support element 7 has an opening 16 that is concentric with the first longitudinal axis 23. An articulated head 29, which has a construction complermenting the cavity 30, can be introduced into the cavity 30 through the openirg 16, so that the articulated head 29 and the articulated socket 28 form a ball and socket joint. The two longitudinal support elements 7, 8 (types A and B), conrected in this manner, are then displaceable relative one another in such a marner, that the first and the second longitudinal axis 23, 24 can pivot relative one another about the centre of the articulate joint. Furthermore, the cavity 30 has a diameter D, that is greater than the diameter d of the opening 16, so that an articulated head 29, introduced into the cavity 30, is axially enclosed by more thara 180°. In addition, the articulated socket 28 is provided with four slots 22 which are parallel to the longitudinal axis 23 and pass through from the outside to the cavity 30 and allow a radial elastic deformation of the articulated socket 28.

The longitudinal support element 8 (type B) comprises also two connecting segments 12, 13 provided coaxially with its longitudinal axis 24 behind one 30» another, as well as a first and a second ewnd 25, 26 at its ends. The first connecting element 12 of the longitudinal support element 8 (type B) is constructed as a sleeve 32 that is coaxial wit h the second longitudinal axis 24 and has a central bore 33, while the central toore 33 is provided with an inside thread 34, that is complementary to the thread 11. The second connecting

Co . , element 13 of the longitudinal support element 8 (type B) is constructed as a spherical articulated head 29, that is complementary to thee articulated socket 28.

The first end-piece 18 has an analogous construction with the articulated head 29, while the second end-piece 21 has an analogous construction with the articulated socket 28. The two end-pieces 18, 21 allow to accommodate the articulated socket 28 and the articulated head 29, respectively, in, for example, a comme rcially available pedicle screw or pedicle hook with a spherical concave recess 36 (Fig.2).

In Figs_-2a and 2b a detail of an embodiment of the devic-e 1 to stabilise bodies of the vertebra with a longitudinal support 20 according to Fig.1 are illustrated with two bore anchoring means 3, connected by the longitudi nal support 20, while the bone anchoring means 3 are constructed in this case as pedicle screws. The longitudinal support 20 comprises several longitudinal su pport elements 7, 8 (type

A and type B) provided alternating behind one another, wherein in the detail illustrated here two longitudinal support elements 7 «type A) are articulately connected via their first connecting segments 9 with the first connecting segme nts 12 of two longitudinal support elements 8 (typwe B) and the longitudinal support element 7 (type A) is connected with the longitaudinal support element 8 (type B3) via its second connecting segment 10 in such a manner that it can be only axially displaceable. The articulated heads 29 of the second longitudinal support elements 8 (type B) are snapped into the articulated sockets 28 of the adjace=nt first longitudinal support elements 7 (type Ax). To connect the head segme=nts 6 of the bone anchoring means 3 with the articulated sockets 29, channels 50 are provided on the head segments 6, with channel axes 53 extending transversely to the central axis 3 of the bone anchoring means 3. The channels 50 pass through the head segments 6 of the bone anchoring means 3 transversely to the central axis 3 and are open to the free end 52 of the head segment 6. For a polyaxially pivotable mounting of the articulated sockets 28 in the chmannels 50, they have spherical recesses 36 at thee bottom of the channels 50, which complement the articulated sockets 28. The head segments 6 further comprise bores 55, penetrating from the free end 52, with inside threads 54. The fixing means 27 to fix the articulated sockets 28 are constructed in this case as oo . 8 tighatening screws 37, which can be screwed into t he inside thread 54 from the frees end 52 of the head segment 6, so that the articulated sockets 28, placed into the channels 50, together with the snapped-in articulated heads 29, can be fixed in ®he channels 50 by tightening the tightening screws 37. When fixing the articulated sockets 28, they are compressed transversely to the longitudinal axes 23 of the first longitudinal support elements 7 (type A), due to which the snapped- in Articulated heads 29 of the second longitudinal sumpport elements 8 (type B) are blo«cked in the articulated sockets 28.

The embodiment of the device 1 illustrated in Fig.3 differs from that illustrated in

Fig s.2a and 2b only by that the fixing means 27 is c onstructed as a clamp 38, the leg s 43 of which can be elastically expanded, so that he clamp 38 can be guided over the articulated socket 28 and can be snapped onto the head segment 6 of the= bone fixing means 3 by its elastic spring-back in such a manner, that after bei ng assembled the articulated socket 28 is compressed by the clamp 38. Thus the= articulated socket 28 is secured in the head segment 6 of the bone anchoring me=ans 3 first by virtue of the clamp 38 and, in addition, by compressing the articulated socket 28 the articulated head 29 snapped in the articulated socket 28 is Bocked in the head segment 6 of the bone anch oring means 3. To fasten the cla mp 38 on the head segment 6, the clamp 38 has at the free ends 39 of both legs 43 an inward directed lug 40, that can snap into the complementary notches 41 , arranged at the fixed end 51 of the head segmemt.

De=scription of the operation:

First of all the bone anchoring means 3, in particular the pedicle screws or pedicle ho oks are placed by the surgeon onto the pedicles of the bodies of the vertebra to be fixed. After this the longitudinal support elements 7, 8 (type A and type B) ares joined alternating together outside of the patiemt's body, until the longitudinal su pport 20 has the desired length and contains the desired number of joints. The as sembled longitudinal support 20 is then introducead into the patient's body by a mi nimally invasive incision and placed below the soft tissue surrounding the body of the vertebra to be fixed and bent at the articulatead joints until it has the desired sh ape and the articulated heads 29 are introdluced into the means 35 to accommodate the articulated heads 29 on the bone anchoring means 3.

Following this the fixing means 27 are pre-assembled on the head segments 6 of the bone anchoring means 3, i.e. not yet locked, so that the longitudinal support 20 can still be adjusted.

At this stage the shape o-f the longitudinal support 20, as well as the distances of the individual longitudinaal support elements 7, 8 are still flexibly adjustable.

As soon as the desired shape of the longitudinal support 20 is set, the fixing means 27 are locked and consequiently the entire fixing device is fixed.

Claims (20)

Patent claims

1. A longitudinal support element with a longitudinal axis, two coaxial connecting segments provided behind osne another, with a first end and a second end, wherein the first conmecting segment has a thread extending parallel to the longitudinal axiss, wherein A) on the second end of the longitudirmal support element the second connecting segment comprises a deformable articulated socket that is axially open and can be deformed transversely to the longitudinal axis, characterised in that B) the articulated socket comprises a hollow spherical segment-like cavity with a diameter of D with an Opening on the second end that is concentric with the longitudinal axis and has a diameter of d, while d < D.

2. A longitudinal support element according to claim 1, characterised in that the articulated socket is made from Nitinol.

3. A longitudinal support element according to claim 1 or 2, characterised in that the articulated socket has an external spherical convex construction.

4. A longitudinal support element accordi ng to any one of claims 1 to 3, characterised in that the first connecting element comprises an outside thread that is coaxial with the longitudiral axis.

5. A longitudinal support to stabilise bones, particularly bodies of the vertebra, with a longitudinal support element according to any one of claims 1 to 4, characterised in that it comprises at least a second longitudinal support element with a Longitudinal axis, and that this second longitudinal support element comprises a first connecting segment that can be connected with the first connecting segment of the longitudinal support element and a sescond connecting segment (13) with an articulated head (29) that is ceomplementary to the articulated socket. AMENDED SHEZETS

Cf WO 2005/023125 PCT/CH 2003/000605

6. A longitudinal support according to claim 5, characteris ed in that the connection between the first connecting segment of the first longitudinal support element and the first connecting segment of the s econd longitudinal support element can be axially | engthened or s hortened.

7. A longitudinal support according to claim 6, characteris-ed in that the connection between the first connecting segment of the first longitudinal support element and the first connecting e=lement of the s econd longitudinal support element can telescope.

8. A lo PCT/CH2003/000605ngitudinal support according to claim 6, characterised in that the connection between the first connecting segment of the first longitudinal support element and the first connecting element of the second longitudinal support element is a s crew connection.

9. .A longitudinal support according to any one of claims 5 to 8, characterised in that the articulated head has a spherical convex construction that is complementary to the cavity.

10. A longitudinal support according to any one of claims 5 to 9, characterised in that the articulated head and the articulated socket can be elastically snapped into one another.

11. A longitudinal support according to any one of claims 8 to 10, characterised in that a) the first connecting segment on the first longitudinal support element is constructed as a shaft and the thread is constructed as an outside thread, and b) the first connecting segment of the second longitudinal support element is constructed as a sleeve, that comprises a central bore with an inside thread that complements the outside th read. AMENDED SHEETS

4 WO 2005/023125 PCT/CH2003/000605

12. A longitudinal support according to any one of claims 5 to 11, characterised in that it comprises at least one end-piece with an articulated head.

13. A longitudinal support according to any one of claims 5 to 12, characterised in that it comprises at least a second end-piece with an articulated socket.

14. A device to stabilise bodies of the vertebra with a longitudinal support according to any one of claims 5 to 13, comprising A) at least two bone anchoring means each with a central axis, an anchoring segment each to fix the bone anchoring means on a bone, in particular on a body" of the vertebra and a head segment each with means to accommodate the articulated socket, and B) fixing means to fix the amticulated sockets in the means to accommodate the articulated socket.

15. A device according to claim 14, «characterised in that to accommodate the articulated socket the means comprise a concave spherical recess that complements the articulated socket.

16. A device according to claim 14 or 15, characterised in that the fixing means comprise a tightening screw, that can be screwed into an inside thread in the head of the bone anchoring means.

17. A device according to claim 14 or 15, characterised in that a) the fixing means comprise an elastically expandable clamp, that can be placed over the articu lated socket and can be snapped onto the head segment of the bonee fixing means, in such a manner that b) after the assembly the articulated socket is compressed by the clamp.

18. A device according to claim 17, characterised in that the clamp has a lug on each of its free end that can be snapped onto the head segment of the bone anchoring rneans. AMENDE.D SHEETS

19. A device according to claim 18, characterised in that the head segment comprises notches, complementing the lugs.

20. A longitudinal support element with a longitudinal axis, two coaxial connecting elements provided behind one another, with a first end and a second end, wherein the connecting segment has a thread extending parallel to the longitudinal axis, substantially as herein described and as illustrated in Figures 1 and 2 or Figures 1 and 3. AMENDED SHEETS