AU723894B2

AU723894B2 - Device for connection of a longitudinal rod with a pedicle screw

Info

Publication number: AU723894B2
Application number: AU30223/97A
Authority: AU
Inventors: Martin Hess; Fridolin Schlapfer
Original assignee: Synthes AG Chur
Current assignee: Synthes GmbH
Priority date: 1997-05-17
Filing date: 1997-06-16
Publication date: 2000-09-07
Anticipated expiration: 2017-06-16
Also published as: CN1254266A; EP0984730A1; DE19720782A1; HK1023710A1; DE19720782B4; ATE245947T1; ZA984064B; CA2289629C; JP4072201B2; DK0984730T3; AU3022397A; CA2289629A1; EP0984730B1; WO1998052482A1; ES2203807T3; CN1146365C; TW409048B; PT984730E; DE59710520D1; KR100509375B1

Abstract

The invention relates to a device for connecting a longitudinal support (1) to a bone anchorage element inside a spinal fixation system. This device consists of the following: a connecting segment (10, 30) having a central axis (4) and a through-opening (11) perpendicular to the central axis (4) for accommodating a longitudinal support (1); a tensioning-screw (23) which can be screwed in from the top end (28) of the connecting segment (10, 30); and a cylindrical hollow spring chuck (7) which is fitted coaxially in the connecting segment (10, 30) and has an open through-cavity (15) in the direction of the central axis (4) for elastically accommodating the head (5) of a bone anchorage element (30). The spring chuck (7) rests axially in the bore hole (6), in the direction of the bottom end (29) and near the bottom end (29) of the connecting segment (10, 30), without this impeding the radial mobility of the spring chuck (7). The device also comprises an insert (9) which can slide coaxially in the bore hole (6) of the connecting segment (10, 30). Said insert (9) has a bore hole (14) which is complementary to the outer surface (32) of the spring chuck (7).

Description

Device for the connection of a longitudinal rod with a pedicle screw The invention relates to a device for the connection of a longitudinal rod with a bone anchoring elementL From prior art pedicle screws to the fixation of vertebral column are known which show the advantage that the longitudinal rod may be inserted afterwards from to topside and the angle between pedicle screw and longitudinal rod is variably adjustable. Such pedicle screws are known among others from the patents EP-B 0 330 881 SHERMAN and EP-B 0 441 729 VIGNAUD. The disadvantage of these known 9 pedicle screws is that in spite of the degree of freedom between pedicle screw and longitudinal rod the latter must often be bent three dimensionally because of the anatomical conditions.

In case of other pedicle screws as for instance according to the DE-C 195 09 332 HARMS this disadvantage has been eliminated. Thanks to the spatial movability of the screw head respective to the screw part the longitudinal rod must be bent up to three t. pedicle screws per longitudinal rod only in one plane when mounted. The e* disadvantages of this known pedicle screw consist therein that the head part and the threaded part are not apt to be separated, the head part and the longitudinal rod are not apt to be fastened separately with respect to the threaded part, the reachable solidity is low because of the one-sided alignment of the longitudinal slots in the pressure element according to the DE-C 195 09 332 and it is difficult to remobilise the head part once it is fastened. The separability of the head part and the threaded part is a necessity to use different head parts according to the need and that the view is S not impeded through the head part during the screwing in of the screw part into the Sone. A separate fastening of the head part and the longitudinal rod and a high solidity 2 between head part and threaded part enable the application of distraction and compression without a loss of angle between the pedicle screw and the longitudinal rod and the conservation of the anatomical bending of the stabilized vertebral segments. Remobilization is especially important in case of explantation or new adjustment of the fixation.

A further such connection device is disclosed in WO 97/02786 ERRICO which allows in a simple manner to connect a pedicle screw or more generally a bone anchoring element with a longitudinal rod and which permits a great freedom regarding the angle between the two elements. In case of this known connection device the disadvantage consists therein that the spring chuck is part of the connection element and therefore consists of the same material impairing the choice and pairing of the material with the bone screw to improve S.the solidity.

*0 00i :The above discussion of documents, acts, materials, devices, articles and the like is included in the specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters formed part of the prior art base or were common general 20 knowledge in the field relevant to the present invention as it existed in Australia before the priority date of each claim of this application.

oleo According to the invention there is provided a device for the connection of a longitudinal rod with a bone anchoring element within a vertebral fixation 25 system, with: A) a connection part with an upper end, a lower end and a bore hole open towards the lower end having a central axis and a through hole running transversely to the central axis for the acceptance of a longitudinal rod; B) a tension means for the fixation of the bone anchoring element insertable from the upper end; and C) a radially and resiliently compressible spring chuck arranged within the connection part coaxial to the central axis with an upper end and a lower end ,which is provided in its inside with a cavity downwardly and in the direction of W:\chris odelete30223doc 2a the central axis open for the springlike acceptance of the head of a bone anchoring element; wherein D) the spring chuck is axially supported in the direction towards the lower end in the bore hole close to the lower end of the connection part without impeding the spring chuck in its radial movability therewith; and E) an insert is provided coaxially slidable in the bore hole of the connection part having a bore complementary to the outer surface of the spring chuck.

The invention therefore provides a device for the connection of a longitudinal rod with a pedicle screw having the following qualities: simple handling; screwing in the threaded part of the device even without the connection part; 15 possible later snap-on of the connection part; S- depending on the situation and the preference of the surgeon the free .choice of or combination of sidewardly open, upwardly open or closed connection parts. For instance an upwardly open connection part facilitates the insertion of the longitudinal rod while a sideward opening enables sideward 20 corrections and thanks to the possibility of the sideward removing of the connection part each pedicle screw may any time be fastened at the longitudinal rod or be removed again without the necessity of demounting the whole fixation system 25 The device according to the invention consists of a connection part accepting the longitudinal rod wherein a pedicle screw having a preferably spherical head may W:\chris\odelete\30223.doc afterwards be snapped-on and fastened. The connection part may be simply snapped-on in the desired number and variant onto the pedicle screws already implanted in the vertebral bodies so that a primary connection between longitudinal rod and pedicle screw is produced. Via the screw-in of the tension means into the fixation device the longitudinal rod is axially and rotatively fastened and simultaneously the device is fastened at a stable angle. Thereby the adjusting screw serving as a tension means presses on the longitudinal rod inserted in the device, this one presses on hollow cylinder which encompasses a hollow truncated cone which is alternatingly slotted and radially not fastened and which is itself compressed because of its conically shaped outer surface and wedging the preferably spherical head of the pedicle screw.

The device according to the invention such offers the advantage compared to the known devices that the pedicle screws are not only fastenable exactly perpendicularly to the longitudinal rod but allows an angle of up to 250 and because of the distance between the rotating center of the connection part and the axis of the longitudinal rod sideward deviations between longitudinal rod and pedicle screw may be compensated to a certain degree depending on the thickness of the longitudinal rod having an amount of between 4 to 10 mm. This qualities enable the application of longitudinal rods standardizedly prebent at the production site what causes serious difficulties by the mounting of conventional systems. A further advantage of a variant of the device according to the invention consists therein that depending on the embodiment of the hollow cylinder and the tension means respectively on the embodiment of the device the longitudinal rod and the preferably spherical head of the bone screw may be fastened separately.

The angular stability may be improved such that the head of the screw consists of a relatively hard material Titanium-Aluminium-Niobium-alloy) and the alternately slotted hollow truncated cone consists of a relatively soft material (e.g.

Titanium in its soft state).

Another possibility for the improvement of the angular stability consists therein to ,provide the preferably spherical head of the pedicle screw and/or the complementary cavity in the hollow truncated cone with a three dimensional structure e.g. in the shape of grooves.

Therewith the structure attached at the head of the screw consisting of a relatively hard material is pressed into the relatively soft material of the hollow truncated cone.

A change of the hardness of the materials is possible at least in the contact area, too. The difference of hardness may also be obtained through different cold forming or different crystallization of the same material and whereby the harder material is preferably highly trained steel 1.4441 and the soft material is hot treated steel 1.4441. Apart from this the difference of hardness may be obtained via surface treatment as coating or ion implantation.

To be able to screw in the pedicle screws into the bone they are provided at the spherical head preferably with a hexagon socket. If the head apt to be snapped-on is also drilled through optionally only the pedicle screw or the whole device may be screwed in at once. The latter has the advantage above all that at any time the device may be farther screwed in or screwed reverse to obtain a compensation in height.

A further embodiment of the invention consists therein that the angles of the cones of the spring chuck and of the insert compressing the spring chuck are different and form a not self-locking cone joining.

Other embodiments of the device according to the invention enable a subsequent insertion of the longitudinal rod from the side or from above. Through the screw in of the tension screw into the fixation device simultaneously the longitudinal rod is fastened axially and rotatively within the device and the device is fastened at a stable angle. Thereby the tension screw presses onto the longitudinal rod inserted in the device, this one presses onto the insert of the fixation device and this insert wedges the springable contact studs of the spring chuck via a preferably conical shaped inner surface and a corresponding likewise conical shaped outer surface of the spring chuck on the preferably spherical head of the pedicle screw.

The invention and further embodiments of the invention are discussed in more detail in the following section by means of the partially schematic representations of several embodiments.

The figures show: Fig. 1 a longitudinal cut through the connection part of a variant of the device according to the invention together with a longitudinal rod and a pedicle screw having a spherical head; Fig. 2 a perspectival representation of a variant of the device according to the invention; Fig. 3 a longitudinal cut through a modified device according to the invention having qualities as disclosed in fig. 1 but with the difference that the longitudinal rod is accepted via a sidewardly open channel in the connectionpart; Fig. 4 a longitudinal cut through a modified device according to the invention having qualities as disclosed in fig. 1 but with the difference that the longitudinal rod is accepted in an oval channel in the connection part; Fig. 5 a perspectival representation of a variant of the device according to the invention; Fig. 6 a perspectival representation of a further variant of the device according to the invention; Fig. 7 a perspectival representation of a further variant of the device according to the invention; Fig. 8 a perspectival representation of a further variant of the device according to the invention; and Fig. 9 a perspectival representation of a further variant of the device according to the invention.

The variant of the device according to the invention shown in fig. 1 essentially consists of a hollow cylindrical sleeve 10 which is provided with a channel 11 open towards the upper end 28 for the acceptance of the longitudinal rod 1. If required the channel 11 may also be open towards the side (fig. 3) or be formed as an oval bore hole (fig. At the lower end 29 of the sleeve 10 a preferably ring shaped channel 17 is provided wherein the flange 18 of the spring chuck 7 inserted in the bore hole 6 of the sleeve 10 is attachable. Such the spring chuck 7 is fastened against displacement along the central axis 4 of the sleeve 10 but not radially fastened. The spring chuck 7 is provided in its inside with a cavity 15 preferably shaped as a hollow sphere. Slots, wherefrom alternately a first number run into the upper base area 8 and another number run into the lower base area 13 of the spring chuck 7 enable a homogeneous expansion and compression of the spring chuck 7. Thanks to the radial freedom of the spring chuck 7 in the channel 17 the head 5 of the pedicle screw 2 may at any time be snapped into respectively out of the spring chuck 7 as long as the device is not fastened through tightening the tension screw 23. Outside the spring chuck 7 is shaped tapering conically towards its upper end 8. A hollow cylindrical insert 9 which is shaped complementarily conical to the cone at the spring chuck 7 at its lower end may slide within the bore hole 6 of the sleeve 10 and depending on the effect of force radially compress the spring chuck 7 via the conical joining 14 and therewith fasten the head 5 of the pedicle screw 2 being inside of the cavity 15. This connection is also loosenable what is facilitated through the attachment of a shoulder 16 in the insert 9. Longitudinal rod 1 and pedicle screw 2 are fastened by means of a tension screw 23 which is screwed in coaxially into an insert screw 21 being at the upper end 28 of the sleeve 10. The tension screw 23 presses when being tightened onto the longitudinal rod 1 which itself presses onto the insert 9 and therewith causes the closure of the spring chuck 7 through pushing into one another the cones 14.

The function of the insert screw consists therein to alter the thread 19 in the sleeve interrupted by the channel 11 into a closed thread wherein the tension screw 23 may run unhindered.

Since the through hole 11 according to the variant of the device according to the invention shown in fig. 1 is formed as a channel open at the upper end 28 of the sleeve 10 and thus the sleeve 10 is weakened at this part a swivel ring 22 is mounted that prevents the widening of the sleeve 10 when the tension screw 23 is tightened.

A further variant of the device according to the invention is shown in fig. 2.

The main difference between the embodiment according to fig. 1 and the one according to fig. 2 consists in the sideward dislocation of the channel 52 to the acceptance of the longitudinal rod 1 with respect to the bore hole 6 with the central axis 4. Thus it is possible to separately fasten the longitudinal rod 1 and the pedicle screw 2. From the lower end 29 of the connection part 30 a bone anchoring element may be inserted and be fastened analogously to the variant shown in fig. 1 by means of a spring chuck 7, an insert 9 and a tension means 50. Thereby the tension means 50 according to the variant shown in fig. 2 presses directly onto the insert 9. A channel 52 running transversely to the central axis 4 without contacting the bore hole 6 which may again be optionally sidewardly open, open towards the upper end 28 or be realized as a bore hole serves to the acceptance of the longitudinal rod 1.

The fastening of the longitudinal rod 1 is done by means of a separate screw 51.

The variant of the device according to the invention shown in fig. 3 differentiates from the variant shown in fig. 1 only by that means that the sidewardly open through opening 26 in the sleeve 10 accepts the longitudinal rod 1. The insert 9 is lower at this side, too. Thus, the longitudinal rod 1 may be subsequently inserted into the device as in case of the variant shown in fig. 1.

The variant of the device according to the invention shown in fig. 4 differentiates from the variant shown in fig. 1 only by that means that a closed oval through opening 27 within the sleeve 10 accepts the longitudinal rod 1.

The variant of the device according to the invention shown in fig. 5 differentiates from the variant shown in fig. 1 only by that means that a nut 42 is employed as a tension means 50. Thereto the sleeve 10 is provided with an exterior thread 41 IA1_whereon the nut 42 is screwed. When tightened the nut 42 presses onto the longitudinal rod 1 which itself presses onto the insert 9 by what means the spring chuck 7 is radially compressed and such the head 5 of the pedicle screw 2 and the longitudinal rod 1 are simultaneously fastened. A collapse of the channel 11 may be prevented by forming the thread 41 as buttress thread or by inserting a cylindrical element 47 into the bore hole 6.

In fig. 6 another variant of the device according to the invention is shown. This one differentiates from the variant shown in fig. 1 only by that means that a locking screw 43 serves as a tension means 50. The widening of the channel 11 is prevented by forming the thread 19 as a buttress thread.

Also the variant shown in fig. 7 differentiates from the variant shown in fig. 1 only through the construction of the tension means 50. The sleeve 10 is provided with an exterior thread 41 whereon the threaded sleeve 44 is screwed. The fastening of the longitudinal rod 1 and pedicle screw 2 happens by means of a tension screw 23 which is screwed into the threaded sleeve 44. The threaded sleeve 44 thus has the same function as the threaded insert 21 shown in fig. 1. Thanks to the threaded sleeve 44 inserted between the slotted thread 41 and the tension screw 23 the tension screw 23 runs within an uninterrupted thread.

Also another variant of the device according to the invention is shown in fig. 8. This variant accentuates by that means that the longitudinal rod 1 and the pedicle screw 2 may be fastened separately. To this purpose the sleeve 10 is provided at its upper end 28 with an interior thread 19 and an exterior thread 41. The channel 12 of the insert 9 is shaped such that the longitudinal rod 1 always lies on the lower edge of the through opening 11 during its fastening by means of the nut 42. When the tension screw 23 which presses directly on the insert 9 extending over the longitudinal rod 1 is tightened the spring chuck 7 is compressed thus fastening the pedicle screw 2.

Furthermore, the variant of the device according to the invention shown in fig. 9 enables a separate fastening of the longitudinal rod 1 and the pedicle screw 2. The trough opening 11 and the channel 12 are shaped such that the longitudinal rod 1 always lies on the channel 12 when fastened. The longitudinal rod 1 is fastened by '"means of a stud bolt 45 which is screwed into an interior thread 46 in the insert 9. The

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9 tension screw 23 serves to fasten the pedicle screw 2 whereby the tension screw 23 presses onto the insert 9 whereby this one is sliding over the spring chuck 7 thus radially compressing it. The widening of the channel 11 may also be prevented either by shaping the threads 19 and 46 as buttress threads or by using a sleeve 22 as shown in fig. 1.

Claims

1. Device for the connection of a longitudinal rod with a bone anchoring element within a vertebral fixation system, with: A) a connection part with an upper end, a lower end and a bore hole open towards the lower end having a central axis and a through hole running transversely to the central axis for the acceptance of a longitudinal rod; B) a tension means for the fixation of the bone anchoring element insertable from the upper end; and C) a radially and resiliently compressible spring chuck arranged within the connection part coaxial to the central axis with an upper end and a lower end which is provided in its inside with a cavity downwardly and in the direction of the central axis open for the springlike acceptance of the head of a bone anchoring element; wherein 15 D) the spring chuck is axially supported in the direction towards the lower end in the bore hole close to the lower end of the connection part without impeding the spring chuck in its radial movability therewith; and E) an insert is provided coaxially slidable in the bore hole of the connection part having a bore complementary to the outer surface of the spring chuck. Vl

2. Device according to claim 1, wherein the spring chuck is axially secured by means of a shoulder substantially in the shape of a ring groove running perpendicular to the central axis in the bore hole. S 25 3. Device according to one of the claims 1 or 2, wherein the connection part is a hollow cylindrical sleeve.

4. Device according to any one of claims 1 to 3, wherein the outer surface of the spring chuck is conically shaped. Device according to any one of claims 1 to 4, wherein the bore of the insert is shaped conically widening downwardly. W:\chrsnodeete\30223.doc 11

6. Device according to claim 5 insofar as dependent on claim 4, wherein the angle of the cone of the conically shaped outer surface of the spring chuck and the angle of the cone of the conically shaped bore in the insert are both greater than 100.

7. Device according to claim 6, wherein the angle of the cone of the conically shaped outer surface of the spring chuck and the angle of the cone of the conically shaped bore in the insert differ by less than

8. Device according to claim 6, wherein the angle of the cone of the conically shaped outer surface of the spring chuck and the angle of the cone of the conically shaped bore in the insert differ by more than

9. Device according to any one of claims 1 to 8, wherein an additional 15 through hole is provided in the connection part, being a sidewardly open :through hole serving for the acceptance of a longitudinal rod. Device according to any one of claims 1 to 8, wherein the throughhole in the connection part is oval shaped in section. S

11. Device according to any one of claims 1 to 10, wherein an interior thread in the connection part and an external thread of the insert are formed as buttress threads whereby the flat sides of the profile of the interior thread are directed towards the spring chuck and provide an angle to the central axis amounting between 870 and 930.

12. Device according to any one of claims 1 to 11 in combination with a pedicle screw serving as a bone anchoring element and having a threaded shaft, whereby the diameter of the threaded shaft conically tapers towards its terminal free section with a conical angle of 30

13. Device according to any one of claims 1 to 11, in combination with a bone anchoring element provided with an external thread below a substantially spherical head. W:Achrs\nodelete30223.doc 12

14. Device according to any one of claims 1 to 13, wherein the bore in the insert is convexly shaped in the area of the contact zone between the insert and the spring chuck.

15. Device according to any one of claims 1 to 14, wherein the spring chuck is convexly substantially spherically shaped in the area of the contact zone between the insert and the spring chuck.

16. Device according to any one of claims 1 to 15, wherein the insert has a shoulder in the upper area providing an anchoring means.

17. Device according to any one of claims 1 to 16, wherein the insert is circular cylindrical. 15 18. Device according to any one of claims 1 to 16, wherein the insert o provides a polygon like cross section transversely to the central axis. S19. Device according to any one of claims 1 to 18, wherein the insert is also open on the inside towards the top. S

20. Device according to any one of claims 1 to 19, wherein the insert provides a channel in the upper section.

21. Device according to any one of claims 1 to 20, wherein the bore hole and 25 the through hole are connected to each other.

22. Device according to any one of claims 1 to 21, wherein the tension means enables a simultaneous fixation of the longitudinal rod and the head of the bone anchoring element.

23. Device according to any one of claims 1 to 22, wherein the tension means is adapted to press directly on the longitudinal rod and not impede the motion of the longitudinal rod during the tensioning action through the through i hole in the connection part. W:chrsnodelete3O223.doc 13

24. Device according to claim 23, wherein the upper end of the connection part provides an external thread on which a nut is screwed to provide the tension means.

25. Device according to claim 23, wherein the upper end of the connection part provides an internal thread in which a locking screw is screwed to provide the tension means.

26. Device according to any one of claims 1 to 25, wherein the tension means is multipiece.

27. Device according to claim 23, wherein an insert screw with integrated tension screw serves as the tension means. Sl 15 28. Device according to claim 23, wherein a threaded sleeve with integrated tension screw serves as the tension means. 9 9 Device according to any one of claims 1 to 22, wherein the upper end of the connection part provides an external thread on which a nut is screwed for S: 20 the fixation of the longitudinal rod. *9S* °4 Device according to any one of claims 1 to 29, including a nut adapted to press directly on the longitudinal rod the device being constructed and arranged such that the motion of the longitudinal rod is not impeded during the tensioning ~25 action through the channel.

31. Device according to claim 30, wherein the upper end of the connection part provides an internal thread, and the insert is adapted to extend over the longitudinal rod so that in case of tightening the tension screw the insert is moved downwards without pressing on the longitudinal rod.

32. Device according to any one of claims 1 to 22, wherein the insert provides an internal thread topside. W:\dXChris\ odelete\30223.dC 14

33. Device according to claim 32, including a stud bolt adapted to press on the longitudinal rod, the device constructed and arranged such that the motion of the longitudinal rod is not impeded during the tensioning action through the through hole.

34. Device according to any one of claims 1 to 33, wherein the spring chuck is provided on its inside with a cavity having the form of a hollow sphere for the acceptance of a substantially spherical head of the bone anchoring element.

35. Device according to any one of claims I to 34, wherein the spring chuck provides at least four slots whereof a number run into the front side at the lower end.

36. Device according to any one of claims 1 to 34, wherein the spring chuck a I 15 provides at least four slots, a number of which run into the front side at the upper end.

37. Device according to any one of claims 1 to 34, wherein the spring chuck provides at least four slots which run alternately into the front side at the lower 20 end and into the front side at the upper end. 9aa°

38. Device according to any one of claims 1 to 23, 25 to 27 and 32 to 37, aincluding a swivel ring at the upper end of the connection part to impede spreading of the connection part.

39. Device according to claim 38, wherein the swivel ring may be attached to the connection part by means of an insert screw. Device according to any one of claims 1 to 39, wherein the connection part through hole is provided by a channel open towards the upper end, threads at the upper end of the connection part and complementary threads of the respective tension means are provided as buttress threads, whereby the flat sides of the thread profile are directed so that in case of tightening the tension W:\chdrisodelete'30223.doc means no spreading of the sleeve appears, the flat side of said profile providing an angle of between 870 and 930 to the central axis.

41. Device according to any one of claims 1 to 21 and 33 to 37, wherein a channel in the connection part running transverse to the central axis and dislocated beside the bore hole serves for the acceptance of the longitudinal rod and a screw serves for the fixation of the longitudinal rod.

42. Device according to any one of claims 1 to 41 in combination with a bone anchoring element, wherein the cavity within the spring chuck and/or the head of the bone anchoring element is provided with a form selected from the group of transverse grooves and transverse ribs.

43. Device according to any one of claims 1 to 42 in combination with a bone 9' 6 15 anchoring element, wherein the spring chuck and the head of the bone anchoring element consist at least in the contact area of materials with different hardness. 9

44. Device according to claim 43, wherein the harder material comprises 20 Titanium-Aluminium-Niobium and the soft material comprises Titanium. Device according to any one of claims 1 to 42 in combination with a bone 0 W anchoring element, wherein the spring chuck and the head of the bone •e:i anchoring element provide at least in the contact area a different hardness S" 25 whereby this difference of hardness is obtained via different cold forming or different crystallization of the same material, whereby the harder material comprises trained steel 1.4441 and the soft material comprises hot-treated steel 1.4441.

46. Device according to any one of claims 1 to 42 in combination with a bone anchoring element, wherein the spring chuck and the head of the bone anchoring element provide at least in the contact area a different hardness, whereby this difference of hardness is obtained via surface treatment as coating or ion implantation. W:'chfsVlodelete30223.doc 16

47. Device according to any one of claims 1 to 46, wherein the spring chuck is axially secured towards the lower end of the connection part by means of a shoulder within the bore hole running orthogonal to the central axis.

48. Device according to any one of claims 1 to 47, wherein the spring chuck is supported axially stable within the bore hole.

49. Device substantially as herein described with reference to any one of the accompanying drawings. DATED: 14 June, 2000 PHILLIPS ORMONDE FITZPATRICK Attorneys for: SYNTHES AG CHUR S** oS «l o W:chris\nodelete\30223.doc