WO2007086053A2

WO2007086053A2 - Fusion rod and method of its use for spinal fusion surgery

Info

Publication number: WO2007086053A2
Application number: PCT/IL2007/000087
Authority: WO
Inventors: Gideon Nehemia Levy; Stefan Buob; Nir Kinory
Original assignee: Facet-Med Ltd.
Priority date: 2006-01-24
Filing date: 2007-01-24
Publication date: 2007-08-02
Also published as: WO2007086053A3

Abstract

A fusion rod (60) adapted to couple between two or more bone gripping devices (30) substantially along an axis (x), the fusion rod comprising at least two elements (62) connected to each other by a connection arrangement having at least one pair of components (68, 70) each associated with one of the elements, the components being a first component (68) and a second component (70) adapted to receive therewithin the first component such that the first component is adapted to move with respect to the second component in two orthogonal directions, each being perpendicular to the axis, to bring one of the elements to a desired position relative to the other element.

Description

FUSION ROD AND METHOD OF ITS USE FOR SPINAL FUSION

SURGERY

FIELD OF THE INVENTION

This invention relates to bridging elements such as fusion rods or the like for use in spinal surgery or similar orthopedic procedures.

BACKGROUND OF THE INVENTION Spinal fusion surgery, as well as other similar procedures, is commonly performed to partially or fully correct an abnormality resulting in a malformed or damaged spine, for example from a fractured spine or due to a degenerative conditions such as scoliosis. In such surgeries, the spine is manipulated to take a desired position, and one or more bone grafts are placed around the spine. A fusion rod is provided to hold the spine in place until the vertebrae fuse together at the locations of the bone grafts.

During the surgery, pedicle screws, orthopedic clamps, or another similar bone gripping device is affixed to the vertebrae, and the fusion rod is attached to each of the devices. The fusion rod is often bent during the surgery to conform to the shape required by the position of the devices. Some types of fusion rods allow a limited motion of the spine even after the surgery, while still maintaining the vertebrae close to the positions desired by the surgeon.

In some cases, limited movement of the spine is desired. In such a case, a variation of a traditional fusion rod, such as an inter-spinal ligament device which has some freedom movement, may be used instead of the fusion rod. This allows the patient to move in such ways that results in flexure of the spine, while the spine is still constrained by the device. Several devices which attach directly or indirectly to the spine for use in spinal surgeries have been developed. For example, WO 2004/093749 discloses a surgical inter-vertebral implant having plates which can be connected to the implant and to the vertebrae. The plates each have a fixable connection for the implant. The plates can be Z- or L-shaped and can have an aperture for a bone screw formed in the middle of its length.

WO 2006/101737 discloses a spinal implant providing support for desired parts of the spine in both fusion and non- fusion situations. The spinal implant includes an implant rod and fasteners for coupling or fastening the implant rod to the affected regions of the spine via the pedicles of the affected vertebrae. The implant rod includes a flexible portion and rigid end portions. The fasteners couple the end portions of the rod to the pedicles in the affected level. The flexible portion can take a variety of shapes, such as non-helical or multi-curve springs. Several implant rods may be combined to provide an overall implant for more than one level of the spine.

US 7,011,685 discloses an article including a spinal prosthesis having a unitary body with at least three attachment points attachable to a spinal structure. The unitary body includes a flexure assembly positioned between first and second attachment members, wherein flexure of the flexure assembly permits movement of the first attachment member relative to the second attachment member.

US 2006/142759 discloses an apparatus including a first spinal prosthetic member attachable to a first spinal structure, and a second spinal prosthetic member attachable to a second spinal structure. The first and second spinal prosthetic members are movably attached to one another with a fastening device. The fastening device has a non-tightened position permitting spatial movement of the first and second spinal prosthetic members with respect to one another at a desired orientation, and a tightened position which fixes the first and second spinal prosthetic members at the desired orientation. SUMMARY OF THE INVENTION

According to one aspect of the present invention, there is provided a connection arrangement, which may be designed to constitute a part of a fusion rod or the like, the rod being adapted for coupling two or more bone gripping devices substantially along an axis, the connection arrangement having at least one pair of components comprising a first component and a second component adapted to receive therewithin said first component, the first component, when received within the second component, being movable with respect thereto in two orthogonal directions, each being perpendicular to the axis, to be brought to a desired position relative to the second component.

It will be appreciated that hereafter in the specification and accompanying claims, the term "bone gripping device" is to be understood to include, but not be limited to, orthopedic clamps or hooks, pedicle screws, and other similar devices.

The bone gripping devices, with which the connection arrangement of the present invention can be used, may be in the form of an orthopedic clamp such as the one disclosed in WO 04/110288, the entire contents thereof and, particularly, the description of the orthopedic clamp therein, is incorporated herein by reference. In general, orthopedic clamps comprise a gripping portion meant to be affixed to a vertebra, either by clamping or by being screwed therein, and a projection portion which, when the gripping portion is fixed to the vertebra, projects therefrom. The purpose of this projecting portion is to allow a fusion rod or other similar device to be secured thereto in order to bridge bone gripping devices to one another, for example once attached to the bone.

It will be appreciated that hereafter in the specification in and claims, the term "fusion rod" should be construed to include not only a traditional fusion rod, which is intended to keep a fixed shape, thus preventing any relative movement between adjacent vertebrae, but also to other inter-spinal ligament devices or other devices adapted to bridge between adjacent bone fastening members, which may or may not allow for movement or bending. - A -

The connection arrangement according to the present invention is adapted to avoid disengagement of the first component from the second component when received therein, by restriction of their movement relative to each other at least in the axial direction, when the connection arrangement is at its final state. This may be accomplished, for example, by fixation of the elements to one another in their final orientation, or by securing the components to the bone gripping devices such that their movement in the axial direction is restricted to an extent which precludes their disengagement.

According to a further aspect of the present invention, there is provided a fusion rod comprising the connection arrangement as described above.

According to a further aspect of the present invention, there is provided a method for coupling two or more bone gripping devices substantially along an axis, comprising the steps of:

(a) providing the connection arrangement as described above; and (b) bringing the connection arrangement to its final state wherein the first and second components are fixed in the desired position such that no freedom of motion is allowed.

According to a still further aspect of the present invention, the connection arrangement further comprises a cushioning layer between the first and second components allowing supported axial motion therebetween. The axial motion is said to be supported in that, for example, when the cushioning layer is not compressed, it supports the topmost component which rests thereon. When an axial force moves one of the two components toward the other, causing the cushioning layer to compress, the cushioning layer prevents the components from moving toward each other any more than is caused by the axial force. When the axial force is removed, the cushioning layer returns the components to their original disposition relative to one another.

According to a still further aspect of the present invention, there is provided a fusion rod comprising the connection arrangement with the cushioning layer, as described above. According to a further aspect of the present invention, there is provided a method for coupling two or more bone gripping devices substantially along an axis, using the connection arrangement with the cushioning layer, as described above. According to any one of the above aspects of the present invention, the connection arrangement may be embodied by any one or more of at least the following:

• At least some of the components may be integrally formed with the bone gripping devices. • Each of the bone gripping devices may comprise a gripping portion adapted to be attached to a bone and a projecting portion projecting therefrom, the connection arrangement constituting a portion of a fusion rod system comprising at least two mounting elements each adapted for attachment to the projecting portion of one of said bone gripping devices, each of the mounting elements comprising at least one of said components formed integrally therewith. The mounting elements may be embodied by one or more of at least the following: o Each of the mounting elements may comprise components of at least two connection arrangements. More specifically, each of the mounting elements may comprise components of four connection arrangements. o The mounting elements may be thin, in a direction substantially along the direction of the projection, compared to the components attached thereto. Specifically, the thickness of the mounting element may be no more than one third that of the thickest of the components in the direction. o The mounting elements may be of different lengths.

• The first component may comprise a projection comprising a substantially curved surface with the second component comprising a socket adapted to receive therein the first component. The components may be embodied by one or more of at least the following: o The projection may be substantially spherical. o The socket may be of a length so as to fully receive therein the projection. o The socket may comprise, at its open end, at least two slits.

• The first component may comprise a neck portion, with the socket comprising a slot adapted to fully receive therein the neck. According to this embodiment, the two components may be disposed at an angle up to 90° relative to one another.

• The connection arrangement may further comprise at least one joint element having two of the components. The joint elements may be embodied by at least one or more of the following: o In at least some of the joint elements the two components may: ^■ comprise one of the first component and one of the second component;

^■ two of the first component; or

^■ two of the second component. o The connection arrangement may comprise two or more of the joint elements between two adjacent bone gripping devices.

• The connection arrangement may comprise two or more of the joint elements between two adjacent bone gripping devices.

• The connection arrangement may be made of titanium or cobalt chrome, or any other appropriate material. • The connection arrangement may be adapted for use in a spinal fusion procedure.

In addition, when in the connection arrangement the first component comprises a projection and the second component comprises a socket, the connection arrangement may be embodied by at least any one or more of the following: • The connection arrangement may be brought into its final state by deforming the socket around the projection.

• The socket may comprise at least one through-going aperture adapted to receive therein a fixing element adapted to fix the position of the projection within the socket. In this case, the socket may be embodied by at least any one or more of the following: o The fixing element may be a through-going pin. o The fixing element may be a set screw. o The socket may comprise two of said apertures, which may be disposed at substantially a 90° angle to one another.

In addition, in case when the connection arrangement comprises a cushioning layer, the connection arrangement may be embodied by any one or more of at least the following:

• The connection arrangement may comprise a single pair of components between each two adjacent bone gripping devices.

• The cushioning layer may comprise a gel. The gel may comprise, e.g., silicone.

• The cushioning layer may comprise fluid sealed within a membrane. The fluid may comprise, e.g., a saline solution, and the membrane may comprise a silicone elastomer.

• At least a portion of the cushioning layer may be attached to the first component.

• At least a portion of the cushioning layer may be attached to the second component. According to a still further aspect of the present invention, there is provided a connection arrangement for coupling two or more bone gripping devices substantially along an axis, the connection arrangement comprising at least one axially extending projection associated with each bone gripping device and a hollow tubular member at each end to receive therein the projections. According to still further aspect of the present invention, there is provided a fusion rod comprising a connection arrangement according to the seventh aspect.

According to still further aspect of the present invention, there is provided a method for coupling two or more bone gripping devices substantially along an axis, the method comprising the step of providing a connection arrangement between each two bone gripping devices, each of the connection arrangements comprising at least one axially extending projection associated with each bone gripping device and a hollow tubular member at each end to receive therein said projections.

According to any one of the three latter aspects of the present invention, the connection arrangement may be embodied by any one or more of at least the following:

• The hollow tubular member may comprise at least two slots being formed laterally to the axis. The slots may extend substantially halfway through the thickness of the hollow tubular member. These slots allow the hollow tubular member to bend slightly. Two of the slots may be disposed 90° to one another.

• The hollow tubular member may be secured to the projections with a through-going pin.

• Each of the bone gripping devices may comprise a gripping portion adapted to be attached to a bone and a projecting portion projecting therefrom, the connection arrangement constituting a portion of a fusion rod system comprising at least two mounting elements each adapted for attachment to the projecting portion of one of the bone gripping devices, each of the mounting elements comprising the projections.

• The projections may be formed integrally with said bone gripping devices. BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the invention and to see how it may be carried out in practice, embodiments will now be described, by way of non-limiting examples only, with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of several vertebrae of a human spine, with mounted thereon a fusion rod comprising connection arrangements according to one example of the present invention;

Fig. 2 is a perspective view of a clamp element, being part of the connection arrangement of the fusion rod illustrated in Fig. 1; Fig. 3 is a perspective view of a joint element, being part of the connection arrangement of the fusion rod fusion rod illustrated in Fig. 1;

Fig. 4 illustrates in axial cross-section one example of how a knob of either the clamp element illustrated in Fig. 2 or the joint element illustrated in Fig. 3 may be received within a socket of either the joint element illustrated in Fig. 3 or the clamp element illustrated in Fig. 2, respectively;

Fig. 5 is a perspective view of a crimping tool useful for deforming the sockets around the knobs, such as illustrated in Fig. 4;

Fig. 6 is a perspective view of orthopedic clamps, with mounted thereon a fusion rod comprising connection arrangements according to another example of the present invention;

Fig. 7 is a perspective view of a clamp element, being part of the connection arrangement of the fusion rod illustrated in Fig. 6;

Figs. 8 A and 8B are, respectively, perspective and side views of a joint rod, being part of the connection arrangement of the fusion rod illustrated in Fig. 6;

Fig. 9 illustrates a modification of the connection arrangement of the fusion rod illustrated in Fig. 6;

Fig. 10 is a perspective view of several vertebrae of a human spine with mounted thereon a fusion rod comprising connection arrangements according to a further example of the present invention; Fig. HA is a cross-sectional view of the connection arrangement taken along line X-X in Fig. 10;

Figs. HB and HC illustrate, in axial cross-section, examples of a knob and a socket, respectively, according to the example of the connection arrangement illustrated in Fig. 10;

Fig. 12A is a side view of a modification of the clamp element according to the examples of the connection arrangement illustrated in Figs. 1 and 10;

Fig. 12B illustrates how two clamp elements of the kind illustrated in Fig. 12A may be mounted to a projection of an orthopedic clamp; and Fig. 13 illustrates a pre-assembled fusion rod as illustrated in Fig. 10.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Fig. 1 illustrates one example of a fusion rod, generally designated at 2, designed in accordance with the present invention for use in spinal' fusion surgery or any similar medical procedure, and shown in use, being secured to projections 32 of orthopedic clamps 30 mounted on a portion of a human spinal column.

The fusion rod extends generally along axis X, and comprises clamp elements 10 each mounted on projection 32, and a plurality of joint elements 12 connected to each other and to the clamp elements 10 via a connection arrangement designated at 11. As illustrated in Fig. 2, each clamp element 10 comprises a main body section 14, constituting a clamp mounting element, and projecting therefrom at opposite ends two connection components in the form of a knob 18 and a socket 20. The main body section 14 comprises a through-going aperture 16, sized such that it may receive therein the projection 32 of an orthopedic clamp, and adapted to secure it therein. Typically, this is done by employing auxiliary hardware, such as nuts and other fasteners (not shown), or by crimping.

As illustrated in Fig. 3, each joint element 12 comprises two connection components in the form of a knob 24 and a socket 26, which are adapted to engage corresponding connection components (socket 20 and knob 18, respectively) of the clamp element 10 or corresponding connection components (socket 24 and knob 26, respectively) of other joint elements 12, thereby forming the connection arrangements 11.

The knob 18 of the clamp element 16 and the knob 24 of the joint element 12 are each in the form of a generally spherical projection, adapted to be received at least partially in any one of the sockets 20 and 26. The sockets 20 and 26 each comprise slits 22 and 28, respectively, which allow the sockets to expand upon insertion therein of one of the knobs 18 and 24. Typically, the depth of each socket is such that the corresponding knob may be fully received therein. The joint element 12 may be provided in a variety of lengths, so that the resultant fusion rod 2 may suit the distance between clamp elements 10, when mounted thereon in accordance with the description of use below. .

In order to mount the fusion rod 2 on several vertebrae, as shown in Fig. 1, the orthopedic clamp 30 with a projection 32 is first secured on each vertebra. The clamp element 10 is secured along vertical axis X to each orthopedic clamp 30, on the projection 32 thereof and joint elements 12 are used to connect adjacent clamp elements 10 via the connection arrangements 11 in which the knob 18, 22 of clamp or joint element 10, 12 is received within the socket 20, 24 of the corresponding element which is located above it. Alternatively, the elements 10, 12 may be arranged such that the knobs 18, 24 of each element are received within the sockets 20, 26 of the element below it. However, all of the elements 10, 12 should be oriented in the same direction (i.e., the knobs 18, 24 should all be directed either toward the top of the spine or toward the bottom of the spine). Alternatively, when the distance between adjacent orthopedic clamps to be connected, is relatively short and/or the clamp elements are of a sufficient axial length, the knobs 18 and sockets 20 of adjacent clamp elements 10 may directly engage each other without the use of joint elements 12 (not illustrated).

When the clamp elements 10, and optionally the joint elements 12, are initially attached, each is free to move with respect to its adjacent element in two directions Y and Z, as illustrated in Fig. 1. As illustrated, each of these directions is perpendicular to the vertical axis X and to one other. Thus, freedom of motion is allowed along two orthogonal axes, each being perpendicular to the vertical axis X in an initial state of the fusion rod 2. The fusion rod 2 is brought into its final state by the fixation of the connection components of the connections arrangement with respect to one another.

To this end, in any pair of adjacent elements 10, 12 the sockets 20, 26 are crimped or otherwise deformed around the knob 18, 24 received therein. When the depth of the socket 20, 26 is sufficient that a knob 18, 24 may be fully received therein, then it may be fully closed therearound, as illustrated in Fig. 4. The deformation facilitated by the slits 22, 28 is to be performed such that it is ensured that the adjacent elements are immovable with respect to each other, thus ensuring that fusion rod 2 has a required fixed special shape. For this purpose, a crimping tool 50, illustrated in Fig. 5, may be provided. However, it will be appreciated that any appropriate tool may be used. A wire may be used to secure the adjacent elements, either before the deformation or in cooperation therewith.

Fig. 6 illustrates another example of a fusion rod, designated at 4, designed in accordance with the present invention. The fusion rod 4 illustrated in Fig. 6 is similar to that illustrated in Fig. 1, but comprises modified clamp elements 34 and j oint rods 36.

As illustrated in Fig. 7, each modified clamp element 34 is similar to the clamp element 10 described with reference to Fig. 2, with the exception that the knob 18 and socket 20 are replaced by cylindrical projections 38. Each projection 38 comprises a through-going aperture 40 and a beveled corner 42.

As illustrated in Figs. 8A and 8B, each the joint rod 36 comprises an axial bore 44 which is sized to permit insertion therein of a projection 38 of the modified clamp element 34, preferably so that it is snuggly received therein. Each end of the joint rod 36 comprises a pair of through-going apertures 46. The apertures 46 may be the same size as the apertures 40 passing through the projections 38 of the modified clamp element 34, and are located such that when the projections are fully received within the bore 44 all three apertures are aligned. The joint rod 36 further comprises slots 48. As best illustrated in the top view of Fig 8B, each slot 48 is formed such that it extends along about half of the circumference of the joint rod 36. The slots are spaced from each other along the length of the joint rod and are angularly shifted with respect to each other along the circumference thereof. The slots have such dimensions and geometry as to allow the joint rod 36 to be slightly bent therealong.

In operation, as illustrated in Fig. 6, the modified clamp elements 34 are secured to projections 32 of orthopedic clamps 30 (although not illustrated in Fig. 6, it is understood that the orthopedic clamps there illustrated are each secured to a vertebra), and are connected by joint rods 36, bent if necessary at the locations of the slots 38 in order to allow for the resultant fusion rod 4 to mimic the curvature of the spine. Pins (not illustrated) of any appropriate design are inserted through the apertures 40, 46 and secured in place in order to prevent axial displacement of the joint rods 36 from the modified clamp elements 34.

It will be appreciated that the clamp elements illustrated above, or any other clamp element that is within the scope of this invention, may be provided in different lengths. In addition, the slots 38 of the modified clamp elements 34 may be provided of different widths, in order to allow for different degrees of their curvature. Both of these features allow the fusion rod to be formed to match the size and curvature of the spine.

Either of the above embodiments may be modified to include a wire- tensioning system, which is illustrated in Fig. 9, being incorporated in the fusion rod and which is associated with a clamp elements 52. Although each clamp element 52is similar to the modified clamp element 34, it will be appreciated that the present modification may be used with any clamp element suitable for use in any fusion rod according to the present invention. Therefore, the term "clamp element 52" will be used in the following description without meaning any particular embodiment thereof. The wire-tensioning system includes guide wings 54, projecting from either side of the clamp element 52, each comprising a through-going aperture 56 which is aligned generally parallel to the spine when the fusion rod is secured thereto, and two wires 58, each passing through the aperture 56 of one of the guide wings 54. Nuts 59, or other securing arrangements, are screwed onto the ends of the wires 58 and tightened in order to further secure the fusion rod. In the event where more than two clamp elements 52 are used, the wire 58 simply passes through the guide wings of the intermediate elements (i.e., those not on the ends) without being secured thereto. After the wires are tightened by the nuts 59, an additional securing device, such as a specialized nut, may be used to secure the wire 58 to the guide wings 54 of the intermediate elements.

Fig. 10 illustrates an additional example of a fusion rod, generally indicated at 60, designed in accordance with the present invention. The fusion rod 60 extends generally along axis X, and comprises at least two clamp elements, generally designated at 62, each of which is constructed similarly to the clamp elements 10 described in connection with Fig. 2. As such, it comprises a main body section 64 with a through-going aperture 66 sized such that it may receive therein the projection 32 of an orthopedic clamp 30, and is adapted to secure it therein, as described above. In addition, the clamp element 62 comprises projecting therefrom at opposite ends a knob 68 and a socket 70. In addition, as illustrated in Fig. 1 IA, a cushioning layer 74 is provided between the knob 68 and the socket 70. As illustrated in Figs. HB and HC, the cushioning layer 74 may be attached to the knob 68, the socket 70, or a portion of it may be attached to each. Alternatively, the cushioning layer may be independent of the knob 68 and socket 70, i.e., not attached to either.

The cushioning layer 74 may be made of a gel, such as silicone. Alternatively, it may comprise a liquid encased in a membrane, for example a saline solution such as salt water encased in a silicone elastomer membrane.

When the fusion rod 60 is initially assembled, its clamp elements 62 are allowed the same freedom of motion with respect to each other as is allowed between clamp and joint elements of the fusion rod 2 described in connection with Figs. 1 through 4 in its initial state, i.e. before its knobs 18, 24 are fixed inside the sockets 20, 26 to secure the desired special shape of the fusion rod 2 However, in the fusion rod 60, this freedom of motion is allowed to an appropriate extent also in the final state of the fusion rod 60, since the sockets are not deformed about the knobs to fix them. For example, the lowermost clamp element 64 illustrated in Fig. 10 is shown displaced in a direction along the Y-axis.

In addition to the freedom of motion in directions along the Y- and Z-axes, motion along the X-axis is allowed. This is due to the cushioning layer 74 allowing the clamp elements 62 to be compressed toward one another in use, for example up to 3 mm. The additional amount of allowed motion permits the entire fusion rod 60 to alter its length slightly even once installed on a patient's spine. This dynamic stabilization allows the patient additional freedom of motion, for example when bending or making other similar movements.

As illustrated in Fig. 10, the knob 68 of one clamp element 62 may be received directly within the socket 70 of an adjacent clamp element. Alternatively, joint elements, similar to the joint element 12 according to the embodiment described in connection with Figs. 1 through 4, may be provided, however modified to include the cushioning layer 74 between sockets and knobs received therein.

As illustrated in Fig. 12A, the clamp element 10, 62 according to either of the embodiments illustrated in Figs. 1 through 4 and 10 through HC may be constructed such that the main body section 14, 64 is thinner., in the direction along which the projection 32 of the orthopedic clamp extends than either the knob 18, 68 or the socket 20, 70. In this way, as illustrated in Fig. 12B, two of the clamp elements 10, 62 may be placed on a single projection 32 of an orthopedic clamp at substantially right angles to one another while talcing up minimal space on the clamp. This is particularly advantageous when a surgeon wishes to limit the degree to which the fusion rod projects from the spine. AIl the fusion rods described above may be as kits allowing a surgeon to assemble it to orthopedic clamps or the like during surgery. Also, fusion rods of the kind as or similar to the fusion rod 60 may be provided pre-assembled, as illustrated in Fig. 13. Such a pre-assembled fusion rod may be mounted directly to orthopedic clamps which have been attached to the vertebrae, without a need to assemble them during surgery.

It will be appreciated that the orthopedic clamps 30 in Figs. I₅ 6, 9 and 10, are shown schematically for illustrative purposes only, and that the elements of the present invention may be adapted to be used in conjunction with any orthopedic clamp. The clamp elements 10, 34, 52 and 62 may be secured to the projecting portions of the orthopedic clamps according to any method which is appropriate, given the particular structure of the orthopedic clamp used.

Fusion rods according to the various embodiments of the present invention, since they each comprises individual elements which combine to form a solid rod in accordance with the locations and positions of the orthopedic clamps, may be particularly suited to the patient. As such, the necessity, which exists in the prior art, to deform existing fusion rods in order to connect several orthopedic clamps is obviated. The results include a precisely fitted fusion rod, and in faster and easier surgeries, resulting in fewer possible complications. Those skilled in the art to which this invention pertains will readily appreciate that numerous changes, variations and modifications can be made without departing from the scope of the invention mutatis mutandis.

Claims

CLAIMS:

1. A fusion rod adapted to couple between two or more bone gripping devices substantially along an axis, said fusion rod comprising at least two elements connected to each other by a connection arrangement having at least one pair of components each associated with one of said elements, said components being a first component and a second component adapted to receive therewithin said first component such that the first component is adapted to move with respect to the second component in two orthogonal directions, each being perpendicular to said axis, to bring one of said elements to a desired position relative to the other element.

2. A fusion rod according to Claim 1, further comprising a cushioning layer between the first and second components allowing supported axial motion therebetween.

3. A fusion rod according to Claim 2, comprising a single pair of components between each two adjacent bone gripping devices.

4. A fusion rod according to any one of Claims 2 and 3, wherein said cushioning layer comprises a gel.

5. A fusion rod according to Claim 4, wherein said gel comprises silicone.

6. A fusion rod according to any one of Claims 2 through 4, wherein said cushioning layer comprises fluid sealed within a membrane.

7. A fusion rod according to Claim 6, wherein said fluid comprises a saline solution.

8. A fusion rod according to any one of Claims 6 and 7, wherein said membrane comprises a silicone elastomer.

9. A fusion rod according to any one of Claims 2 through 8, wherein at least a portion of said cushioning layer is attached to said first component.

10. A fusion rod according to any one of Claims 2 through 9, wherein at least a portion of said cushioning layer is attached to said second component.

11. A fusion rod according to Claim 1, wherein: (a) in an initial state, said first component of each pair is adapted to move with respect to said second component in said two orthogonal directions; and

(b) in a final state, the first and second components are fixed in the desired position such that no freedom of motion is allowed.

12. A fusion rod according to Claim 11, wherein:

(a) said first component comprises a projection comprising a substantially curved surface; and

(b) said second component comprises a socket adapted to receive therein the first component; said connection arrangement being adapted to be brought into its final state by deforming the socket around the projection.

13. A fusion rod according to Claim 12, wherein said socket comprises at least one through-going aperture adapted to receive therein a fixing element adapted to fix the position of the projection within the socket.

14. A fusion rod according to Claim 13, wherein said fixing element is a through-going pin.

15. A fusion rod according to Claim 13, wherein said fixing element is a set screw.

16. A fusion rod according to any one of Claims 13 through 15, wherein said socket comprises two of said apertures.

17. A fusion rod according to Claim 16, wherein said apertures are disposed at substantially a 90° angle to one another.

18. A fusion rod according to any one of the preceding claims, wherein at least some of said components are integrally formed with said bone gripping devices.

19. A fusion rod according to any one of Claims 1 through 17, wherein each of said bone gripping devices comprises a gripping portion adapted to be attached to a bone and a projecting portion projecting therefrom, the connection arrangement comprising at least two mounting elements each adapted for attachment to the projecting portion of one of said bone gripping devices, each of said mounting elements comprising at least one of said components formed integrally therewith.

20. A fusion rod according to Claim 19, wherein said each of said mounting elements comprises components of at least two connection arrangements.

21. A fusion rod according to Claim 19, wherein each of said mounting elements comprises components of four connection arrangements.

22. A fusion rod according to any one of Claims 19 through 21, wherein said mounting elements are thin, in a direction substantially along the direction of the projection, compared to the components attached thereto.

23. A fusion rod according to Claim 22, wherein the thickness of the mounting element is no more than one third that of the thickest of the components in said direction.

24. A fusion rod according to any one of Claims 19 through 23, wherein at least two of said mounting elements are of different lengths.

25. A fusion rod according to any one of the preceding claims, wherein:

(a) said first component comprises a projection comprises a substantially curved surface; and

(b) said second component comprises a socket adapted to receive therein the first component.

26. A fusion rod according to Claim 25, wherein said projection is substantially spherical.

27. A fusion rod according to any one of Claims 25 and 26, wherein said socket is of a length so as to fully receive therein said projection.

28. A fusion rod according to any one of Claims 25 through 27, wherein said socket comprises, at its open end, at least two slits.

29. A fusion rod according to any one of Claims 25 through 28, wherein said first component further comprises a neck portion, and said socket comprises a slot adapted to fully receive therein the neck.

30. A fusion rod according to any one of the preceding claims, further comprising at least one joint element having said components.

31. A fusion rod according to Claim 30, wherein at least some of said joint element comprises two of said first component or two of said second component.

32. A fusion rod according to Claim 30, wherein at least some of said joint element comprises one first component and one second component.

33. A fusion rod according to any one of Claims 30 through 32, comprising two or more of said joint elements between two adjacent bone gripping devices.

34. A fusion rod according to any one of the preceding claims, made of a material selected from the group comprising titanium and cobalt chrome.

35. A connection arrangement for use in a fusion rod according to any one of the preceding claims.

36. A method for constructing a fusion rod for coupling two or more bone gripping devices substantially along an axis, comprising the step of providing at least two adjacent elements from which the rod is to be constructed and at least one connection arrangement therebetween , said connection arrangement having at least one pair of components, each component being associated with one of said elements, said component being a first component and a second component adapted to receive therewithin said first component such that the first component of each pair is adapted to move with respect to the second component in two orthogonal directions, each being perpendicular to said axis, bring said elements to a desired position relative to each other.

37. A method according to Claim 36, further comprising a cushioning layer between the first and second components allowing supported axial motion therebetween.

38. A method according to Claim 37, wherein said connection arrangement comprises a single pair of components between each two adjacent bone gripping devices.

39. A method according to any one of Claims 37 and 38, wherein said cushioning layer comprises a gel.

40. A method according to Claim 39, wherein said gel comprises silicone.

41. A method according to any one of Claims 37 through 39, wherein said cushioning layer comprises fluid sealed within a membrane.

42. A method according to Claim 41, wherein said fluid comprises a saline solution.

43. A method according to any one of Claims 41 and 42, wherein said membrane comprises a silicone elastomer.

44. A method according to any one of Claims 37 through 43, wherein at least a portion of said cushioning layer is attached to said first component.

45. A method according to any one of Claims 37 through 44, wherein at least a portion of said cushioning layer is attached to said second component.

46. A method according to Claim 36, wherein:

(a) in an initial state of the connection arrangement, said first component of each pair is adapted to move with respect to said second component in said two orthogonal directions; and

47. A method according to Claim 46, wherein:

48. A method according to Claim 47, wherein said socket comprises at least one through-going aperture adapted to receive therein a fixing element adapted to fix the position of the projection within the socket.

49. A method according to Claim 48, wherein said fixing element is a through-going pin.

50. A method according to Claim 48, wherein said fixing element is a set screw.

51. A method according to any one of Claims 48 through 50, wherein said socket comprises two of said apertures.

52. A method according to Claim 51, wherein said apertures are disposed at substantially a 90° angle to one another.

53. A method according to any one of Claims 36 through 52, wherein at least some of said components are integrally formed with said bone gripping devices.

54. A method according to any one of Claims 36 through 52, wherein each of said bone gripping devices comprises a gripping portion adapted to be attached to a bone and a projecting portion projecting therefrom, the connection arrangement comprising at least two mounting elements each adapted for attachment to the projecting portion of one of said bone gripping devices, each of said mounting elements comprising at least one of said components formed integrally therewith.

55. A method according to Claim 54, wherein said each of said mounting elements comprises components of at least two connection arrangements.

56. A method according to Claim 54, wherein each of said mounting elements comprises components of four connection arrangements.

57. A method according to any one of Claims 54 through 56, wherein said mounting elements are thin, in a direction substantially along the direction of the projection, compared to the components attached thereto.

58. A method according to Claim 57, wherein the thickness of the mounting element is no more than one third that of the thickest of the components in said direction.

59. A method according to any one of Claims 54 through 58, wherein at least two of said mounting elements are of different lengths.

60. A method according to any one of Claims 54 through 59, wherein:

(a) said first component comprises a projection comprises a substantially curved surface; and (b) said second component comprises a socket adapted to receive therein the first component.

61. A method according to Claim 60, wherein said projection is substantially spherical.

62. A method according to any one of Claims 60 and 61, wherein said socket is of a length so as to fully receive therein said projection.

63. A method according to any one of Claims 60 through 62, wherein said socket comprises, at its open end, at least two slits.

64. A method according to any one of Claims 60 through 63, wherein said first component further comprises a neck portion, and said socket comprises a slot adapted to fully receive therein the neck.

65. A method according to any one of Claims 54 through 64, wherein said connection arrangement further comprises at least one joint element having said components.

66. A method according to Claim 65, wherein at least some of said joint element comprises two of said first component or two of said second component.

67. A method according to Claim 65, wherein at least some of said joint element comprises one first component and one second component.

68. A method according to any one of Claims 65 through 67, wherein said connection arrangement comprises two or more of said joint elements between two adjacent bone gripping devices.

69. A method according to any one of Claims 54 through 68, wherein said connection arrangement is made of a material selected from the group comprising titanium and cobalt chrome.

70. A method according to any one of Claims 54 through 69, wherein said connection arrangement is adapted for use in a spinal fusion procedure.

71. A connection arrangement for coupling two or more bone gripping devices substantially along an axis, said connection arrangement comprising at least one axially extending projection associated with each bone gripping device and a hollow tubular member at each end to receive therein said projections.

72. A connection arrangement according to Claim 71, wherein said hollow tubular member comprises at least two slots being formed laterally to said axis.

73. A connection arrangement according to Claim 72, wherein said slots extend substantially halfway through the thickness of the hollow tubular member.

74. A connection arrangement according to any one of Claims 72 and 73, wherein two of said slots are disposed 90° to one another.

75. A connection arrangement according to any one of Claims 71 through

74, wherein said hollow tubular member is secured to said projections with a through-going pin.

76. A connection arrangement according to any one of Claims 71 through

75, wherein each of said bone gripping devices comprises a gripping portion adapted to be attached to a bone and a projecting portion projecting therefrom, the connection arrangement constituting a portion of a fusion rod system comprising at least two mounting elements each adapted for attachment to the projecting portion of one of said bone gripping devices, each of said mounting elements comprising said projections.

77. A connection arrangement according to any one of Claims 71 through

75, wherein said projections are formed integrally with said bone gripping devices.

78. A fusion rod comprising a connection arrangement according to any one of Claims 71 through 77.

79. A method for coupling two or more bone gripping devices substantially along an axis, comprising the step of providing a connection arrangement between each two bone gripping devices, each of said connection arrangements comprising at least one axially extending projection associated with each bone gripping device and a hollow tubular member at each end to receive therein said projections.

80. A method according to Claim 79, wherein said hollow tubular member comprises at least two slots being formed laterally to said axis.

81. A method according to Claim 80, wherein said slots extend substantially halfway through the thickness of the hollow tubular member.

82. A method according to any one of Claims 80 and 81, wherein two of said slots are disposed 90° to one another.

83. A method according to any one of Claims 79 through 82, wherein said hollow tubular member is secured to said projections with a through-going pin.

84. A method according to any one of Claims 79 through 83, wherein each of said bone gripping devices comprises a gripping portion adapted to be attached to a bone and a projecting portion projecting therefrom, the connection arrangement constituting a portion of a fusion rod system comprising at least two mounting elements each adapted for attachment to the projecting portion of one of said bone gripping devices, each of said mounting elements comprising said projections.

85. A method according to any one of Claims 79 through 83, wherein said projections are formed integrally with said bone gripping devices.

86. A connection arrangement for coupling two or more bone gripping devices substantially along an axis, said connection arrangement having at least one pair of components, said pair comprising a first component and a second component adapted to receive therewithin said first component such that the first component of each pair is adapted to move with respect to the second component in two orthogonal directions, each being perpendicular to said axis, said arrangement further comprising a cushioning layer between the first and second components allowing supported axial motion therebetween.

87. A method for coupling two or more bone gripping devices substantially along an axis, comprising the step of providing a connection arrangement between each two bone gripping devices, each of said connection arrangements having at least one pair of components, said pair comprising a first component and a second component adapted to receive therewithin said first component such that the first component of each pair is adapted to move with respect to the second component in two orthogonal directions, each being perpendicular to said axis, said arrangement further comprising a cushioning layer between the first and second components allowing supported axial motion therebetween.

88. A connection arrangement for coupling two or more bone gripping devices substantially along an axis, said connection arrangement having at least one pair of components, said pair comprising a first component and a second component adapted to receive therewithin said first component such that:

(a) in an initial state, the first component of each pair is adapted to move with respect to the second component in two orthogonal directions, each being perpendicular to said axis, to be brought to a desired position relative to said second component; and

89. A method for coupling two or more bone gripping devices substantially along an axis, comprising the steps of: (a) providing a connection arrangement between each two bone gripping devices, each of said connection arrangements having at least one pair of components, said pair comprising a first component and a second component adapted to receive therewithin said first component in an initial state such that the first component of each pair is adapted to move with respect to the second component in two orthogonal directions, each being perpendicular to said axis, to be brought to a desired position relative to said second component; and

(b) bringing said connection arrangement to a final state wherein the first and second components are fixed in the desired position such that no freedom of motion is allowed.