CONNECTOR FOR SPINAL CORRECTION

Abstract

A connector for slidably connecting an anchoring device to a rod in a spinal correction system, comprising a body, a coupling mechanism for coupling the body to the anchoring device, a guiding mechanism arranged to guide the rod in a sliding movement along a longitudinal direction of the rod, wherein said guiding mechanism is further arranged to prevent any movement, with respect to the rod, other than a translation along the longitudinal direction of the rod and a rotation around said longitudinal direction of the rod.

Claims

1. A connector for slidably connecting an anchoring device to a rod in a spinal correction system, comprising a body, wherein the body has a first tubular opening, a coupling mechanism for coupling the body to the anchoring device, a guiding mechanism provided in said first tubular opening (11) and arranged to guide the rod in a sliding movement along a longitudinal direction of the rod, wherein said guiding mechanism has at least two guiding portions provided at a mutual distance in said first tubular opening and is further arranged to prevent any movement, with respect to the rod, other than a translation along the longitudinal direction of the rod and a rotation around said longitudinal direction of the rod.

2. The connector according to claim 1, wherein the guiding mechanism is arranged to prevent any rotation of the body with respect to the rod in any plane containing the longitudinal direction or axis of the rod.

3. The connector according to claim 1, wherein the at least two guiding portions are provided at the end parts of the first tubular opening.

4. The connector according to claim 1, wherein the first tubular opening has a first internal diameter, the guiding portions have a second internal diameter, and the first internal diameter is larger than the second internal diameter.

5. The connector according to claim 1, wherein each guiding portion has a bearing and a bearing holder.

6. The connector according to claim 1, wherein the guiding portions are spherical bearings.

7. The connector according to claim 1, wherein the guiding portions are slid inside the body through slot openings in the body.

8. The connector according to claim 1, wherein the guiding portions are slid inside the body via the ends of the first tubular opening.

9. The connector according to claim 8, wherein the guiding portions are fixed using one of a pin mechanism, a thread mechanism, a bayonet mechanism, and a snap fit mechanism.

10. The connector according to claim 5, wherein the bearing holders are fixed using one of a pin mechanism, a thread mechanism, a bayonet mechanism, and a snap fit mechanism.

11. The connector according to claim 1, further comprising a spring for constraining the translation of the rod along its longitudinal direction.

12. The connector according to claim 1, wherein the body has a locking mechanism for locking the rod in a fixed position with respect to the body.

13. The connector according to claim 1, wherein the coupling mechanism has a second tubular opening for receiving a stationary rod, said second tubular opening having a direction substantially parallel to the direction of the first tubular opening.

14. The connector according to claim 13, wherein the coupling mechanism has a locking mechanism for locking the stationary rod with respect to the coupling mechanism.

15. A connector assembly for spinal correction comprising: the connector according to claim 1, and an anchoring device for anchoring to the spine, said anchoring device being coupled to the connector via the coupling mechanism of the connector.

16. The connector assembly according to claim 15, wherein the anchoring device has a stationary rod.

17. The connector assembly according to claim 15, wherein the anchoring device has one or more anchoring elements for anchoring in one or more vertebrae.

18. The connector assembly according to claim 16, wherein the stationary rod is fixed by two anchoring elements in two neighboring vertebrae.

19. A spinal correction system comprising the rod for spinal correction and at least one said connector according to claim 1.

20. The spinal correction system according to claim 19, further comprising an anchoring device to form a connector assembly with the at least one connector, said anchoring device being coupled to the connector via the coupling mechanism of the connector.

21. The spinal correction system according to claim 20, further comprising one or more anchors for anchoring the rod in the spine.

22. A kit of parts comprising at least two of a connector, an anchoring device, and a rod, according to claim 1.

23. A method for providing a spinal correction to a patient, comprising the steps of: providing a rod for attachment to the spine of the patient; providing an anchoring device for attachment to the spine of the patient; providing the connector according to claim 1 for connection to the rod and the anchoring device; and coupling the connector to the rod.

24. The method according to claim 23, further comprising coupling the connector to the anchoring device.

Description

[0043] This and other aspects of the present invention will now be described in more detail, with reference to the appended drawings showing currently preferred embodiments of the invention, wherein:

[0044] FIG. 1 illustrate a view of a complete spinal correction system comprising the connector;

[0045] FIG. 2 illustrates a cross-section of the connector according to an embodiment with a straight rod;

[0046] FIG. 3 illustrates a cross-section of the connector according to an embodiment with a rod having a curvature;

[0047] FIG. 4 illustrates a perspective view and three cross-sections of the connector according to an alternative embodiment with a connector body having spherical bearing holders;

[0048] FIG. 5 illustrates a cross-section of the connector according to an alternative embodiment with a connector body configured having a pin mechanism for locking bearing holders;

[0049] FIG. 6 illustrates a cross-section of the connector according to an alternative embodiment with a connector body configured having a thread mechanism for locking bearing holders;

[0050] FIG. 7 illustrates a cross-section of the connector according to an alternative embodiment with a connector body configured having a bayonet mechanism for locking bearing holders;

[0051] FIG. 8 illustrates a cross-section of the connector according to an alternative embodiment with a connector body provided with a locking ring mechanism for locking bearing holders;

[0052] FIG. 9 illustrates a cross-section of the connector according to an alternative embodiment with a connector body having a snap fit mechanism for locking bearing holders;

[0053] FIG. 10 illustrates a cross-section of the connector according to an alternative embodiment with a connector body configured for interlocking bearing holders.

[0054] FIG. 1 shows a spinal correction system 1 comprising a connector 100, an anchoring device 200, a rod 300 and anchoring elements 400 and 500 for anchoring to the spine 1000. Each element of the system will now be described successively.

[0055] As shown in FIG. 1, the rod 300 is an elongate member, having a cylindrical shape and being secured to the spinal column 1000 via two anchoring elements 500, 600. The anchoring elements 500 600 are mounted, or fixed to two vertebrae 1001, 1002 located at a first position along the spine 1000, in an inferior part of the spinal column 1000. Optionally the rod 300 may be anchored at additional anchoring points. The anchoring elements 400, 500 are further adapted to receive and secure the rod 300, such that the rod 300 is made solidary with the two vertebrae 1001 and 1002.

[0056] The rod 300 in FIG. 1 is further illustrated as having a round cross section with a diameter D1. Yet other embodiments may be envisaged with a rod having a different contour and in particular with a rod having one or more flat portions. As illustrated in FIG. 1, the rod 300 is a straight rod having an axis of symmetry. In such a case, a longitudinal direction A of the rod 300 coincides with the longitudinal axis of the rod 300.

[0057] The anchoring device 200 comprises a stationary rod 210 extending along a longitudinal direction B and two anchoring elements 220 and 230. The anchoring elements 220 and 230 may be similar to the anchoring elements 400 and 500 and may be mounted or fixed to two vertebrae 100n and 100(n+1) located at a second position along the spine 1000, in a superior part of the spinal column 1000. The second position is in this example located above the first position along the spinal column 1000. Optionally the stationary rod 210 may be anchored at additional anchoring points.

[0058] The connector 100 comprises a body 10, a coupling mechanism 20 for coupling the body 10 to the anchoring device 200, and a guiding mechanism 30. The guiding mechanism 30 (see also FIGS. 2a and 2b) is configured to guide the rod 300 in a sliding movement along the longitudinal direction A of the rod 300, and is further arranged to prevent any movement with respect to the rod other than a movement with respect to said longitudinal direction A of the rod 300.

[0059] The body 10 illustrated in FIG. 1 has an elongated tubular shape with a longitudinal direction (see arrow C in FIG. 1) matching the longitudinal direction A of the axis of the rod 300, such that the rod 300 may cross right through the body 10 along the longitudinal direction A. Although represented as rather a tubular shaped element, other shapes of a body may be envisaged for receiving the rod 300 in the body 10.

[0060] The connector 100 is such that when assembled in the system of FIG. 1 any movement in a sagittal plane (see arrow S in FIG. 1 illustrating this movement) may be constrained. When the rod 300 is mounted in the connector 100, or in other words, when the connector 100 is coupled to the rod 300, the connector 100 may slide freely along the longitudinal direction A of the rod 300 while any other movement is prevented. In particular any movement in a sagittal plane is prevented. Only a translation along the direction A and a roll rotation movement around the axis of the rod are allowed by the guiding mechanism 30 of the connector 100. In this way, rotational and axial mobility for growth or distraction is maintained while preventing the issue of kyphosis, particularly present in cases of growing or distraction systems.

[0061] For the option where some distraction between the lower vertebrae 1001, 1002 and the upper vertebrae 100n, 100(n+1) is desired, a spring mechanism 40 may be provided around the rod 300 for constraining the translation movement of the connector 100 along the rod 300 by exerting a compression effort between a stopper element 45 and the body 10 of the connector 100. The stopper element can be used proximal and distal depending on the desired function.

[0062] In the embodiment of FIG. 1, the coupling mechanism 20 is integrally attached to the body 10 to form an L-shaped connector 100. The long side of the L-shape corresponds substantially to the body 10 of the connector 100 and extends in the longitudinal direction A of the rod 300. The short side of the L-shaped connector 100 corresponds substantially to the coupling mechanism 20. Alternatively the coupling mechanism 20 may provide coupling to an additional element (not represented in any of the figures) configured solely for anchoring and/or to receive and secure the stationary rod 210 or any other orthopaedic device.

[0063] The coupling mechanism 20 is configured to receive and secure the stationary rod 210, such that the stationary rod 210 is made solidary with the coupling mechanism 20 and thus with the connector 100. The coupling mechanism 20 is configured to secure the stationary rod 210 in a direction B. The direction B may be substantially parallel to the direction A such that the rod 300 and the rod 210 are substantially parallel to each other and at a mutual lateral distance L1 chosen to minimize the transmission of a torque between the rods 210 and 300. The rod 300 is further positioned next to the anchoring device 200 to preserve mobile segments of the spine as much as possible

[0064] The coupling mechanism 20 may comprise a locking mechanism 25 for locking the stationary rod 210 with respect to the coupling mechanism 20. A screw may for instance be provided in an opening in the coupling mechanism 20 for securing the stationary rod 210 to the coupling mechanism 20.

[0065] Similarly the body 10 may comprise a locking mechanism 15 for locking the rod 300 with respect to the body 10. A screw may for instance be provided in an opening in the body 10 for securing the rod 300 to the body 10.

[0066] FIG. 2a illustrates a cross-section of the connector 100 connected to a straight rod 300. In particular FIG. 2a shows how the body 10 has a first tubular opening 11 extending through the body 10 in a longitudinal direction of the body 10 (coinciding with direction A in FIG. 2a), creating a receptacle for the rod 300. The guiding mechanism 30 is then provided in the first tubular opening 11 for guiding the rod 300 in a sliding movement along the longitudinal direction A of the rod 300.

[0067] As illustrated the guiding mechanism 30 provided inside the tubular opening 11 has at least two guiding portions 32, 33 provided at a mutual distance D in said first tubular opening 11. In particular the two guiding portions 32, 33 are provided at or near the end parts of the first tubular opening 11. Each guiding portion 32, 33 comprises an annular bearing 34 housed in a bearing holder 35. Each annular bearing 34 can rotate in its bearing holder such that the rod 300 may slide and roll with respect to the direction A. The bearings 34 may be spherical bearings.

[0068] The cross section of the coupling mechanism 20 shows further a second tubular opening 21 in the coupling mechanism 20 for receiving the stationary rod 210. The second tubular opening 21 has a longitudinal direction B substantially parallel to the longitudinal direction of the first tubular opening 11.

[0069] FIG. 2b illustrates a cross-section of the connector when connected to a rod 300 having a curvature. Of significance is that the bearings 34 are spherical bearings allowing a rotation according to a roll, pitch and yaw rotation axis, see arrows R1 and R2 in FIG. 2b, allowing the bearings to adjust to the surface of the curved rod 300. The first internal diameter D1 of the tubular opening 11 is larger than the second internal diameter D2 of the bearings 34 to allow the movement of the rod having a curvature in the region there between. The second internal diameter D2 is dimensioned relative to the diameter of the rod 300 to allow a translation with a predetermined friction. In this case the sliding movement of the rod is guided locally at each guiding portion 32, respectively 33 in a longitudinal direction A1, respectively A2. It is noted that the longitudinal directions A1 and A2 of the sliding movement of the rod at the guiding portions 32 and 33 are substantially the same as the longitudinal direction C of the first tubular opening 11.

[0070] FIG. 3 illustrates a perspective view and three cross-sections of a connector 100 with a connector body 10 comprising two bearing holders 35 formed as spherical cavities inside the tubular opening 11 in the body 10. At the extremities 10a and 10b of body 10 along the longitudinal direction A, the tubular opening 11 mouths into an oval shape having a long axis dimension D3 greater than a short side dimension D4, wherein D3 and D4 are chosen relative to the external diameter of the bearings 34, such that D4 is greater than the external diameter of the bearings 34 and D4 is smaller than the external diameter of the bearings 34. The oval shaped holes at the ends 10a and 10b of the body allow the insertion and the shape locking of annular bearings 34 in the spherical bearing holder cavities 35.

[0071] FIGS. 4-10 illustrate alternative embodiments where the bearing holders 35 are separate elements form the body 10. In particular the embodiments of FIGS. 4-10 show alternatives where the bearings 34 and their bearings holders 35 are slid inside the body 10 via the ends of the first tubular opening 11.

[0072] FIG. 4 illustrates a cross-section of the connector according to an alternative embodiment of the invention with a connector body configured having a pin mechanism 36 for locking bearing holders 35. First the bearing holders 35 housing the bearings 34 are slid from each end of the body 10 inside the tubular opening 11, then pins 36 are engaged from the outside of the housing into holes provided in the body 10 and the bearing holders 35 to lock the bearing holders 35 inside the body 10.

[0073] FIG. 5 illustrates a cross-section of a connector with a connector body 10 configured having a thread mechanism 37 for locking bearing holders 35. Each bearing holder 35 is provided with a thread 37 mating a thread provided on the inner side of the body 10 such that the bearing holders and the bearings 34 may be presented via the ends and fixed by rotation inside the body 10.

[0074] FIG. 6 illustrates a cross-section of the connector with a connector body 10 configured having a bayonet mechanism 38 for locking bearing holders 35. Each bearing holder 35 is provided with a bayonet 38 mating a bayonet thread provided on the inner side of the body 10 such that the bearing holders 35 and the bearings 34 may be presented via the ends and fixed by rotation inside the body 10.

[0075] FIG. 7 illustrates a cross-section of the connector with a connector body 10 provided with a locking ring mechanism 38a for locking bearing holders 35. Each bearing holder 35 is provided with a locking ring 38a meant to lock into a recess provided on the inner side of the body 10 such that the bearing holders 35 and the bearings 34 may be presented via the ends and snap-fitted when the locking ring 38a falls into the recess inside the body 10.

[0076] FIG. 9 illustrates a cross-section of the connector with a connector body 10 having a snap fit mechanism for locking bearing holders 35. Each bearing holder 35 is provided with a locking profile 38b for a snap fit with a complementary locking profile provided on the inner side of the body 10 such that the bearing holders 35 and the bearings 34 may be presented via the ends and snap fitted inside the body 10 when the locking profiles 38b on the bearing holder 35 and the body interlock.

[0077] FIG. 9 illustrates a cross-section of the connector with a connector body 10 configured for interlocking bearing holders 35. Bearing holders 35 on opposite ends of the body are configured to interlock inside the body via interlocking profiles 39c such that the bearing holders 35 and the bearings 34 may be presented via the ends and snap fitted together inside the body 10 when the locking profiles 39c of the bearing holders 35 interlock.

[0078] It is further noted that the above list of ways of mounting the bearings 34 inside the connector 10 is not exhaustive. Other alternatives may be envisaged by a skilled person depending on the circumstances and materials used. One can imagine for instance alternatives where the bearings would not be inserted by the ends of the tubular opening 11 but for instance via lateral openings and slots in the body 10.

[0079] As far as materials are concerned, the connector is preferably made of titanium and the rod of cobal-chromium (CoCr) to prevent titanium-on titanium friction and metal debris. Other materials suitable, such as for instance poly ethylene, for the above described movements may however be envisaged as well.

[0080] According to a further embodiment a method for spinal correction is provided, comprising the steps of: [0081] Providing a rod 300 for attachment to the spine, [0082] Providing an anchoring device 200 for attachment to the spine [0083] Providing a connector 100 according to the invention for connection to the rod 300 and the anchoring device 200, and [0084] Further comprising the step of coupling the connector 100 to the rod 300.

[0085] A further step comprises coupling the connector (100) to the anchoring device (200).

[0086] The method preferably comprises a step of attaching the rod 300 to the spine 1000, for instance using anchoring elements 400 and 500, being bone screws or bone pins. Providing the anchoring device 200 may comprise attaching the anchoring device 200 to the spine 1000, in particular to at least one vertebra 100n and optionally to another vertebrae 100(n+1). The anchoring device 200 may be unitary with the connector 100, in the alternative the connector 100 can be coupled to the anchoring device 200.

[0087] The connector 100 is preferably coupled to the rod 300 by sliding the connector 100, preferably using the guiding mechanism 30 as described above, over the rod 300. After connection to the anchoring device 200, the anchoring device 200 can be attached to the spine.

Alternatively the connector 100 can be attached to the anchoring device 200 once the anchoring device 200 is attached to the spine.

[0088] Surgery can be performed in particular through a posterior midline skin incision. The anchoring elements 400, 500, 220, 230 can be placed with the freehand technique. The rods 200 and 300 can be passed sub-fascially and contoured into the desired shape in both the coronal and sagittal plane.

[0089] It is noted that a surgeon may decide depending on circumstances to alter the sequence of the steps, and start with any one of the anchoring device, the rod and or the connector.

[0090] The present invention is further illustrated by the following embodiments, which are not intended to limit the scope of the invention in any way: [0091] 1. Connector (100) for slidably connecting an anchoring device (200) to a rod (300) in a spinal correction system, comprising [0092] a body (10), [0093] a coupling mechanism (20) for coupling the body (10) to the anchoring device (200), [0094] a guiding mechanism (30) arranged to guide the rod (300) in a sliding movement along a longitudinal direction (A) of the rod (300), wherein said guiding mechanism is further arranged to prevent any movement, with respect to the rod (300), other than a translation along the longitudinal direction (A) of the rod (300) and a rotation around said longitudinal direction (A) of the rod (300). [0095] 2. Connector according to embodiment 1, wherein the guiding mechanism is arranged to prevent any rotation of the body with respect to the rod in any plane containing the longitudinal direction or axis of the rod. [0096] 3. Connector according to any of the above embodiments, wherein the body (10) has a first tubular opening (11), and wherein the guiding mechanism (30) is provided in said first tubular opening (11). [0097] 4. Connector according to the previous embodiment, wherein the guiding mechanism (30) has at least two guiding portions (32, 33) provided at a mutual distance (d) in said first tubular opening (11). [0098] 5. Connector according to the previous embodiment, wherein the at least two guiding portions (32, 33) are provided at the end parts of the first tubular opening (11). [0099] 6. Connector according to any one of embodiments 3-5, wherein the first tubular opening (11) has a first internal diameter (D1), the guiding portions (32, 33) have a second internal diameter (D2), and the first internal diameter (D1) is larger than the second internal diameter (D2). [0100] 7. Connector according to any one of embodiments 4-6, wherein each guiding portion (32, 33) has a bearing (34) and a bearing holder (35). [0101] 8. Connector according to any one of embodiments 4-7, wherein the guiding portions (32, 33) are spherical bearings. [0102] 9. Connector according to any one of embodiments 4-8, wherein the guiding portions (32, 33) are slid inside the body 10 through slot openings (12, 13) in the body (10). [0103] 10. Connector according to any one of embodiment 4-8, wherein the guiding portions (32, 33) are slid inside the body (10) via the ends of the first tubular opening (11). [0104] 11. Connector according to the previous embodiment, wherein the guiding portions (32, 33) are fixed using one of a pin mechanism (36), a thread mechanism (37), a bayonet mechanism (38), a snap fit mechanism (39). [0105] 12. Connector according to any one of embodiments 7-11, wherein the bearing holders (32, 33) are fixed using one of a pin mechanism (35), a thread mechanism (36), a bayonet mechanism (37), a snap fit mechanism (38). [0106] 13. Connector according to any of the above embodiments, further comprising a spring (40) for constraining the translation of the rod (300) along its longitudinal direction (A). [0107] 14. Connector according to any of the above embodiments, wherein the body (10) has a locking mechanism (15) for locking the rod in a fixed position with respect to the body (10). [0108] 15. Connector according to any of the above embodiments, wherein the coupling mechanism (20) has a second tubular opening (21) for receiving a stationary rod (210), said second tubular opening (21) having an direction (B) substantially parallel to the direction of the first tubular opening (11). [0109] 16. Connector according to the previous embodiment, wherein the coupling mechanism (20) has a locking mechanism (25) for locking the stationary rod (210) with respect to the coupling mechanism (20). [0110] 17. Connector assembly (100,200) for spinal correction comprising a connector (100) according to any of the above embodiments and an anchoring device (200) for anchoring to the spine, said anchoring device (200) being coupled to the connector (100) via the coupling mechanism (20) of the connector. [0111] 18. Connector assembly according to the previous embodiment, wherein the anchoring device (200) has a stationary rod (210). [0112] 19. Connector assembly according to embodiment 17 or 18, wherein the anchoring device (200) has one or more anchoring elements (220,230) for anchoring in one or more vertebrae. [0113] 20. Connector assembly connector according to embodiment 18 or 19, wherein the stationary rod (210) is fixed by two anchoring elements (220, 230) in two neighboring vertebrae. [0114] 21. Spinal correction system comprising a rod (300) for spinal correction and at least one connector (100) according to any of embodiments 1-16. [0115] 22. System according to the previous embodiment further comprising an anchoring device (200) to form with the at least one connector (100) a connector assembly (100, 200) according to any one of the embodiments 17-20. [0116] 23. System according to the previous embodiment, further comprising one or more anchors (400, 500) for anchoring the rod (300) in the spine. [0117] 24. Kit of parts comprising at least two of a connector (100), an anchoring device (200), and a rod (300) according to any of the preceding embodiments. [0118] 25. Method for providing a spinal correction to a patient, comprising the steps of: [0119] providing a rod (300) for attachment to the spine of the patient; [0120] providing an anchoring device (200) for attachment to the spine of the patient; [0121] providing a connector (100) according to any of embodiments 1-16 for connection to the rod (300) and the anchoring device (200); [0122] coupling the connector (100) to the rod (300). [0123] 26. Method according to embodiment 25, further comprising coupling the connector (100) to the anchoring device (200).

[0124] Whilst the principles of the invention have been set out above in connection with specific embodiments, it is understood that this description is merely made by way of example and not as a limitation of the scope of protection which is determined by the appended claims.