ELONGATED STABILIZATION MEMBER AND BONE ANCHOR USEFUL IN BONE AND ESPECIALLY SPINAL REPAIR PROCESSES
A bone interface anchor for use with an elongated stabilization member, the anchor having: a receptor having a retaining device for receiving the elongated stabilization member; a compression assembly for securing the elongated stabilization member within the receptor; bone fixation screws which secure the anchors relative to bone segments of the human spine, the receptor having a surface forming a mating cooperation with the screw such that the receptor can be variably positioned relative to the screw, a lock member to fix the screw relative to the receptor, and the retaining device having a retaining member between the elongated stabilization member and the interior of the receptor.
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- ELONGATED STABILIZATION MEMBER AND BONE ANCHOR USEFUL IN BONE AND ESPECIALLY SPINAL REPAIR PROCESSES
- SPINAL IMPLANT AND INSTRUMENT
The present invention relates to a bone interface anchor for use with elongated stabilization members, and to an elongated stabilization member.
BACKGROUNDIn prior art EP-A-0 755 228 discloses a stabilization member and a bone interface anchor, wherein the stabilization member is a rod. The anchor has a retaining member which has a channel which is adapted to receive said rod and compression means for compressively securing the stabilization member in the retaining member with the compression means. With a downward compression force can be applied on the rod to bias it against a screw head.
EP-A-0 934 027 describes a multi-axial bone crew assembly, which comprises a crown member for engagement with the bone crew. With a compression member a rod is pressed against said crown member and said crown member is pressed against the head of a bone screw.
EP-A-1 240 875 discloses a spinal osteosynthesis member which has inside a U-shaped opening of the connector a ring cable of coming into contact with the head of a bone screw. A rod is inserted into the U-shaped opening and biased with a locking member against said ring to the head of a pedicle screw.
Similar polyaxial fixing systems are known from WO 02/02024, WO 2005/016161 and WO 2006/083773.
SUMMARY OF THE INVENTIONThe invention relates to a bone interface anchor for use with elongated stabilization members. The invention also relates to an elongated stabilization member useful in bone and especially spinal repair processes. The elongated stabilization member comprises a composite rod having a uniform cross-section essentially throughout its length and said rod having first and second segments each of which has a different modulus of elasticity. The stabilization member of the present invention has the advantage that it can approach the modular elasticity of bone without any danger of breakage. It further provides limited motion to the connected bones and can fulfill the biomechanical requirement which are needed to increase the muscle as well as the strength of the bones to which the muscles are connected. The rod can have variable stress characteristics throughout its length and a uniform cross-section essentially throughout its length. The uniform cross-section makes it possible to use the rod with almost any of the standard connectors. As the rod is made from composite it has the advantage of enhanced imaging throughout the length of the rod. The invention is especially useful for treatment of spinal bone cancer which requires radiation treatment in addition to stabilization, wherein it facilitates proper dosage of radiation adjoint to the implant.
The receptor 18 has a threaded portion 7 configured to engage the nut 10 which has a corresponding outer thread 22. The nut 10 also includes a tool recess 11 which can be a hex recess.
The rod R is locked between the nut 10 and the crown member 12. The upper side of the crown member 12 has a groove 5 which engages the rod R. This groove 5 increases the contact surface to the rod R and therefore the crown member 12 can be better propagate forces. The rod R is gripped tighter and with less deformation. The rod R as illustrated in
The crown member 12 has a bottom surface 6 which is vex and especially spherical. This surface 6 engages the concave surface 9 of the screw head 14 which is preferably spherical as well. The surfaces 6 and 9 are glide and lock surfaces. Further glide and lock surfaces are a convex surface at the bottom of the screw head 14 and a concave surface 3 at the bottom of the bore 4. Within the concave surface 3 there is an opening 15 for receiving the screw 2. The screw 2 has a shank 29 with a recess 17. The diameter of the shank 29 at the recess 17 is smaller than the diameter of the opening 15. The opening 15 can be round or oval.
When the nut 10 is not tightened, the receptor 18 is pivotable with respect to the longitudinal axis of the screw 2. In order to fix the rod R, the surgeon tightens the nut 10. The pressure between the nut 10, the rod R, the crown member 12, the screw head 14 and the bottom of the receptor 18 secures the assembly regardless of the angle between the screw 2 and the receptor 18.
The fixed rod R not only connects the vertebra to be fused, it is well exerts stable pressure upon the crown member 12. In order to have enough friction between the surface 3 of the receptor 18, the crown member 12 is made with a comparatively large mass. Furthermore, the crown member 12 has the shape of a saddle and engages the rod R with a comparatively large surface. The crown member 12 can therefore without much loss propagate the force to the screw head 14 and therefore effects a solid fixation regardless of the angle between the screw 2 and the receptor 18. It has been shown that the anchor is especially suitable for a rod R made from a composite material, and especially a composite material with carbon fibers disposed therein. When the rod R is made from a composite material, there is almost no friction between the nut 10 and the rod R. Therefore, almost all of the pressure from the torque exerted on the nut 10 is upon the rod R and upon the threads of the anchor. When the rod R is made of titanium, there is considerably more friction between the nut 10 and the rod R and this friction absorbs part of the torque and part of the pressure, placing less stress on the threads and less pressure on the rod R.
The rod R is especially suitable in combination with the anchor, when it contains fibers 30 and especially carbon fibers as illustrate in
The
The rods R as illustrated in
The reinforcement of the rod R with fibers 30 helps to eliminate creep and spreads the load more evenly over a larger area. With the different moduli of elasticity it is possible to control motion between fused vertebral bones. The rod R can provide limited motion to the fused bones which helps to increase the muscle as well the strength of the bones to which the muscles are connected.
The sections A and C as shown in
The plies 26, 27 and 28 can be arranged in a sandwich design as illustrated in
The stiffeners 33 and 34 are made from a stable metal preferably of titanium. As shown in
The rod 32 preferably contains carbon fibers 30 as shown in
Claims
1. A bone interface anchor for use with an elongated stabilization member said anchor comprising:
- a receptor having retaining means for receiving said elongated stabilization member,
- a compression assembly for securing said elongated stabilization member within said receptor,
- bone fixation screws which secure said anchors relative to bone segments of the human spine,
- said receptor having a surface forming a mating cooperation with said screw such that said receptor can be variably positioned relative to said screw,
- lock means to fix said screw relative to said receptor, and
- said retaining means having a retaining member between said elongated stabilization member and the interior of said receptor.
2. The bone interface anchor of claim 1, wherein said elongated stabilization member has a uniform cross-section throughout its length, and
- said elongated stabilization member having first and second segments each of which as a different modulus of elasticity.
3. The bone interface anchor of claim 2, wherein said elongated stabilization member is comprised of plastic with carbon fibers disposed therein and said first and second segments have different direction or densities of fiber to provide said different moduli of elasticity.
4. The bone interface anchor of claim 2, wherein the ratio density of fiber to plastic varies along the length of the elongated stabilization member.
5. The bone interface anchor of claim 1, wherein the retaining member is a crown member.
6. An elongated stabilization member useful in bone and especially spinal repair processes comprising:
- a composite rod having a uniform cross-section essentially throughout its length and
- said rod having at least first and second segments each of which has a different modulus of elasticity.
7. The composite rod of claim 6, wherein said rod is comprised of plastic with carbon fibers disposed therein and said first and second segments have different orientation of fiber to provide said different moduli of elasticity.
8. The composite rod of claim 6, wherein the ratio direction of fiber to plastic varies along the rod length.
9. The composite rod of claim 6, wherein said plastic and fibers of said rod will not block imaging rays.
10. The composite rod of claim 6, wherein said rod is comprised with carbon fibers disposed therein and said first and second segments have different densities of fibers to provide said different moduli of elasticity.
11. The rod of claim 6, wherein said rod comprises carbon fibers disposed therein and said first and second segments have fibers of different lengths to provide said different moduli of elasticity.
12. The rod of claim 6, wherein the plastic and fibers of said rod an said anchor will not block imaging rays.
13. An elongate rod for location approximately parallel to and adjacent to a spine,
- said rod having a uniform cross-section throughout its length and is comprised of fiber reinforced plastic, and
- said rod having moduli of elasticity along its length corresponding to, but less than, the moduli of elasticity of the spine segments closest to said rod segments.
14. A device for treating a human spine having a series of bone segments comprising:
- an elongated stabilization member,
- first and second anchors each according to claim 1 adapted to be secured to said elongated stabilization member in spaced relationship to one another, and
- each of said anchors including a screw which is adapted to secure said anchors to spaced spinal bone segments.
15. The device of claim 14, wherein each of said anchors has a bottom surface facing a spinal bone segment,
- means to slidably receive said screw in said anchors, and
- lock means to affix said anchors to said elongated stabilization member.
16. The device of claim 14, wherein said anchors, said screws and said lock means are made of a carbon reinforced plastic that will not block imaging rays and facilitate radiation treatment.
17. The device of claim 16, wherein first and second anchors of composite material are adapted to be secured to said elongated stabilization member in spaced relationship to one another and each of said anchors includes a screw adapted to secure said anchors to spaced bone segments of the spine.
18. A device for treating a human spine having a series of bone segments comprising:
- an elongated stabilization member,
- first and second anchors each according to claim 2 adapted to be secured to said elongated stabilization member in spaced relationship to one another, and
- each of said anchors including a screw which is adapted to secure said anchors to spaced spinal bone segments.
19. The device of claim 18, wherein each of said anchors has a bottom surface facing a spinal bone segment,
- means to slidably receive said screw in said anchors, and
- lock means to affix said anchors to said elongated stabilization member.
20. The device of claim 18, wherein said anchors, said screws and said lock means are made of a carbon reinforced plastic that will not block imaging rays and facilitate radiation treatment.
21. The device of claim 20, wherein first and second anchors of composite material are adapted to be secured to said elongated stabilization member in spaced relationship to one another and each of said anchors includes a screw adapted to secure said anchors to spaced bone segments of the spine.
22. A device for treating a human spine having a series of bone segments comprising:
- an elongated stabilization member,
- first and second anchors each according to claim 3 adapted to be secured to said elongated stabilization member in spaced relationship to one another, and
- each of said anchors including a screw which is adapted to secure said anchors to spaced spinal bone segments.
23. The device of claim 22, wherein each of said anchors has a bottom surface facing a spinal bone segment,
- means to slidably receive said screw in said anchors, and
- lock means to affix said anchors to said elongated stabilization member.
24. The device of claim 22, wherein said anchors, said screws and said lock means are made of a carbon reinforced plastic that will not block imaging rays and facilitate radiation treatment.
25. The device of claim 24, wherein first and second anchors of composite material are adapted to be secured to said elongated stabilization member in spaced relationship to one another and each of said anchors includes a screw adapted to secure said anchors to spaced bone segments of the spine.
26. A device for treating a human spine having a series of bone segments comprising:
- an elongated stabilization member,
- first and second anchors each according to claim 4 adapted to be secured to said elongated stabilization member in spaced relationship to one another, and
- each of said anchors including a screw which is adapted to secure said anchors to spaced spinal bone segments.
27. The device of claim 26, wherein each of said anchors has a bottom surface facing a spinal bone segment,
- means to slidably receive said screw in said anchors, and
- lock means to affix said anchors to said elongated stabilization member.
28. The device of claim 26, wherein said anchors, said screws and said lock means are made of a carbon reinforced plastic that will not block imaging rays and facilitate radiation treatment.
29. The device of claim 28, wherein first and second anchors of composite material are adapted to be secured to said elongated stabilization member in spaced relationship to one another and each of said anchors includes a screw adapted to secure said anchors to spaced bone segments of the spine.
30. A device for treating a human spine having a series of bone segments comprising:
- an elongated stabilization member;
- first and second anchors each according to claim 1 adapted to be secured to said elongated stabilization member in spaced relationship to one another,
- each of said anchors including a screw which is adapted to secure said anchors to spaced spinal bone segments,
- each of said anchors having a bottom surface facing a spinal bone segment,
- means securing said screws to said anchors such that said screws can be variably positioned relative to said anchors, and
- lock means to fix said anchors to said elongated stabilization members after positioning.
31. A device for treating a human spine having a series of bone segments comprising:
- an elongated stabilization member;
- first and second anchors each according to claim 2 adapted to be secured to said elongated stabilization member in spaced relationship to one another,
- each of said anchors including a screw which is adapted to secure said anchors to spaced spinal bone segments,
- each of said anchors having a bottom surface facing a spinal bone segment,
- means securing said screws to said anchors such that said screws can be variably positioned relative to said anchors, and
- lock means to fix said anchors to said elongated stabilization members after positioning.
32. A device for treating a human spine having a series of bone segments comprising:
- an elongated stabilization member;
- first and second anchors each according to claim 3 adapted to be secured to said elongated stabilization member in spaced relationship to one another,
- each of said anchors including a screw which is adapted to secure said anchors to spaced spinal bone segments,
- each of said anchors having a bottom surface facing a spinal bone segment,
- means securing said screws to said anchors such that said screws can be variably positioned relative to said anchors, and
- lock means to fix said anchors to said elongated stabilization members after positioning.
33. A device for treating a human spine having a series of bone segments comprising:
- an elongated stabilization member;
- first and second anchors each according to claim 4 adapted to be secured to said elongated stabilization member in spaced relationship to one another,
- each of said anchors including a screw which is adapted to secure said anchors to spaced spinal bone segments,
- each of said anchors having a bottom surface facing a spinal bone segment,
- means securing said screws to said anchors such that said screws can be variably positioned relative to said anchors, and
- lock means to fix said anchors to said elongated stabilization members after positioning.
34. An assembly for the stabilization of one or more spinal bone segments, comprising:
- first and second anchors,
- an elongated stabilization member,
- first and second screws each having enlarged heads received respectively by said first and second screws and said anchors and which secure said anchors to a spinal bone segment,
- said anchors having cylindrical side walls with a reduced bottom opening of lesser diameter than said heads which retain said heads in a manner providing limited universal movement of said screws with respect to said anchors,
- said anchors each having a reception channel to receive said elongated stabilization member,
- a retaining member disposed between said heads and said elongated stabilization member,
- said retaining members each having a grove formed therein to receive said elongated stabilization member and space said elongated stabilization member from said heads, and
- means to compress said elongated stabilization member against said retaining members and said retaining members against said heads to fix their relationship to one another after the angular disposition of said screws have been selected.
35. The assembly of claim 34, wherein said elongated stabilization member is comprised of plastic with carbon reinforcing fibers disposed therein, the density of said fibers providing selected moduli of elasticity throughout the length by varying fiber density.
36. The assembly of claim 35, wherein the components of said anchors are of reinforced plastic that will not block imaging rays.
37. The assembly of claim 35, wherein the elongated stabilization member contains fibers directed to prevent deformation of the elongated stabilization member due to the pressure of the anchor.
38. A rod useful in bone and especially spinal repair processes, made of plastic with fibers disposed therein, wherein at least a part of the fibers are directed to prevent expansion of the rod with respect to its cross-section.
Type: Application
Filed: Oct 26, 2012
Publication Date: Feb 28, 2013
Applicant: coLigne AG (Zurich)
Inventor: coLigne AG (Zurich)
Application Number: 13/661,754
International Classification: A61B 17/70 (20060101);