STEERABLE INTERBODY FUSION CAGE

• US 20070067035A1
• Filed: 09/18/2006
• Published: 03/22/2007
• Est. Priority Date: 09/16/2005
• Status: Active Grant

• Current Assignee: CTL Medical Corporation
• Original Assignee: US Spine Inc. (SiNtx Technologies, Inc.)
• Inventors: Falahee, Mark
• Granted Patent: US 8,882,841 B2
• Time in Patent Office: Days
• US Class Current: 623/17.110
• CPC Class Codes: A61F 2/4455 for the fusion of spinal bodies, e.g. intervertebral fusion of adjacent spinal bodies, e.g. fusion cages intervertebral discs A61F2/442
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2002/2835 Bone graft implants for filling a bony defect or an endoprosthesis cavity, e.g. by synthetic material or biological material
• CPC Class Codes: A61F 2002/30092 using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2002/30112 Rounded shapes, e.g. with rounded corners
• CPC Class Codes: A61F 2002/30133 kidney-shaped or bean-shaped
• CPC Class Codes: A61F 2002/30471 connected by a hinged linkage mechanism, e.g. of the single-bar or multi-bar linkage type
• CPC Class Codes: A61F 2002/30565 having spring elements
• CPC Class Codes: A61F 2002/3082 Grooves
• CPC Class Codes: A61F 2002/4415 elements of the prosthesis being arranged in a chain like manner
• CPC Class Codes: A61F 2002/4629 connected to the endoprosthesis or implant via a threaded connection
• CPC Class Codes: A61F 2210/0014 using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2220/0091 connected by a hinged linkage mechanism, e.g. of the single-bar or multi-bar linkage type
• CPC Class Codes: A61F 2230/0004 Rounded shapes, e.g. with rounded corners
• CPC Class Codes: A61F 2230/0015 Kidney-shaped, e.g. bean-shaped

Abstract

An interbody vertebral cage facilitates minimally invasive approaches to the intervertebral disc for corrective restoration of disc height, stabilization between vertebra, and fusion. The preferred embodiment provides a streamlined, slender straight contour with a central hinge or other articulating apparatus that allows the introduction of the cage into the operative field and disc space in a minimally invasive, bone-sparing manner. After partial insertion, the hinge component is activated, allowing the operator to steer the cage anterior-medially within the disc space to an anterior-central position within the intervertebral space. In this state the cage is shaped like a crescent, chevron or boomerang.

Claims

1. A steerable intervertebral cage, comprising

a distal portion having front, back, top, bottom, inner and outer surfaces;

a proximal portion having a front, back, top, bottom, inner and outer surfaces;

a hinge joining the front outer surface of the proximal portion to the back outer surface of the distal portion; and

at least one of portions having an inner surface that is shorter than its outer surface, such that the cage has a first, straightened shape with the hinge open and a second, crescent shape with the hinge closed.

2. The steerable intervertebral cage of claim 1, wherein one or both portions are hollow or include apertures facilitating bone or biological material packing.

3. The steerable intervertebral cage of claim 1, wherein the back surface of the proximal portion includes a feature for coupling to an introducer instrument.

4. The steerable intervertebral cage of claim 1, wherein the front surface of the distal portion includes a smooth, blunt tip.

5. The steerable intervertebral cage of claim 1, wherein the outer surfaces of the proximal and distal portions are convex, such that with the hinge open in the second, crescent shape a continuous, outer curve is established including the outer surfaces of both portions.

6. The steerable intervertebral cage of claim 1, wherein the inner surfaces of the proximal and distal portions are straight, such that:

with the hinge closed in the second, crescent shape the inner portions form a “

V”

; and

with the hinge open in the first, straightened shape the straight inner surfaces are substantially coplanar.

7. The steerable intervertebral cage of claim 1, wherein the top and bottom surfaces of the proximal portion include recesses running the length of the portion to receive upper and lower arms of an introducer instrument.

8. The steerable intervertebral cage of claim 1, wherein the top and bottom surfaces of the proximal and distal portions include recesses running the length of each portion to receive upper and lower arms of an introducer instrument maintaining the portions in the first, straightened shape.

9. A method of fusing vertebrae, comprising the steps of:

providing the steerable intervertebral cage of claim 1;

introducing the cage in the first, straightened shape into an intervertebral disc space using a posterior lumbar interbody fusion (PLIF) or transverse lumbar interbody fusion (TLIF) approach; and

steering or allowing the cage to assume the second, crescent shape once within the intervertebral disc space.

10. The method of claim 9, wherein the cage in the second, crescent shape assumes an anterior-central position within the intervertebral space.

11. The method of claim 10, including the steps of:

using a first instrument to maintain the cage in the straightened shape for introduction; and

switching to a different instrument that facilitates articulation and final positioning.

16. The steerable intervertebral cage of claim 1, wherein the inner surfaces of the proximal and distal portions are straight, such that:

with the hinge closed in the second, crescent shape the inner portions form a “

V”

; and

with the hinge open in the first, straightened shape the straight inner surfaces are substantially coplanar.

12. A steerable intervertebral cage, comprising:

a distal portion having front, back, top, bottom, inner surfaces and a convex outer surface;

a proximal portion having a front, back, top, bottom, inner surfaces and a convex outer surface;

a hinge joining the front outer surface of the proximal portion to the back outer surface of the distal portion, such that the cage has a first, straightened shape and a second, crescent shape wherein the outer surfaces of both portions form a continuous convex curve.

13. The steerable intervertebral cage of claim 12, wherein one or both portions are hollow or include apertures facilitating bone or biological material packing.

14. The steerable intervertebral cage of claim 12, wherein the back surface of the proximal portion includes a feature for coupling to an introducer instrument.

15. The steerable intervertebral cage of claim 12, wherein the front surface of the distal portion includes a smooth, blunt tip.