Spinal fusion implant for oblique insertion

Patent metadata

Field	Value
Publication number	US-10555818-B2
Application number	US-201615138078-A
Country	US
Kind code	B2
Filing date	Apr 25, 2016
Priority date	Apr 23, 2015
Publication date	Feb 11, 2020
Grant date	Feb 11, 2020

Abstract

Intervertebral spinal fusion implants for interbody fusion of the anterior column of the spine are described. The implants have a substantially bi-convex or a substantially offset bi-convex shape. The implants are placed through a transforaminal or posterior approach at an oblique insertion angle. The implants have an outermost point on the superior convex surface and an outermost point on the inferior convex surface and four edges of differing heights. The outermost superior and inferior points of the implants are connected with the four edges with convex surfaces of different curvatures. The curvatures of the convex surfaces of the implants are designed to match the curvatures of concave vertebral surfaces when the implants are inserted at an oblique insertion angle.

First claim

We claim:

1. A unitary intervertebral fusion implant for spinal fusion between two adjacent vertebrae comprising
a superior convex surface,
an inferior convex surface, and
four vertical edges, wherein each edge has a different height than the other edges, wherein each edge comprises a superior end and an inferior end, wherein each superior end terminates at the superior convex surface, and wherein each inferior end terminates at the inferior convex surface,
wherein the superior convex surface comprises a first outermost point, the first outermost point being the apex of the implant, and
wherein the inferior convex surface comprises a second outermost point, wherein the apex is the highest point of the implant, and wherein none of the four vertical edges contains the apex, and
wherein the implant is configured for a transforaminal or posterior approach at an oblique insertion angle.

2. The intervertebral fusion implant of claim 1 , wherein the first outermost point and the second outermost point are positioned on a median plane of the implant, and the implant has a bi-convex shape.

3. The intervertebral fusion implant of claim 1 , wherein the first outermost point and the second outermost point are positioned offset from a median plane of the implant, and the implant has an offset bi-convex shape.

4. The intervertebral fusion implant of claim 1 , wherein the height of an imaginary line connecting the apex and the second outermost point is the apex height, and wherein the apex height is greater than each of the heights of the four vertical edges.

5. The intervertebral fusion implant of claim 1 , wherein the implant further comprises an opening for receiving a bone graft material.

6. The intervertebral fusion implant of claim 1 , wherein the superior convex surface and inferior convex surface further comprise one or more bone engagement members.

7. The intervertebral fusion implant of claim 1 , wherein curvatures of the inferior and superior convex surfaces match the concavities of the two adjacent vertebrae at an insertion angle when the insertion angle is an oblique angle relative to the median plane of the spine.

8. The intervertebral fusion implant of claim 1 , wherein a curvature of the superior convex surface is defined by connecting the first outermost point to each of the superior ends of each of the four vertical edges to form four superior curved lines of different curvatures, and
wherein a curvature of the inferior convex surface is defined by connecting the second outermost point to each of the inferior ends of each of the four edges to form four inferior curved lines of different curvatures.

9. The intervertebral fusion implant of claim 8 ,
wherein the curvature of each of the superior curved lines or the inferior curved lines is calculated using Equation 1:

E
=

b
2

-

a
2

b

Eq
.

⁢
1

wherein
E is eccentricity of the curved line;
a is the difference between the apex height and the height of the edge connected with the first or second outermost point via the curved line, and
b is the length of a straight line running from the edge to the first outermost point or the second outermost point.

10. The intervertebral fusion implant of claim 9 , wherein a ranges from 0.03 mm to 0.88 mm and b ranges from 5 mm to 21 mm, and wherein the implant has a bi-convex shape.

11. The intervertebral fusion implant of claim 9 , wherein a ranges from 0.5 mm to 4.2 mm and b ranges from 5 mm to 28.3 mm, and wherein the implant has an offset bi-convex shape.

12. The intervertebral fusion implant of claim 2 , further comprising a central opening and an oblique divider, and wherein the apex is located on the oblique divider.

13. The intervertebral fusion implant of claim 1 , wherein
(a) the first outermost point of the superior convex surface is positioned on a median plane of the implant,
(b) the second outermost point of the inferior convex surface is positioned on a median plane of the implant,
and
wherein the implant further comprises:
(c) an anterior vertical surface and a posterior vertical surface,
(d) a lateral longitudinal surface and a medial longitudinal surface,
(e) a central opening, and
(f) an oblique divider dividing the central opening,
wherein the distance between the first outermost point and the second outermost point is the apex height, and
wherein the apex height is greater than each of the heights of the four vertical edges, and
wherein the implant has a bi-convex shape.

14. The intervertebral fusion implant of claim 13 , wherein a first curvature of the superior convex surface and a second curvature of the inferior convex surface along a sagittal plane of the implant form a sagittal profile of the implant, and
wherein the first curvature is defined by connecting the first outermost point with each of the superior ends of the four vertical edges to form four superior curved lines, and wherein the second curvature is defined by connecting the second outermost point with each of the inferior ends of the four vertical edges to form four inferior curved lines,
wherein the curvature of each of the superior curved lines or the inferior curved lines is calculated from Equation 1:

E
=

b
2

-

a
2

b

Eq
.

⁢
1

wherein
E is eccentricity of the curved line;
a is the difference between the apex height and the height of the edge connected with the first or second outermost point via the curved line, and
b is the length of a straight line running from the edge to a coronal plane passing through the first and second outermost points and meeting the coronal plane at a right angle.

15. The intervertebral fusion implant of claim 13 , wherein a first curvature of the superior convex surface and a second curvature of the inferior convex surface along a coronal plane of the implant form a coronal profile of the implant, and

Assignees

• Camber Spine Tech Llc
• Inst Musculoskeletal Science & Education Ltd

Inventors

• Mcconnell Jeffrey R
• Duffield William

Classifications

• A61F2/4684

  Trial or dummy prostheses · CPC title

• A61F2002/30828

  parallel · CPC title

• A61F2002/30797

  internally-threaded · CPC title

• A61F2/447

  substantially parallelepipedal, e.g. having a rectangular or trapezoidal cross-section · CPC title

• A61F2002/30151

  rhomboidal or parallelogram-shaped · CPC title