Interbody spacer for spinal fusion

1. An interbody spacer for spinal fusion surgery, the interbody spacer comprising:

first and second opposite longitudinal end portions, wherein a longitudinal axis of the interbody spacer extends through the first and second opposite end portions;

first and second opposite side walls extending longitudinally between and interconnecting the first and second longitudinal end portions, wherein the first and second opposite side walls define a width of the interbody spacer therebetween, the first and second opposite side walls having interior and exterior surfaces;

upper and lower faces at respective upper and lower portions of the corresponding first and second opposite longitudinal end portions and first and second opposite side walls, wherein the upper and lower faces define a height of the interbody spacer therebetween; and

an interior cavity defined by the first and second opposite longitudinal end portions and the interior surfaces of the first and second opposite side walls, wherein the interior cavity extends through the upper and lower faces,

wherein each of the first and second opposite side walls includes

open-cell metal foam at the upper and lower faces, and

a three-dimensional lattice disposed between the open-cell metal foam at the upper and lower faces.

2. The interbody spacer set forth in claim 1 , wherein the three-dimensional lattice of each of the first and second opposite side walls defines a set of transverse passages extending transversely through the corresponding side wall from the interior cavity through the exterior surface of the side wall, a set of heightwise passages extending heightwise through the three-dimensional lattice from an upper end of the three-dimensional lattice to a lower end of the three-dimensional lattice, and a set of longitudinal passages extending generally longitudinally through the three-dimensional lattice from a first longitudinal end to a second longitudinal end of the three-dimensional lattice.

3. The interbody spacer set forth in claim 2 , wherein the transverse passages, the heightwise passages, and the longitudinal passages intersect and are in communication with one another.

4. The interbody spacer set forth in claim 2 , wherein an open area of each three-dimensional lattice increases from adjacent the exterior surface of the corresponding side wall toward the interior surface of the corresponding side wall.

5. The interbody spacer set forth in claim 4 , wherein a structural integrity of each three-dimensional lattice increases from adjacent the exterior surface of the corresponding side wall toward the interior surface of the corresponding side wall.

6. The interbody spacer set forth in claim 2 , wherein the transverse passages are arranged in longitudinal and heightwise rows extending longitudinally and heightwise of the corresponding side wall.

7. The interbody spacer set forth in claim 6 , wherein a cross-sectional area of each transverse passage gradually increases from the exterior surface to the interior surface of the corresponding side wall.

8. The interbody spacer set forth in claim 2 , wherein the heightwise passages are arranged in rows extending longitudinally and transversely along the corresponding side wall.

9. The interbody spacer set forth in claim 8 , wherein a cross-sectional area of each heightwise passage generally increases from adjacent the exterior surface toward the interior surface of the corresponding side wall.

10. The interbody spacer set forth in claim 2 , wherein the longitudinal passages are arranged in rows extending heightwise and transversely along the corresponding side wall.

11. The interbody spacer set forth in claim 10 , a cross-sectional area of each longitudinal passage generally increases from adjacent the exterior surface toward the interior surface of the corresponding side wall.

12. The interbody spacer set forth in claim 1 , wherein the three-dimensional lattice of each of the first and second opposite side walls comprises interconnected structural strut members.

13. The interbody spacer set forth in claim 12 , wherein the strut members are connected to one another at nodes and define intersecting passages extending through the side walls.

14. The interbody spacer set forth in claim 13 , wherein the strut members adjacent the exterior surface of each side wall have cross-sectional areas greater than the cross-sectional areas of the strut members adjacent the interior surface of the corresponding side wall.

15. The interbody spacer set forth in claim 14 , wherein the cross-sectional areas of the strut members decreases gradually toward the interior surface of the corresponding side wall.

16. The interbody spacer set forth in claim 1 , wherein the interbody spacer is an integrally formed, one-piece component formed by additive manufacturing.

17. The interbody spacer set forth in claim 1 , wherein the three-dimensional lattice of each of the first and second opposite side walls defines a plurality of interconnected passages.

18. A method of forming an interbody spacer comprising:

forming the interbody spacer as an integral, one-piece interbody spacer by additive manufacturing process, wherein the formed integral, one-piece interbody spacer comprises:

first and second opposite longitudinal end portions, wherein a longitudinal axis of the interbody spacer extends through the first and second opposite end portions;

first and second opposite side walls extending longitudinally between and interconnecting the first and second longitudinal end portions, wherein the first and second opposite side walls define a width of the interbody spacer therebetween, the first and second opposite side walls having interior and exterior surfaces;

upper and lower faces at respective upper and lower portions of the corresponding first and second opposite longitudinal end portions and first and second opposite side walls, wherein the upper and lower faces define a height of the interbody spacer therebetween; and

an interior cavity defined by the first and second opposite longitudinal end portions and the interior surfaces of the first and second opposite side walls, wherein the interior cavity extends through the upper and lower faces,

wherein each of the first and second opposite side walls includes

open-cell metal foam at the upper and lower faces, and

a three-dimensional lattice disposed between the open-cell metal foam at the upper and lower faces.

19. An interbody spacer for spinal fusion surgery, the interbody spacer comprising:

first and second opposite longitudinal end portions, wherein a longitudinal axis of the interbody spacer extends through the first and second opposite end portions;

first and second opposite exterior side surfaces extending longitudinally between and interconnecting the first and second longitudinal end portions, wherein the first and second opposite exterior side surfaces define a width of the interbody spacer therebetween;

upper and lower faces at respective upper and lower portions of the corresponding first and second opposite longitudinal end portions and first and second opposite side walls, wherein the upper and lower faces define a height of the interbody spacer therebetween;

open-cell metal foam at the upper and lower faces,

wherein each of the first and second opposite side exterior surfaces including a lattice defining a plurality of transverse openings extending inward toward the interior cavity,

wherein the open-cell metal foam is disposed inward of the first and second opposite side surfaces at the upper and lower faces.

20. The interbody spacer set forth in claim 19 , further comprising first and second rows of teeth at the upper and lower faces adjacent the respective first and second opposite exterior side surfaces, wherein the open-cell metal foam is disposed inward of the first and second rows of teeth.