Nested interbody spinal fusion implants

An interbody spinal fusion implant for insertion across a disc space between two adjacent vertebral bodies of a human spine, said implant comprising:

• a leading end, a trailing end opposite said leading end and a length therebetween;
• a hollow interior;
• opposite arcuate portions adapted for placement toward and at least in part within the adjacent vertebral bodies and having a distance therebetween defining an implant height greater than the normal height of the disc space, each of said opposite arcuate portions having at least one opening communicating with one another and said hollow interior;
• at least a portion of a thread formed on the exterior of each of said opposite arcuate portions for penetrably engaging the adjacent vertebral bodies;
• a lateral side and a medial side opposite said lateral side, said lateral side including a side support wall connecting said opposite arcuate portions, said medial side of said implant including an open area extending from one of said opposite arcuate portions to the other of said opposite arcuate portions and extending from said leading end to said trailing end of said implant along a majority of the length of said implant;
• a leading support wall connecting said opposite arcuate portions and said side support wall at said leading end of said implant, said leading support wall having a concave portion at said medial side of said implant adjacent said open area, said concave portion of said leading support wall and said opposite arcuate portions having substantially the same radius of curvature;
• and
• a trailing support wall connecting said opposite arcuate portions and said side support wall at said trailing end of said implant, said trailing support wall having a concave portion at said medial side of said implant adjacent said open area, said concave portion of said trailing support wall and said opposite arcuate portions having substantially the same radius of curvature.

A pair of non-identical, complementary, interbody spinal fusion implants for insertion across a disc space between two adjacent vertebral bodies of a spine, said pair of implants comprising:

• a first spinal fusion implant having a leading end, a trailing end opposite said leading end, a length, and a hollow interior therebetween, said first implant having opposite arcuate portions adapted for placement toward and at least in part within the adjacent vertebral bodies and having a distance therebetween defining a first implant height greater than the normal height of the disc space, each of said opposite arcuate portions having at least one opening communicating with one another and said hollow interior, at least a portion of a thread formed on the exterior of each of said opposite arcuate portions for penetrably engaging the adjacent vertebral bodies, a leading support wall connecting said opposite arcuate portions at said leading end, a trailing support wall connecting said opposite arcuate portions at said trailing end, said first implant having a lateral side and a medial side and having a distance therebetween defining a first implant width transverse to said first implant height, said first implant width being less than said first implant height along at least a portion of the length of said first implant, said lateral side of said first implant including a side support wall connecting said opposite arcuate portions, said medial side of said first implant including an open area extending from one of said opposite arcuate portions to the other of said opposite arcuate portions and extending from said leading support wall to said trailing support wall along a majority of the length of said first implant;
• a second spinal fusion implant having a leading end, a trailing end opposite said leading end, a length, and a hollow interior therebetween, said second implant having opposite arcuate portions adapted for placement toward and at least in part within the adjacent vertebral bodies and having a distance therebetween defining a second implant height greater than the normal height of the disc space, each of said opposite arcuate portions having at least one opening communicating with one another and said hollow interior, at least a portion of a thread formed on the exterior of each of said opposite arcuate portions for penetrably engaging the adjacent vertebral bodies, a leading support wall connecting said opposite arcuate portions at said leading end, a trailing support wall connecting said opposite arcuate portions at said trailing end, said second implant having a lateral side and a medial side and having a distance therebetween defining a second implant width transverse to said second implant height, said medial side and said lateral side of said second implant each including a side support wall connecting said opposite arcuate portions, said first implant being configured to receive at least a portion of said medial side of said second implant in said open area of said medial side of said first implant;
• and
• said first and second implants having a combined width when said medial side of said second implant is received by said medial side of said first implant being less than a sum of said first implant width and said second implant width.