Intervertebral spacers with side wall accessible interior cavity

An interbody fusion spacer, comprising:

• an elongated body having a first end wall, an opposite second end wall, and a side wall extending between said first and second end walls, said elongated body defining an outer surface and an interior chamber for receiving an osteogenic material, said side wall defining a main side wall opening in communication with said interior chamber, said main side wall opening sized and configured for loading said osteogenic material into said interior chamber, said side wall defining a plurality of secondary side wall openings extending from said outer surface and in communication with said interior chamber for bone ingrowth into said interior chamber.

An interbody fusion spacer, comprising:

• a generally cylindrical elongated body having opposite first and second end walls and a side wall, said first and second end walls integral with said side wall to provide said elongated body as a unitary, single-piece structure, said elongated body defining an outer surface and an interior chamber for receiving an osteogenic material, said side wall defining a main side wall opening in communication with said interior chamber, said side wall defining a plurality of secondary side wall openings sized smaller than said main side wall opening and extending from said outer surface and in communication with said interior chamber to provide for bone ingrowth into said interior chamber;
• and
• wherein said main side wall opening is sized to extend over at least about 20% of an outer circumference of said body and along at least about 50% of an overall length of said elongated body to provide said side wall opening with a size sufficient for loading said osteogenic material into said interior chamber.

An interbody fusion implant system, comprising:

• a first interbody fusion spacer according to claim 1;
• and
• a second interbody fusion spacer having a second elongated body, said second elongated body having a third end wall, a fourth end wall, a second side wall extending between said third and fourth end walls, said second interbody fusion spacer nestable with said first interbody fusion spacer.