Abstract: The invention relates to interbody spacers constructed of allograft material. These allograft implants include a first plank of allograft that has a first fusion surface and a first mating surface, opposite the first fusion surface. A second plank of allograft includes second fusion surface and a second mating surface, opposite the second fusion surface. At least one interior plank of allograft has a third mating surface attached to the first mating surface, and a fourth mating surface opposite the third mating surface, attached to the second mating surface. At least one transverse connector interconnects the first, second, and interior planks of the allograft implants. The allograft implants may have at least one transverse passage, and transverse connectors may interconnect the planks through this passage. The ends of transverse connectors may be flush with the fusion surfaces, and those ends may comprise patterned projections.