A spinal interbody cage implant includes a cage, an endplate, and flexible barbs. The endplate is separately attached to the cage and is configured to receive, hold and direct a flexible barb into an upper vertebral surface and a flexible barb into a lower adjacent vertebral surface. Each proximal leg of the cage is configured to receive the endplate, and has a lateral bore that receives a pin which retains the endplate. The endplate directs a first flexible barb upwardly toward an upper vertebral surface, and directs a second flexible barb downwardly toward a lower vertebral surface. Each flexible barb has a proximal head, a shaft extending from the head with a bore extending from the head to its distal end. Teeth are provided along the exterior surface of the shaft with two flats disposed on opposite sides thereof with a slit extending from the distal end towards the head.