Current interbody fusion devices for lumbar fusion need improvement owing to lower than desireable success in fusion and difficulty in postoperative assessment effusion. A promising and novel approach for intervertebral fusion is to provide a cortico-cancellous structure that can withstand spine load adequately and provide a bioactive bony ingrowth surface to effect rapid bony bridging across the adjacent vertebral segments. If a device made from such a structure can be fabricated to mimic the natural achitecture of the vertebral body, have imaging compatibility and be osteogenic, clinical issues associated with spine fusion such as inadequate fusion, imaging difficulty, subsidence and collapse can be resolved. A novel cortico-cancellous structured ceramic (CSC), has been developed which offers [a] high mechanical safety, [b] good imaging characteristics unlike metals, and [c] a bio-mimetic scaffold necessary for ingrowth and rapid integration with host bone. Static and dynamic mechanical properties of the CSC materials have been established and the fabrication processes to make bio-mimetic structures have been developed. We have also succeeded in demonstrating the in-vivo efficacy of prototypical devices in a sheep model. These developments enable design of safe load bearing hybrid spine fusion implants. In the Phase 1 program, we propose to design and validate in-vitro, a graded porosity h-CSIF device that mimics natural vertebral body architecture. This will have a lower porosity outer"""""""" cortical"""""""" ring, and a higher porosity """"""""cancellous"""""""" core. We will demonstrate, by direct comparison with competing devices made from titanium and allograft bone, the favorable mechanical, and imaging features of these implants. Phase 1 results will establish the merit and feasibility of the novel approach by comprehensive in vitro mechanical testing and imaging characterization on the h-CSIF implant design. In Phase 2 we will demonstrate the combination of rapid bone in-growth characteristics, effective integration with host vertebral bodies and imaging compatibility in a sheep intervertebral model in comparison to current state-of-the-art.
