Research Project
10323105
PROJECT SUMMARY?When neck and back pain becomes intractable, spinal fusion is the gold-standard treatment. However, up to 12% of these fusions fail due to infection, resulting in substantial personal and financial costs. In most cases, these infections are associated with the hardware used to stabilize the fusion. Traditionally molded or machined polyether ether ketone (PEEK) cages are widely used for this purpose due to PEEK?s strength, elastic modulus comparable to bone, biocompatibility, and radiolucency. However, traditional PEEK cages and common alternatives are prone to spinal infection. Silicon nitride (Si3N4) spacers have been used in other spinal applications with an excellent antimicrobial performance history (i.e., only 0.006% of implants have been associated with infection), and they provide superior osseointegration compared to other materials. Unfortunately, Si3N4 is not ideal for stabilizing spinal fusions because the material may be susceptible to subsidence and brittle fracture. In this Phase I STTR, SINTX Technologies, in collaboration with Drexel University and Thomas Jefferson University, will combine the antimicrobial and osseointegrative properties of Si3N4 with the strength and elasticity of PEEK to develop novel 3-D-printed antimicrobial cervical cages. Development and commercialization of a 3DP Si3N4-PEEK cervical cage would address a critical unmet clinical need for an antimicrobial spinal fusion stabilizer that promotes osseointegration, withstands in vivo loading, and facilitates imaging. Aim 1. Design a 3DP Si3N4-PEEK cervical cage that meets the static loading requirements of ASTM F2077. Milestone: Demonstrate static compression, shear, and torsion strength of 3DP Si3N4-PEEK?s porous cages that meets or exceeds the guidelines for cervical cages established by ASTM F2077 and benchmarked for many cage manufacturers in the literature. Aim 2. Determine antibacterial activity and osteoblast proliferation/maturation as a function of Si3N4 percentage. Milestone: A >1.5 log reduction in bacterial colonization while retaining osteoblastic proliferation/maturation. Impact?This project is expected to demonstrate the feasibility of creating cervical cages that simultaneously retain the superior radiological and biomechanical qualities of 3DP PEEK biomaterials while preserving the osseointegrative and antimicrobial qualities of Si3N4. A Phase II STTR or SBIR would advance the 3DP Si3N4-PEEK cervical cage to IDE-enabling studies, including assessments of fatigue performance, subsidence resistance, and preclinical performance in a full-scale rigorously powered in vivo model. Rationally designed antibacterial spinal cages that reliably reduce infection are critical, especially given the personal and financial costs of failed fusions as well as the increasing numbers of spinal fusions in the US due to our aging population. Milestone for Progression to Phase II? Delivery of a 3DP Si3N4-PEEK cervical cage that (1) meets the static loading requirements of ASTM F2077, (2) meets minimum performance thresholds for osseointegration, and (3) meets minimum performance thresholds for antibacterial activity. Quantitative targets are included in the Approach.
