Can activated titanium interbody cages accelerate or enhance spinal fusion? a review of the literature and a design for clinical trials

Abstract

While spinal interbody cage options have proliferated in the past decade, relatively little work has been done to explore the comparative potential of biomaterial technologies in promoting stable fusion. Innovations such as micro-etching and nano-architectural designs have shown purported benefits in in vitro studies, but lack clinical data describing their optimal implementation. Here, we critically assess the pre-clinical data supportive of various commercially available interbody cage biomaterial, topographical, and structural designs. We describe in detail the osteointegrative and osteoconductive benefits conferred by these modifications with a focus on polyetheretherketone (PEEK) and titanium (Ti) interbody implants. Further, we describe the rationale and design for two randomized controlled trials, which aim to address the paucity of clinical data available by comparing interbody fusion outcomes between either PEEK or activated Ti lumbar interbody cages. Utilizing dual-energy computed tomography (DECT), these studies will evaluate the relative implant-bone integration and fusion rates achieved by either micro-etched Ti or standard PEEK interbody devices. Taken together, greater understanding of the relative osseointegration profile at the implant–bone interface of cages with distinct topographies will be crucial in guiding the rational design of further studies and innovations.

Effect of Interbody Implants on the Biomechanical Behavior of Lateral Lumbar Interbody Fusion: A Finite Element Study

“…Similarly, McGilvray et al [ 38 ] also found that porous Ti significantly increased bone ingrowth over PEEK in their ovine lumbar fusion model. Recently, a number of porous Ti cages have been commercially available, but there have been limited long-term clinical trials supporting their efficacy in promoting early osseointegration and fusion [ 39 ]. Although increasing the porosity may be more beneficial to bone growth, the mechanical strength of the porous Ti should be taken into account [ 24 ].…”