Fogel G, Martin N, Williams GM, Unger J, Yee-Yanagishita C, Pelletier M, Walsh W, Peng Y, Jekir M. Choice of Spinal Interbody Fusion Cage Material and Design Influences Subsidence and Osseointegration Performance.
World Neurosurg 2022;
162:e626-e634. [PMID:
35346883 DOI:
10.1016/j.wneu.2022.03.087]
[Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 03/18/2022] [Accepted: 03/19/2022] [Indexed: 12/19/2022]
Abstract
OBJECTIVE
The objective of the study was to quantify the effect of cage material (titanium-alloy vs. polyetheretherketone or PEEK) and design (porous vs. solid) on subsidence and osseointegration.
METHODS
Three lateral cages (solid PEEK, solid titanium, and 3-dimension-printed porous titanium cages) were evaluated for cage stiffness, subsidence compression stiffness, and dynamic subsidence displacement under simulated postoperative spine loading. Dowel-shaped implants made of grit-blasted solid titanium alloy (solid titanium) and porous titanium were fabricated using commercially available processes. Samples were processed for mechanical push-out testing and polymethylmethacrylate histology following an established ovine bone implantation model.
RESULTS
The solid titanium cage exhibited the greatest stiffness (57.1 ± 0.6 kN/mm), followed by the porous titanium cage (40.4 ± 0.3 kN/mm) and the solid PEEK cage (37.1 ± 1.2 kN/mm). In the clinically relevant dynamic subsidence, the porous titanium cage showed the least amount of subsidence displacement (0.195 ± 0.012 mm), significantly less than that of the solid PEEK cage (0.328 ± 0.020 mm) and the solid titanium cage (0.538 ± 0.027 mm). Bony on-growth was noted histologically on all implant materials; however, only the porous titanium supported bony ingrowth with marked quantities of bone formed within the interconnected pores through 12 weeks. Functional differences in osseointegration were noted between groups during push-out testing. The porous titanium showed the highest maximum shear stress at 12 weeks and was the only group that demonstrated significant improvement (4-12 weeks).
CONCLUSIONS
The choice of material and design is critical to cage mechanical and biological performances. A porous titanium cage can reduce subsidence risk and generate biological stability through bone on-growth and ingrowth.
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