By: 6 October 2020
ST-Line – Next in fusion

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With its new ST-Line, SIGNUS has applied the progress from endoprosthetic research to spinal surgery

Regardless of the application, the excellent mechanical and biological properties of titanium and its alloys have made it a permanent fixture in modern medicine [1].

New findings have facilitated continuous improvements to this high-performance material for the purposes of endoprosthetic procedures. As a result, porous implants with good to excellent long-term results for osseous integration have now become the gold standard [2]. It is important to reproduce the structure of natural bone: diameter, depth and interconnectivity of the pores and their surface roughness are fundamental factors for achieving the successful integration and bony in-growth. By selecting the appropriate parameters, an optimal supply of oxygen and nutrients to the newly formed bone can be guaranteed and so achieve secure anchorage of the implant [3].



As stable as cortical bone and as porous as cancellous bone. Hence the rapid and seamless fusion of implant and adjacent bone are guaranteed. To achieve this, the ST-Line implants are made up of 70 per cent pores but have the same mechanical strength as conventional interbody fusion implants. This has been verified by tests following ASTM standards.



The open, porous structure maximises the contact surface between the implant and endplate of the adjacent vertebral body. This, in combination with the surface roughness, minimises the risk of migration and ensures excellent primary stability. Additionally, the pore size, structure and surface roughness have been optimised to permit rapid vascularisation and bony integration. Further, the interconnectivity of the pores permits the bone to not just grow into intimate contact with the implant, but also through the structure to achieve a solid fusion and optimal stability of the fused segment.



A sophisticated manufacturing process enables the ST-Line implants to be produced with a complex internal and external structure. Titanium powder is fused into a matrix using precision 3D printing techniques. Using this process, which is well-established in the aerospace industry, it is possible to precisely define and create the desired pore geometries. As a result, the natural structure and mechanical properties of bone can be used to guide development achieving the optimal foundation for a rapid and solid fusion.

With its new ST-Line, SIGNUS has applied the progress from endoprosthetic research to spinal surgery: Structural Titanium (ST) – an open pore titanium matrix with anatomic parameters designed to optimise interbody fusion.



  1. Rader CP; Hendrich C; Löw S; Walther M; Eulert J. Unfallchirurg 103, 846-852, 2000. Selmitsch M. In: Zweymüller K (Hrsg): 10 Jahre Zweymüller-Hüftendoprothese; S. 14-19, 1990
  2. Kinner B; Willmann G; Storz S; Kinner J. Z Orthop 137, 114-121, 1999. Ewerbeck V. Der Unfallchirurg 11, 917-927, 2000
  3. Jean-Philippe St-Pierre; Maxime Gauthier; Louis-Philippe Lefebvre; Maryam Tabrizian. Three-dimensional growth of differentiating MC3T3-E1 preosteoblasts on porous titanium scaffolds, 2005