By: 15 November 2021
POSEIDON ST – Expandable vertebral body replacement

Promotional feature

SIGNUS expands its ST portfolio with the expandable vertebral body replacement POSEIDON ST: Slim diameter – large contact area.

The variability of POSEIDON® ST when placing the endplates on the base body enables the surgeon to freely choose the approach to treat defects caused by tumours, fractures or infections in the TH1 to L5 spinal segment.

The endplates of POSEIDON® ST are made of structured titanium and are toothed, which anchors them into the inferior and superior endplates of the adjacent vertebral bodies after distraction, thus providing the necessary protection against dislocation without loading the less stable central core of the vertebral body. The open-pore titanium grid structure of the POSEIDON® ST endplates optimises the osseointegration behaviour.

The inserted cage, combined with additional posterior instrumentation, leads to immediate biomechanical stabilisation.

The overall structure of the POSEIDON® ST is made up of a base body that can be distracted in situ and two endplates. If required, the implant construct can be expanded by an extension at either the superior and / or the inferior end of the base body. The distraction modules are available in different heights. Extension modules available.

Thanks to the narrow base body with a diameter of only 16 mm, there is plenty of space available for fusion material such as harvested bone or synthetic bone graft material, e.g. KAINOS® +, and they can be combined with a large selection of endplates in different sizes and angles. This highly modular design of POSEIDON® ST provides the surgeon with a great degree of flexibility so that the implant can be customised as precisely as possible to the patient’s individual situation, fully utilising the maximum possible area1 of the bone–implant interface to achieve rotational stability of the implant. The locking screw secures the cage at the desired height.


Reference: 1 YOUSSEF MASHARAWI, 1, 2 KHALIL SALAME, 3* YIGAL MIROVSKY, 4 SMADAR PELEG, 2 GALI DAR, 2, 5 NILI STEINBERG, 2, 6 AND ISRAEL HERSHKOVITZ2, „Vertebral Body Shape Variation in the Thoracic and Lumbar Spine: Characterization of Its Asymmetry and Wedging“, Clinical Anatomy 21: 46–54 (2008)


POSEIDON ST Product-Specific Advantages

Secure construction

  • Large overlapping heights between the base bodies
  • Fixed connection between the endplates and the base body
  • Locking of the distraction mechanism
  • Narrow base body with a diameter of only 16 mm

Highly modular design

  • Free choice of approach by attaching endplates in 30° increments
  • Stepless expansion, heights of 18 – 89 mm
  • Optimal reconstruction of the natural spinal anatomy

Sophisticated endplate design

  • Greatest possible bone–implant interface to support the cortical bone
  • Teeth for high primary stability and secure prevention of dislocation
  • Large selection of straight and angled endplates for individual restoration of the sagittal alignment

Open, macroporous titanium structure*

  • Resembles natural cancellous architecture
  • Enables both growing-on and growing-in of bone

SIGNUS modular solution

  • Can be optimally combined with the DIPLOMAT® screw-rod systems
  • Additional application of bone graft material (e.g. KAINOS® +) possible

*Only applies for the endplates of POSEIDON® ST


More information on POSEIDON ST:



Innovative high-end implants made in Germany: For more than 25 years, SIGNUS has been the experienced specialist for comprehensive solutions in the surgical spine care sector. Founded in 1994 in Germany’s Lower Franconian city of Alzenau by Susanne and Uwe Siedler, our family-owned company currently has staff of approx. 80 at sites in Germany and Australia. SIGNUS offers the comprehensive product range of cervical spine to SIG sacroiliac joints, which are predominately manufactured at the nearby production site of ProCon Medizintechnik. In addition to Europe (CE) and the USA (FDA), we sell our certified implants throughout the world on every continent. Target-oriented further development of the products in connection with the continuous exchange with the users as well as international further education and hospitalisation programs make SIGNUS a reliable global partner.

The entire SIGNUS Portfolio with detailed information and descriptions are available for you online at