The effect of CFR-PEEK cross-link in short fixation for the stabilization of lumbar metastasis: an in vitro comparative study

The stabilisation of the spine after the orthopaedic management of vertebral bone metastasis is a crucial step for the success of the surgery. Carbon fiber reinforced PEEK (CFR-PEEK) is being widely adopted for fixation instruments thanks to its good biomechanical performances and radio transparency. The study investigates whether the integration of a CFR-PEEK cross link in a short fixation could become a viable alternative to long gold standard fixation. An experimental in-vitro study was then conducted, comparing different surgical CFR-PEEK stabilisations by characterizing their kinetic (i.e., Moment vs ROM curves and long-chain stiffness) and kinematic (i.e., segmental angular contribution) responses in flexion-extension, lateral bending and axial rotation. To provide additional insights on long-term applicability, the event of a pedicle screw loosening was also replicated. The experimental results suggest that a CFR-PEEK short fixation augmented with cross-link can be a promising conservative strategy. This unprecedent biomechanical quantitative comparison of CFR-PEEK stabilisations could support future clinical studies.