Biomechanical Comparison of Subsidence Between Patient-Specific and Non-Patient-Specific Lumbar Interbody Fusion Cages

Renan J R Fernandes; Aaron Gee; Andrew J Kanawati; Fawaz Siddiqi; Parham Rasoulinejad; Radovan Zdero; Christopher S Bailey

doi:10.1177/21925682221134913

Biomechanical Comparison of Subsidence Between Patient-Specific and Non-Patient-Specific Lumbar Interbody Fusion Cages

Global Spine J. 2024 May;14(4):1155-1163. doi: 10.1177/21925682221134913. Epub 2022 Oct 19.

Authors

Renan J R Fernandes^{1

2

3}, Aaron Gee^{1

3}, Andrew J Kanawati⁴, Fawaz Siddiqi^{1

2}, Parham Rasoulinejad^{1

2

3}, Radovan Zdero³, Christopher S Bailey^{1

2

3}

Affiliations

¹ Combined Orthopaedic and Neurosurgery Spine Program, London Health Science Centre, London, ON, Canada.
² Schulich School of Medicine, Western University, London, ON, Canada.
³ Lawson Health Research Institute, London, ON, Canada.
⁴ Department of Orthopaedic Surgery, Westmead Hospital, Sydney, NSW, Australia.

PMID: 36259252
DOI: 10.1177/21925682221134913

Abstract

Study design: Biomechanical study.

Objectives: Several strategies to improve the surface of contact between an interbody device and the endplate have been employed to attenuate the risk of cage subsidence. 3D-printed patient-specific cages have been presented as a promising alternative to help mitigate that risk, but there is a lack of biomechanical evidence supporting their use. We aim to evaluate the biomechanical performance of 3D printed patient-specific lumbar interbody fusion cages in relation to commercial cages in preventing subsidence.

Methods: A cadaveric model is used to investigate the possible advantage of 3D printed patient-specific cages matching the endplate contour using CT-scan imaging in preventing subsidence in relation to commercially available cages (Medtronic Fuse and Capstone). Peak failure force and stiffness were analyzed outcomes for both comparison groups.

Results: PS cages resulted in significantly higher construct stiffness when compared to both commercial cages tested (>59%). PS cage peak failure force was 64% higher when compared to Fuse cage (P < .001) and 18% higher when compared to Capstone cage (P = .086).

Conclusions: Patient-specific cages required higher compression forces to produce failure and increased the cage-endplate construct' stiffness, decreasing subsidence risk.

Keywords: 3d print; cage; interbody fusion; patient-specific; subsidence.