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Updated: Aug 17, 2026
A Millimeter Scale Flexural Testing System for Measuring the Mechanical Properties of Marine Sponge Spicules
Published on: October 11, 2017
[Biomechanical evaluation of stiffness of long-segment instrumented spine]
Jia Zhang1, William W Lu, Qi-bin Ye
1Department of Orthopaedics Surgery, PUMC Hospital, CAMS and PUMC, Beijing 100730, China. zhangjia@medmail.com.cn
Objective:
To test the changes of the stiffness of the intact, released, and instrumented spines in an in vitro porcine model.
Methods:
Twelve porcine spines (12 segments each) were harvested for the biomechanical tests with Material Test System. Stiffness during flexion, extension, lateral bending, and axial rotation were recorded; then the specimen was released with intervertebral discs and the facet joints removed, followed by repeating the biomechanical tests for stiffness; and finally, a double-rod titanium construct was applied for internal fixation to each released spine and stiffness tests were repeated again.
Results:
Compared with the intact porcine spines [stiffness during flexion, extension, lateral bending, and axial rotation was 52.89 +/- 15.98, 105.43 +/- 56.38, 42.09 +/- 14.73, and (16.94 +/- 4.85) N x mm/degrees, respectively], the stiffness of the released porcine spines [stiffness during flexion, extension, lateral bending, and axial rotation was 44.04 +/- 13.73, 41.46 +/- 10.80, 31.75 +/- 7.23, and (9.10 +/- 2.07)N x mm/degrees, respectively] significantly decreased (P < 0.05), while significantly increased stiffness was found in the instrumented porcine spines [stiffness during flexion, extension, lateral bending, and axial rotation was 385.96 +/- 143.25, 138.96 +/- 59.41, 152.56 +/- 87.15, and (55.91 +/- 16.49) N x mm/degrees, respectively] (P < 0.05).
Conclusion:
Higher instant stiffness was found in instrumented spine than the intact one during flexion, extension, lateral bending and axial rotation.
