The Biomechanical Properties of Porcine Intervertebral Disc Tissue Treated with Different Fixation Solutions

This study evaluated how embalming fixation solutions alter the mechanical behavior of porcine annulus fibrosus, providing critical context for biomechanical testing of preserved human cadaveric tissue. Porcine cervical discs were immersed for 14 days in four commonly used fixatives (Surgical Reality Fluid, Ethanol, Saturated Salt Solution, Imperial College London formulation) and compared to unfixed controls. Three mechanical assays were conducted: single-layer intralamellar tension, bilayer circumferential tension, and interlamellar peel tests. Results revealed that fixation significantly altered mechanical response depending on solution composition. Saturated salt solution (containing formaldehyde) caused the greatest reduction in toe region strain (≈60%) and interlamellar adhesion (−59%) compared to controls, while Imperial College London and ethanol solutions preserved tissue behavior closest to native state. The findings provide practical recommendations for selecting fixatives compatible with biomechanical disc testing.