Mechanoadaptive collagen fiber reorientation in the spinal dura mater under biaxial stretch: Implications for protective mechanisms.

Abstract

The spinal dura mater plays an important role in maintaining the mechanical integrity of the central nervous system by enclosing cerebrospinal fluid (CSF) and protecting the spinal cord. Structurally, the dura mater primarily comprises collagen fibers. However, the orientation and mechanical response of these fibers to deformation remain poorly understood. Understanding these structural behaviors is crucial for elucidating the dura's biomechanical function and its vulnerability to injury, including CSF leakage. The present study aimed to elucidate the dynamic behavior of the collagen fiber orientation in the spinal dura mater under biaxial tensile loading. We quantified the orientation angle distributions and analyzed their realignment patterns under different loading ratios using a custom-built polarization imaging system combined with stereomicroscopic observation. The results suggest that collagen fiber reorganization plays an essential role in the ability of the spinal dura mater to withstand mechanical stress, acting as an important mechanism for energy dissipation and structural protection. Notably, fiber alignment changes were sensitive to the direction and magnitude of the applied load, implying that regional tissue properties are closely linked to the local mechanical environments. The quantitative insights obtained in this study will help inform the development of subject-specific finite element models, enabling a more accurate simulation of mechanical failure and CSF leakage. Ultimately, these models could contribute to improved strategies for predicting, preventing, and treating dural injuries in clinical and biomechanical applications.