The Effect of Prolonged Vibration Exposure on the Tensile Mechanical Properties of Single Layers of the Annulus Fibrosus

This study investigated whether prolonged axial vibration alters the tensile mechanical properties of single annulus fibrosus lamellae harvested from porcine cervical intervertebral discs. Following two hours of cyclic axial vibration or static compression, isolated annular layers were mechanically tested in tension perpendicular to collagen fiber orientation. While elastic modulus, maximum stress, and strain at failure were not significantly different between groups, vibrated tissues exhibited a significantly larger toe region in the stress–strain response. The authors interpret this expanded toe region as damage to the inter-collagen matrix, suggesting that vibration may initiate microstructural weakening that predisposes discs to herniation.