Annulus Fibrosus Repair via Interpenetration of a Non-Woven Scaffold Supports Tissue Integration and Prevents Re-Herniation.

Abstract

Current surgical management of intervertebral disc herniation often fails to adequately address the risk of recurrence, primarily due to the disc's limited regenerative capacity. Regenerative, biomaterial-based approaches for tissue augmentation, while showing preclinical promise, have consistently failed to meet the extreme mechanical demands of the intervertebral disc, impeding their clinical translation. In this study, we introduce a novel annulus repair strategy that employs the mechanical interpenetration of a non-woven PET scaffold into intervertebral disc tissue to resist reherniation. We investigate the efficacy in preventing herniations under compression using a bovine explant model and validate its performance in a pilot in vivo study in a goat cervical spine injury model. Healing and scaffold integration are assessed over 4 weeks using computed tomography, magnetic resonance imaging, and histopathology. We demonstrate that this approach effectively prevents mechanically induced herniation. In vivo, the scaffold interpenetration enables biological integration at 4 weeks post-surgery, with no evidence of scaffold migration or disc degeneration. The scaffold supports matrix deposition and cell infiltration, with no observed endplate pathologies or osteolysis. These findings highlight a promising combination of biomechanical reliability and favorable histological outcomes, underscoring the potential of this technology for advancing toward human clinical applications.