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

Background: 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. Methods: 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. Results: 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. Conclusions: 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.