Hydrogel-Based Biomaterials in Spinal Repair: Evaluating Mechanisms for IVDD, SCI, and Dural Regeneration

Spinal disorders, such as intervertebral disc degeneration (IVDD) and spinal cord injury (SCI), pose substantial challenges in modern healthcare, exacerbated by an aging population and the limited effectiveness of current treatments. IVDD, characterized by extracellular matrix (ECM) degradation, dehydration of the nucleus pulposus, and inflammation, is a leading cause of chronic low back pain, affecting approximately 266 million people worldwide each year. Likewise, SCI, frequently resulting from traumatic incidents, can induce irreversible neurological impairment due to both primary mechanical injury and secondary inflammatory responses, encompassing glial scar formation and axonal disruption. Despite advancements in pain management, surgery, and cell therapies, these conditions remain difficult to treat effectively. This review examines recent developments in hydrogel materials for spinal surgery, with a focus on their applications in the treatment of IVDD and SCI. Hydrogels, due to their biocompatibility, tunable mechanical properties, and ability to mimic the native ECM, have shown enormous promise in spinal repair. Their high water content and porous structure enable the efficient delivery of drugs and cells, and their injectability makes them useful for minimally invasive procedures. Hydrogels offer potential in regenerating the nucleus pulposus, modulating inflammation, supporting axonal regrowth, and preventing fibrosis. Furthermore, their injectable and self-healing properties enable less invasive surgical interventions. While showing clear advantages, they continue to struggle with mechanical strength, controlled therapeutic delivery, and precise structural outcomes in 3D printing. Ongoing research is needed to optimize these properties for clinical applications. This review provides an overview of the biological mechanisms, material design, and fabrication techniques of hydrogels, aiming to support the future development of hydrogel-based therapies in spinal disorder treatment.