Use of ceramic synthetic allografts in spine surgery: a narrative review with early basic science and clinic data of novel nanosynthetic bone graft

Background and objective: As the global population ages, degenerative spinal disorders are on the rise, leading to an increased focus on optimizing spinal fusion therapies. Despite the high success rate of iliac crest bone autografts, their usage is hampered by donor site morbidity and limited supply. The objective of this review is to assess the viability of ceramic-based synthetic materials as alternatives in spinal fusion surgeries.

Methods: A review of national databases was performed using key terms "allograft", "nanosynthetic", "spine", and "surgery" for literature from 1900 to 2024. Studies that aimed to describe the utility of ceramic allografts, associated outcomes, limitations, and future directions were included. Studies that were not in English were excluded.

Key content and findings: Successful spinal fusion relies on osteoconductivity, osteoinductivity, osteogenesis, and osteointegration. Ceramic-based materials, primarily calcium sulfates, phosphates, hydroxyapatites (HAs), and silicon nitrides, are recognized for their osteoconductive properties. Recent studies suggest the efficacy of ceramics as graft extenders and highlight both their compatibility and cost-effectiveness. Innovations like nanosynthetic bone grafts have shown potential in preclinical trials, offering enhanced bone formation and resorption properties. The narrative review details comparative outcomes of various synthetic grafts against autografts and allografts, indicating similar fusion rates with potentially lower complication rates.

Conclusions: Ceramic-based synthetic materials represent a significant advancement in spinal fusion procedures, with properties that can potentially match those of autografts. Nanosynthetic grafts, in particular, exhibit promising results in animal studies and initial clinical trials. The continuous development and evaluation of these materials could optimize fusion rates and reduce the morbidity associated with autograft harvesting. However, further research is required to assess long-term outcomes and determine the best practices for their use in spinal surgeries.