Innovative 3D Printing Technology Enables Direct Bone Graft Application During Surgery

Researchers have introduced an innovative device resembling a glue gun that utilizes 3D printing technology to produce bone grafts directly on fractures and bone defects during surgical procedures. This development, detailed in the journal Device, has shown promising results in animal studies, particularly with rabbits, facilitating the rapid creation of complex bone implants without the need for pre-surgical fabrication.

The newly engineered tool allows for immediate and precise scaffold formation at the surgical site, enhancing anatomical accuracy even in cases of irregular or complicated bone breaks. The device's design eliminates the necessity for preparatory imaging, modeling, and trimming, significantly streamlining the surgical process.

The material used in the device comprises a filament that combines hydroxyapatite (HA), a natural component known for its bone healing properties, with polycaprolactone (PCL), a biocompatible thermoplastic. This combination allows the printed grafts to adjust in hardness and strength based on the required anatomical specifications.

PCL's ability to liquefy at relatively low temperatures (around 60°C) is crucial, as it minimizes the risk of tissue damage during application while allowing the material to adapt to the irregularities of fractured bone surfaces. Surgeons can manipulate the printing parameters in real time, adjusting the direction, angle, and depth of the graft application, which contributes to increased procedural efficiency.

Infection prevention is a critical concern in surgical interventions, prompting the researchers to incorporate two antibacterial agents, vancomycin and gentamicin, into the filament. Laboratory tests demonstrated that the scaffold effectively inhibited the growth of E. coli and Staphylococcus aureus, common bacteria associated with post-surgical infections. The unique properties of HA and PCL facilitate a sustained release of the antibiotics over several weeks, providing localized protection that may reduce systemic side effects and mitigate the risk of developing antibiotic resistance.

As a proof of concept, the device was applied to treat severe femoral fractures in rabbits. Over a 12-week postoperative period, the results indicated no signs of infection or tissue death, along with enhanced bone regeneration compared to traditional bone cement treatments. The scaffold not only integrates biologically with surrounding bone tissue but is also designed to gradually degrade, making way for new bone growth.

Future research aims to refine the antibacterial capabilities of the scaffold and prepare for human clinical trials, which will necessitate standardized manufacturing processes, validated sterilization methods, and extensive preclinical studies in larger animal models to adhere to regulatory standards. The researchers envision that, upon successful validation, this innovative approach could revolutionize bone repair techniques directly within the operating room.