South Korean researchers have developed a revolutionary 3D-printing device that can create bone grafts directly at surgical sites, potentially transforming how complex fractures are treated in operating rooms. The modified glue gun technology, developed by scientists at Sungkyunkwan University, enables real-time fabrication of bone scaffolds that conform to irregular fracture patterns without requiring pre-operative preparation.
Novel Approach to Bone Repair
The device addresses a significant limitation in current bone grafting procedures, where implants must be designed and produced prior to surgery for appropriate fitting. "This allows for highly accurate anatomical matching even in irregular or complex defects without the need for preoperative preparation such as imaging, modeling, and trimming processes," said study co-author Professor Jung Seung Lee.
The technology uses a specialized filament comprised of two major components: hydroxyapatite (HA), a natural bone feature known to promote healing, and polycaprolactone (PCL), a biocompatible thermoplastic. PCL can liquify at temperatures as low as 60 degrees Celsius, which when applied with the heat-modified glue gun, remains cool enough to prevent tissue damage during surgical application while conforming to jagged grooves of fractured bone.
Customizable Properties and Infection Prevention
By adjusting the proportion of HA to PCL within the filament, researchers can customize the hardness and strength of grafts to fit different anatomical needs. The compact, manually operated device allows surgeons to adjust printing direction, angle, and depth during procedures in real time, with the entire process completed in minutes.
To address infection concerns common with surgical implants, the researchers incorporated vancomycin and gentamicin, two anti-bacterial compounds, into the filament. Research published in the journal Device showed the filament scaffold successfully inhibited growth of E. coli and S. aureus, two common bacteria prone to cause post-surgery infections.
"This localized delivery approach offers meaningful clinical advantages over systemic antibiotic administration by potentially reducing side effects and limiting the development of antibiotic resistance, while still effectively protecting against postoperative infection," Professor Lee explained.
Superior Clinical Outcomes in Animal Studies
The device was tested on severe femoral bone fractures in New Zealand white rabbits, demonstrating significant advantages over conventional treatments. Within 12 weeks of surgery, researchers found no signs of infection or necrosis and greater bone regeneration compared to rabbits grafted with traditional bone cement.
The rabbits treated with 3D-printed bone grafts showed better outcomes, including superior bone tissue formation and denser bone growth over three months. Key structural parameters such as bone surface area, cortical thickness, and polar moment of inertia all showed superior results, suggesting more effective bone healing and integration. By the study's end, the experimental bone material had degraded by approximately 10%.
Path to Clinical Translation
"We have confirmed the therapeutic potential of this technology using a rabbit model," Lee noted, emphasizing that further studies in larger animal models are needed before human application. The researchers are now optimizing the scaffold's anti-bacterial potential and preparing for human trials.
"To my knowledge, there are virtually no previous examples of applying the technology directly as a bone substitute," Lee said. "This makes the approach quite unique and sets it apart from conventional methods." The team believes their approach can become a practical and immediate solution for bone repair directly in operating rooms, potentially revolutionizing trauma surgery procedures.
