3D-printed antibiotic-eluting pedicle screws for antimicrobial prophylaxis in instrumented spinal fusion

• Published in: Cell reports physical science 2024-12, Vol.5 (12), p.102320, Article 102320
• Main Authors: Karavasili, Christina, Boyce, Hannah, Blanco, Julianna, Young, Thomas, Connolly, Ian D., Park, Sanghyun, Bernstock, Joshua D., Jimenez, Miguel, Kang, Ziliang, Muller, Ben, Min, Seokkee, Wentworth, Adam, Gwynne, Declan, Fabian, Niora, Su, Yuyan, Zhao, Ming, Shankar, Ganesh M., Traverso, Giovanni
• Format: Article
• Language: English
• Subjects: 3D-printed pedicle screws; antibiotic-eluting implant; cannulated; fenestrated implants; in situ-forming hydrogel; injectable hydrogel; spinal instrumentation; Staphylococcus aureus; surgical site infections
• ISSN: 2666-3864; 2666-3864
• DOI: 10.1016/j.xcrp.2024.102320

Antibiotic bone cement is the only approved material for antibiotic prophylaxis in instrumented spine surgeries. However, its application has been linked to multiple complications and risks for patients and surgical staff. Here we report the fabrication of customizable cannulated and fenestrated Ti-6Al-4V pedicle screws, designed to provide sustained antibiotic elution through an injectable hydrogel comprised of sodium polyacrylate (SP), doxycycline, and β-tricalcium phosphate. The 3D-printed screws and SP hydrogels are compatible with human fetal osteoblasts, enhancing attachment, proliferation, and mineral deposition on the micro-structured implant surface, which all serve as key indicators of new bone formation. Sustained antibiotic elution through the screws’ fenestrations proved effective at inhibiting Staphylococcus aureus growth in vitro and ex vivo using a bacterially infected porcine lumbar spine model. The injectable hydrogel and 3D-printed antibiotic-eluting screws offer potential as a patient-specific and safer alternative to traditional cemented machined implants for antimicrobial prophylaxis in instrumented spinal procedures. [Display omitted] •Sodium polyacrylate hydrogels as a safer alternative to bone cement•3D printed screws offer potential as a personalized alternative to machined implants•3D printed antibiotic-eluting screws effectively inhibited Staphylococcus aureus growth In this work, we developed an injectable hydrogel composite for sustained antibiotic elution through the fenestrations of cannulated 3D-printed Ti-6Al-4V pedicle screws. We demonstrate that 3D printing of the screws enables precise control over cannula geometry, fenestration placement, and implant properties while providing a mechanism for delivering sustained-release formulations. Furthermore, we show that sodium polyacrylate hydrogels can act as effective carriers for therapeutic and bioactive agents to address spine diseases and disorders such as cancers and osteoporosis.