Ana Grzeszczak

Development of a 3D-printable and degradable polymeric material for composite implants

Additive manufacturing (AM) has enabled patient-specific implants to be produced in an affordable way. However, most implants are non-degradable, including cranial implants used to reconstruct the skull integrity after events such as traumatic injuries to the head, tumor resection, decompressive craniectomy, and calvarial defects. The complication rate of these procedures was found to decrease when using cranial implants manufactured by the MedTech company OssDsign. Clinical results from OssDsign’s cranial patient-specific implant demonstrate extensive bone formation on the implant, even in large defects (>100 cm2), showing that the bone tissue has the capacity to regrow in the calcium phosphate ceramic part of the implant. The latter is currently reinforced by a titanium alloy mesh. By replacing the titanium by a resorbable material, complete regeneration of the defects would be feasible, thus providing several patient benefits. Primarily, the implant could be used to a larger extent for paediatric patients whose bones are still growing, potentially reducing the need for revision surgeries. Furthermore, the degrading implant would progressively be providing fewer potential sites for bacterial adhesion and infections, which have become a major concern due to increasing bacterial resistance worldwide. In addition, the titanium mesh interferes with the most common imaging techniques (MRI and X-ray), often required for the follow-up of cranioplasty procedures, and it would be beneficial to have a mesh material that is degradable. The main objective of this project is thus to develop a polymer material that can be additively manufactured and combined with a calcium phosphate ceramic, to resorb in the body while being replaced by the patient’s own tissue, allowing for the complete regeneration of the bone defects.

The research project is divided as follows:

• Development of Poly(L-lactic acid) - ceramic composite structures
• In vitro cell study of the Poly(L-lactic acid) - ceramic composite structures
• Addition of PCL in 3D-printable PLA/HA composite filaments
• Optimization of extrusion and 3D-printing of a co-blend of polymers, starting with PLLA/PCL