Evaluation of the neovascularisation of 3D-printed hydroxyapatite implants in rats

Abstract

Introduction: Maxillo-facial defects are a commonly encountered problem that cranio-facial and plastic surgeons have to face in hospital practice. It can have either a pathologic or a non-pathologic origin. The current gold standard for bone replacement for in those defects is an autograft from a fibula free flap. However, the current gold standard has limitations and synthetic bone replacement overcoming those limitations have known an expansion in the recent years. Objective: Two main objectives were pursued during this master thesis. The first one was to develop and evaluate the design of the sub-scapular implant as well as the surgical implantation protocol. The second was to develop and evaluate the imaging protocols to visualise the neovascularisation inside the implant. Methods: First a cadaver test was realised to test and evaluate the design of the implant as well as the surgical implantation technique. Secondly, a pilot study was realised in a small group of 5 rats. During this pilot study, the surgical technique was adapted and the vascularisation was evaluated by micro-CT. Both in-vivo and ex-vivo micro-CT were used. Results: The design medium rectangular L was the design the most fitting regarding size and implan- tation incision closure. The tail catheter injection technique was chosen over the needle injection. The in-vivo micro-CT show vascularisation only on the outside of implant. The pre-test ex-vivo micro-CT shown vascularisation inside organs. Conclusion: The medium rectangular L design was chosen to be implanted in the rats of the pilot study. The placement of the medium rectangular L at the interscapular area in rats with the chosen protocol was successful. The vascularisation surrounding the implant can be seen with the in-vivo micro-CT. However, the neovascularisation inside the implant could not be seen with that imaging method.