Personalized Treatment of Cleft Lip/ Palate Deformities of Canine Patients With Organo-Mineral 4d Scaffolds

Advancements in additive manufacturing have revolutionized scaffold design for treating bone defects, incorporating physicochemical and architectural cues to stimulate bone regeneration. However, challenges persist in achieving precise fit between scaffolds and patients' bone defects due to workflow inaccuracies, which can detrimentally impact regenerative outcomes. Additionally, current scaffolds often lack appropriate mechanical properties, biodegradation rates, and potential for promoting vascularized bone tissue formation. To address these issues, we 3D-printed organo-mineral scaffolds with elastic behavior before setting to treat canine patients with spontaneous cleft lip and palate deformities (CLP). Ethical approval was obtained for canine patient treatment (CERVO-2022-14-V). To date, 18 puppies with spontaneous CLP have been recruited and treated using either patient-specific 4D scaffolds (experimental group) or autologous bone graft (control group). Patient specific scaffolds were designed based on pup CT-scan 2 weeks prior intervention, and after validation of the surgical strategy to adopt. Patented organo-mineral formulation was developed combining α-tricalcium phosphate, silanized hyaluronic acid and hydroxypropyl methylcellulose. This paste was printed by robocasting (27G cones, BioX CellInk), using if needed, 40% w/v Pluronic F127 as a support material. Surgical intervention involved soft tissue reconstruction and placement of scaffolds soaked in autologous bone marrow. Bone formation was monitored at 3- and 6-months post-reconstruction, with detailed analyses conducted at 6 months (µCT, histology, SEM). Compulsory, influence of several sterilization methods of the scaffolds were also assessed to ensure the transfer of the developed technology to human clinical settings. This implied extensive physico-chemical, morphological and mechanical characterization before and after sterilization. Scaffolds exhibited excellent handling properties (elastic deformation) and were effectively inserted into complex bone defects, achieving significant contact between bone edges and scaffolds. Osteointegration was observed at 3 months, with evidence of bone formation within the scaffold's macroporous network. Results at 6 months are comparable if not better with the personalized scaffolds (compared to autograft) when soft tissue dehiscence did not occur at early timepoint. Ethylene oxide seems a suitable sterilization modality, with no degradation of the flexible behavior before cement setting ( in situ once implanted). Preliminary results demonstrate the promising potential of our strategy in treating spontaneous CLP deformities in a veterinary setting. Sterilization of scaffolds after printing is achievable, even with the presence of fragile macromolecules) which represents a major step toward human clinical translation. Animal patients represent an ethical way for the development of innovative treatments within the OneHealth concept.