Orbital floor repair using patient specific osteoinductive implant made by stereolithography.

The orbital floor (OF) is an anatomical location in the craniomaxillofacial (CMF) region known to be highly variable in shape and size. When fractured, implants commonly consisting of titanium meshes are customized by plying and crude hand-shaping. Nevertheless, more precise customized synthetic grafts are needed to meticulously reconstruct the patients' OF anatomy with better fidelity. As alternative to titanium mesh implants dedicated to OF repair, we propose a flexible patient-specific implant (PSI) made by stereolithography (SLA), offering a high degree of control over its geometry and architecture. The PSI is made of biodegradable poly(trimethylene carbonate) (PTMC) loaded with 40 wt % of hydroxyapatite (called Osteo-PTMC). In this work, we developed a complete work-flow for the additive manufacturing of PSIs to be used to repair the fractured OF, which is clinically relevant for individualized medicine. This work-flow consists of (i) the surgical planning, (ii) the design of virtual PSIs and (iii) their fabrication by SLA, (iv) the monitoring and (v) the biological evaluation in a preclinical large-animal model. We have found that once implanted, titanium meshes resulted in fibrous tissue encapsulation, whereas Osteo-PMTC resulted in rapid neovascularization and bone morphogenesis, both ectopically and in the OF region, and without the need of additional biotherapeutics such as bone morphogenic proteins. Our study supports the hypothesis that the composite osteoinductive Osteo-PTMC brings advantages compared to standard titanium mesh, by stimulating bone neoformation in the OF defects. PSIs made of Osteo-PTMC represent a significant advancement for patients whereby the anatomical characteristics of the OF defect restrict the utilization of traditional hand-shaped titanium mesh.

Humoral Factors From Musculoskeletal Polytrauma Patients Impair Antibacterial Responses Of Neutrophils In vitro.

Polytrauma is associated with increased risk of sepsis, but the risk for implant infection is less clear. Neutrophil antibacterial responses are significantly reduced in polytrauma patients (n= 9, ISS≥15) for at least 5 days compared to healthy controls. Reduced neutrophil activity could influence implant infection in addition to sepsis.

Interaction of gentamicin sulfate with alginate and consequences on the physico-chemical properties of alginate-containing biofilms.

BACKGROUND: Alginate is one of the main extracellular polymeric substances (EPS) in biofilms of Cystic Fibrosis (CF) patients suffering from pulmonary infections. Gentamicin sulfate (GS) can strongly bind to alginate resulting in loss of pharmacological activity; however neither the mechanism nor its repercussion is fully understood. In this study, we investigated how GS modifies the alginate macromolecular network and its microenvironment. MATERIAL AND METHODS: Alginate gels of two different compositions (either enriched in guluronate units (G) or enriched in mannuronate units (M)) were crosslinked with Ca2+ and exposed to GS at varying times and concentrations. The complexes formed were characterized via turbidimetry, mechanical tests, swelling assay, calorimetry techniques, nuclear magnetic resonance, Ca2+ displacement, macromolecular probe diffusion and pH alteration. RESULTS: In presence of GS, the alginate network and its environment undergo a tremendous reorganization in terms of gel density, stiffness, diffusion property, presence and state of the water molecules. We noted that the intensity of those alterations is directly dependent on the polysaccharide motif composition (ratio M/G). CONCLUSION: Our results underline the importance of alginate as biofilm component, its pernicious role during antibiotherapy and could represent a potential macromolecular target to improve anti-infectious therapies.