Reconstruction for diverse fronto-orbital defects with computer-assisted designed and computer-assisted manufactured PEEK implants in one-stage operation: Case reports

Neuroinflammation and neurodegeneration following traumatic brain injuries

Traumatic brain injuries (TBI) commonly occur following head trauma. TBI may result in short- and long-term complications which may lead to neurodegenerative consequences, including cognitive impairment post-TBI. When investigating the neurodegeneration following TBI, studies have highlighted the role reactive astrocytes have in the neuroinflammation and degeneration process. This review showcases a variety of markers that show reactive astrocyte presence under pathological conditions, including glial fibrillary acidic protein (GFAP), Crystallin Alpha-B (CRYA-B), Complement Component 3 (C3) and S100A10. Astrocyte activation may lead to white-matter inflammation, expressed as white-matter hyperintensities. Other white-matter changes in the brain following TBI include increased cortical thickness in the white matter. This review addresses the gaps in the literature regarding post-mortem human studies focussing on reactive astrocytes, alongside the potential uses of these proteins as markers in the future studies that investigate the proportions of astrocytes in the post-TBI brain has been discussed. This research may benefit future studies that focus on the role reactive astrocytes play in the post-TBI brain and may assist clinicians in managing patients who have suffered TBI.

An HA/PEEK scaffold with modified crystallinity via 3D-bioprinting for multiple applications in hard tissue engineering

Hard tissues, especially teeth and bones, are highly mineralized and the large-scale defect or total loss of them is irreversible. There is still no ideal strategy for the reconstruction of various hard tissue defects that can achieve the balance between biological and mechanical properties. Polyether ether ketone (PEEK) has the potential to substitute for natural hard tissue in defect areas but is limited by its biological inertness. The addition of hydroxyapatite (HA) can significantly improve the osteogenic properties and osteointegration of PEEK materials. But the mechanical properties of HA/PEEK scaffolds are far from satisfaction making scaffolds easy to fracture. We put forward a strategy to balance the mechanical and biological properties of HA/PEEK scaffolds via the regulation of the inner crystallinity and HA mixing ratio and we systematically evaluated the modified HA/PEEK scaffolds through material characterization,in vitroandin vivoexperiments. And we found that the 20%HA/PEEK scaffolds with low crystallinity achieved the required strength and elasticity, and exhibited the characteristics of promoting the proliferation, migration and osteogenic differentiation of bone marrow mesenchymal stem cells. The results of the implantation of beagles' teeth, mandible and rib showed that the 20%HA/PEEK scaffold with low crystallinity could well withstand the local complex force in the defect area and combine well with natural bone tissue, which made it a candidate for a practical versatile hard tissue engineering scaffold.

Outcomes of surgical management and implant consideration for depressed skull fractures: A systematic review

Background

Traumatic brain injuries (TBIs) are associated with high mortality and morbidity. Depressed skull fractures (DSFs) are a subset of fractures characterized by either direct or indirect brain damage, compressing brain tissue. Recent advances in implant use during primary reconstruction surgeries have shown to be effective. In this systematic review, we assess differences in titanium mesh, polyetheretherketone (PEEK) implants, autologous pericranial grafts, and methyl methacrylate (PMMA) implants for DSF treatment.

Methods

A literature search was conducted in PubMed, Scopus, and Web of Science from their inception to September 2022 to retrieve articles regarding the use of various implant materials for depressed skull fractures. Inclusion criteria included studies specifically describing implant type/material within treatment of depressed skull fractures, particularly during duraplasty. Exclusion criteria were studies reporting only non-primary data, those insufficiently disaggregated to extract implant type, those describing treatment of pathologies other than depressed skull fractures, and non-English or cadaveric studies. The Newcastle-Ottawa Scale was utilized to assess for presence of bias in included studies.

Results

Following final study selection, 18 articles were included for quantitative and qualitative analysis. Of the 177 patients (152 males), mean age was 30.8 years with 82% implanted with autologous graft material, and 18% with non-autologous material. Data were pooled and analyzed with respect to the total patient set, and additionally stratified into those treated through autologous and non-autologous implant material.There were no differences between the two cohorts regarding mean time to encounter, pre-operative Glasgow coma scale (GCS), fracture location, length to cranioplasty, and complication rate. There were statistically significant differences in post-operative GCS (p < 0.0001), LOS (p = 0.0274), and minimum follow-up time (p = 0.000796).

Conclusion

Differences in measurable post-operative outcomes between implant groups were largely minimal or none. Future research should aim to probe these basic results deeper with a larger, non-biased sample.

Functional engineering strategies of 3D printed implants for hard tissue replacement

Three-dimensional printing technology with the rapid development of printing materials are widely recognized as a promising way to fabricate bioartificial bone tissues. In consideration of the disadvantages of bone substitutes, including poor mechanical properties, lack of vascularization and insufficient osteointegration, functional modification strategies can provide multiple functions and desired characteristics of printing materials, enhance their physicochemical and biological properties in bone tissue engineering. Thus, this review focuses on the advances of functional engineering strategies for 3D printed biomaterials in hard tissue replacement. It is structured as introducing 3D printing technologies, properties of printing materials (metals, ceramics and polymers) and typical functional engineering strategies utilized in the application of bone, cartilage and joint regeneration.