Reconstruction Of Bone Defects Research Articles

Use of Fibular Strut Graft for Reconstruction of Bone Defects

Introduction • Bone recalcitrant nonunion and bone defects usually follow trauma, resection of a malignant tumor of the musculoskeletal system and osteomyelitis. • Instead of amputation, which was used in the past, limb salvage surgeries, including non-vascularized or vascularized autografts and allografts, bone transport and replacement with prostheses are performed. • Among the above methods, nonvascularized autogenous bone graft use is an important treatment strategy that has been performed for over a hundred years. • The fibula is a tubular bone that has a suitable length, geometrical shape and mechanical strength and is considered to be the best donor bone for large bone defects. • Free vascularized fibular grafts achieve higher union rate than non-vascularized fibular grafts in the reconstruction of long bone defects. • In this study, 6 patients with bone defects treated by non-vascularized fibular grafts .We intended to assess the clinical outcomes of graft union, functional outcome.

Surgical Management of Periprosthetic Joint Infections in Hip and Knee Megaprostheses.

Periprosthetic joint infection is a feared complication after the megaprosthetic reconstruction of oncologic and non-oncologic bone defects of including the knee or hip joint. Due to the relative rarity of these procedures, however, optimal management is debatable. Considering the expanding use of megaprostheses in revision arthroplasty and the high revision burden in orthopedic oncology, the risk of PJI is likely to increase over the coming years. In this non-systematic review article, we present and discuss current management options and the associated results focusing on studies from the last 15 years and studies from dedicated centers or study groups. The indication, surgical details and results in controlling infection are presented for debridement, antibiotics, irrigation and retention (DAIR) procedure with an exchange of the modular components, single-stage implant exchange, two-stage exchanges and ablative procedures.

Conductive and Enhanced Mechanical Strength of Mo2Ti2C3 MXene-Based Hydrogel Promotes Neurogenesis and Bone Regeneration in Bone Defect Repair.

Bone defects are common with increasing high-energy fractures, tumor bone invasion, and implantation revision surgery. Bone is an electroactive tissue that has electromechanical interaction with collogen, osteoblasts, and osteoclasts. Hydrogel provides morphological plasticity and extracellular matrix (ECM) 3D structures for cell survival, and is widely used as a bone engineering material. However, the hydrogels have poor mechanical intensity and lack of cell adhesion, slow gelation time, and limited conductivity. MXenes are novel nanomaterials with hydrophilic groups that sense cell electrophysiology and improve hydrogel electric conductivity. Herein, gelatin had multiple active groups (NH2, OH, and COOH) and an accelerated gelation time. Acrylamide has Schiff base bonds to cross-link with gelatin and absorb metal ions. Deacetylated chitosan improved cell adhesion and active groups to connect MXene and acrylamide. We constructed Mo2Ti2C3 MXene hydrogel with improved elastic modulus and viscosity, chemical cross-linking structure, electric conductivity, and good compatibility. Mo2Ti2C3 MXene hydrogel exhibits outstanding osteogenesis in vitro. Mo2Ti2C3 MXene hydrogel promotes osteogenesis via alkaline phosphatase (ALP) and alizarin red S (ARS) staining, improving osteogenic marker genes and protein expressions in vitro. Mo2Ti2C3 MXene hydrogel aids new bone formation in the in vivo calvarial bone defect model via micro-CT and histology. Mo2Ti2C3 MXene hydrogel facilitates neurogenesis factors nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) expression, and aids newly born neuron marker Tuj-1 and sensory neuron marker serotonin (5-HT) and osteogenesis pathway proteins, runt-related transcription factor 2 (Runx2), osteocalcin (OCN), SMAD family member 4 (SMAD4), and bone morphogenetic protein-2 (BMP2) in the bone defect repair process. Mo2Ti2C3 MXene hydrogel promotes osteogenesis and neurogenesis, which extends its biomedical application in bone defect reconstruction.

Nonvascularized Bone Grafting for Scaphoid Nonunion

Abstract Background Surgical management of scaphoid nonunions requires not only stable fixation but restoration of carpal alignment and reconstruction of bone defects. The latter can be done with either vascularized or non-vascularized bone grafts, depending largely on surgeon preference. Materials and Methods This article describes the use of non-vascularized bone grafts for scaphoid nonunions and examines reported outcomes. We also describe the senior author's preferred surgical treatment, the hybrid Russe procedure. Description of Technique The hybrid Russe procedure utilizes a corticocancellous strut from the volar aspect of the distal radius to restore anatomy in scaphoid nonunions with flexion deformities. Once the alignment of the scaphoid and associated lunate postural deformities are corrected, fixation then proceeds with a headless compression screw. This combination resulted in healing of 17 scaphoid fracture nonunions at an average time of 15 weeks. Conclusions The literature does not demonstrate a difference in union rates when comparing the use of vascularized and non-vascularized grafts for scaphoid nonunions. When the proximal pole of the scaphoid can be salvaged, the choice of fixation is left to the surgeon's discretion.

Mechanical Characteristics of Individualized Biodegradable Augmentation Scaffold-In Vitro Pilot Study.

The alveolar ridge reconstruction of vertical and combined bone defects is a non-predictable procedure with varying percentages of success. The greatest challenge for vertical and combined bone augmentation is to maintain mechanical stability of the bone graft; therefore, it is mandatory to provide and preserve space for bone regeneration. The development of biomaterials and 3D printing has enabled the use of polymer scaffolds in the reconstruction of alveolar ridge defects. The aim of this pilot study was to evaluate the mechanical characteristics of an innovative individualized biodegradable polylactic acid (PLA) scaffold, under dynamic conditions, simulating biodegradation and the influence of masticatory forces. After the design and 3D printing of PLA scaffolds, two groups of 27 scaffolds were formed according to the compression testing procedure. The compression tests were performed in occlusal and lateral directions. In each of the two groups, nine subgroups of three scaffolds were formed for different testing periods during in vitro degradation with a total period of 16 weeks. Results showed that biodegradation and load application had no significant influence on mechanical characteristics of tested scaffolds. It can be concluded that simulated masticatory forces and biodegradation do not significantly influence the mechanical characteristics of an individualized biodegradable augmentation scaffold.

Vascular study of decellularized porcine long bones: Characterization of a tissue engineering model

IntroductionMassive bone allografts enable the reconstruction of critical bone defects in numerous conditions (e.g. tumoral, infection or trauma). Unfortunately, their biological integration remains insufficient and the reconstruction may suffer from several postoperative complications. Perfusion-decellularization emerges as a tissue engineering potential solution to enhance osseointegration. Therefore, an intrinsic vascular study of this novel tissue engineering tool becomes essential to understand its efficacy and applicability. Material and methods32 porcine long bones (humeri and femurs) were used to assess the quality of their vascular network prior and after undergoing a perfusion-decellularization protocol. 12 paired bones were used to assess the vascular matrix prior (N = 6) and after our protocol (N = 6) by immunohistochemistry. Collagen IV, Von Willebrand factor and CD31 were targeted then quantified. The medullary macroscopic vascular network was evaluated with 12 bones: 6 were decellularized and the other 6 were, as control, not treated. All 12 underwent a contrast-agent injection through the nutrient artery prior an angio CT-scan acquisition. The images were processed and the length of medullary vessels filled with contrast agent were measured on angiographic cT images obtained in control and decellularized bones by 4 independent observers to evaluate the vascular network preservation. The microscopic cortical vascular network was evaluated on 8 bones: 4 control and 4 decellularized. After injection of gelatinous fluorochrome mixture (calcein green), non-decalcified fluoroscopic microscopy was performed in order to assess the perfusion quality of cortical vascular lacunae. ResultsThe continuity of the microscopic vascular network was assessed with Collagen IV immunohistochemistry (p-value = 0.805) while the decellularization quality was observed through CD31 and Von Willebrand factor immunohistochemistry (p-values <0.001). The macroscopic vascular network was severely impaired after perfusion-decellularization; nutrient arteries were still patent but the amount of medullary vascular channels measured was significantly higher in the control group compared to the decellularized group (p-value <0.001). On average, the observers show good agreement on these results, except in the decellularized group where more inter-observer discrepancies were observed. The microscopic vascular network was observed with green fluoroscopic signal in almost every canals and lacunae of the bone cortices, in three different bone locations (proximal metaphysis, diaphysis and distal metaphysis). ConclusionDespite the aggressiveness of the decellularization protocol on medullary vessels, total porcine long bones decellularized by perfusion retain an acellular cortical microvascular network. By injection through the intact nutrient arteries, this latter vascular network can still be used as a total bone infusion access for bone tissue engineering in order to enhance massive bone allografts prior implantation.

Novel Sheep Model to Assess Critical-Sized Bone Regeneration with Periosteum for In Vivo Bioreactors.

Considerable research is being undertaken to develop novel biomaterials-based approaches for surgical reconstruction of bone defects. This extends to three-dimensional (3D) printed materials that provide stable, structural, and functional support in vivo. However, few preclinical models can simulate in vivo human biological conditions for clinically relevant testing. In this study we describe a novel ovine model that allows evaluation of in vivo osteogenesis via contact with bone and/or periosteum interfaced with printed polymer bioreactors loaded with biomaterial bone substitutes. The infraspinous scapular region of 14 Dorset cross sheep was exposed. Vascularized periosteum was elevated either attached to the infraspinatus muscle or separately. In both cases, the periosteum was supplied by the periosteal branch of the circumflex scapular vessels. In eight sheep, a 3D printed 4-chambered polyetheretherketone bioreactor was wrapped circumferentially in vascularized periosteum. In 6 sheep, 12 double-sided 3D printed 2-chambered polyetherketone bioreactors were secured to the underlying bone allowing direct contact with the bone on one side and periosteum on the other. Our model enabled simultaneous testing of up to 24 (12 double-sided) 10 × 10 × 5 mm bioreactors per scapula in the flat contact approach or a single 40 × 10 mm four-chambered bioreactor per scapula using the periosteal wrap. De novo bone growth was evaluated using histological and radiological analysis. Of importance, the experimental model was well tolerated by the animals and provides a versatile approach for comparing the osteogenic potential of cambium on the bone surface and elevated with periosteum. Furthermore, the periosteal flaps were sufficiently large for encasing bioreactors containing biomaterial bone substitutes for applications such as segmental mandibular reconstruction.

Spatiotemporal Synergism in Osteomyelitis Treatment with Photoactivated Core-Shell Zinc Oxide/Silver Sulfide Heterogeneous Nanoparticles.

Osteomyelitis is primarily caused by bacterial infections, and treatment requires precise sequential therapy, including antibacterial therapy in the early stages and bone defect reconstruction in later stages. We aimed to synthesize core-shell-structured zinc oxide/silver sulfide heterogeneous nanoparticles (ZnO/Ag2S NPs) using wet chemical methods. Using density functional theory and ultraviolet photoelectron spectroscopy, we showed that the optimized band structure endowed ZnO/Ag2S NPs with photodynamic properties under near-infrared (NIR) irradiation. Moreover, ZnO/Ag2S NPs exhibited a distinguished and stable photothermal performance within the same wavelength range. With single-wavelength irradiation, ZnO/Ag2S NPs achieved a bifunctional antibacterial effect during the acute stage of osteomyelitis. Antibacterial action was confirmed through colony-forming unit (CFU) counting assays, scanning electronic microscopy (SEM) observations, live-dead staining, growth curves, and quantitative real-time polymerase chain reaction (qPCR) assays. The Ag2S coating on the NPs realized the sustained release of zinc ions, thereby controlling the zinc ion concentration. Alkaline phosphatase (ALP) staining, alizarin red S (ARS) staining, and qPCR assays confirmed that the ZnO/Ag2S NPs exhibited good osteogenic effects in vitro. These effects were verified in an in vivo mouse femur model during chronic stages using micro-computed tomography (micro-CT) and histological analysis. This study provides a novel biocompatible core-shell nanomaterial for the two-phase treatment of osteomyelitis, contributing to versatile nanotherapies for infections and inflammation.

Midterm Donor Site Morbidity After Vascularized Free Fibula Flap Harvesting.

Vascularized fibula grafts (VFGs) have become one of the most preferred grafts for the reconstruction of bone defects. However, despite the many advantages over other graft options, recipient and donor site morbidities are also common. Donor site morbidity has been reported at rates ranging from 5% to 67%. The aim of this study was to present a single-center series examining the clinical, functional, and radiologic aspects of donor site morbidity following VFG harvesting. The study included 69 patients who underwent biological reconstruction with VFG for bone tumors, avascular necrosis of the femoral head, or bone defects after trauma. Patients were evaluated functionally, clinically, and radiologically for donor site morbidity. Donor site morbidity was observed in 33 of 69 patients (48%). The most complications were sensation deficits around the feet and ankles (20 of 69; 29%). Knee laxity was more common in patients who underwent osteoarticular fibular resection (P = .006). We found VFG to be an effective method for the reconstruction of large bone defects, but associated with a relatively high rate of complications. Complications requiring surgical intervention were rare and the majority of patients did not have long-term functional limitations. Level IV, retrospective case series.

Mechanical and permeability properties of skeletal and sheet triply periodic minimal surface scaffolds in bone defect reconstruction

Triply periodic minimal surface (TPMS) structures have proven to be suitable for biomorphic scaffold designs orientated towards bone ingrowth applications. In this work, different types of gyroid Ti-6Al-4V scaffolds (skeletal-TPMS-based and sheet-TMPS-based) have been designed and fabricated by laser powder bed fusion for the purposes of analysing them and clarifying which type of scaffolds could be the best option to use in bone defect repair. The compression and bending tests conducted demonstrated that the skeletal gyroid scaffolds were flexible enough to promote bone healing. On the other hand, the sheet gyroid scaffolds tested might be too rigid to promote optimal bone growth inside the scaffold. The torsional properties were acceptable for most of the scaffolds. The values of Darcian permeability for all the tested scaffolds seemed to promote bone rather than cartilage ingrowth.

Effect of Therapeutic Radiation on Polycaprolactone/Hydroxyapatite Biomaterials in a Calvarial Model.

Bone defects caused by cancer resection often require postoperative radiotherapy. Although various synthetic polymers have been introduced as graft materials, their biological behavior after radiation exposure remains unclear. Here, we investigated how polycaprolactone/hydroxyapatite (PCL/HA) implants respond to therapeutic radiation exposure (in terms of volume and bone regeneration). Four 8mm diameter calvaria defects were surgically created on the parietal bone of 6 rabbits. PCL/HA implants made of porous, solid, and hybrid polymers were grafted by random placement in each defect. The fourth defect was left untreated. Four weeks after surgery, radiation exposure was conducted weekly for 6 weeks (total: 48Gy). Micro-computed tomography and histologic analysis were performed at 3 and 6 months, and 6 months postradiation, respectively. The total augmented volumes of all implants showed no significant differences between 3- and 6-months postradiation computed tomography images. In histologic analysis, new bone areas were 0.45±0.11mm2, 2.02±0.34mm2, and 3.60±0.77mm2 in solid, hybrid, and porous polymer grafts, respectively. Bone regeneration was limited to the periphery of the defect in the hybrid and porous polymer grafts, whereas new bone formed inside the porous implant. The total augmented volume of the defect was maintained without significant absorption even after radiation exposure. The PCL/HA implant maintained its structure despite radiation exposure. The porous PCL/HA implant demonstrated excellent bone regeneration, followed by the hybrid and solid implants. The PCL/HA implant is a promising candidate for bone defect reconstruction.

The application of custom 3D-printed prostheses with ultra-short stems in the reconstruction of bone defects: a single center analysis

Objective: Considering the advantages and widespread presence of 3D-printing technology in surgical treatments, 3D-printed porous structure prostheses have been applied in a wide range of the treatments of bone tumor. In this research, we aimed to assess the application values of the 3D-printed custom prostheses with ultra-short stems for restoring bone defects and maintaining arthrosis in malignant bone tumors of lower extremities in children.Methods: Seven cases of pediatric patients were included in this study. In all cases, the prostheses were porous titanium alloy with ultra-short stems. MSTS 93 (Musculoskeletal Tumor Society) scores were recorded for the functional recovery of the limbs. VAS (Visual analogue scale) scores were utilized to assess the degree of painfulness for the patients. X-ray and MRI (magnetic resonance imaging) were applied to evaluate the bone integration, prostheses aseptic loosening, prostheses fracture, wound healing, and tumor recurrence during follow-up.Results: During follow-up, none of the patients developed any postoperative complications, including prostheses aseptic loosening, prostheses fracture, or tumor recurrence. Radiological examinations during the follow-up showed that prostheses implanted into the residual bone were stably fitted and bone defects were effectively reconstructed. The MSTS 93 scores were 24.9 ± 2.9 (20–28). VAS scores were decreased to 5.8 ± 1.2 (4.0–7.0). No statistically significant differences in leg length discrepancy were observed at the time of the last follow-up.Conclusion: 3D-printing technology can be effectively applied throughout the entire surgical treatment procedures of malignant bone tumors, offering stable foundations for the initial stability of 3D-printed prostheses with ultra-short stems through preoperative design, intraoperative precision operation, and personalized prosthesis matching. With meticulous postoperative follow-up, close monitoring of postoperative complications was ensured. These favorable outcomes indicate that the utilization of 3D-printed custom prostheses with ultra-short stems is a viable alternative for reconstructing bone defects. However, further investigation is warranted to determine the long-term effectiveness of the 3D-printing technique.

Polydioxanone Enhances Bone Regeneration After Resection and Reconstruction of Rat Femur with rhBMP2.

The aim of this study was to assess the bone regeneration potential of a polydioxanone (PDO) scaffold together with recombinant human bone morphogenetic protein-2 (rhBMP-2) for the reconstruction of large bone defect. In total, 24 male rats (6 months old) were subjected to bilateral femoral stabilization using titanium plates to create a 2 mm gap, and reconstruction using rhBMP-2 (Infuse®; 3.25 μg). The bone defects were covered with PDO (PDO group), or with titanium mesh (Ti group). Animals were euthanized on days 14 and 60. Simultaneously, 16 rats received PDO and Ti in their dorsum for the purpose of biocompatibility analysis at 3, 5, 7, and 10 days postoperatively. X-ray densitometry showed a higher density in the PDO group on day 14. On day 60, coverage of the bone defect with PDO showed a larger quantity of newly formed bone than that found for the Ti group, a lower inflammatory infiltrate value, and a more significant number of blood vessels on day 14. By immunohistochemical assessment, runt-related transcription factor 2 (RUNX2) and osteocalcin (OCN) showed higher labeling on day 14 in the PDO group. On day 60, bone morphogenetic protein-2 (BMP-2) showed higher labeling in the PDO group, whereas Ti showed higher labeling for osteoprotegerin, nuclear factor kappa B ligand-activating receptor, RUNX2, and OCN. Furthermore, biocompatibility analysis showed a higher inflammatory response in the Ti group. The PDO scaffold enhanced bone regeneration when associated with rhBMP-2 in rat femur reconstruction. Impact statement Regeneration of segmental bone defects is a difficult task, and several techniques and materials have been used. Recent advances in the production of synthetic polymers, such as polydioxanone (PDO), produced by three-dimensional printing, have shown distinct characteristics that could improve tissue regeneration even in an important bone defect. The present preclinical study showed that PDO membranes used as scaffolds to carry recombinant human bone morphogenetic protein-2 (rhBMP-2) improved bone tissue regeneration by more than 8-fold when compared with titanium mesh, suggesting that PDO membranes could be a feasible and useful material for use in guided bone regeneration. (In English, viable is only used for living creatures capable of sustaining life.

Our Experience With Extracorporeal Irradiation and Reimplantation of the Irradiated Bone for the Reconstruction of Bone Defects Following Tumor Resection.

With tremendous improvement in the survival of patients with malignant bone tumors, there is a greater emphasis on the functional outcome and durability of reconstruction following tumor resection. Tumor resection and extracorporeal irradiation (ECI) followed by reimplantation of the irradiated bone in malignant bone tumors is drawing popularity across various centers. In this study, we aim to put forward our experience with ECI, the outcomes achieved, and the complications faced by us. This is a prospective study conducted in patients with malignant and locally aggressive bone tumors who underwent ECI at our center. A total number of 20 patients were selected for the study and followed up for a mean duration of 32.5 months (maximum duration: 58 months, minimum duration: eight months). Orthopedic outcome was measured using the Enneking score. We assessed for local recurrence, functional outcome, union, and complications during the follow-up. During the course of follow up, local recurrence was seen in two patients. The mean MSTS score of the remaining patients was found to be 23.6. Complications seen included limb length discrepancy, surgical site infection, and graft lysis. Tumor resection and ECIis an effective procedure for biological reconstruction which gives satisfactory functional outcomes. In spite of certain complications, patients expressed satisfaction with the overall outcome of the procedure.

Controlled domain gels with a wide stiffness gradient simultaneously promote bone regeneration and suppress tumor recurrence through DAPK activity

The reconstruction of bone defects following bone tumor resection pose significant challenges, including high risks for tumor recurrence. To address these challenges, we designed controlled-domain gels that possessed exceptional anti-tumorigenic effectiveness and osteogenic activity. This was achieved through the selection of an amino-acid-based low-molecular-weight gels (LMWGs) with superior biocompatibility and antitumor efficacy, and further construction of three-domain structure with a large-range stiffness gradient, through the assembly/disassembly of LMWGs inside a stable methacrylated alginate (AlgMA) network using photopolymerization. Such layered design not only constructed a top anti-tumorigenic domain at 0.6 kPa and a bottom osteogenic domain at 500 kPa, allowing for selectively inducing tumor cell apoptosis and promoting osteogenic differentiation of mesenchymal stem cells (MSCs), but also generated a gradient selectively confining the migration of tumor cells along soft-to-hard direction, without affecting the recruiting of MSCs toward the injury sites. In particular, the critical involvement of the DAPK-mediated signaling cascades might lead to the selected apoptosis of tumor cells on LMWG domain. The in-vivo results further suggested that multi-domain gel effectively inhibited tumor growth and displayed excellent bone-forming activity. Overall, such strategies could advance our fundamental understanding of the bone tumor postoperative treatment, in addition to offering new therapeutic opportunities.

[Translated article] Mechanical resistance of polylactic acid bone matrices developed by 3D printing for the reconstruction of bone defects

IntroductionBone defects are one of the main limitations in orthopaedic surgery and traumatology. For this reason, multiple bone replacement systems have been developed, either by prosthetic implant or by substitution with osteoforming substances, whose limitations are their survival and lack of structurality, respectively. The objective of this work is the generation of a new material for the creation of biologically active structures that have sufficient tensile strength to maintain the structure during remodelling. Material and methodsA new filament based on the fusion of natural polylactide acid (PLA) powder was designed for the generation of pieces by means of fused deposition modelling (FDM) on which to carry out tensile mechanical tests of osteosynthesis material. A total of 13 groups with different cortical thickness, filling and layer height were carried out, with 10 tensile tests in each group, defining the tensile breaking limit for each group. The regression lines for each group and their mechanical resistance to traction on the filament used were determined. ResultsThe filament ratio per contact surface unit with the osteosynthesis used was the main determinant of the mechanical resistance to traction, either at the expense of the increase in cortical thickness or by the increase in the percentage of cancellous bone filling. Layer height had a minor effect on tensile strength. The regression value was high for cortical thickness and cancellous filling, being elements with a predictable biomechanical behaviour. ConclusionsThe new methodology allows the creation of personalised neutral and implantable PLA bone matrices for the reconstruction of large bone defects by means of 3D printing by FDM with a mechanical resistance to traction greater than that of current biological support structures.

MicroRNA-146a-loaded magnesium silicate nanospheres promote bone regeneration in an inflammatory microenvironment

Reconstruction of irregular oral-maxillofacial bone defects with an inflammatory microenvironment remains a challenge, as chronic local inflammation can largely impair bone healing. Here, we used magnesium silicate nanospheres (MSNs) to load microRNA-146a-5p (miR-146a) to fabricate a nanobiomaterial, MSN+miR-146a, which showed synergistic promoting effects on the osteogenic differentiation of human dental pulp stem cells (hDPSCs). In addition, miR-146a exhibited an anti-inflammatory effect on mouse bone marrow-derived macrophages (BMMs) under lipopolysaccharide (LPS) stimulation by inhibiting the NF-κB pathway via targeting tumor necrosis factor receptor-associated factor 6 (TRAF6), and MSNs could simultaneously promote M2 polarization of BMMs. MiR-146a was also found to inhibit osteoclast formation. Finally, the dual osteogenic-promoting and immunoregulatory effects of MSN+miR-146a were further validated in a stimulated infected mouse mandibular bone defect model via delivery by a photocuring hydrogel. Collectively, the MSN+miR-146a complex revealed good potential in treating inflammatory irregular oral-maxillofacial bone defects.

A biomimetic three-dimensional porous scaffold of mineralized recombinant collagen-sodium alginate for efficiently repairing critical-size cranial defects

The reconstruction of critical-size bone defects caused by trauma, tumor resection, and congenital anomalies remains a fundamental challenge in tissue engineering. Biomimetic scaffolds have received extensive attention for the discovery of advanced artificial bone substitutes due to their inherent biocompatibility and biodegradability. Herein, we have for the first time developed a biomimetic three-dimensional porous scaffold of mineralized recombinant collagen-sodium alginate (MRCSA) with supreme healing efficacy for critical-size cranial defects. In situ biomineralization using recombinant collagen as the unique biotemplate results in the formation of nano-hydroxyapatite with well-ordered mineralized recombinant collagen with fibrous morphology. The MRCSA scaffold finely mimics the organic-inorganic composition and the uniform porous nanostructures of natural bone, which exhibits excellent biocompatibility, adequate biodegradability, superior cellular activity, and exceptional osteogenic differentiation capability. Magnetic resonance imaging (MRI), Micro-computed tomography (micro-CT), and histological characterization of rat models of critical-size cranial defects have consistently demonstrated that the MRCSA scaffold has regenerated an abundance of new bones to refill the defect sites with much higher bone mineral density, bone volume/total volume as well as trabeculae. The novel biomimetic scaffold provides a remarkably improved remedy of critical-size cranial defects, suggesting very promising applications in orthopedics and plastics.

Osseointegration Potential Assessment of Bone Graft Materials Loaded with Mesenchymal Stem Cells in Peri-Implant Bone Defects.

Many studies have been exploring the use of bone graft materials (BGMs) and mesenchymal stem cells in bone defect reconstruction. However, the regeneration potential of Algipore (highly purified hydroxyapatite) and Biphasic (hydroxyapatite/beta-tricalcium phosphate) BGMs combined with bone marrow-derived mesenchymal stem cells (BMSCs) remains unclear. Therefore, we evaluated their osseointegration capacities in reconstructing peri-implant bone defects. The cellular characteristics of BMSCs and the material properties of Algipore and Biphasic were assessed in vitro. Four experimental groups-Algipore, Biphasic, Algipore+BMSCs, and Biphasic+BMSCs-were designed in a rabbit tibia peri-implant defect model. Implant stability parameters were measured. After 4 and 8 weeks of healing, all samples were evaluated using micro-CT, histological, and histomorphometric analysis. In the energy-dispersive X-ray spectroscopy experiment, the Ca/P ratio was higher for Algipore (1.67) than for Biphasic (1.44). The ISQ values continuously increased, and the PTV values gradually decreased for all groups during the healing period. Both Algipore and Biphasic BGM promoted new bone regeneration. Higher implant stability and bone volume density were observed when Algipore and Biphasic BGMs were combined with BMSCs. Biphasic BGM exhibited a faster degradation rate than Algipore BGM. Notably, after eight weeks of healing, Algipore with BSMCs showed more bone-implant contact than Biphasic alone (p < 0.05). Both Algipore and Biphasic are efficient in reconstructing peri-implant bone defects. In addition, Algipore BGM incorporation with BSMCs displayed the best performance in enhancing implant stability and osseointegration potential.

上前牙区复杂牙槽骨缺损重建的研究进展——牙槽骨缺损重建

上前牙区复杂牙槽骨缺损重建的研究进展——牙槽骨缺损重建