Use of Cryopreserved Osteogenic Matrix Cell Sheets for Bone Reconstruction

Skeletal diseases, such as nonunion and osteonecrosis, are now treatable with tissue engineering techniques. Single cell sheets called osteogenic matrix cell sheets (OMCSs) grown from cultured bone marrow-derived mesenchymal stem cells show high osteogenic potential;however, long preparation times currently limit their clinical application. Here, we report a cryopreservation OMCS transplantation method that shortens OMCS preparation time. Cryopreserved rat OMCSs were prepared using slow- and rapid-freezing methods, thawed, and subsequently injected scaffold-free into subcutaneous sites. Rapid- and slow-frozen OMCSs were also transplanted directly to the femur bone at sites of injury. Slow-freezing resulted in higher cell viability than rapid freezing, yet all two cryopreservation methods yielded OMCSs that survived and formed bone tissue. In the rapid- and slow-freezing groups, cortical gaps were repaired and bone continuity was observed within 6 weeks of OMCS transplantation. Moreover, while no significant difference was found in osteocalcin expression between the three experimental groups, the biomechanical strength of femurs treated with slow-frozen OMCSs was significantly greater than those of non-transplant at 6 weeks post-injury. Collectively, these data suggest that slow-frozen OMCSs have superior osteogenic potential and are better suited to produce a mineralized matrix and repair sites of bone injury.

The polycaprolactone/silk fibroin/carbonate hydroxyapatite electrospun scaffold promotes bone reconstruction by regulating the polarization of macrophages

Macrophages are known to modulate the osteogenic environment of bone regeneration elicited by biological bone grafts.Alteration in certain chemical components tends to affect macrophages polarization.Comparatively to hydroxyapatite(HAp),carbonate hydroxyapatite(CHA)consists of 7.4(wt%)carbonate ions and more closely resembles the mineral content of bone.It remains unknown whether CHA scaffolds or HA scaffolds have better osteogenic properties.In this study,we fabricated PCL/SF scaffold,PCL/SF/HAp scaffold and PCL/SF/CHA scaffold using the electrospinning technique.Despite comparable mechanical properties,the PCL/SF/CHA scaffold exhibited better osteogenic properties than the PCL/SF/HAp scaffold.Although no significant differences were observed between the two scaffolds for promoting osteoblast differentiation in vitro,the PCL/SF/CHA group appeared to be more effective at promoting bone regeneration in cranial defects in vivo.The PCL/SF/CHA scaffold was found to promote macrophage polarization toward M2 via activating the JAK/STAT5 pathway which caused a pro-osteogenic microenvironment to facilitate osteoblast differentiation.The results of this study indicated a higher potential of CHA to substitute HAp in the production of bone scaffolds for better bone regeneration.

Reconstruction of Post-Traumatic Bone Loss (BL) Members: Our Experience about 27 Cases

The purpose of this study is to evaluate our results of treatment of post-traumatic bone defect of members through various bone reconstruction techniques. Patients and method: It is a retrospective study continues from January 2008 to December 2012. It involved 27 patients who had bone loss following trauma members. The average age of patients was 36.2 years. We noted a male predominance (22 men). The causes of injuries were dominated by accidents of public roads (12 cases) and ballistic trauma (14 cases). We noted one case of work accident. The BL was localized in 10 cases the tibia, femur in 4 cases, 8 cases in the humerus, 2 cases in the fibula, 1 case was located in the olecranon, 1 case at the distal radius and 1 case to the ball. All lesions were open fractures. After a mean of support for 3 days, we performed emergency around 19 associated with internal fixation (10 cases external fixation, internal fixation 9 cases), 8 single around. Bone reconstruction was performed secondarily in the majority of cases (24 cases). Only 4 reconstructions were performed in emergency. Reconstruction techniques were dominated by conventional grafts (24 cases) associated or not with the technique of induced membrane. Bone reconstruction techniques we used were as follows: 24 cases of traditional autografts and 3 cases of intertibio-fibular graft. After an average decline of 43.6 months, our patients were evaluated clinically (axis and limb length) and radiological (bone healing). Results: bone healing was achieved in 22 cases after a mean of 3.8 surgeries and an average of 14.8 months. Conclusion: the main principles governing the reconstruction of a defect are pre healing associated infection and repair soft tissue whenever it can do. The current trend is to hybridization of the reconstruction process of the great losses of substance by developing strategies based on both the deliberate shortening.

Experimental Study of Porous Beta-tricalcium Phosphate and Bone Morphogenetic Protein/porous Beta-tricalcium Phosphate Complex in Rabbit Mandibular Reconstruction

We investigated the osteogenic characteristic and biodegradation behavior of porous beta-tricalcitum phosphate （ β- TCP ） and bone morphogenetic protein/beta-tricalcium phosphate （ BMP/ β- TCP ） complex in mandibular reconstruction and evaluated the advantages of BMP / β- TCP complex in repairing bone defects. Bone defects created in the lower margin of bilateral mandible bodies in 12 rabbits were repaired with β- TCP （ control group ） and BMP/ β- TCP complex （ experimental group ） respectively. The rabbits were euthanized after 2, 4, 8 and 12 weeks and examined by macroscopy, radiography, histology, histomorphometry and image analysis. 2 weeks after surgery, ossftcation of newly-generated tissue in BMP/ β- TCP complex group appeared and after 12 weeks, massive new bone and ossification maturation were seen. However, in β- TCP group without BMP , ossification was not found until 12 weeks after operation. Image analysis showed that bone regeneration rate of BMP/ β- TCP was 30%-40% higher and the degradation rate was 20%- 30% higher than that of β- TCP. Therefore, as a reconstructive material for bone defects, BMP/ β-TCP complex is superior to β-TCP and can be used in oral and maxillofacial surgery.

Digital measurement of bone tumor volume by CT three-dimensional reconstruction technology

Objective To discuss the measurement of bone tumor volume on the basis of three dimensional images segmentation technology. Methods Twenty patients with lacunar bone tumor from Tianjin Hospital and Tongji Hospital were included in the

Magnesium-based biomaterials as emerging agents for bone repair and regeneration:from mechanism to application

Magnesium(Mg)is the fourth most abundant element in the human body and is important in terms of specific osteogenesis functions.Here,we provide a comprehensive review of the use of magnesium-based biomaterials(MBs)in bone reconstruction.We review the history of MBs and their excellent biocompatibility,biodegradability and osteopromotive properties,highlighting them as candidates for a new generation of biodegradable orthopedic implants.In particular,the results reported in the field-specific literature(280 articles)in recent decades are dissected with respect to the extensive variety of MBs for orthopedic applications,including Mg/Mg alloys,bioglasses,bioceramics,and polymer materials.We also summarize the osteogenic mechanism of MBs,including a detailed section on the physiological process,namely,the enhanced osteogenesis,promotion of osteoblast adhesion and motility,immunomodulation,and enhanced angiogenesis.Moreover,the merits and limitations of current bone grafts and substitutes are compared.The objective of this review is to reveal the strong potential of MBs for their use as agents in bone repair and regeneration and to highlight issues that impede their clinical translation.Finally,the development and challenges of MBs for transplanted orthopedic materials are discussed.

Reconstruction of anterior skull base defects using frontalis muscle galea aponeurotica skull pedicle flaps

Objective： The aim of our study was to reconstruct soft and hard tissue perforating defects of the anterior skull base in a 1-stage surgical procedure with a combined craniofacial approach. Methods： Soft and hard tissue defects of the anterior skull base were successfully reconstructed in 43 patients during a 1-stage surgery through the use of frontalis muscle galea aponeuretica skull flaps with 1 or 2 vascularized pedicles. The skull flap areas were up approximately 7 cmx 14 cm. Results： Intracranial infection and cerebrospinal fluid leakage were not observed in the 43 patients, and all incisions healed. Of 33 malignant tumor patients, 25 patients received follow-up examinations for longer than 2 years, and 18 patients survived for 2 years. Conclusion： Frontalis muscle galea aponeurotica skull pedicle flaps provided a constant blood supply and re- suited in soft and thin tissue. The pedicle flaps, together with the external cranial bone plate, strengthened the support, but still allowed for bending and shaping. In addition, the flap harvesting approach was consistent with surgery approach, without aesthetic compromises.

FEATURE EXTRACTION OF BONES AND SKIN BASED ON ULTRASONIC SCANNING

In the prosthetic socket design, aimed at the high cost and radiation deficiency caused by CT scanning which is a routine technique to obtain the cross-sectional image of the residual limb, a new ultrasonic scanning method is developed to acquire the bones and skin contours of the residual limb. Using a pig fore-leg as the scanning object, an overlapping algorithm is designed to reconstruct the 2D cross-sectional image, the contours of the bone and skin are extracted using edge detection algorithm and the 3D model of the pig fore-leg is reconstructed by using reverse engineering technology. The results of checking the accuracy of the image by scanning a cylinder work pieces show that the extracted contours of the cylinder are quite close to the standard circumference. So it is feasible to get the contours of bones and skin by ultrasonic scanning. The ultrasonic scanning system featuring no radiation and low cost is a kind of new means of cross section scanning for medical images.

Automatic Bone Surface Restoration for Markerless Computer-Assisted Orthopaedic Surgery

An automatic markerless knee tracking and registration algorithm has been proposed in the literature to avoid the marker insertion required by conventional computer-assisted knee surgery,resulting in a shorter and less invasive surgical workflow.However,such an algorithm considers intact femur geometry only.The bone surface modification is inevitable due to intra-operative intervention.The mismatched correspondences will degrade the reliability of registered target pose.To solve this problem,this work proposed a supervised deep neural network to automatically restore the surface of processed bone.The network was trained on a synthetic dataset that consists of real depth captures of a model leg and simulated realistic femur cutting.According to the evaluation on both synthetic data and real-time captures,the registration quality can be effectively improved by surface reconstruction.The improvement in tracking accuracy is only evident over test data,indicating the need for future enhancement of the dataset and network.

Reconstruction of extremity long bone defects with vascularized fibula bone grafts

Aim: Composite tissue defects encompassing bone and/or isolated bony defects can pose a surgical challenge;however, their reconstruction is critical for successful functional limb salvage. These cases become increasingly problematic as secondary defects, following multiple nonvascularized grafting attempts resulting in complex bony nonunion. Herein, our experience utilizing fibula vascularized bone grafts (VBGs) for bone restoration will be presented to demonstrate their utility in a variety of reconstructions for limb salvage. Methods: This is a case series describing a series of vascularized fibula grafts for extremity reconstruction performed by a single academic surgeon over multiple institutions in seven years. Results: Twenty-seven (27) total VBGs met inclusion criteria and underwent reconstruction for traumatic (16), oncologic (6) and chronic degenerative (5) etiologies. Bony union was achieved in 26 of 27 cases. Conclusion: The decision-making process for bony reconstruction in these scenarios is difficult and multivariable. Fibula VBGs can provide a single-stage solution for autologous bony and soft tissue replacement of large or complex bone defects and can often be superior options compared with non-vascularized bone grafts or non-bone internal fixation techniques. Their osteogenic potential is unmatched by allogenic or synthetic substitutions. These benefits are evident in a variety of clinical settings such as pediatrics, oncology and trauma.

Histomorhological and clinical evaluation of maxillary alveolar ridge reconstruction after craniofacial trauma by applying combination of allogeneic and autogenous bone graft

A variety of techniques and materials for the rehabilitation and reconstruction of traumatized maxillary ridges prior to dental implants placement have been described in literature. Autogenous bone grafting is considered ideal by many researchers and it still remains the most predictable and documented method. The aim of this report is to underline the effectiveness of using allogeneic bone graft for managing maxillofacial trauma. A case of a 30-year-old male with severely atrophic maxillary ridge as a conse- quence of complex craniofacial injury is presented here. Augmentation procedure in two stages was performed using allogeneic and autogenous bone grafts in different areas of the osseous defect. Four months after grafting, during the implants placement surgery, samples of both sectors were withdrawn and submitted to histological evaluation. On the examination of the specimens, treated by hematoxylin and eosin staining, the morphology of integrated allogeneic bone grafts was revealed to be similar to the autologous bone. Our clinical experience shows how the allogeneic bone graft presented normal bone tissue architecture and is highly vascularized, and it can be used for reconstruction of severe trauma of the maxilla.

Customized bioceramic scaffolds and metal meshes for challenging large-size mandibular bone defect regeneration and repair

Large-size mandible graft has huge needs in clinic caused by infection,tumor,congenital deformity,bone trauma and so on.However,the reconstruction of large-size mandible defect is challenged due to its complex anatomical structure and large-range bone injury.The design and fabrication of porous implants with large segments and specific shapes matching the native mandible remain a considerable challenge.Herein,the 6%Mg-doped calcium silicate(CSi-Mg6)andβ-andα-tricalcium phosphate(β-TCP,α-TCP)bioceramics were fabricated by digital light processing as the porous scaffolds of over 50%in porosity,while the titanium mesh was fabricated by selective laser melting.The mechanical tests showed that the initial flexible/compressive resistance of CSi-Mg6 scaffolds was markedly higher than that ofβ-TCP andα-TCP scaffolds.Cell experiments showed that these materials all had good biocompatibility,while CSi-Mg6 significantly promoted cell proliferation.In the rabbit critically sized mandible bone defects(∼13 mm in length)filled with porous bioceramic scaffolds,the titanium meshes and titanium nails were acted as fixation and load bearing.The results showed that the defects were kept during the observation period in the blank(control)group;in contrast,the osteogenic capability was significantly enhanced in the CSi-Mg6 andα-TCP groups in comparison with theβ-TCP group,and these two groups not only had significantly increased new bone formation but also had thicker trabecular and smaller trabecular spacing.Besides,the CSi-Mg6 andα-TCP groups showed appreciable material biodegradation in the later stage(from 8 to 12 weeks)in comparison with theβ-TCP scaffolds while the CSi-Mg6 group showed much outstanding mechanical capacity in vivo in the early stage compared to theβ-TCP andα-TCP groups.Totally,these findings suggest that the combination of customized strength-strong bioactive CSi-Mg6 scaffolds together with titanium meshes is a promising way for repairing the large-size load-bearing mandible defects.

Advances in osseointegration of biomimetic mineralized collagen and inorganic metal elements of natural bone for bone repair

At this stage,bone defects caused by trauma,infection,tumor,or congenital diseases are generally filled with autologous bone or allogeneic bone transplantation,but this treatment method has limited sources,potential disease transmission and other problems.Ideal bone-graft materials remain continuously explored,and bone defect reconstruction remains a significant challenge.Mineralized collagen prepared by bionic mineralization combining organic polymer collagen with inorganic mineral calcium phosphate can effectively imitate the composition and hierarchical structure of natural bone and has good application value in bone repair materials.Magnesium,strontium,zinc and other inorganic components not only can activate relevant signaling pathways to induce differentiation of osteogenic precursor cells but also stimulate other core biological processes of bone tissue growth and play an important role in natural bone growth,and bone repair and reconstruction.This study reviewed the advances in hydroxyapatite/collagen composite scaffolds and osseointegration with natural bone inorganic components,such as magnesium,strontium and zinc.

Effects of Quenching Temperature and Time on Pore Diameter of Poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) Porous Scaffolds and MC3T3-E1 Osteoblast Response to the Scaffolds

Poly（3-hydroxybutyrate-co-3-hydroxyhexanoate） （PHBHHx） scaffolds were prepared by thermally inducing phase separation （TIPS） for bone reconstruction. Scanning electron microscopy and porosity measurements were used to analyze the structure and properties of the scaffolds. The pore diameter of the scaffolds could be easily controlled by changing the quenching temperature and time. The biocompatibility was assessed by examining the proliferation and morphology of MC 3T3-E1 osteoprogenitor cells seeded on the scaffolds. Cultures grown in the presence of a source of phosphate ions showed the formation of a mineralized extracellular matrix. The results indicate that PHBHHx scaffolds prepared using TIPS are a promising candidate for bone reconstruction.