Objective To compare and evaluate the capability of pure autogenous bone and the enhanced autogenous bone combined with bone morphogenetic protein in bone repair of femoral head. Methods Eighteen femoral heads of 9 dogs weredrilled by trephine, 4 mm in diameter, followed by respective implantations of autogenous bone grafting (group B) and of the enhanced autogenous bone composite, combined with bone morphogenetic protein (group C), with the selfrepair of bone defect as the control (group A). Three, six, nine weeks after the operation, radiological examination, computerized tomography, light and electronic microscopes were performed to investigate the bone healing of the defect in the femoral head. Results In group A, it could be observed that there washematoma organization and delayed woven bone formation in the 3rd week after operation, and therewas little replacement of woven bone by bone trabecula in the 9th week; in group B, the autogenous bone implanted were dead in the 3rd week and maintained in situ in the 9th week; in group C, active new bone formation, either endochondral or intramembranous ossification, was found in the 3rd week and entire repair of the bone defect by bone trabecula in the 9th week after operation. Conclusion The enhanced autogenous bone combined with bone morphogenetic protein could promote reconstruction of the bone defect in femoral head, superior to pure autogenous bone which could provide a framework for the new bone formation.
OBJECTIVE To investigate the feasibility of prefabricating a specified shape autograft capable of transfer using coral and type I collagen as a carrier for recombinant human bone morphogenetic protein-2 (rhBMP-2). METHODS In this study, the composite of rhBMP-2, coral and type I collagen was made certain shape to prefabricate vascularized osteomuscular autograft capable of microvascular free tissue transfer and autogenous bone graft with certain shape and titanium implant in it. The composite was implanted in the iliac area in dog with the titanium implant at the same time. After 3 months and 4 and a half months of implantation, the composites were studied with gross measurement, X-ray, and histological examinations. RESULTS After 3 months, composited bone was turned to bone tissue, and the shape of iliac bone was changed with implant in it, bone interface was seen between new bone and implant. And new bone was matured after 4 and a half months. CONCLUSION Coral and type I collagen are effective carrier for rhBMP-2 to prefabricate vascular osteomuscular autograft with certain shape. The use of rhBMP-2 for tissue engineered microvascular free bone flaps has an unlimited potential and adds a new dimension to maxillofacial reconstruction.
Bioactive glass (BG) has been widely used in the preparation of artificial bone scaffolds due to its excellent biological properties and non-cytotoxicity, which can promote bone and soft tissue regeneration. However, due to the brittleness, poor mechanical strength, easy agglomeration and uncontrollable structure of glass material, its application in various fields is limited. In this regard, most current researches mainly focus on mixing BG with organic or inorganic materials by freeze-drying method, sol-gel method, etc., to improve its mechanical properties and brittleness, so as to increase its clinical application and expand its application field. This review introduces the combination of BG with natural organic materials, metallic materials and non-metallic materials, and demonstrates the latest technology and future prospects of BG composite materials through the development of scaffolds, injectable fillers, membranes, hydrogels and coatings. The previous studies show that the addition of BG improves the mechanical properties, biological activity and regeneration potential of the composites, and broadens the application of BG in the field of bone tissue engineering. By reviewing the recent BG researches on bone regeneration, the research potential of new materials is demonstrated, in order to provide a reference for future related research.
Objective To evaluate the cl inical effect and the pathological characteristics of acellular allogeneic dermal matrix in repairing unstable burn scar. Methods From January 2007 to June 2008, 19 cases of unstable burn scars (24 parts) were treated, including 16 males (20 parts) and 3 females (4 parts) with a median age of 27 years (range, 3-58 years). Theinjury was caused by flame (14 cases, 18 parts), electricity (4 cases, 5 parts), and hot water (1 case, 1 part). The unstable burn scars located on hands (8 cases), forearms (2 cases), thighs (3 cases), legs (2 cases), feet (2 cases), chest (1 case), and abdomen (1 case). Scar formed for 3 months to 1 year. The area of defect varied from 7 cm × 5 cm to 22 cm × 15 cm after scar removal. Defects were covered with acellular allogeneic dermal matrix and autogenous spl it-thickness skin graft. At 6-18 months after operation, the pathological observations of the epidermis, the basal membrane, and structural components of the dermis were done. Results All wounds healed by first intention. Scar ulcer disappeared completely in 18 cases and the composite skin grafts all survived. Some bl isters occurred in 1 case and were cured after dressing changing. All patients were followed up 10 months to 2 years (18 months on average). The grafted-skin was excellent in the appearance, texture, and elasticity. The function recovered well. Only superficial scar was observed at skin donor sites. Pathological observation showed that the epidermis and the basal membrane of the skin grafts were similar to that of normal skin, and no significant difference was found in newly capillaries between them. Collagen fibers arranged regularly, and there were few inflammatory cells in the matrix. Conclusion Acellular allogeneic dermal matrix with autogenous spl it-thickness skin graft may effectivly repair the wound after removing the unstable burn scar, and its structure is similar to that of normal skin.
Objective To study cl inical effects of the graft material of allogenic cancellus combined with autologousred marrow in the treatment of traumatic bone defect. Methods From February 2002 to April 2006, 38 patients of traumaticbone defect, 25 males and 13 females, aged 21-68 years old (38 on average), were treated with allogenic cancellus combined with autologous red marrow. Among them, there were 11 cases of bone nonunion caused by failure of internal fixation, 13 of serious comminuted fracture, 9 of bone defect caused by open fractures or bone infection, 5 of old fracture in need of graft. Of these fractures, there were 8 cases of shaft of humerus, 4 of intercondylar comminuted fracture of humerus, 8 of intercondylar comminuted fracture of femur, 5 of shaft of femur, 4 of open tibia fracture (Gustilo I, II type) and 9 of tibial plateau fracture. They included 17 cases of fresh fracture and 21 of old fracture. There were 23 cases of l imitations of bone defect, and the range was 3 cm × 3 cm × 2 cm - 7 cm × 4 cm × 3 cm; and the range of the large bone defect was less than 3 cm in 15 cases. According to AO/ASIF classification, there were 5 cases of type B2, 10 of type B3, 16 of type C2 and 7 of type C3. The time from fresh fracture to operation was 5-17 days (8 days on average), and the time from old fracture to operation was 5-13 months (7.5 months on average). The amount of the allograft implantation was 20-50 g (28 g on average). Results The wounds in all 38 cases obtained heal ing by first intention. All the patients were followed up for 8 months to 4 years (3.2 years on average). The X-ray films at reexamination showed that 36 patients had bone heal ing, with fresh fracture heal ing time of 2-6 months (4 months on average) and old fracture heal ing time of 3-10 months (7 months on average). The allogenic cancellus particles began to be fused with autogenous bone through creeping substitution 6-8 weeks after operation. One case, which had delayed infection, had bone union by removing internal fixation, placing irrigating tube and grafting after local stabil ity. During the follow-up of 25 months, no relapse was found. Another case had nonunion because of plate loosening. According to the Mankin and Komender standard evaluation, there were 36 cases with satisfaction (94.7%) and 2 with dissatisfaction (5.3%). Conclusion The composite graft material of allogenic cancellus combined with autologous red marrow is safe and effective for repairing fractures and bone defect.
OBJECTIVE: To modify the design of the Achilles tendon-scar composite flap into the Z-shape and to apply it into clinic situations to correct the tendon-scar contracture after burn and other injures. METHODS: According to degree of contracture and strephenopedia, the central limb of Z-shaped design lay in contracture line of posterior ankle area just over the Achilles tendon and extended 8 to 12 cm in length. Lateral limbs extended 5 to 8 cm and usual angles of the Z-shape was 60 degrees. The two tendon-scar composite flaps were made and slipped along the central limb between them. From March 1994 to August 1999, seven patients with Achilles tendon scar contracture were operated with this method. RESULTS: Excellent relieving of the Achilles tendon-scar contractue was achieved. No such complications happened as ischemia and necrosis of the flaps. CONCLUSION: The Z-shaped tendon-scar composite flap is practical in clinics. It is characterized by abundant blood supply, easily procedure and reliable result.
It is in urgent need clinically to look for an ideal substance for the coverage of burn wounds owing to shortage of autografts or allografts. After the cadaveric skin was extracted with acetic acid, salted out with NaCl and freeze-dried to prepare a porous collagen membrane. The membrane was seeded with allo-epidermal cells and allo-fibroblasts on its two sides, respectively, and then was cultured to achieve an artificial composite allograft. The artificial composite allograft was then transplanted onto ten severly burned wounds. One-year follow-up showed satisfactory results and the histological examination confirmed that the composite allograft could improve the adherence and growth of the epidermal cells and was helpful for blood vessels and healing of non-inflammatory connective tissues in the wounds.
Objective To explore the shortterm clinical effects of complex transplantation among the acellular dermal matrix(ADM) of heterogenic or heterocatal and autogenic split on the burnt wound as to find out a permanent substitution for the treatment on full skin thickness defect without scar. Methods Two kinds of ADM were used on the 18 patients with full thicknessburn wound through complex transplantation with autogenic splits. The patients with medialthickness autograft was used as control group. Survival rate was obtained 2 weeks after operation; contraction rate and the scores of Vancouver burn scale were obtained 8 weeks after operation. Results No significant difference was observed in survival rate among the three groups 2 weeks after operation(P＞0.05); no significant difference was observed in contraction rate of autografts and scores of Vancouver burn scale among the three groups 8 weeks after operation(P＞0.05). Conclusion ADM of heterogenic and ADM of heterocatal have similar effect on the reconstruction of skin, so the piglet ADM made in this way could be used as a substitution.
OBJECTIVE: To prove the biological characteristics of spinal intervertebral fusion with allograft cortical ring plus autogenous cancellus from iliac bone (called as composite ring). METHODS: Eight hybrid dogs were adopted in the study. The composite ring and autogenous tri-cortical blocks were implanted into the intervertebral space of dogs respectively. The intervertebral discs were removed before implantation. The fusion segments were evaluated by x-ray, histological examinations at 1, 2, 4 and 6 months after operation to compare the healing status of two implants. RESULTS: The X-ray film and histological examination showed the lumbar interbody was fused after 4 months of operation in composite ring group, while the autogenous iliac bone blocks fused with peripheral bone tissue after 6 months of operation. Composite ring healed more quickly and completely, showed different osteogenesis behavior compared with that of massive allografts. CONCLUSION: Composite ring can promote the fusion of intervertebral body and can be used as a potential material for spinal surgery.
Objective To develop a novel porous three-dimensional scaffold and to investigate its physico-chemical properties for tissue engineering cartilage.Methods Refined 88% deacetylation degree chitosan was prepared and dissolved in 0.2 mol/L acetate acid and fully mixed with highly purified porcine type Ⅱcollagen in 0.5 mol/L acetate acid solution in a ratio of 4 to 1 (wt/wt). Freeze-drying process was employed to fabricate the composite scaffold. The construct wascross-linked by use of 1-ethyl-3(3-dimethyl aminopropyl) carbodiimide (EDC) and Nhydroxysuccinimide (NHS). A mechanical tester was utilized to determine the tensilestrength change before and after cross-linking. The microstructure was observed via scanning electron microscopy (SEM). The lysozyme degradation was performedto evaluate the degradability of the scaffold in vitro. Results A bulk scaffold with desired configuration was obtained. The mechanical test showed that the crosslinking treatment could enhance the mechanical strength of the scaffold. The SEM results revealed that the two constituents evenly distributed in the scaffold and that the matrix was porous, sponge-like with interconnected pore sizing 100250 μm. In vitro lysozyme degradation indicated that crosslinked or uncross-linked composite scaffolds had faster degradation rate than the chitosan matrix. Conclusion Chitosan and typeⅡcollagen can be developed into a porous three-dimensional scaffold. The related physico-chemical tests suggest that the composite socaffold meets requirements for tissue engineered scaffold and may serve as an alternative cellcarrier for tissue engineering cartilage.