OBJECTIVE: To investigate the feasibility of the chitosan-collagen membrane (CCM) as a dermal substitute. METHODS: Fresh bovine tendo calcaneus collagen was dispersed in 0.5 mol/L acetic acid, co-precipitated with chitosan and lyophilized. Dry membranes were cross-linked in 0.05% glutaraldehyde for 24 hours. In vitro its degrading rate was measured by use of collagenase degrading test. The chitosan-collagen membrane was implanted to subcutaneous dorsal sites of SD rats. After implantation, histocompatibility, vascularity and degradation were observed in vivo. RESULTS: The chitosan-collagen membrane was yellowish, translucent, and porous. Pore size ranged 50-250 microns, and collagen fiber bundles were reticular arrangement in the membrane. It had slower degradation than pure collagen membrane by collagenase in vitro. Subcutaneous implantation test showed the minimal inflammation, good histocompatibility and earlier vascularization. The membrane degradation was slower in vivo. Eight weeks after implantation, organized collagen structure was retained. CONCLUSION: The chitosan-collagen membrane has better physical and biological properties, ideal histocompatibility, earlier vascularization and slower degradation. Therefore, It is an optimum substitute for dermal scaffold.
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.
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 investigate a new grafting material of bone xenograft with b bone inductive and conductive capacity. Methods Based on successful clinical application of the reconstituted bone xenograft (RBX), a new xenograft was made by combining recombinant human bone morphogenetic protein-2 (rhBMP-2) with antigen-free bovine cancellous bone (BCB). Sixty male BALB/C mice aged 4 weeks were divided into study group of 30 and control group of 30 randomly. rhBMP-2 / BCB was implanted in the left thigh muscle pouch in the study group andBCB in the control group. The mice were sacrificed at 7 d, 14d and 21d after implantation. Inductivity of rhBMP-2/BCB was detected by histological observation and biochemical determination of the samples. Results Histological examinationshowed that rhBMP-2/BCB induced chondrogenesis on the 7th day, with woven boneformed on the 14th day, and lamellar bone and marrow on the 21st day, while BCBfailed to induce chondrogenesis or osteogenesis on the 7th, 14th and 21st days. The alkaline phosphatase activities and calcium content in study group were higher than those in control group with significant difference (P＜0.01). Conclusion rhBMP-2/BCB is an ideal grafting material with b bone inductive and conductive capacity without evoking immune reaction.
Objective To evaluate the biological safety of continuous carbonfiber reinforced polyolefin as hard tissue repair material. Methods Biocompatibility of the material was evaluated through hemolysis test, pyrogen test,skin irritation test, cytotoxicity test, ames test,in vitro chromosome aberration test, and bone marrow cells Micronuclei test. Results No obvious hemolysis, pyrogenic characteristics, sensitivity, cytotoxxicity, and mutagenicity were observed. Conclusion The continuous carbonfiber reinforced polyolefin composite material is of good biological safety. It meets all the demand made by biological safety as hardtissue repair material.
Objective To evaluate the ability of inductive osteogenesis of allgraft demineralized bone containing basic fibroblast growth factor (bFGF/ALB) in repairing bone defect. Methods Thirty-two New Zealand white rabbits were randomly divided into four groups (groups A,B,C and D, n=8). A segmental bone defect of15 mm inlength was made on the bilateral radius respectively and the defects filled with ALB/bFGF in group A, with ALB in group B, with bFGF in group C and without any materials in group D serving as blank control. At 2, 4, 6 and 8 weeks after operation, all restored bones were evaluated by roentgenography, histological observation and Ca2+detection of osteotylus. Results The X-ray films showed that groups A and B had a little shadow of bone formation at 2 weeks, while groups C and D had transparent shadow; that group A had denser shadow and new bone formation at 4 weeks and 6 weeks, groups B and C had a little increase of shadow and group D had little shadow at fractured ends; and that group A had formation of bone bridge at 8 weeks, the new formed bone in fractured ends of group B closed with each other, the gap still existed in group C, and the defects filled with the soft tissue in group D. The Ca2+content of group A was higher than that of groups B, C and D at 4 weeks (Plt;0.05) and 8 weeks (Plt;0.01). The histological observaton showed that the degree of bone restoration of group A was superior to that of groups B, C and D. Conclusion bFGF/ALB is a good material to improve bone restoration.
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 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.
Objective To assess the clinical outcome of thelimb salvage surgery and complications occurring in the lower extremities after a wide resection of sarcoma. 〖WTHZ〗Methods A total of 167 patients underwent a limb-sparing procedure by means of the implantation of a custom-made or modular tumor endoprosthesis from July 1997 to July 2004. Of the 167 patients, 100 were followed up, including 56 males and 44 females, with their ages ranging from 13 to 57 years at surgery.In 5 patients, a proximal femur prosthesis was implanted; in 57 patients, a distal femur prosthesis was implanted; and in 38 patients, a proximal tibia prosthesis was implanted. According to the Enneking staging, 3 patients were grouped in the stage of ⅡA, 85 in ⅡB, and 12 in Ⅲ. Seventy-one patients used a domestic prosthesis, and 29 patients used a prosthesis made in Link Company, Germany. For the reconstruction, 17 patients used an autograft prosthesis composite, 21 patients used the allograft prosthesis composite, and the remaining 62 patients used an artificial prosthesis. All the patients received chemotherapy for 1-2 courses and 3-5 courses before operation and after operation, respectively. After operation, The Musculoskeletal Tumor Society(MSTS) score was used to evaluate the recovery of their corresponding functions. Results According to the follow-up for 1-8 years, with a median of 3.5 years, and the assessment by the Kaplan-Meier estimate, the 3-year survival rate of the prostheses was 81.8%, and the 5year survival rate was 65%. As for the complications, prosthesis breakage occurred in 6 patients, periprosthesis infection in 13 patients, aseptic loosening in 2 patients, non-union between the host bone and graft bone in 5 patients, allograft absorption in 2 patients, prosthesis sinking in 2 patient, and periprosthesis fracture in 1 patient. Local recurrence developed in 7 patients within 6 months to 2 years after operation. Of the 7 patients, 4 had a recurrence of the softtissue tumor for which resection was performed; the other 3 patients underwent amputation of the diseased limb. The mean MSTS score was 23.30±5.17, with an excellent limb function in 62 patients, good in 27 patients, fair in 7 patients, and poor in 4 patients. The overall excellent and good function was obtained in 89% of the patients. Conclusion We conclude that tumor prostheses can give a satisfactory functional outcome after the tumor around the knee is removed; however, the tumor prostheses still need to be further improved because of a high complication rate.
Objective To study the clinical application ofheterogenous bone graft combined with auto-marrow. Methods Deproteinated and degreased heterogenouscancellous bone combined with auto-marrow was used in 21 cases of anterior cervical interbody fusion. Among them, 2 cases were treated by bone graft only, and the other 19 cases were further treated by anterior plate fixation. Results The follow-up time was 12-36 months with an average of 21 months. After operation, posteroanterior and lateral radiograph of all the cases revealed that the reduction and the position of the grafting bone were good without inflammation or other complications. After 6 months of operation, the radiograph of 2 cases of cervical disk herniation, which were treated by bone graft only, showed the bones lost their height and the curve of the cervical spine returned to the state of preoperation. For the other cases, the grafting bonesremained their original figure without dislocation of the bone or fracture of the plate or the screw. The nervous function recovered variously. Before operation, 10 cases were ranked as grade A,7 cases grade C, 4 cases grade D according to Frankel classification. After operation, in grade A cases, 5 cases did not recover, 3 cases recovered to grade B, 2 cases to grade C; in grade C cases, 5 to grade D, 2 to grade E; all ofgrade D 4 cases to grade E. Conclusion Heterogenous bone combined with auto-marrow can be used as grafting material in the anterior cervical interbodyfusion, but its mechanical rigidity need to be improved or the fusion shouldbe aided with rigid internal fixation.