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.
Forty-eight cases of multi-structural defects of hands were primarily repaired or reconstructed from July 1989 to 1997. The structural defects included: the defects of radial or ulnar aspect of hands involving fingers and skin, multiple fingers defects and the fingers and skin defects of whole hand. In this series, there were 32 males and 16 females with age ranged from 17 to 46 years old. The composite tissue grafts were obtained from wrap-around flap or 2nd toe skin flap of the foot. The result showed that composite 108 tissues transplantations, or 48 cases, were all survived. After a follow-up of 38.5 months (ranged from 5 months to 6 years), the grasp, pinch and opposition function of the reconstructed finger were restored, the two-point discrimination sensation was 4 mm-12 mm. Most of the patients had resumed their original works. So that the primary repair of multi-structural defects of hands by composite tissues transplantation was feasible and valuable, but thorough debridement and skilled microsurgecal technique were required.
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 review the appl ication of collagen and biodegradable polymer composite scaffolds in vascular tissue engineering, and describe the multi-layering vascular scaffolds of collagen-based material in recent years. Methods The l iterature concerning collagen composite scaffold production for scaffold of vascular tissue engineering was extensively reviewed and summarized. Results As one of the structural proteins in natural blood vessel, collagen is widely used in vascular tissue engineering because of good biocompatibil ity, biodegradabil ity, and cell recognition signal. The vascular scaffolds with biological activity and good mechanical properties can be made by collagen-polymer composite materials. In addition, the structure and function of the natural blood vessel can be better simulated by multi-layering vascularscaffolds. Conclusion Collagen-polymer composite material is the hot spot in the research of vascular scaffolds, and multilayering vascular scaffolds have a brill iant future.
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 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.
ObjectiveTo explore a new improved technique and its effectiveness to repair dorsal thumb composite tissue defects including interphalangeal joint by transplantation of modified hallux toe-nail composite tissue flap. MethodsThe hallux toe-nail composite tissue flap carrying distal half hallux proximal phalanx, extensor hallucis longus, and interphalangeal joint capsule were designed and applied to repair the dorsal skin, nails, and interphalangeal joint defect of thumb in 14 cases between January 2007 and June 2013. They were all males, aged from 19 to 52 years (mean, 30 years). The time from injury to hospital was 0.5-2.0 hours (mean, 1.2 hours). The area of the thumb nail and dorsal skin defects ranged from 2.5 cm×1.5 cm to 5.0 cm×2.5 cm. The dorsal interphalangeal joint had different degrees of bone defect, with residual bone and joint capsule at the palm side. The length of bone defect ranged from 2.5 to 4.0 cm (mean, 3.4 cm). The hallux nail flap size ranged from 3.0 cm×2.0 cm to 6.0 cm×3.0 cm. The donor sites were repaired by skin grafting in 5 cases, and retrograde second dorsal metatarsal artery island flap in 9 cases. ResultsAfter operation, arterial crisis occurred in 1 case and the flap survived after relieving pressure; the other flaps survived, and wounds healed by first intention. Liquefaction necrosis of the skin grafting at donor site occurred in 3 cases, and the other skin grafting and all retrograde second dorsal metatarsal artery island flaps survived. The follow-up ranged from 9 months to 3 years and 6 months (mean, 23 months). The secondary plastic operation was performed in 4 cases at 6 months after operation because of slightly bulky composite tissue flaps. The other composite tissue flaps had good appearance, color, and texture. The growth of the nail was good in 12 cases, and slightly thickened in 2 cases. At last follow-up, X-ray examination showed that bone graft and proximal phalanx of the thumb had good bone healing in 12 cases. Good bone healing was obtained at the donor site. According to the Hand Surgical Branch of Chinese Medical Association standard for thumb and finger reconstruction function, the results were excellent in 12 cases and good in 2 cases, and the excellent and good rate was 100%. No pain at donor site was observed, with normal gait. ConclusionTransplantation of modified hallux toe-nail composite tissue flap to repair dorsal thumb composite tissue defects including interphalangeal joint can effectively improve the appearance and function of the impaired thumb.
Objective To investigate the application and effect of the crossbridge vascular anastomosis free flap transplantation for tissue defects of extremities. Methods From May 1982 to November 2005, 110 cases of tissue defects of extremities were treated with cross-bridgevascular anastomosis free tissue transplantation. Of 110 patitents, 80 were male and 30 were female with a median age of 30 years(5 to 54 years). Tissue defects were caused by traffic accidents (59 cases), machine injuries (32 cases) and mangled injuries (19 cases). The locations were the forearms in 2 cases and the legs in 108 cases. And 69 cases had simple soft tissue defects, 6 cases had simple bone defects, and 35 cases had complicated defects. The length of bone defectranged from 5 cm to 19 cm and the area of soft tissue defect ranged from 6 cm×10 cm to 15 cm×35 cm. The graft tissue included latissimus dorsi musculocutaneous flap, vastus anterolateral flap,cutaneous fibula flap, osseous fibula flap, and cutaneous iliac flap. The cross-bridge of the two lower extremities wasperformed in 106 cases, the cross-bridge of the two upper extremities in 2 cass, and the crossbridge of the upper-lower extremities in 2 cases. The compoite tissue transplantation was used if the graft tissues were two or more. The wounds of donor site was directly sutured in 67 cases, and partly sutured with skingrafting in 43 cases. Results Vascular crisis occurred in 9 cases. Vascular crisis was relieved in 5 cases and grafting tissues was survival after exploring the vessel; 4 cases failed. The graft tissue was survival in 101 cases, and the survivalrate was 96.4%. The follow-up time was 4 months to 22 years with an average of 6.3 years. Graft bone healed and mean healing time was 4 months. The flap appearance was satisfactory and extremity function was restored to normal. One case became necrosis in the edge of the flap and cured by debridement, dressing and skingrafting, the other got primary healing at 2-3 weeks after operation. Conclusion The application of the cross-bridge vascular anastomosis free tissue transplantation for tissue defects of extremities is an effective method, when extremities have no vessel anastomosed.
Objective To summarize and review the development and experience of anastomosis vascular pedicle free composite tissue flap. Methods From July 1987 to March 2007， 321 patients with complete records were treated. Fourteen tissue flaps were applied for the repair of trauma or tumor excision defects of the body, and for organ reconstruction. Results Vascular crisis occurred in 20 patients within 48 hours postoperatively. Necrosis occurred at flap end in 6 patients. The total survival rate was 94.8%. The main experience was: ① Training to grasp the basic microvascular anastomosis technique was very importantstarting up period for surgeons. The basic technique should be often practiced to ensure the safty of clinical application. ②Restoring appearance and function were equally important in practice.③Utilizing the minimal invasive methods and decreasing the loss of function of donor site were important for improvement of reconstruction quality. The purpose was to achieve functional and esthetic restoration in the condition of lowest donor site scarification. Conclusion The application of free composite tissue flap is important for the development of plastic surgery. There are extensive applications for free flap, especially for those critical patients. The application of free flap could decrease the mobility rate, shorten the treatment period, ease the pain of patients and improve the reconstruction effect. The experience of donor site selection, the strategy of poor recipient site condition, the advantages and disadvantages of muscle flap, the applications time, infections wound treatment and application, are helpful for the future application.