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.
Objective To investigate the influence of collagen on the biomechanics strength of tissue engineering tendon. Methods All of 75 nude mice were madethe defect models of calcaneous tendons, and were divided into 5 groups randomly. Five different materials including human hair, carbon fibre (CF), polyglycolic acid (PGA), human hair and PGA, and CF and PGA with exogenous collagen were cocultured with exogenous tenocytes to construct the tissue engineering tendons.These tendons were implanted to repair defect of calcaneous tendons of right hind limb in nude mice as experimental groups, while the materials without collagenwere implanted to repair the contralateral calcaneous tendons as control groups. In the 2nd, 4th, 6th, 8th and 12th weeks after implantation, the biomechanicalcharacteristics of the tissue engineering tendon was measured, meanwhile, the changes of the biomechanics strength were observed and compared. Results From the 2nd week to the 4th week after implantation, the experimental groups were ber than the control groups in biomechanics, there was statistically significantdifference (Plt;0.05). From the 6th to 12th weeks, there was no statisticallysignificant difference between the experiment and control groups (Pgt;0.05). Positivecorrelation existed between time and intensity, there was statistically significant difference (Plt;0.05). The strength of materials was good in human hair,followed by CF, and PGA was poor. Conclusion Exogenous collagen can enhance the mechanics strength of tissue engineering tendon, and is of a certain effect on affected limb rehabilitation in early repair stages.
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.
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 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.
ObjectiveTo explore the therapeutic effect of Masquelet technique combined with tissue flap grafting for bone defect and soft tissue defect. MethodsBetween August 2012 and April 2015, 18 cases of bone defect and soft tissue defect were treated by using Masquelet technique combined with tissue flap grafting. There were 11 males and 7 females, aged from 23 to 59 years (mean, 37.1 years). The time between injury and treatment was 15 days to 39 months (mean, 0.9 months). Defect located at the proximal tibia in 4 cases, at the middle tibia in 8 cases, at the distal tibia in 4 cases, and at the lateral heel in 2 cases. All patients were treated with debridement. After debridement, the bone defect was (5.7±1.8) cm in length, and the soft tissue defect was 5 cm×4 cm to 13 cm×11 cm in size. In one-stage operation, bone defect was repaired with the antibiotic cement and fracture was fixed by temporary external fixation. The surfaces of wound were repaired with tissue flap. After 6 to 8 weeks when wounds healed with no sign of infection, bone grafting from iliac bone and/or fibula was performed in two-stage operation. ResultsEighteen patients followed up 10-38 months (mean, 24.3 months). After one-stage operation, 6 cases had pin track infection, which was cured by strengthened disinfection and oral antibiotics. All the tissue flaps survived. Bone healing was observed on X-ray film at 15-57 weeks (mean, 25.3 weeks) after two-stage operation. The function of the knee and ankle joint recovered well. According to the American Orthopaedic Foot and Ankle Society (AOFAS) score for the ankle joint, the scores of ankle function ranged from 74 to 98, with an average of 89.7; the results were excellent in 7 cases, good in 10 cases, and fair in 1 case. ConclusionThe Masquelet technique combined with tissue flap grafting is an effective method to treat bone defect and soft tissue defect.
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.
【Abstract】 Objective To evaluate the long-term effectiveness of composite grafts of acellular dermal matrix (ADM)and autologous spl it-thickness skin in repairing deep burn wounds. Methods Between June 2002 and December 2008, 30 patients (42 wound) were treated. There were 25 males and 5 females, aged 3-52 years with a median age of 31 years. Of them, 24 burned patients had 35 wounds, including 23 deep second degree and 12 third degree wounds with a mean disease duration of 24 days (range, 3-45 days); 6 patients with hyperplastic scar had 7 wounds with a mean disease duration of 16 days (range, 9-21 days). The wound locations were neck (2 wound), hand (4 wounds), forearm and elbow (8 wounds), shoulder (3 wounds), poples (6 wounds), laps (4 wounds), ankle and legs (15 wounds), and the area of wounds ranged from 10 cm × 10 cm to 30 cm × 20 cm. After thorough debridement, tangential excision, and scar excision, ADM and autologous spl it-thickness skin graft were used to repair the wounds by one-step method. Results After operation, composite skin graft survived completely in 39 wounds of 27 patients, with a survival rate of 92.9%; partial necrosis occurred in 3 wounds of 3 patients (7.1%), and healed after dressing change and secondary skin graft. The patients were followed up 30-34 months (mean, 32 months) postoperatively. The appearance of the composite grafts were smooth and soft with good elasticity and low pigmentation. The activity and function of limbs recovered well. No scar hyperplasia was observed at the donor sites. Conclusion It can achieve good outcomes in appearance and function to use ADM and autologous spl it-thickness skin graft for repairing deep burn wounds in functional regions.
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.
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.