Publications (21) View all
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Article: Anteromedial thigh flaps: an anatomical study to localize and classify anteromedial thigh perforators.
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ABSTRACT: Until now, research on flaps in the anteromedial thigh region has focused on flaps in specific regions. To elucidate the complete pattern of suitable anteromedial thigh perforators, an anatomical study was performed by dissecting nine thighs from different cadavers. The ideal perforator has maximum length and diameter and runs through a septum. According to the data found in our study, these perforators can predominantly be found in the middle third of the anteromedial thigh region. All of the three main thigh vessels supply perforators which can be used for flaps. Pertaining to length and diameter the most suitable perforators originate from the deep femoral artery, which can be found in the proximal and middle third of the anteromedial thigh. Musculocutaneous perforators are found to be longer than septocutaneous perforators. Because of their position, the proximal and distal third perforators should preferentially be used for local pedicled flaps. Defects in the pelvic area and around the knee can be closed with perforator flaps from the proximal and distal anteromedial thigh, respectively. Because of their diameter, length, and number, the middle third perforators should be the first choice for harvesting free flaps. Skin closure is easily achieved in the anteromedial thigh region even when larger flaps are used.Microsurgery 09/2009; 30(1):43-9. · 1.61 Impact Factor -
Article: Ectopic bone formation in titanium mesh loaded with bone morphogenetic protein and coated with calcium phosphate.
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ABSTRACT: The osteoinductive properties of porous titanium fiber mesh, with or without a calcium phosphate coating and loaded with recombinant human bone morphogenic protein-2 (rhBMP-2) or rhBMP-2 and native bovine BMP (S-300) were investigated in a rat ectopic assay model. A total of 112 calcium phosphate-coated and 112 noncoated porous titanium implants, either loaded with rhBMP-2 and S-300 or loaded with rhBMP-2 alone, were subcutaneously placed in 56 Wistar-King rats. The rats were killed 5, 10, 20, and 40 days postoperatively, and the implants were retrieved. Histologic analysis demonstrated that all growth factor and carrier combinations induced ectopic cartilage and bone formation at 5 and 10 days, respectively. At 20 days, bone formation increased and was characterized by trabecular bone and bone marrow-like tissue. At 40 days, more lamellar bone and hemopoietic bone marrow-like tissue were present. At both times, more bone had been formed in calcium phosphate-coated implants than in noncoated samples. Further, in rhBMP-2 and S-300-loaded specimens, bone formation was higher than in rhBMP-2 only-loaded specimens. In rhBMP-2 only-loaded specimens, bone formation was mainly localized inside the mesh material, whereas in specimens loaded with both rhBMP-2 and S-300, the bone was localized inside and surrounding the titanium mesh. The histological findings were confirmed by calcium content and alkaline phosphatase activity measurements. In addition, all specimens showed osteocalcin expression as early as 5 days postoperatively. Our results show that the combination of titanium mesh with BMPs can induce ectopic bone formation and that this bone formation seems to be similar to "enchondral" ossification. In addition, a thin calcium phosphate coating can have a beneficial effect on the bone-inducing properties of a scaffold material. Finally, rhBMP-2 and native BMP act synergistically in ectopic bone induction.Plastic & Reconstructive Surgery 09/2001; 108(2):434-43. · 3.38 Impact Factor -
Article: Influence of rhBMP-2 on rat bone marrow stromal cells cultured on titanium fiber mesh.
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ABSTRACT: Titanium (Ti) fiber mesh is a candidate scaffold material for the creation of bone graft substitutes (BGS). Two densities (3.54 x 10(4) cells/cm(2) [LD or low density] and 3.54 x 10(5) cells/cm(2) [HD or high density]) of rat bone marrow stromal cells were seeded on Ti-fiber mesh discs. Cells were cultured for up to 16 days, 7 days of which the cells were in the presence of various concentrations of rhBMP-2 (0, 10, 100, and 1,000 ng/mL) in order to evaluate osteogenic expression. Scanning electron microscopy (SEM), light microscopy (LM), energy dispersive spectroscopy (EDS), DNA and calcium (Ca) content measurements, and x-ray diffraction (XRD) analysis were performed. SEM and EDS evaluation showed that a confluent layer of cells was present on top of the meshes together with collagen bundles and calcified globular accretions. Light microscopical evaluation showed a densely stained layer in the upper part of the mesh. SEM and Ca content measurement showed that calcification starts at 8 days. In addition, it was demonstrated that DNA content peaked at 8 days. LM, SEM, and Ca content evaluation revealed positive effects of increasing the cell seeding density, the rhBMP-2 concentration and the culture time on mineralization. Increasing the cell seeding density also showed a positive effect on DNA content. No effects of rhBMP-2 concentration were seen on DNA content. Finally, XRD revealed that the deposited matrix contained a precipitate of a stable calcium phosphate phase. We conclude that (1) titanium fiber mesh sustains excellent osteogenic expression in vitro, (2) increasing the cell seeding density has a positive effect on osteogenic expression in titanium mesh in vitro, and (3) in high density specimens, rhBMP-2 concentrations of 100 ng/mL and 1,000 ng/mL stimulate extracellular matrix calcification in a dose-responsive manner.Tissue Engineering 09/2001; 7(4):373-83. · 4.02 Impact Factor -
Article: Orthotopic bone formation in titanium fiber mesh loaded with platelet-rich plasma and placed in segmental defects.
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ABSTRACT: The effect of platelet-rich plasma (PRP) on bone formation was investigated in a rabbit segmental radial defect model. The purpose of the study was to evaluate the bone inductive properties of PRP with titanium fiber mesh and autologous bone chips in a 15-mm rabbit radial defect model. Eighteen New Zealand white rabbits were divided into three groups: I, PRP with autologous bone (PRP-Ti-Bone); II, autologous bone (Ti-Bone); III, control group (Ti). The implants were placed in the radial defect for 12 weeks. After sacrifice, all specimens were harvested for histological, histomorphometrical and radiographic analysis. Histomorphometrical analysis showed that bone formation was higher in the implants with PRP (PRP-Ti-Bone: 37+/-8%) than in those without PRP (Ti-bone: 25+/-6% and Ti: 25+/-5%) after 12 weeks of implantation. It was concluded that PRP has a stimulatory effect on bone formation in titanium fiber mesh filled with autologous bone graft in segmental bone defects. Titanium fiber mesh was also shown to be an excellent scaffold material for the application of autologous bone grafts with or without PRP.International Journal of Oral and Maxillofacial Surgery 07/2008; 37(6):542-9. · 1.51 Impact Factor -
Article: Growth factor-loaded scaffolds for bone engineering.
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ABSTRACT: The objective of the study presented here was to investigate the bone inductive properties as well as release kinetics of rhTGF-beta1- and rhBMP-2-loaded Ti-fiber mesh and CaP cement scaffolds. Therefore, Ti-fiber mesh and porous CaP cement scaffolds were provided with these growth factors and inserted in subcutaneous and cranial implant locations in rats and rabbits. In vitro, a rapid release of rhTGF-beta1 was observed during the first 2 h of the Ti-fiber mesh scaffolds. During this time, more than 50% of the total dose of rhTGF-beta1 was released. Following this initial peak, a decline in the level of rhTGF-beta1 occurred. After 1 week, the entire theoretical initial dose was observed to have been released. This in contrast to the rhTGF-beta1 and rhBMP-2 release of the porous CaP cement scaffolds. Here, no substantial initial burst release was observed. The scaffolds showed an initial release of about 1% after 1 day, followed by an additional marginal release after 1 week. Histological analysis revealed excellent osteoconductive properties of non-loaded Ca-P material. Inside non-loaded Ti-mesh fiber scaffolds, also bone ingrowth occurred. Quantification of the bone ingrowth showed that bone formation was increased significantly in all scaffold materials by administration of rhTGF-beta1 and rhBMP-2. Consequently, we conclude that the release kinetics of growth factors from porous CaP cement differs from other scaffold materials, like metals and polymers. Nevertheless, orthotopic bone formation in a rabbit cranial defect model was stimulated in rhTGF-beta1- and rhBMP-2-loaded CaP cement and Ti-fiber mesh scaffolds compared with non-loaded implants.Journal of Controlled Release 02/2005; 101(1-3):127-36. · 5.73 Impact Factor
