Traditional Grafting Techniques Research Articles

Demineralized Bone Matrix in Spine Surgery: A Review of Current Applications and Future Trends

Graft augmentation for spinal fusion is an area of continued interest, with a wide variety of available products lacking clear recommendations regarding appropriate use. While iliac crest autograft has long been considered the "gold standard", suboptimal fusion rates along with harvest-related concerns continue to drive the need for graft alternatives. There are now multiple options of products with various characteristics that are available. These include demineralized bone matrix (DBM) and demineralized bone fibers (DBF), which have been used increasingly to promote spine fusion. The purpose of this review is to provide an updated narrative on the use of DBM/DBF in spine surgery. Literature review. The clinical application of DBM in spine surgery has evolved since its introduction in the mid-1900s. Early preclinical studies demonstrated its effectiveness in promoting fusion. When used in the cervical, thoracic, and lumbar spine, more recent clinical data suggest similar rates of fusion compared with autograft, although clinical studies are primarily limited to level III or IV evidence with few level I studies. However, significant variability in surgical technique and type of product used in the literature limits its interpretation and overall application. DBM and DBF are bone graft options in spine surgery. Most commonly used as graft extenders, they have the ability to increase the volume of traditional grafting techniques while potentially inducing new bone formation. While the literature supports good fusion rates when used in the lumbar spine and when used with adjuvant cages or additional grafting techniques in the cervical spine, care should be taken when using as a stand-alone product. As new literature emerges, DBM and DBF can be a useful method in a surgeon's armamentarium for fusion-based procedures.

Synthesis and Characterization of Hierarchical Mesoporous-Macroporous TiO2-ZrO2 Nanocomposite Scaffolds for Cancellous Bone Tissue Engineering Applications

Bone tissue engineering has been introduced several decades ago as a substitute for traditional grafting techniques to treat bone defects using engineered materials. The main goal in bone tissue engineering is to introduce materials and structures which can mimic the function of bone to restore the damaged tissue and promote cell restoration and proliferation. Titania and zirconia are well-known bioceramics which have been widely used in tissue engineering applications due to their unsurpassed characteristics. In this study, hierarchical meso/macroporous titania-zirconia (TiO2-ZrO2) nanocomposite scaffolds have been synthesized and evaluated for bone tissue engineering applications. The scaffolds were produced using the evaporation-induced self-assembly (EISA) technique along with the foamy method. To characterize the samples, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), simultaneous thermal analysis (STA), and Brunauer-Emmett-Teller (BET) analysis were performed. The results showed that TiO2-ZrO2 scaffolds can be produced after sintering the samples at 550°C for 2 h. Among samples with different weight percentages of zirconia and titania, the sample containing 13 wt.% zirconia was considered as the optimum sample due to its structural integrity. This scaffold had pore size, pore wall size, and mesopores in the range of 185±66 μm, 15±4 μm, and 7-13 nm, respectively. The specific surface area obtained from the BET theory, total volume, and mean diameter of pores of this sample was 13.627 m2g1-, 0.03788 cm3g-1, and 11 nm, respectively. The results showed that the produced scaffolds can be considered as the promising candidates for cancellous bone regeneration.

Treatment of congenital syndactyly

Defined as the union of two adjacent digits, syndactyly is one of the most common congenital deformities. The severity of the malformation depends on the fusion level, the tissues involved in the union, and whether it is isolated or syndromic. In order to improve the hand's appearance and function, surgery is recommended in the great majority of cases, ideally during early childhood (i.e., before entering school). Web space reconstruction is done using local flaps. Depending on the flap design, digital resurfacing can be done with or without skin grafts. While graftless techniques have shorter operating times and no morbidity associated with skin harvesting, their cosmetic outcomes seem to be worse than those of traditional grafting techniques, with more postoperative complications; furthermore, such techniques cannot be used in all cases, especially those with osteoarticular fusions. When the fingertip is involved, paronychial reconstruction is carried out with pulp flaps. The prognosis for these deformities directly depends on their severity, with excellent outcomes in cases of cutaneous fusion, and much less predictable ones when osteoarticular and/or tendinous tissues are involved.

Evaluation of the role of autogenous bone-marrow–derived mesenchymal stem cell transplantation for the repair of mandibular bone defects in rabbits

The repair of craniofacial bony defects by traditional grafting techniques requires substantial time and effort, with associated morbidity. Tissue engineering has therefore become a novel approach targeting application for bone regeneration. This study used the rabbit model for radiographic and histological evaluation of bone bioengineering for mandibular defects reconstruction using only β-tricalcium phosphate (β-TCP) and, when loaded with autogenous; bone marrow–derived undifferentiated mesenchymal stem cells (BM-MSCs). Critical-sized defects (10 × 15 mm) were created unilaterally in the mandibular body region of each rabbit (n = 16), to be filled with the BM-MSCs/β-TCP constructs for the study group (group I) (n1 = 8) and with scaffold devoid of cells for the control group (group II) (n2 = 8). Two rabbits from each group were sacrificed after healing periods of 2, 4, 12, and 24 weeks. The results revealed that the BM-MSCs endowed β-TCP scaffold with a better and more rapid bone regenerating potential: since the first evaluation period of 2 weeks, the regenerated bone tissue in group I was more mature, denser and homogeneously distributed. From these findings we could infer that the bone regeneration process was jump-started within the study group cases, which led to better quality of regenerated bone.

Incorporation of cubane-type Mo 3S 4 molybdenum cluster sulfides in the framework of mesoporous silica

A new molybdenum siloxo cluster of formula [Mo 3S 4(dmpe) 3(MPTES) 3]PF 6 (dmpe = 1,2-(bis)dimethylphosphinoethane; MPTES = (3-mercaptopropyl)triethoxysilane) has been synthesized with the ultimate goal of incorporating it into ordered mesoporous silica via covalent attachment. For this purpose, two different approaches, in situ and grafting, are employed. The first one is based in the co-condensation of the Mo 3S 4 siloxo cluster and tetraethylorthosilicate (TEOS) as mixed silicon sources in the presence of a surfactant (CTAB). The use of this approach allows for the incorporation of the Mo 3S 4 siloxo cluster into the structure of the mesoporous silica. For comparison purposes, the same Mo 3S 4 siloxo cluster has been immobilized on the surface of conventional mesoporous silica MCM-41, using more traditional grafting techniques. The physical and structural properties of both series of materials, containing different Mo 3S 4 cluster loadings, have been thoroughly investigated by means of powder X-ray diffraction (XRD), N 2 adsorption/desorption isotherms, transmission electron microscopy (TEM), magic-angle spinning (MAS) 31P and CP/MAS 29Si NMR, Fourier transform infrared (FT-IR) and UV–Vis diffuse reflectance (DRUV–Vis) spectroscopies. The chemical and structural integrity of the diphosphino Mo 3S 4 siloxo cluster is preserved in both the in situ and grafted mesoporous silica based materials. Depending on the incorporation approach, immobilization of the trinuclear sulfido cluster occurs into the silica matrix structure for the in situ materials or on the surface for the grafted ones. With these results, we show that it is possible to extend the incorporation of chemical functionalities into the structure of mesoporous materials to Mo 3S 4 siloxo clusters.

Low-dose corticosteroid and regenerative cell therapies for acute laminitis.

The repair of craniofacial bony defects by traditional grafting techniques requires substantial time and effort, with associated morbidity. Tissue engineering has therefore become a novel approach targeting application for bone regeneration. This study used the rabbit model for radiographic and histological evaluation of bone bioengineering for mandibular defects reconstruction using only β-tricalcium phosphate (β-TCP) and, when loaded with autogenous; bone marrow–derived undifferentiated mesenchymal stem cells (BM-MSCs). Critical-sized defects (10 × 15 mm) were created unilaterally in the mandibular body region of each rabbit (n = 16), to be filled with the BM-MSCs/β-TCP constructs for the study group (group I) (n1 = 8) and with scaffold devoid of cells for the control group (group II) (n2 = 8). Two rabbits from each group were sacrificed after healing periods of 2, 4, 12, and 24 weeks. The results revealed that the BM-MSCs endowed β-TCP scaffold with a better and more rapid bone regenerating potential: since the first evaluation period of 2 weeks, the regenerated bone tissue in group I was more mature, denser and homogeneously distributed. From these findings we could infer that the bone regeneration process was jump-started within the study group cases, which led to better quality of regenerated bone.

Bone Regeneration and Docking Site Healing After Bone Transport Distraction Osteogenesis in the Canine Mandible

Bone transport distraction osteogenesis provides a promising alternative to traditional grafting techniques. However, existing bone transport distraction osteogenesis devices have many limitations. The purpose of this research was to test a new device, the mandibular bone transport reconstruction plate, in an animal model with comparable mandible size to humans and to histologically and mechanically examine the regenerate bone. Eleven adult foxhounds were divided into an unreconstructed control group of 5 animals and an experimental group of 6 animals. In each animal, a 34-mm segmental defect was created in the mandible. The defect was reconstructed with a bone transport reconstruction plate. Histologic and biomechanical characteristics of the regenerate and unrepaired defect were analyzed and compared with bone on the contralateral side of the mandible after 4 weeks of consolidation. The reconstructed defect was bridged with new bone, with little bone in the control defect. Regenerate density and microhardness were 22.3% and 42.6%, respectively, lower than the contralateral normal bone. Likewise, the anisotropy of the experimental group was statistically lower than in the contralateral bone. Half the experimental animals showed nonunion at the docking site. The device was very stable and easy to install and activate. After 1 month of consolidation, the defect was bridged with new bone, with evidence of active bone formation. Regenerate bone was less mature than the control bone. Studies are underway to identify when the regenerate properties compare with normal bone and to identify methods to augment bone union at the docking site.

Spinal reconstruction and bone morphogenetic proteins: Open questions

Abstract Spinal fusion is a proven surgical tool for the treatment of degenerative, traumatic, neoplastic, and infectious conditions of the spine. Traditional grafting techniques using autogenous bone graft or allograft have inherent drawbacks including varying pseudoarthrosis rates and well recognized bone graft harvest site complications. Bone morphogenetic proteins (BMPs) offer the exciting prospect of enhanced union rates equal to or greater than autograft and potentially eliminate graft harvest site complications. Many studies have clearly demonstrated the efficacy of BMP products for various applications in spine surgery. BMP has proven effective in achieving union in anterior and posterior lumbar surgery and recently in anterior cervical surgery. Despite the reported success, the universal adoption of BMP is tempered by high costs and lingering safety concerns with reported complications specific to BMP use including vertebral osteolysis, ectopic bone formation, radiculitis and cervical soft tissue swelling. Ongoing clinical and basic-science research is focused on clearly defining guidelines for BMP use in spine surgery and on developing more affordable BMP formulations with dosing that predictably results in spine fusion yet minimizes the possible side effect profile.

Cellulose modification by polymer grafting: a review

This critical review is concerned with the recent advances in graft polymerisation techniques involving cellulose and its derivatives. It summarises some of the features of cellulose structure and cellulose reactivity. Also described are the various techniques for grafting synthetic polymers from the cellulosic substrate. In addition to the traditional grafting techniques, we highlight the recent developments in polymer synthesis that allow increased control over the grafting process and permit the production of functional celluloses that possess improved physical properties and chemical properties (189 references).

Optimization of Reaction Conditions for the Metalorganic Modification of MCM-41

The modification of periodic mesoporous silica with organic groups following an optimized metalorganic route is described. Organolithium and Grignard reagents (n-butyllithium and allyl-magnesium bromide) were used to directly substitute silicon atoms with organic moieties in the channel walls of the silica host. A detailed study of several representative reactions with respect to reaction parameters, that is, reaction temperature, reaction time, and reagent concentration, shows that the degree of surface substitution can be controlled within a broad range and up to very high levels while still maintaining the integrity of the ordered silica host. The functionalized mesoporous materials can also retain high surface areas and pore volumes. Furthermore, the reactions can be performed at low temperatures compared to the more traditional grafting techniques on the basis of organosilanes.

Discussion

A new molybdenum siloxo cluster of formula [Mo3S4(dmpe)3(MPTES)3]PF6 (dmpe = 1,2-(bis)dimethylphosphinoethane; MPTES = (3-mercaptopropyl)triethoxysilane) has been synthesized with the ultimate goal of incorporating it into ordered mesoporous silica via covalent attachment. For this purpose, two different approaches, in situ and grafting, are employed. The first one is based in the co-condensation of the Mo3S4 siloxo cluster and tetraethylorthosilicate (TEOS) as mixed silicon sources in the presence of a surfactant (CTAB). The use of this approach allows for the incorporation of the Mo3S4 siloxo cluster into the structure of the mesoporous silica. For comparison purposes, the same Mo3S4 siloxo cluster has been immobilized on the surface of conventional mesoporous silica MCM-41, using more traditional grafting techniques. The physical and structural properties of both series of materials, containing different Mo3S4 cluster loadings, have been thoroughly investigated by means of powder X-ray diffraction (XRD), N2 adsorption/desorption isotherms, transmission electron microscopy (TEM), magic-angle spinning (MAS) 31P and CP/MAS 29Si NMR, Fourier transform infrared (FT-IR) and UV–Vis diffuse reflectance (DRUV–Vis) spectroscopies. The chemical and structural integrity of the diphosphino Mo3S4 siloxo cluster is preserved in both the in situ and grafted mesoporous silica based materials. Depending on the incorporation approach, immobilization of the trinuclear sulfido cluster occurs into the silica matrix structure for the in situ materials or on the surface for the grafted ones. With these results, we show that it is possible to extend the incorporation of chemical functionalities into the structure of mesoporous materials to Mo3S4 siloxo clusters.