The biology of bone grafting

Many approaches are used to repair skeletal defects in reconstructive orthopaedic surgery, and bone grafting is involved in virtually every procedure. The type of bone graft used depends on the clinical scenario and the anticipated final outcome. Autogenous cancellous bone graft, with its osteogenic, osteoinductive, and osteoconductive properties, remains the standard for grafting. However, the high incidence of morbidity during autogenous graft harvest may make the acquisition of grafts from other sources desirable. The clinical applications for each type of bone graft are dictated by the structure and biochemical properties of the graft. An elegant cellular and molecular cascade follows bone transplantation. Bone graft incorporation within the host, whether autogenous or allogeneic, depends on many factors: type of graft (autogenous versus allogeneic, vascular versus nonvascular), site of transplant, quality of transplanted bone and host bone, host bed preparation, preservation techniques, systemic and local disease, and mechanical properties of the graft.     

The current status of lumbar total disc replacement

Total disc replacement is an exciting technology that may one day replace fusion as the gold standard treatment for DDD, but it is currently an experimental procedure in the United States. Promising short- and mid-term results have been reported for TDR, but longer follow-up and randomized trials comparing TDR to fusion and nonsurgical treatment are needed to fully define the role of TDR in the spine surgeon's armamentarium. Short-term complication rates have been acceptably low, but in the long term the durability of TDR implants and the vertebral endplate will provide challenges. Finally, it is essential that practitioners understand that a limited subset of patients are good candidates for TDR and that indiscriminate application of this technology will result in poor outcomes.     

Apolipoprotein E gene polymorphism in Indian patients with Alzheimer's disease and vascular dementia

The association of apolipoprotein E (ApoE) gene polymorphism with Alzheimer's disease (AD) has been reported in several populations including one from a rural community in North India. However, the association of ApoE polymorphism with vascular dementia (VaD) is yet to be established in this population. In a case-control study involving 54 cases of dementia (29 AD and 25 VaD) and 76 age-matched healthy controls, the frequency of epsilon4 allele was significantly higher among cases of AD and VaD compared with controls (p < 0.001). The epsilon3epsilon3 (p < 0.05) and epsilon2epsilon3 (p < 0.001) genotypes were found to be protective. The odds of developing AD or VaD were 4.4 and 3.7 times higher, respectively, in the presence of even a single epsilon4 allele. Our results suggest that the increased risk of developing AD or VaD is similar among Asian Indians with ApoE epsilon4 compared with the Caucasian population.     

Threaded cortical bone dowels in lumbosacral arthrodesis: a review

Lumbar fusion is a common spinal surgery, for which numerous devices have been developed to aid in segment stabilization. A threaded cortical bone dowel is a machined and processed bone allograft which is one such development. Threaded cortical bone dowels are attractive because of their osteoconductive nature and the opportunity to load them with osteogenic morselized bone autograft or osteoinductive growth factors, such as bone morphogenetic proteins. Although threaded cortical bone dowels have been in clinical use for more than 5 years, they have not been the subject of a comprehensive review. The current article covers the history, preparation, uses, safety, and efficacy of threaded cortical bone dowels in lumbosacral interbody fusion.     

Potential impact of [<Superscript>18</Superscript>F]3'-deoxy-3'-fluorothymidine versus [<Superscript>18</Superscript>F]fluoro-2-deoxy-<Emphasis Type="SmallCaps">d</Emphasis>-glucose in positron emission tomography for colorectal cancer

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