Search

The review is based on the analysis of 53 literature sour­ces from PubMed, Google, Google Scholar, and Cochrane Library. Among the substitutes for autogenous bone grafts in spine surgery, ceramic biomaterials are the largest studied group, among which certain niche is occupied by calcium phosphate ceramics (CPCs). Hydroxylapatite, tricalcium phosphate and biphasic ceramics with all parts of hydroxylapatite and tricalcium phosphate are widely used in spine surgery. The advantage of using CPCs is their biocompa­tibility, osteoconductivity, osteoinductivity, osteoimmunomodulation and the ability to stimulate angiogenesis — the main components that ensure bone regeneration. In the given review, the peculiarities of regeneration in the interface “ceramic material — bone tissue” depending on the composition, surface structure, and crystallinity of the material are noted. The positive results of the experimental studies led to the use of CPCs in the clinic. CPCs with auto­genous bone grafts are successfully used in posterior and posterolateral lumbar spondylodesis, which allows reducing significantly the volume of autologous bone. A new direction is the development of non-metallic combined cages, which are used to perform anterior cervical discectomy and spondylodesis. The composition of these cages includes various polymers in combination with CPCs and bone autogenous graft to ensure high-quality spondylodesis, reduce of stress-shiel­ding and subsidence of the cage. A special approach requires the study of degradation and resorption by osteoclasts of various CPCs in order to control and synchronize the process of “resorption — bone formation”. Among the issues for the further research, the molecular mechanisms of osteoimunomodulation and factors that stimulate osseointegration and osteoinduction in the management of reparative osteogenesis should be further explored.

The review is based on the analysis of 53 literature sources from PubMed, Google, Google Scholar, and Cochrane Library. Among the substitutes for autogenous bone grafts in spine surgery, ceramic biomaterials are the largeststudied group, amongwhich certain niche is occupied by calcium phosphate ceramics (CPCs). Hydroxylapatite, tricalcium phosphate and biphasic ceramics with all parts of hydroxylapatite and tricalcium phosphate are widely used in spine surgery. The advantage of using CPCs is their biocompatibility, osteoconductivity, osteoinductivity, osteoimmunomodulation and the ability to stimulate angiogenesis — the main components that ensure bone regeneration. In the given review, the peculiarities of regeneration in the interface “ceramic material — bone tissue” depending on the composition,surface structure, and crystallinity of the material are noted. The positive results of the experimentalstudiesled to the use of CPCsin the clinic. CPCs with autogenous bone grafts are successfully used in posterior and posterolateral lumbar spondylodesis, which allows reducing significantly the volume of autologous bone. A new direction is the development of non-metallic combined cages, which are used to perform anterior cervical discectomy and spondylodesis. The composition of these cagesincludes various polymers in combination with CPCs and bone autogenous graft to ensure high-quality spondylodesis, reduce of stress-shielding and subsidence of the cage. A special approach requires the study of degradation and resorption by osteoclasts of various CPCs in order to control and synchronize the process of “resorption — bone formation”. Among the issues for the further research, the molecular mechanisms of osteoimunomodulation and factorsthatstimulate osseointegration and osteoinduction in the management of reparative osteogenesis should be further explored. [ABSTRACT FROM AUTHOR]

The mineral components of powdered samples of cortical dense bone tissue of domestic animals (pig and cow) were studied by electron paramagnetic resonance (EPR). Bone tissue was heated in a temperature range 600-1000 ºС in an oven and then held for more than one year at room temperature. This was done to allow short-lived defects to decay and to let the mineral structures stabilize. In these heat-treated samples, within the limits of the sensitivity of the experiments, no EPR signals were detected, but after irradiation with X-rays, multicomponent EPR signals appeared. Spectra vary depending on the heating temperatures. Paramagnetic centers related to PO3 2–, NO4 2– ³- groups are observed. The g-factor of spectroscopic splitting and amplitude of ultrafine interaction of the indicated paramagnetic centers in the spectra were determined. Due to different relaxation behavior of the paramagnetic centers, and hence their saturation effects, the form of the total EPR signals significantly depends on the microwave power level at which the spectra are recorded. Therefore, EPR signals were recorded at high (5 mW) and low (0.13 mW) microwave power levels. The temperature dependency of EPR signal amplitude was determined for some paramagnetic centers in the range of 600-1000 ºС. The EPR signal properties of the heated bone samples and synthetic hydroxylapatites were compared. The spectra indicate that phosphates in bone tissue have a more complex structure than simple synthetic hydroxylapatite. The results of this work can be used to create synthetic analogs of bone tissue, to help in the manufacturing of implants that are used to treat bone tissue, and to study the processes related to the assimilation of mineralogic-based implants by living bone tissue. [ABSTRACT FROM AUTHOR]2 –, CO3 ³- groups are observed. The g-factor of spectroscopic splitting and amplitude of ultrafine interaction of the indicated paramagnetic centers in the spectra were determined. Due to different relaxation behavior of the paramagnetic centers, and hence their saturation effects, the form of the total EPR signals significantly depends on the microwave power level at which the spectra are recorded. Therefore, EPR signals were recorded at high (5 mW) and low (0.13 mW) microwave power levels. The temperature dependency of EPR signal amplitude was determined for some paramagnetic centers in the range of 600-1000 ºС. The EPR signal properties of the heated bone samples and synthetic hydroxylapatites were compared. The spectra indicate that phosphates in bone tissue have a more complex structure than simple synthetic hydroxylapatite. The results of this work can be used to create synthetic analogs of bone tissue, to help in the manufacturing of implants that are used to treat bone tissue, and to study the processes related to the assimilation of mineralogic-based implants by living bone tissue. [ABSTRACT FROM AUTHOR]

Copyright of Travma is the property of Zaslavsky O.Yu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)