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    08 April 2020, Volume 24 Issue 10 Previous Issue    Next Issue
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    Relationship between thoracic and lumbar vertebral posterior wall morphology and bone cement leakage into the spinal canal during the percutaneous kyphoplasty
    Zhang Shuai, Wang Gaoju, Wang Qing
    2020, 24 (10):  1477-1483.  doi: 10.3969/j.issn.2095-4344.2201
    Abstract ( 370 )   PDF (31388KB) ( 76 )   Save

    BACKGROUND: Percutaneous kyphoplasty (PKP) is an effective method for treating osteoporotic vertebral compression fracture. Although satisfactory clinical outcomes can be achieved, bone cement leakage is still one of the main complications of PKP. Based on previous studies, there are many high risk factors for bone cement leakage into the spinal canal; however, less attention to the posterior wall morphology of different vertebral bodies may be an important reason for bone cement leakage into spinal canal.

    OBJECTIVE: To investigate the effect of thoracic and lumbar vertebral posterior wall morphology in the patients with osteoporotic vertebral compression fracture on bone cement leakage into the spinal canal during the PKP.

    METHODS: The clinical data of osteoporotic vertebral compression fracture patients with PKP were selected. There were 98 osteoporotic vertebral compression fracture patients with CT scan and three-dimensional reconstruction image data from T6 to L5. The three-dimensional reconstruction of CT and multiplanar reconstruction were used to measure the depth of the concave vertebral posterior wall (OC) and the corresponding middle-sagittal diameter of the vertebra (PC) of the non-fractured vertebral body, the ratio of OC to PC was calculated. All subjects were divided into thoracic group (T6-T12) and lumbar group (L1-L5) based on the location of measured vertebral, and the differences of the OC between groups were compared. 357 patients (548 vertebrae) with osteoporotic vertebral compression fracture without CT three-dimensional reconstruction underwent PKP within the same period. They were also divided into thoracic vertebra and lumbar vertebra groups. The degree of bone cement leakage into the spinal canal was compared between thoracic and lumbar vertebra groups.

    RESULTS AND CONCLUSION: (1) The morphological parameters of posterior vertebral wall in 98 patients showed that the depth of the concave vertebral posterior wall gradually (OC) deepened from T6 to T12, with an average of 4.6 mm. The depth became gradually shallow from L1 to L5, with an average of 0.6 mm. The ratio of the depth of the concave vertebral posterior wall to the corresponding middle-sagittal diameter of the vertebra was approximately 16% (1/6) from T6 to T12. The average value of ratios from L1 to L5 was 3%. The ratios in lumbar vertebra were significantly decreased compared with thoracic vertebra (16%, 1/6). (2) Results form 357 patients who underwent PKP at the same time showed that the rate of bone cement leakage into spinal canal was 10.2% (31/304) in the thoracic vertebra group during the PKP, and the rate of lumbar vertebra group was 3.7% (9/244). In the thoracic group, the average maximal sagittal diameter of the bone cement intruded spinal canal was (3.1±0.2) mm, the average maximal area of the bone cement intruded spinal canal was (30.8±0.3) mm2, and the spinal canal encroachment rate was (22.5±0.2)%. In the lumbar group, the average maximal sagittal diameter of the bone cement intruded spinal canal was (1.4±0.1) mm, the average maximal area of the bone cement intruded spinal canal was (14.9±0.2) mm2, and the spinal canal encroachment rate was (11.4±0.3)%. There was significant difference between thoracic and lumbar groups (P < 0.05). (3) The above results imply that due to the presence of OC structure in the middle and lower thoracic vertebra, it is possible to reduce the occurrence of bone cement leakage into spinal canal through avoiding bone cement distribution over the posterior 1/6 (16%) of vertebral body in PKP. The effect of the difference between thoracic and lumbar vertebral posterior wall morphology in osteoporotic vertebral compression fracture patients on bone cement leakage into the spinal canal during the PKP may be one of the reasons why the rate of bone cement leakage into spinal canal in thoracic vertebra significantly higher than that in lumbar vertebra. The study protocol was approved by the Ethics Committee of the Affiliated Hospital of Southwest Medical University (approval No. K2018008).

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    Comparison of percutaneous vertebroplasty and percutaneous curved vertebroplasty for osteoporotic vertebral compression fractures: distribution and leakage rate of injected bone cement 
    Li Fanjie, Du Yibin, Liu Yiming, Zhang Zhidong, Li Jian, Ma Li, Li Chun, Cheng Yonghong
    2020, 24 (10):  1484-1490.  doi: 10.3969/j.issn.2095-4344.2248
    Abstract ( 372 )   PDF (34148KB) ( 50 )   Save

    BACKGROUND: Percutaneous curved vertebroplasty is a modified surgical method of percutaneous vertebroplasty; the most prominent feature of which is that it can make the bone cement distributed symmetrically and balance the strength on both sides of the vertebral body. In theory, it can ensure the distribution of bone cement in the vertebral body, and solve the problem that the uneven distribution of bone cement in the traditional percutaneous vertebroplasty and single injection leads to poor pain relief effect in the fracture area.

    OBJECTIVE: To compare the clinical efficacy of percutaneous curved vertebroplasty and percutaneous vertebroplasty bone cement injection in the treatment of osteoporotic vertebral compression fractures, and to discuss the value of percutaneous curved vertebroplasty in clinical application.

    METHODS: Seventy patients with single vertebral osteoporotic vertebral compression fractures from the Third Affiliated Hospital of AnHui Medical University between 2017 and 2018 were selected. The patients were randomly divided into two groups. Percutaneous curved vertebroplasty group (n=35) received treatment with percutaneous curved vertebroplasty. Percutaneous vertebroplasty group (n=35) received treatment with percutaneous vertebroplasty. Distribution and leakage of bone cement were observed in the two groups. Visual analogue scale score and Oswestry disability index were assessed preoperatively and 1 day postoperatively. Postoperative follow-up was conducted for 1 year to observe the recovery of the height of the anterior edge of the injured vertebra and the occurrence of adjacent vertebral fractures. The trial was approved by the Ethics Committee of the Third Affiliated Hospital of Anhui Medical University.

    RESULTS AND CONCLUSION: (1) Compared with the percutaneous vertebroplasty group, the distribution of bone cement was more uniform and satisfactory (P < 0.05), and the leakage rate of bone cement was lower in the percutaneous curved vertebroplasty group (P < 0.05). (2) Both the visual analogue scale score and Oswestry disability index of the two groups at 1 day after surgery were significantly improved compared with those before surgery (P < 0.05). The improvement of Oswestry disability index of the percutaneous curved vertebroplasty group was better than that of the percutaneous vertebroplasty group (P < 0.05). (3) The height of the anterior edge of the injured vertebral body of the two groups improved significantly one year after surgery compared with that before surgery (P < 0.05), and there was no significant difference between the two groups (P > 0.05). (4) There was no significant difference in the incidence of adjacent vertebral fractures between the two groups (P > 0.05). (5) The results showed that compared with the treatment of percutaneous vertebroplasty, the treatment of osteoporotic vertebral body compression fractures by percutaneous curved vertebroplasty can reduce the rate of bone cement leakage and improve the quality of life of patients. 

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    Three-dimensional finite element analysis of mini implants supported mandibular overdentures
    Chen Junliang, Li Mingxia, Lü Dongmei, He Yun
    2020, 24 (10):  1491-1495.  doi: 10.3969/j.issn.2095-4344.2236
    Abstract ( 357 )   PDF (23965KB) ( 64 )   Save

    BACKGROUND: Overdenture supported by two to four implants located in the mandibular mental foramen area has been widely used in edentulous patients. However, in patients with severe mandibular resorption, it is a challenging to insert conventional implants. Mini-implants are a better choice in these cases.

    OBJECTIVE: To compare and analyze the biomechanical characteristics of conventional and mini-implants supported mandibular complete overdenture and to reveal the influence of different implant repair methods on implants and its surrounding tissues.

    METHODS: The cone beam CT data of a healthy patient scheduled to receive complete edentulous implant supported overdenture was obtained. CT data of the patient, implant and attachment data were imported into the software to create four models: 2 normal implants, 4 normal implants, 4 mini implants, and 5 mini implants supported mandibular overdentures respectively. The overdenture was bilaterally subjected to a vertical load of 150 N. The displacement and stress of implants and the stress of bone were compared.

    RESULTS AND CONCLUSION: For all models, the lowest and highest maximum values of stress in bone were obtained from 4 normal implant model (2.71 MPa) and 4 mini implant model (7.93 MPa). The lowest and highest maximum values of displacement in implant were obtained from 4 normal implant model (1.37 µm) and 2 normal implant model (1.57 µm). Moreover, the lowest and highest maximum values of stress in implant were demonstrated from 4 normal implant model (12.90 MPa) and 4 mini implant model (22.17 MPa). The biomechanical values of mini implant models were higher than those of conventional models. The biomechanical values of all models were below the critical limits. The distribution was more homogenous and the maximum values of displacement in the implant, stress in implant and stress in bone were reduced as the number of implants increased. Three-dimensional finite element analysis revealed that mandibular overdenture supported by four or five mini implants is a reliable treatment option.

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    Construction and characterization of nano-hydroxyapatite/chitosan/polycaprolactone composite scaffolds by 3D printing
    Yu Hedong, Zhang Li, Xia Lingyun, Mao Min, Ni Xiaobing, Leng Weidong, Luo Jie
    2020, 24 (10):  1496-1501.  doi: 10.3969/j.issn.2095-4344.2238
    Abstract ( 573 )   PDF (23416KB) ( 47 )   Save

    BACKGROUND: At present, there are many types of bone defect repair scaffolds, but a single type of material is difficult to meet the requirements of bone tissue engineering scaffold materials. Several suitable materials can be combined into a composite material by appropriate methods, taking into account the advantages and disadvantages of various materials. It is the focus of scholars in recent years.

    OBJECTIVE: To construct nano-hydroxyapatite/chitosan/polycaprolactone composite scaffolds and analyze characterization of composite scaffolds.

    METHODS: Nano-hydroxyapatite/chitosan/polycaprolactone porous ternary composite scaffold material was prepared by 3D printing and molding technology. The characterization of scaffold material was studied from X-ray diffraction analysis, stent water absorption rate, stent compressive strength, stent degradation performance in vitro, stent aperture analysis, scanning electron microscope analysis and other dimensions.

    RESULTS AND CONCLUSION: (1) X-ray diffraction analysis showed that the crystal-shaped peak map of nano-hydroxyapatite/chitosan/ polycaprolactone scaffold materials was similar to the hydroxyapatite powder diffraction standard card, suggesting that the scaffold materials were integrated with each other through physical interaction, and did not affect the biological function of hydroxyapatite. (2) The average water absorption rate of the scaffold was 18.28%, and the hydrophilicity was good. The maximum pressure that the scaffold could withstand was 1 415 N, and the degradation rate was similar to the osteogenic rate. (3) Under a microscope, a ternary scaffold material with an aperture of 250 μm was successfully produced. The pore size was uniform and distributed regularly. (4) Scanning electron microscope demonstrated that the fibers composed of chitosan and polycaprolactone were arranged orderly and grid like, hydroxyapatite was distributed uniformly on the fiber surface in granular form, and the ternary composite material presented uniform and loose microporous structure. (5) Nano-hydroxyapatite/chitosan/polycaprolactone ternary composite scaffold material can be successfully prepared through 3D printing and molding technology, which has moderate compressive strength, certain porosity, appropriate degradation rate and water absorption rate, and can lay a foundation for repairing bone defects.

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    Effects of changes in surface morphology of bone cement spacer on the expression of bone growth factor in induced membrane 
    Li Shuyuan, Zhou Qishi, Li Yue, Lin Zhiyi, Zhou Hongliang, Shen Zhen, Hu Cheng, Yang Jiabao
    2020, 24 (10):  1502-1507.  doi: 10.3969/j.issn.2095-4344.2217
    Abstract ( 284 )   PDF (25224KB) ( 33 )   Save

    BACKGROUND: At present, scholars at home and abroad try to promote the growth of bone graft by changing the types and morphology of implant materials, and improving the thickness and smoothness of induced membrane.

    OBJECTIVE: To compare the degree of vascularization and the expression of some osteogenic factors in the polymethylmethacrylate bone cement membrane with different surface roughness degrees at different femoral bone defects in rats.

    METHODS: Forty-eight male Sprague-Dawley rats (purchased from the Experimental Animal Center of Guangzhou University of Chinese Medicine) were used to establish rat models of critical-size femur defect. These rat modes were then randomly divided into groups A, B, C and D. Polymethylmethacrylate bone cement occupiers with surface roughness < 1.5 μm, 1.5-2.0 μm, 5.0-7.0 μm, and 14.0-20.0 μm were implanted in the femoral bone defects, respectively. At 6 weeks after implantation of bone cement spacer, the induced membranes around bone cement were removed. The morphological changes of the induced membranes were observed by hematoxylin-eosin staining. Western blotting and immunohistochemical staining were used to detect bone morphogenetic protein 2, transforming growth factor beta 1 and vascular endothelial growth factor protein in the induced membranes for quantitative and qualitative analyses. This study was approved by the Animal Ethics Committee of Guangzhou University of Chinese Medicine, China (approval No. 20181101006).

    RESULTS AND CONCLUSION: Hematoxylin-eosin staining showed that four kinds of bone cement with different surface roughness degrees could form a relatively regular induced membrane. The degree of vascularization and the number of cells in the induced membrane were similar among the four groups. Western blot analysis showed that the average levels of bone morphogenetic protein 2, transforming growth factor β1 and vascular endothelial growth factor protein were similar among four groups (P > 0.05). Immunohistochemical staining revealed that the positive expression of bone morphogenetic protein 2, transforming growth factor β1 and vascular endothelial growth factor protein was similar among four groups (P > 0.05). These findings suggest that the change of surface roughness of bone cement has no significant effect on the histomorphological structure of induced membrane and the expression of bone morphogenetic protein 2, transforming growth factor β1 and vascular endothelial growth factor in induced membrane at 6 weeks after implantation of bone cement spacer.

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    Extraction of porcine cancellous bone by supercritical carbon dioxide
    Luo Xujiang, Xian Hai, Peng Liqing, Shen Shi, Zhang Bin, Gao Chao, Wang Zhenyong, Sui Xiang, Huang Jingxiang, Han Gang, Liu Shuyun, Guo Quanyi, Lu Xiaobo
    2020, 24 (10):  1508-1514.  doi: 10.3969/j.issn.2095-4344.2218
    Abstract ( 421 )   PDF (29753KB) ( 38 )   Save

    BACKGROUND: In recent years, there have been many studies on the use of supercritical fluids for biological material treatment in countries outside China. However, little is reported on application of supercritical fluids to bone tissue extraction, in particular in China.

    OBJECTIVE: To evaluate the effectiveness of supercritical carbon dioxide extraction technology in the treatment of porcine femur cancellous bone and its effect on bone biological properties.

    METHODS: Porcine femoral bone blocks that were subjected to supercritical carbon dioxide extraction (study group) or not (control group) were prepared to determine bone mineral density, microstructure, maximum compressive strength, elastic modulus, bone tissue composition, collagen content and perform histological analysis. Bone marrow mesenchymal stem cells (BMSCs) were inoculated into two groups of bone blocks, and cultured for 1 day. The microporous structure of trabecular bone and cell adhesion and growth in bone material-cell composite were observed by scanning electron microscopy. The two groups of bone blocks were implanted subcutaneously in SD rats. The inflammatory reaction of subcutaneous tissue was observed histologically at 1, 2 and 4 weeks after surgery. The experimental protocol had been approved by the Animal Ethics Committee of Chinese PLA General Hospital, China.

    RESULTS AND CONCLUSION: There were no significant differences in pore size, bone mineral density, maximum compressive strength, elastic modulus and collagen content between the study and control groups (P > 0.05). Scanning electron microscopy showed that in the control group, the material pores had poor connectivity and there was soft tissue residue; in the study group, material pores were connected to each other and the structure was intact. Fourier transform infrared spectroscopy and X-ray diffraction analysis showed that the two groups of bone tissue materials had similar absorption and diffraction peaks. Thermogravimetric analysis showed that supercritical carbon dioxide extraction could reduce water content in bone tissue. Hematoxylin-eosin staining showed that there were no soft tissue residues in the bone, and the cell residues in the bone pit were significantly reduced in the study group, while soft tissue and cell residues were observed in the control group. Sirius red staining and modified Masson staining showed that the structure of bone collagen in the study group was intact, the cytoplasmic components reduced, and the cytoplasmic components in the control group remained significantly. Scanning electron microscopy showed that there was no obvious cell adhesion in the control group, but cell adhesion growth was obvious in the study group. Perivascular inflammatory response in the bone tissue implantation region was obviously weaker in the study group than in the study group. These results suggest that supercritical carbon dioxide extraction technology is an effective and environment-friendly bone tissue processing technology. It can effectively remove porcine cancellous bone cells and soft tissue without affecting its collagen structure and content and mechanical properties, retaining intact bone pore structure, increasing cell adhesion and growth, and effectively reducing inflammatory rejection.

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    A comparative study on the bone repair effects of two kinds of tissue regeneration membranes
    Yin Ying, Wang Jiaqi, Dai Xiaohan, Li Yiping, Zhang Xuehui
    2020, 24 (10):  1515-1520.  doi: 10.3969/j.issn.2095-4344.2235
    Abstract ( 454 )   PDF (26471KB) ( 41 )   Save

    BACKGROUND: Our previous study confirmed that BTO/P(VDF-TrFE) piezoelectric nanocomposite membrane containing 5%BTO (BaTO3, BTO) nanoparticles could significantly promote bone marrow mesenchymal stem cells (BMSCs) adhesion, growth, osteogenic differentiation and repair of bone defects due to its bionic potential. However, for clinical applications, it is not clear whether there is any difference between the bone repair effect of this material as a guide for tissue regeneration and that of the existing clinically non-degradable membrane products.

    OBJECTIVE: To compare the effects of BTO/P(VDF-TrFE) piezoelectric nano-composite membrane materials with commercial PTFE membrane in repairing critical-sized defects of SD rat skull.

    METHODS: BTO/P(VDF-TrFE) piezoelectric nanocomposite membrane containing 5% BTO nanoparticles was prepared by solution casting method. Scanning electron microscope, atomic force microscope and water contact angle measuring instrument were used to observe the surface morphology, measure the surface roughness and surface hydrophilicity and hydrophobicity of the material. In SD rats (purchased from the Laboratory Animal Center, Beijing University Hospital of Stomatology, China), a 5-mm sized full-thick bone defect was made on both sides of the sagittal suture of the skull. The left bone defect was covered with PTFE membrane (control group). The right bone defect was covered with BTO/P(VDF-TrFE) piezoelectric nano-composite membrane (experimental group). At postoperative 4 and 12 weeks, micro-CT and histological methods were used to evaluate the repair of the skull defect in rats. This study was approved by Animal Ethics Committee, Beijing University Hospital of Stomatology.

    RESULTS AND CONCLUSION: The piezoelectric nanocomposite membrane had smooth and dense surface and BTO nanoparticles were evenly distributed. PTFE membrane was composed of loose coarse fibers. The piezoelectric nanocomposite membrane had lower surface roughness (P < 0.001) and higher hydrophilicity (P < 0.001) than PTFE membrane. Micro-CT and histological results showed that at 4 weeks after surgery, new bone formation was found in both groups, but new bone formation was more obvious in the center of the defect in the experimental group than in the control group. At 12 weeks after surgery, bone defects healed in both groups, but the maturity of newly formed bone in the experimental group was greater than that in the control group. These results suggest that BTO/P(VDF-TrFE) piezoelectric nanocomposite membrane containing 5%BTO (BaTO3, BTO) nanoparticles can be used as a membrane guiding tissue regeneration.

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    Effect of relative position of planting denture on interdental food impaction: finite element analysis
    Pang Guobao, Zhao Ning, An Meiwen
    2020, 24 (10):  1521-1527.  doi: 10.3969/j.issn.2095-4344.2237
    Abstract ( 311 )   PDF (27168KB) ( 40 )   Save

    BACKGROUND: Implant denture is a kind of dental restoration with excellent retention, support and stability. However, the phenomenon of dental fillings after implantation is a common phenomenon that troubles the majority of patients with dental defects.

    OBJECTIVE: The finite element analysis method was used to analyze the food impaction after planting denture by biomechanical numerical simulation, and find the quantitative relationship between the food impaction and relative width, relative height, relative angle of the denture.

    METHODS: To study fully relative teeth under the conditions of different widths, heights and angles influence on food embedded plug, we designed different width groups of the upper structure of the denture (5 subgroups: 5.6, 5.7, 5.8, 5.9, 6.0 mm), different height groups of the upper structure of the denture (5 subgroups: 6.6, 6.8, 7.0, 7.2, 7.4 mm), different planting angle groups of the denture (5 subgroups: 92°, 91°, 90°, 89°, 88°), different width groups of natural crowns (5 subgroups: 5.6, 5.7, 5.8, 5.9, 6.0 mm), different height groups of natural crowns (5 subgroups: 6.6, 6.8, 7.0, 7.2, 7.4 mm), and different natural tooth growth angle groups (5 subgroups: 92°, 91°, 90°, 89°, 88°) as a 4-teeth partial denture model. Each subgroup was designed by changing the relative position of the third dental component, with the same remaining conditions. The numerical simulation of food impaction was carried out for all dentition models, and the deformation of the teeth was analyzed. The tooth gap width curves were compared before and after stress between each group.

    RESULTS AND CONCLUSION: (1) After force, the total horizontal displacement of the denture was slowly reduced with the increase of the width of the upper part of the denture. When the width of the upper structure was between 5.9 and 6.0 mm, the interdental space of the natural tooth was rapidly reduced after the deformation of the tooth. The effect of food impaction was closer to the food impaction condition in the case of natural teeth. (2) When the height of the upper structure of the denture was lower than that of the adjacent teeth, with the increase of the height of the upper structure of the denture, the gap between the teeth increased first and then decreased. When the denture was lower than the adjacent tooth and the height was between 6.8 and 7.0 mm, the tooth space decreased rapidly after the force was applied. (3) The total horizontal displacement decreased slowly with increasing planting angle. (4) The results show that to reduce food impaction, the interdental distance of the implant denture and adjacent teeth should be less than 0.05 mm. The height of the implant denture should be less about 0.2 mm than adjacent teeth, and the planting angle should be about 90°. 

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    Preparation and mechanical properties of zirconia-based nano-hydroxyapatite functionally graded material
    Niu Yueyue, Wang Chunyan, Shu Jingyuan, Cui Yingying, Liu Zhen, Gao Yan, Wang Qian, Wang Qingshan
    2020, 24 (10):  1528-1533.  doi: 10.3969/j.issn.2095-4344.2234
    Abstract ( 452 )   PDF (27165KB) ( 39 )   Save

    BACKGROUND: Studies have shown that the nano-hydroxyapatite coating on the surface of zirconia has not only high strength and toughness, but also good biocompatibility. It is an ideal substitute for hard tissue. However, the coating is easy to fall off from the surface of zirconia, which is a fatal defect.

    OBJECTIVE: To prepare functionally graded bioceramics with pure zirconia as matrix, gradient layer in the middle and nano-hydroxyapatite on the surface by gradient composite technology and to screen the optimal mechanical properties and sintering temperature.

    METHODS: Using zirconia and nano hydroxyapatite powder as raw materials, ceramic specimens were prepared by the lamination method in powder metallurgy. According to the thickness of zirconia layer, three groups A (40 mm), B (30 mm) and C (20 mm) were designated. Each group was sub-divided into three subgroups 1 (3 layers), 2 (5 layers) and 3 (7 layers). Thus, there were 162 ceramic specimens in nine subgroups. The ceramic specimens were sintered at different temperatures (1 300, 1 350, 1 400, 1 450, 1500, and 1 550 °C) and then processed into rectangular specimens for mechanical property testing.

    RESULTS AND CONCLUSION: The zirconia-based nano-hydroxyapatite functionally graded material can be formed by 10 MPa single side vertical pressure. With the increases in the number of gradient layers and sintering temperature, the mechanical properties of the functionally graded bioceremics in each group were enhanced. The functionally graded bioceramics had the optimal mechanical properties when sintering temperature was 1 550 °C, the number of gradient layers was 7, and substrate thickness was 40 mm. The optimal mechanical property of the functionally graded bioceramics produced at above parameter was significantly superior to that produced at other eight sets of parameters (P < 0.05). According to the optimal gradient design, the zirconia-based nano-hydroxyapatite functionally graded ceramic specimens prepared by high temperature sintering technique have stronger mechanical properties.

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    Characterization of self-assembled bone-like nano-hydroxyapatite/collagen composites
    Zhang Xuemei, Ma Zheng, Wu Mixun, Fang Changyun
    2020, 24 (10):  1534-1539.  doi: 10.3969/j.issn.2095-4344.2226
    Abstract ( 305 )   PDF (24718KB) ( 117 )   Save

    BACKGROUND: The materials that are similar to natural bone and can be used for repair of bone defects or as tissue engineering material have become the focus of research.

    OBJECTIVE: To investigate the feasibility of self-assembly of nano-hydroxyapatite /collagen composite.

    METHODS: Collagen was immersed in 0.25% glutaraldehyde solution for 0.5 (group A), 24 (group B) and 72 hours (group C) for cross-linking reaction. In the group D, collagen was immersed in carbodiimide for 4 hours. After cross-linking reaction, collagen in each group was immersed in nano-hydroxyapatite solution for 7 days to prepare bone-like composite materials. The mineral phase analysis, composition, and microstructure of composite materials and natural bone were analyzed.

    RESULTS AND CONCLUSION: X-ray diffraction analysis: the amorphous diffraction peaks of the composites were slightly higher than those of the natural bone. The amorphous change of the composite was not obvious. With the prolongation of glutaraldehyde cross-linking time, the peak value of the crystal of the composite tended to increase. The amorphous diffraction peaks of the composites crosslinked with carbodiimide were slightly lower than those crosslinked with glutaraldehyde. Fourier transform infrared spectroscopy analysis: the chemical composition of the composites was similar to that of the natural bone, which was composed of collagen and hydroxyapatite, in which PO43- was partly replaced by CO32- ion in hydroxyapatite. Different cross-linking methods had no obvious effects on inorganic phase change of the materials. Scanning electron microscopy: the effects of different collagen cross-linking methods on the morphology of the formed crystals were not significantly different. Collagen fibers intertwined. A large number of fine needle-like crystals deposited on them, clustered, and were uniformly distributed. The crystal was nano-scaled in size. These results suggest that bone-like composite can be self-assessmbled with nano-hydroxyapatite precursor and collagen.

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    P38/Akt pathway regulates the oriented differentiation of bone marrow mesenchymal stem cells in nanofiber annulus fibrosus scaffolds with different spatial structures
    He Yunfei, Wang Shuang, Ma Jun, Yu Lei, Wen Jiankun, Ye Xiaojian
    2020, 24 (10):  1540-1546.  doi: 10.3969/j.issn.2095-4344.1886
    Abstract ( 336 )   PDF (32700KB) ( 39 )   Save

    BACKGROUND: Previous studies have shown that a variety of materials can be used for the construction of tissue engineering scaffolds. The topological structure of the scaffold surface has a regulatory effect on the biological behaviors such as stem cell proliferation and differentiation, but the specific mechanism is still unclear.

    OBJECTIVE: To investigate the role of P38 and Akt pathways in the oriented differentiation of bone marrow mesenchymal stem cells in nanofiber scaffolds.

    METHODS: Three kinds of nanofiber scaffolds (AFS, AYS, 3-DPS) with different structures were constructed. Rat bone marrow mesenchymal stem cells were inoculated on the surface of three kinds of nanofiber scaffolds. After osteogenic induction, cell morphology, adhesion and proliferation were detected. mRNA expression levels of key phenotype molecules (COLIα1, COLIIα1, Aggrecan, Sox-9) were measured using qRT-PCR. Intracellular P38, AKT, ERK1/2 and JNK expression was detected by western blot assay.

    RESULTS AND CONCLUSION: After 4 and 8 hours of culture, cell adhesion rate of the 13-DPS scaffold group was higher than that of the AFS and AYS scaffold groups (P < 0.05). After 7 days of culture, cells of the 13-DPS scaffold group proliferated faster than those of AFS and AYS scaffold groups (P < 0.05). Bone marrow mesenchymal stem cells adhered firmly and grew well on three kinds of scaffolds. Fibroblast-like growth was observed on the AFS and AYS scaffolds and chondrocyte-like growth was observed on the 3-DPS scaffold. After 3 weeks of cartilage induction, mRNA expression of COLIIα1, Aggrecan and Sox-9 was higher, and the mRNA expression of COLIα1 was lower, in the 3-DPS scaffold group compared with the other two groups (both P < 0.05). After 3 weeks of cartilage induction, relative expression level of p-AKT and p-P38 in the 3-DPS scaffold group was significantly higher than that in the other two groups (both P < 0.05). There were no significant differences in AKT total protein and ERK1/2, JNK, P38, p-ERK1/2, p-JNK and p-P38 protein expression levels among three groups. These findings suggest that nanofiber annulus fibrosus scaffolds with different spatial structures can induce the oriented differentiation of bone marrow mesenchymal stem cells through the P38 and AKT pathway, which were the downstream of the Integrin-FAK signaling pathway. 

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    Comparison of the effects of topical application of zoledronic acid and silver nanoparticles on osseointegration of immediate implant
    Fan Shifeng, Qie Hui, Zhang Wenxuan, Hou Xiaowei, Wang Lijie, Zheng Yu
    2020, 24 (10):  1547-1552.  doi: 10.3969/j.issn.2095-4344.2227
    Abstract ( 358 )   PDF (25153KB) ( 52 )   Save

    BACKGROUND: Some studies have shown that topical application of zoledronic acid and topical application of silver nanoparticles can promote bone formation, but the difference between two methods has not been reported.

    OBJECTIVE: To investigate the effect of topical application of zoledronic acid versus topical application of silver nanoparticles on rabbit tooth extraction socket immediate implantation of titanium screw bonding.

    METHODS: Twenty-four New Zealand white rabbits were randomly divided into zoledronic acid and silver nanoparticles groups (n=12/group). After removing four incisors of the upper and lower jaws, the mixture of nanometer silver and nanometer hydroxyapatite and nanometer zoledronic acid hydroxyapatite were respectively filled in the tooth extraction pit of the two groups, and titanium screw was implanted at the same time. The isolated specimens of the upper and lower mandibles were taken at 4, 8 and 12 weeks after surgery. The data reflecting the osseointegration around the implant were obtained through gross observation, torque test, bone density test and histomorphological observation. The study was approved by the Ethical Committee of the Third Hospital of Hebei Medical University in December 2015, approval No. Z2015-021-1.

    RESULTS AND CONCLUSION: (1) The test results of torque mechanics showed that the average torque peak value of all titanium nails increased with the extension of time (the average value of torque peak value) and reached the maximum value at 12 weeks (the average value of torque peak value). At 4, 8 and 12 weeks after surgery, the torque peak value of titanium screw in the zoledronic acid group was higher than that in the silver nanoparticles group, and the stability of titanium screw in zoledronic acid group was better than that in silver nanoparticles group, but the difference was insignificant (P > 0.05). (2) General observation and histological observation showed that at 4, 8 and 12 weeks after surgery, the hardness and structure of bone around the implants in the zoledronic acid group were significantly better than those in the silver nanoparticles group. (3) Bone mineral density analysis results showed that, at 4, 8 and 12 weeks after surgery, the gray value of bone tissue around the titanium screw in the zoledronic acid group was higher than that in the silver nanoparticles group at the same period (P > 0.05). (4) These results suggest that the osseointegration of immediate implantation using nanometer zoledronic acid hydroxyapatite is better than that of the mixture of nanometer silver and nanometer hydroxyapatite. 

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    Preparation of the surface patterned polyacrylamide-acrylic hydrogel
    Li Shuhua, Li Meilan
    2020, 24 (10):  1553-1556.  doi: 10.3969/j.issn.2095-4344.2230
    Abstract ( 455 )   PDF (18168KB) ( 81 )   Save

    BACKGROUND: Polyacrylamide hydrogels have good biocompatibility, but their mechanical properties are poor, which affect their application in the field of biomaterials.

    OBJECTIVE: To prepare the polyacrylamide-acrylic hydrogels with a particular size by micromolding graphical imprinting.

    METHODS: Polyacrylamide-acrylic hydrogel was prepared by sequentially mixing different volumes of polyacrylamide solution, acrylic acid and ammonium persulfate solution into an orifice plate containing a micromolded patterned seal. Group A: polyacrylamide solution 1.4 mL, acrylic acid 0.1 mL; group B: polyacrylamide solution 1.3 mL, acrylic acid  0.2 mL; group C: polyacrylamide solution 1.2 mL, acrylic acid 0.3 mL; group D: polyacrylamide solution 1.1 mL, acrylic acid 0.4 mL; group E: polyacrylamide solution 1.0 mL, acrylic acid 0.5 mL; group F: polyacrylamide solution 0.9 mL, acrylic acid 0.6 mL. Six groups of ammonium persulfate solution were all 50 μL. The patterned structure of the hydrogel was observed under a light microscope. The mechanical properties of the hydrogel were examined by an electronic universal testing machine.

    RESULTS AND CONCLUSION: Light microscope showed that the stripes on the surface of each group of hydrogels were clearly visible. The addition of acrylic acid effectively improved the mechanical properties of hydrogels. As the proportion of acrylic acid increased, the mechanical properties of hydrogels gradually increased. These results suggest that polyacrylic acid/acrylamide hydrogel has good mechanical properties and is expected to have good application prospects in the field of tissue engineering damage repair.

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    Host response of different cross-linked hyaluronic acid composite gels and matrix metalloproteinase-9 expression
    Nie Wei, Liu Weiwei, Liu Dawei, Cui Xiaoxue, Liu Shanhai, Li Xu, Xiao Guangli, Wang Shiwei, Niu Huanyun, Li Ruizhi
    2020, 24 (10):  1557-1562.  doi: 10.3969/j.issn.2095-4344.2243
    Abstract ( 410 )   PDF (29211KB) ( 41 )   Save

    BACKGROUND: The interaction between hydroxyl in hydroxypropyl methylcellulose and hydroxyland carboxyl in hyaluronic acid can reduce the enzymatic hydrolysis of hyaluronic acid and increase the usability when used as a skin filling material.

    OBJECTIVE: To investigate the host response of different cross-linked hyaluronic acid composite gels after they were implanted in vivo and matrix metalloproteinase-9 expression.

    METHODS: Twelve New Zealand white rabbits (purchased from Beijing Longan Laboratory Animal Breeding Center) were injected with cross-linked hyaluronic acid composite gels through 10 points in subcutaneous tissue at both sides of the spine. On the left side, chemically cross-linked sodium hyaluronate-hydroxypropyl methylcellulose gel was injected via 4 points (chemical cross-linking group). On the right side, physically mixed sodium hyaluronate-hydroxypropyl methylcellulose gel was injected via 4 points (physical cross-linking group). The modified sodium hyaluronate gel which was marketed was injected via 1 point on each side (control group). Subcutaneous tissues including implant material was excised at 1, 4, and 12 weeks after injection. Hematoxylin-eosin staining was performed to evaluate the degree of inflammation and fibrosis. Masson staining was performed to observe the formation of collagen fibers. Immunohistochemical staining was performed to detect the expression of matrix metalloproteinase-9. This study was approved by the Animal Ethics Committee of Tianjin Institute of Medical and Pharmaceutical Sciences (approval No. IMPS-EAEP-H-2017030).

    RESULTS AND CONCLUSION: Hematoxylin-eosin staining: In the chemical cross-linking group, at 1 and 4 weeks after injection, inflammatory reaction was more obvious, and the capsule wall and the microcapsule wall were thicker compared with the control group. At 12 weeks after injection, the degree of inflammation and fibrosis were similar between chemical cross-linking and control groups. At 1 week after injection, in the physical cross-linking group, a small amount of inflammatory cells were observed, and the fiber wrap and microcapsule wall formation were slightly more obvious than those in the control group. At 4 weeks after injection, the fiber wrap and microcapsule wall were thicker in the physical cross-linking group compared with the control group. At 12 weeks after injection, the degrees of inflammatory reaction and fibrosis in the physical cross-linking group were similar to those of the control group. Masson staining: In the chemical cross-linking group and physical cross-linking group, at 1 and 4 weeks after injection, the collagen fibers were increased compared with the control group and they further increased at 12 weeks, and at this time, there was no significant difference between chemical cross-linking and physical cross-linking groups. Immunohistochemical staining: in the chemical cross-linking group, matrix metalloproteinase-9 expression in the chemical cross-linking group was lower than that in the control group at 1 week after injection, and there was no significant difference at other time points. At 1 week after injection, matrix metalloproteinase-9 expression in the physical cross-linking group was lower than that in the control group. At 4 weeks after injection, matrix metalloproteinase-9 expression in the physical cross-linking group was higher than that in the control group. At 12 weeks after injection, there was no significant difference in matrix metalloproteinase-9 expression between physical cross-linking and control groups. These results showed that the biocompatibility of the two cross-linked sodium hyaluronate composite gels was good in 12 weeks after subcutaneous implantation. The expression of collagen fiber and matrix metalloproteinase-9 was gradually increased. All these are conducive to tissue remodeling. In the physical cross-linking gel, tissue reaction is smaller at the early stage, and matrix metalloproteinase-9 expression is significantly increased at the middle stage, which are more conducive to tissue repair and remodeling.

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    Bio-engineering cornea versus human donor cornea in the treatment of fungal corneal ulcer 
    Liu Zhiling, Gao Minghong, Chen Yingxin
    2020, 24 (10):  1563-1569.  doi: 10.3969/j.issn.2095-4344.2219
    Abstract ( 518 )   PDF (25484KB) ( 53 )   Save

    BACKGROUND: Searching for a substitute donor corneal is a hotspot for treating fungal corneal ulcer.

    OBJECTIVE: To investigate the clinical effect of bio-engineering cornea and donor cornea on treating fungal corneal ulcer.

    METHODS: Forty-four cases (44 eyes) of fungal corneal in General Hospital of Northern Theater Command were enrolled, and were randomized into two groups, followed by underwent lamellar keratoplasty using acellular porcine corneal matrix (bio-engineering group, n=22) and human donor cornea (donor group, n=22). The patients were followed up for 12 months. The control rate of infection, visual acuity, graft transparency, epithelization time and complications were observed in both groups. The study was approved by the Ethical Committee of General Hospital of Northern Theater Command, approval No. K(2018)05.

    RESULTS AND CONCLUSION: (1) The control rate of infection showed no significant difference between two groups (91%, 91%, P > 0.05). (2) The visual acuity in both groups was improved with time. The visual acuity in the donor group was significantly better than that in the bio-engineering group at 12 months after surgery (P < 0.05). (3) The graft transparency in the donor group was significantly better than that in the bio-engineering group at 1, 3 and 6 months after surgery (P < 0.05), and had no significant difference at 12 months after surgery (P > 0.05). (4) The epithelization time showed no significant difference [(6.6±2.0) days, (6.7±1.9) days, P > 0.05]. (5) There was no significant difference in the incidence of delayed healing of corneal epithelium, rejection reaction of graft, neovascularization, or recurrence between two group (P > 0.05). The rate of graft dissolved in the bio-engineering group was significantly higher than that in the donor group (32%, 8%, P < 0.05). (6) In summary, bio-engineering cornea used for lamellar keratoplasty holds significant efficacy, high safety and good prognosis in the treatment of fungal cornea ulcer, which may as substitute when donor cornea is deficient.

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    Effects of the new type Palindrome H-heparin-coated dialysis catheter on the systemic coagulation function
    Li Dao, Xiao Guanqing, Zhang Yu, Xie Chao, Ye Peiyi, Li Xiaolei, He Hanchang, Chen Youyuan, Kong Yaozhong
    2020, 24 (10):  1570-1573.  doi: 10.3969/j.issn.2095-4344.2232
    Abstract ( 383 )   PDF (17873KB) ( 66 )   Save

    BACKGROUND: The new type Palindrome H-heparin-coated dialysis catheter is supposed to reduce the incidence of catheter-related infection and catheter dysfunction. However, the effect of this new type catheter on the systemic coagulation function is little reported.

    OBJECTIVE: To evaluate the effects of the new type heparin-coated dialysis catheter of Palindrome H on the systemic coagulation function in hemodialysis patients.

    METHODS: Patients who underwent maintenance hemodialysis and could not establish internal fistula at Blood Purification Center of the First People's Hospital of Foshan from January 2014 to June 2016 were enrolled. All participants were divided into Palindrome H heparin-coated and Permcath noncoated groups depending on the catheter type. The blood platelet count, prothrombin time, international normalized ratio, activated partial thromboplastin time, thrombin time and fibrinogen degradation products were detected and compared between two groups. The study was approved by the Ethics Committee of the First People’s Hospital of Foshan, approval No. L[2014]5.

    RESULTS AND CONCLUSION: Sixty patients were involved in the study (28 patients used the Palindrome H heparin-coated catheter and 32 patients used Permcath noncoated catheter). All patients were followed up for 30 months. The final measurement outcome was the average value at 0, 3, 6, 9, 12, 15, 18, 21, 24, 27 and 30 months after surgery. No significant difference was found in the blood platelet count, prothrombin time, international normalized ratio, activated partial thromboplastin time, thrombin time or fibrinogen degradation products between two groups (P > 0.05). No heparin induced thrombocytopenia was observed in all participants. Therefore, in clinical practice, the new type Palindrome H-heparin-coated dialysis catheters makes no effect on the systemic coagulation function compared with noncoated catheter.

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    Orthopedic screw parameters in the orthogonal test: biocompatibility evaluation
    Long Dengyan, Ji Aimin, Zhao Zhonghang, Fang Runxin, Chen Changsheng
    2020, 24 (10):  1574-1579.  doi: 10.3969/j.issn.2095-4344.1887
    Abstract ( 366 )   PDF (25698KB) ( 43 )   Save

    BACKGROUND: Most current studies of orthopedic screw parameters focus on mechanical properties but lack biocompatibility assessment.

    OBJECTIVE: To investigate the influence of geometric parameters and material properties of orthopedic screws on biomechanical compatibility, explore the optimal combination of various factors and parameterization levels, providing a theoretical reference for the design of orthopedic screws.

    METHODS: An orthogonal experiment protocol was designed according to the five factors and three parameterization levels of orthopedic screws. Factor A was the screw diameter (4.5, 5.5, 6.5 mm), factor B was thread profile (rectangular, trapezoidal, triangular), factor C was screw pitch (1.75, 2.25, 2.75 mm), factor D was the thread depth (0.5, 1.0, 1.5 mm), and factor E was elastic modulus (45, 110, 200 GPa). The biomechanical finite element analysis of the three-dimensional bone-nail model under different sets of screw parameters was carried out. Stress distribution and two experimental indicators (the stress transfer parameter STPα between the cortical bone and the screw, and the stress transfer parameter STPβ between the cancellous bone and the screw) under different experimental schemes were obtained. The weighted matrix analysis method was used to analyze the orthogonal experimental data to obtain the influence law and the optimal combination.

    RESULTS AND CONCLUSION: Different levels of different factors have different degrees of influence on biocompatibility. Among them, the screw material properties are the most important factors, followed by the thread profile, pitch and thread diameter, and the last was the thread depth. The thread profile, pitch, and thread diameter had similar influence on biocompatibility. The optimal combination of the orthogonal experiment was an orthopedic screw with a large diameter of 6.5 mm, a trapezoidal thread, a pitch of 2.75 mm, a thread depth of 0.5 mm, and an elastic modulus of 45 GPa. 

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    Effects of long-acting antimicrobial material on pathogenic distribution and serum inflammatory factor concentration in patients with indwelling catheter
    Liang Changwei, Pan Weixin, Cai Zhikang, Wang Zhong
    2020, 24 (10):  1580-1584.  doi: 10.3969/j.issn.2095-4344.2242
    Abstract ( 430 )   PDF (21448KB) ( 59 )   Save

    BACKGROUND: Long-acting antimicrobial material is a new polymer activator of organosilicon quaternary ammonium salt and has obvious advantages in anti-infection.

    OBJECTIVE: To investigate the effects of Jieyoushen, a long-acting antimicrobial material, on pathogenic distribution and serum inflammatory factors in patients with indwelling catheters.

    METHODS: A total of 200 male patients with indwelling catheter who received treatment during January 2014 to January 2018 in Hainan West Central Hospital, China were included in this study. These patients were aged 35-55 years and were randomly divided into two groups: a control group (n=100) and an observation group (n=100). Patients in the control group were given routine urethral orifice nursing. Patients in the observation group were sprayed with long-acting antimicrobial material “Jieyoushen” on the urethral orifice, catheter and catheter bag interface. Infection was detected at 1, 3, 5 and 7 days after catheterization. The changes of pathogenic bacteria and serum inflammatory factors in two groups were analyzed at 7 days after catheterization. This study was approved by the Medical Ethics Committee, Hainan West Central Hospital, China (approval No. 2013120602).

    RESULTS AND CONCLUSION: Compared with the control group, the infection rates of the patients in the observation group decreased significantly at 1, 3, 5 and 7 days after catheterization (P < 0.05). Twenty pathogenic bacteria were isolated in patients of the control group, including 13 Gram-positive bacteria (65.0%) and 7 Gram-negative bacteria (35.0%). Seven pathogenic bacteria were isolated in patients of the observation group, including 5 Gram-positive bacteria (71.4%) and 2 Gram-negative bacteria (28.6%). Compared with before indwelling catheter, serum levels of interleukin-1β, interleukin-2, homocysteine, and procalcitonin increased significantly in each group after catheterization (P < 0.05). After catheterization, serum levels of above-mentioned factors in the control group were significantly higher than those in the observation group (P < 0.05). These results suggest that long-acting antimicrobial material "Jieyoushen" can effectively reduce the infection rate of pathogenic bacteria and lower serum levels of inflammatory factors in patients with indwelling catheter.

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    A randomized controlled trial of knotless barbed suture stitching deep fascia in posterior lumbar decompression and fusion
    Sun Qi, Yang Yingxia, Wang Dong, Chen Jiang, Li Jinyu, Zheng Chenying, Bai Chunxiao, Zhang Fan, Jia Yusong
    2020, 24 (10):  1585-1590.  doi: 10.3969/j.issn.2095-4344.2231
    Abstract ( 480 )   PDF (26463KB) ( 57 )   Save

    BACKGROUND: Whether knotless barbed suture applied in lumbar posterior fusion can shorten the suturing time and reduce incision complication has not been confirmed in clinical practice.

    OBJECTIVE: To explore whether knotless barbed suture has advantages in shortening the suturing time and reducing incision complication in lumbar posterior fusion.

    METHODS: Sixty-two patients with lumbar degenerative disease at Dongzhimen Hospital, Beijing University of Chinese Medicine from January to December 2018 were selected, and all received lumbar posterior fusion. The patients were randomly divided into trial group (n=33, the deep lumbar fascia was sutured using knotless barbed suture) and control group (n=29, the deep lumbar fascia was sutured using absorbable suture). The incision length, and the suturing time of deep fascia and subcutaneous tissue were compared between two groups. The suture quality was analyzed by leakage test. The incision healing and complications were observed and recorded. The Visual Analogue Scale scores and Oswestry Dysfunction Index at baseline and 2 and 6 weeks, and 3 months after surgery were detected. The trial was approved by the Ethics Committee of Dongzhimen Hospital, Beijing University of Chinese Medicine (approval No. DZMEC-KY-2018-11).

    RESULTS AND CONCLUSION: (1) The incision length and subcutaneous tissue suture time showed no significant difference (P > 0.05). The suture time of deep fascia in the trial group was shorter than that in the control group [(8.0±0.9) vs. (11.6±1.7) minutes, P < 0.05]. The positive rate in leakage test in the trial group was significantly lower than that in the control group (P < 0.05). (2) The incision complications in the trial group were lower than those in the control group (P < 0.05). (3) The Visual Analogue Scale scores and Oswestry Dysfunction Index at 2 and 6 weeks, and 3 months after surgery were significantly decreased compared with the baseline scores (P < 0.05). The scores showed no significant differences between two groups (P > 0.05). (4) These results indicate that the knotless barbed suture can reduce suturing time and incidence of incision complications in posterior lumbar fusion.

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    Arthroscopic technique with Fiber Tape circular fixation for treating avulsion fracture of tibial insertion of anterior cruciate ligament 
    Li Guangfeng, Wang Sicheng, Peng Yong, Yang Guoqing, Wu Xianmin, Liu Xiangfei, Cao Zhonghua, Yin Zhifeng, Zhang Xin, Zhang Youzhong
    2020, 24 (10):  1591-1596.  doi: 10.3969/j.issn.2095-4344.2250
    Abstract ( 386 )   PDF (27517KB) ( 47 )   Save

    BACKGROUND: The avulsion fracture of tibial insertion of anterior cruciate ligament needs to be operated and fixed as early as possible. At present, the open reduction (absorbable screw, hollow screw, steel wire, and titanium cable) is commonly used in the clinical treatment plan for internal fixation, which is more traumatic and has many postoperative complications. Arthroscopic reduction and elastic (suture) internal fixation of anterior cruciate ligament fracture has the advantages of minimally invasive, clear surgical field, high fixation accuracy, few complications, good fracture reduction and healing, meeting the biomechanical requirements, and allowing rapid recovery of joint function, but also has the disadvantages of insufficient strength, and osteotomy.

    OBJECTIVE: To compare the treatment efficacy of arthroscopic technique with Fiber Tape circular fixation and open reduction and fixation for the avulsion fracture of tibial insertion of anterior cruciate ligament.

    METHODS: Thirty-two patients with tibial eminence fracture at Department of Orthopedics of Shanghai China Metallurgical Hospital from January 2017 to December 2018 were enrolled. All patients signed the informed consents and the study was approved by the Ethics Committee. The patients were divided into two groups based on surgical methods: minimally invasive group (n=17, arthroscopic reduction and Fiber Tape circular fixation) and open group (n=15, open reduction and hollow tension screw fixation). The operation time, blood loss, and postoperative complications were recorded. The range of motion of knee joint, Lysholm score, and International Knee Documenting Committee score before operation, 1 and 6 months after surgery were recorded. X-ray film was used to evaluate fracture healing.

    RESULTS AND CONCLUSION: (1) All patients were followed up for 6-13 months. (2) There were no significant differences in age composition, fracture type, cause of injury or preoperative score between two groups. (3) X-ray film showed satisfactory fracture reduction after operation. There were no neurological, vascular injury or fracture displacement after surgery. The fractures healed well after 6 months. (4) There was no significant difference in the operation time and postoperative complications between two groups. The blood loss showed significant difference between two groups (P=0.036). (5) The range of motion of knee joint at postoperative 1 month in both groups was significantly larger than that at baseline (P < 0.05). The range of motion of knee joint at postoperative 6 months was significantly larger than that at postoperative 1 month (P < 0.05). The range of motion of knee joint at postoperative 1 and 6 months in the minimally invasive group was significantly larger than that in the open group (P < 0.05). (6) The Lysholm and International Knee Documenting Committee scores at postoperative 1 month in both groups were significantly higher than those at baseline (P < 0.05). The scores at postoperative 6 months were significantly higher than those at postoperative 1 month (P < 0.05). The scores at postoperative 1 and 6 months in the minimally invasive group were significantly higher than those in the open group (P < 0.05). (7) These findings suggest that the patients in both groups after undergoing surgical methods had restored motion of range with time going. Compared with open fixation, arthroscopic reduction and Fiber Tape circular fixation for treating tibial eminence fracture has less blood loss, less trauma, shorter recovery time and higher functional recovery. 

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    Preparation method of acellular matrix and its application in tissue engineering of parotid gland
    Zhang Lin, Wang Shuai, Zhang Nini, Huang Guilin
    2020, 24 (10):  1597-1603.  doi: 10.3969/j.issn.2095-4344.2247
    Abstract ( 278 )   PDF (43673KB) ( 39 )   Save

    BACKGROUND: Bioscaffolds composed of acellular matrix are widely used in animal and clinical research to repair and reconstruct tissues and organs, but all decellularization methods will destroy matrix structure and function to some extent.

    OBJECTIVE: To review the preparation methods, advantages and disadvantages of acellular matrix and its application in the study of parotid gland and other tissue engineering.

    METHODS: A computer-based search of CNKI, CBM, PubMed and Elsevier databases was performed to retrieve related articles published from 2008 to 2019. The search term were “decellular matrix, preparation method, parotid gland, tissue engineering, regeneration, decellularization, preparation method, parotid gland tissue engineering” in Chinese and English, respectively. Seventy-four eligible articles were included.

    RESULTS AND CONCLUSION: Acellular matrix preparation methods of most tissues and organs require chemical, biological (enzyme), physical methods and the their combination, which depend on the thickness, compositions and nature. Although not all decellularization methods can remove cellular components from tissues and organs, tissues and organs that completely remove cells have the advantage of remodeling tissue specificity, providing a favorable microenvironment for the proliferation and differentiation of inoculated cells. Due to the complex structure of the parotid gland and the challenges of tissue engineering in clinical applications, clinical transplantation in patients is limited. In vivo studies in this field are limited to animals, and applications based on submandibular gland acellular matrix bioscaffold materials are expected to be a favorable source of organizational parotid glands.   

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    Polymer nanomedicines for osteosarcoma therapy
    Li Ke, Xu Weiguo, Huang Chao, Zhang Zhiyu, Ding Jianxun
    2020, 24 (10):  1604-1614.  doi: 10.3969/j.issn.2095-4344.2221
    Abstract ( 469 )   PDF (67115KB) ( 134 )   Save

    BACKGROUND: In recent years, various polymer nanoparticles have been developed as anticancer drug carriers to prolong blood circulation time and improve intratumoral accumulation, and then enhance the therapeutic efficacy on osteosarcoma.

    OBJECTIVE: To review the application and development of polymer nanomedicines for treatment of osteosarcoma based on latest related studies.

    METHODS: A computer-based online search of Web of Science, NCBI, and PubMed was performed to search publications published between January 1900 and June 2019 with the search terms “osteosarcoma; polymer; nanoparticle; controlled drug delivery; tumor therapy". A total of 265 publications were screened out, and 107 of them regarding polymer nanoparticles for treatment of osteosarcoma were included in the final analysis.

    RESULTS AND CONCLUSION: Osteosarcoma is the most common primary malignant bone tumor, mainly affecting children and adolescents. The long-term survival rate of osteosarcoma patients is low due to early lung metastasis and high local invasiveness. Although chemotherapy increases the survival rates of patients with osteosarcoma, its application potential is limited by severe side effects and drug resistance. Compared with traditional chemotherapy, polymer nanomedicines reduce the toxicity to healthy tissues, prolong the blood circulation time in vivo, and provide continuous release of chemotherapy drugs at the tumor sites, thereby improving the therapeutic efficacy. Therefore, polymer nanomedicines have great application prospects in the treatment of osteosarcoma because of their unique advantages.

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    Research hotspots and progress of bone repair materials in tissue engineering
    Wei Chenxu, He Yiwen, Wang Dan, Hou Jingxia, Xie Hui, Yin Fangzhou, Chen Zhipeng, Li Weidong
    2020, 24 (10):  1615-1621.  doi: 10.3969/j.issn.2095-4344.1884
    Abstract ( 569 )   PDF (34543KB) ( 110 )   Save

    BACKGROUND: With the improvement in medical level, the clinical demand for bone repair materials is gradually increasing, and the requirements are also getting more and more.

    OBJECTIVE: To review the related research progress in the field of bone repair materials in recent years, to analyze the advantages and disadvantages of different materials, and to guide future development in this research field.

    METHODS: A computer-based online search of CNKI, Wanfang, PubMed, Web of Science databases was performed to retrieve papers published during 1950-2019 with the search terms “tissue engineering, bone repair material, bone defect, natural bone material, bone graft replacement material, traditional Chinese medicine” in Chinese and English. A total of over 900 papers were retrieved, and 68 of them were included in the final analysis.

    RESULTS AND CONCLUSION: In recent year, with the flourish development of bone tissue engineering, the research of bone tissue repair materials is in the ascendant. In addition to optimizing natural bone, a variety of bone graft substitute materials have been developed, for example, natural macromolecule materials, synthetic macromolecule materials, biomedical ceramics materials, biomedical metal materials, etc., but these materials have different properties. Although there are many bone repair materials at present, the ideal bone repair materials are few. Therefore, bone tissue repair and bone remodeling is still one of the urgent orthopedic problems to be solved in the clinic. In addition, the traditional Chinese medicine for bone repair, such as pyritum combined with modern bone repair materials, can effectively avoid some of the drawbacks of the current bone repair materials, thereby effectively treating bone defect diseases. This deserves in-depth investigation in the field of bone repair. 

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    Application status of 3D printed polyetheretherketone and its composite in bone defect repair
    Lin Liulan, Zhou Jianyong
    2020, 24 (10):  1622-1628.  doi: 10.3969/j.issn.2095-4344.2211
    Abstract ( 554 )   PDF (50456KB) ( 84 )   Save

    BACKGROUND: Polyetheretherketone (PEEK) and its composites have a unique set of properties, and 3D printing technology can customize personalized implants according to the patient's condition, and the effective combination of the two plays a significant role in the field of bone repair.

    OBJECTIVE: To summarize the application status of PEEK and its composite combined with 3D printing technology in the field of bone repair, and to further predict the application prospects of the effective combination of the two.

    METHODS: CNKI, PubMed, and Web of Science databases were retrieved with the search terms “PEEK, PEEK composites, bone defect repair, PEEK implants, PEEK 3D printing, prosthodontics” in English and Chinese, respectively, for the articles published from April 1995 to April 2019. Totally 147 articles were searched, and finally 51 eligible articles were enrolled for review in accordance with the inclusion and exclusion criteria.

    RESULTS AND CONCLUSION: Biologically active materials and the particles or fibers with improved mechanical properties were introduced into the PEEK matrix to prepare its composite. 3D printing technology was used to precisely customize implants that are highly matched to the patient's defect. The implants with good biocompatibility, bioactivity, and mechanical properties exhibited good therapeutic effects in the repair of skull, jaw, spine, lumbar vertebra, artificial joint and oral defects. They improved patient satisfaction after treatment. This article summarized the application of PEEK, its composite and 3D printing technology in the repair of various bone defects, and expressed its views on the application and prospect of personalized PEEK implants or prostheses prepared with 3D printing technology.

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    Application of 3D-printed drug composite material in biomedicine
    Hou Jingxia, Wang Dan, Wei Chenxu, Lin Shangyang, Chen Zhipeng, Li Weidong
    2020, 24 (10):  1629-1633.  doi: 10.3969/j.issn.2095-4344.1924
    Abstract ( 327 )   PDF (26576KB) ( 76 )   Save

    BACKGROUND: Combining drugs with materials using 3D printing technology can be formulated into a dosage form with a specific release rate, which is better for clinical use.

    OBJECTIVE: To review the preparation technique, advantages and indications of pharmaceutical composites made from western medicine, traditional Chinese medicine, metal elements and ions and related materials.

    METHODS: The first author used the search terms “Drug; Chinese medicine; Metal; Composite materials; 3D printing” to search the CNKI and Wanfang databases in Chinese and the PubMed and Web of Science in English to retrieve papers published during 1950-2019. A total of 339 papers were preliminarily retrieved. After screening, 46 papers were included in the final analysis.

    RESULTS AND CONCLUSION: Pharmaceutical composite materials made of western medicine, traditional Chinese medicine, metal elements and ions and related materials have certain advantages in the pharmaceutical field and clinical use. It can not only improve the bioavailability of drugs, reduce toxic side effects, but also achieve a combination of drugs. In recent years, drug composite materials have been used in orthopedics, dentistry, cardiovascular medicine, otolaryngology and other fields, but its application is still in its infancy. Many aspects need to be improved, such as improving the quality of drug composites, increasing mechanical stability, reducing the brittleness, printing the full-featured blood vessels and organs that fit the size of the human body, and better imitating the biomechanics and tissue structure of human body.

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    Antimicrobial mechanism of antimicrobial peptide and research progress
    Zhang Xi, Gong Lei
    2020, 24 (10):  1634-1640.  doi: 10.3969/j.issn.2095-4344.2202
    Abstract ( 699 )   PDF (46425KB) ( 66 )   Save

    BACKGROUND: As a potential candidate that can be extracted from natural sources and used to fight antibiotic-resistant bacteria, antimicrobial peptides have attracted extensive attention of scientists. Familiarity with the antimicrobial mechanism of antimicrobial peptides is conducive to the clinical application of antimicrobial peptides.

    OBJECTIVE: To review the advance in research of antimicrobial mechanism of antimicrobial peptides.

    METHODS: The first author conducted a computer-based retrieval of PubMed, Springerlink, Web of Science, ScienceDirect databases for articles regarding the antimicrobial mechanism and research advance published from January 2013 to March 2019.

    RESULTS AND CONCLUSION: Antimicrobial peptides are a class of special molecules with broad-spectrum antimicrobial activity. In some organisms, antimicrobial peptides are considered to be an important part of innate immune system. The antimicrobial mechanism of antimicrobial peptides can be divided into two main modes: direct killing and immune regulation, and direct killing mechanism can be further divided into membrane targeting and non-membrane targeting. At the same time, based on the extensive application of antimicrobial peptides, it is expected that many resistance strategies have been developed in microbial environments such as staphylococcus, oral bacteria (including streptococcus) and intestinal bacteria (including salmonella). These resistance strategies mainly include passive resistance and induction or adaptive resistance mechanisms. In the future research and application, cationic peptide is an effective choice to solve the increasing multidrug resistance. In addition to the obligation to design new methods to combat the resistance of antimicrobial peptides in bacteria, general preventive measures against the resistance of conventional antibiotics should also be paid attention to.

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