west china medical publishers
Keyword
  • Title
  • Author
  • Keyword
  • Abstract
Advance search
Advance search

Search

find Keyword "position" 219 results
  • Comparative Studies on the Material Performances of Natural Bone-like Apatite from Different Bone Sources

    The compressive strength of the original bone tissue was tested, based on the raw human thigh bone,bovine bone,pig bone and goat bone. The four different bone-like apatites were prepared by calcining the raw bones at 800℃ for 8 hours to remove organic components. The comparison of composition and structure of bone-like apatite from different bone sources was carried out with a composition and structure test. The results indicated that the compressive strength of goat bone was similar to that of human thigh bone, reached (135.00±7.84) MPa; Infrared spectrum (IR), X-ray diffraction (XRD) analysis results showed that the bone-like apatite from goat bone was much closer to the structure and phase composition of bone-like apatite of human bones. Inductively Coupled Plasma (ICP) test results showed that the content of trace elements of bone-like apatite from goat bone was closer to that of apatite of human bone. Energy Dispersive Spectrometer (EDS) results showed that the Ca/P value of bone-like apatite from goat bone was also close to that of human bone, ranged to 1.73±0.033. Scanning electron microscopy (SEM) patterns indicated that the macrographs of the apatite from human bone and that of goat bone were much similar to each other. Considering all the results above, it could be concluded that the goat bone-like apatite is much similar to that of human bone. It can be used as a potential natural bioceramic material in terms of material properties.

    Release date: Export PDF Favorites Scan
  • Application of a new point contact pedicle navigation template as an auxiliary screw implant in scoliosis correction surgery

    ObjectiveTo explore the effectiveness of a new point contact pedicle navigation template (referred to as “new navigation template” for simplicity) in assisting screw implantation in scoliosis correction surgery. MethodsTwenty-five patients with scoliosis, who met the selection criteria between February 2020 and February 2023, were selected as the trial group. During the scoliosis correction surgery, the three-dimensional printed new navigation template was used to assist in screw implantation. Fifty patients who had undergone screw implantation with traditional free-hand implantation technique between February 2019 and February 2023 were matched according to the inclusion and exclusion criteria as the control group. There was no significant difference between the two groups (P>0.05) in terms of gender, age, disease duration, Cobb angle on the coronal plane of the main curve, Cobb angle at the Bending position of the main curve, the position of the apical vertebrae of the main curve, and the number of vertebrae with the pedicle diameter lower than 50%/75% of the national average, and the number of patients whose apical vertebrae rotation exceeded 40°. The number of fused vertebrae, the number of pedicle screws, the time of pedicle screw implantation, implant bleeding, fluoroscopy frequency, and manual diversion frequency were compared between the two groups. The occurrence of implant complications was observed. Based on the X-ray films at 2 weeks after operation, the pedicle screw grading was recorded, the accuracy of the implant and the main curvature correction rate were calculated. ResultsBoth groups successfully completed the surgeries. Among them, the trial group implanted 267 screws and fused 177 vertebrae; the control group implanted 523 screws and fused 358 vertebrae. There was no significant difference between the two groups (P>0.05) in terms of the number of fused vertebrae, the number of pedicle screws, the pedicle screw grading and accuracy, and the main curvature correction rate. However, the time of pedicle screw implantation, implant bleeding, fluoroscopy frequency, and manual diversion frequency were significantly lower in trial group than in control group (P<0.05). There was no complications related to screws implantation during or after operation in the two groups. ConclusionThe new navigation template is suitable for all kinds of deformed vertebral lamina and articular process, which not only improves the accuracy of screw implantation, but also reduces the difficulty of operation, shortens the operation time, and reduces intraoperative bleeding.

    Release date:2023-06-07 11:13 Export PDF Favorites Scan
  • Imaging and clinical risk factors and predictive models for lymph node metastasis in patients with resectable lung adenocarcinoma

    ObjectiveTo investigate the risk factors for lymph node metastasis in resectable lung adenocarcinoma by combining spatial location, clinical, and imaging features, and to construct a lymph node metastasis prediction model. MethodsA retrospective study on patients who underwent chest computed tomography (CT) at the First Affiliated Hospital of Nanjing Medical University from June 2016 to June 2020 and were surgically confirmed to have invasive lung adenocarcinoma with or without lymph node metastasis was conducted. Patients were divided into a positive group and a negative group based on the presence or absence of lymph node metastasis. Clinical and imaging data of the patients were collected, and the independent risk factors for lymph node metastasis in resectable lung adenocarcinoma were analyzed using univariate and multivariate logistic regression. A combined spatial location-clinical-imaging feature prediction model for lymph node metastasis was established and compared with the traditional lymph node metastasis prediction model that does not include spatial location features. ResultsA total of 611 patients were included, with 333 in the positive group, including 172 males and 161 females, with an average age of (58.9±9.7) years; and 278 in the negative group, including 127 males and 151 females, with an average age of (60.1±11.4) years. Univariate and multivariate logistic regression analyses showed that the spatial relationship of the lesion to the lung hilum, nodule type, pleural changes, and serum carcinoembryonic antigen (CEA) levels were independent risk factors for lymph node metastasis. Based on this, the combined spatial location-clinical-imaging feature prediction model had a sensitivity of 91.67%, specificity of 74.05%, accuracy of 87.88%, and area under the curve (AUC) of 0.885. The traditional lymph node metastasis prediction model, which did not include spatial location features, had a sensitivity of 76.40%, specificity of 72.10%, accuracy of 53.86%, and AUC of 0.827. The difference in AUC between the two prediction methods was statistically significant (P=0.026). Compared with the traditional prediction model, the predictive performance of the combined spatial location-clinical-imaging feature prediction model was significantly improved. ConclusionIn patients with resectable lung adenocarcinoma, those with basal spatial location, solid density, pleural changes with wide base depression, and elevated serum CEA levels have a higher risk of lymph node metastasis.

    Release date: Export PDF Favorites Scan
  • Development and evaluation of a positioning system for radiotherapy patient based on structured light surface imaging

    This paper aims to propose a noninvasive radiotherapy patient positioning system based on structured light surface imaging, and evaluate its clinical feasibility. First, structured light sensors were used to obtain the panoramic point clouds during radiotherapy positioning in real time. The fusion of different point clouds and coordinate transformation were realized based on optical calibration and pose estimation, and the body surface was segmented referring to the preset region of interest (ROI). Then, the global-local registration of cross-source point cloud was achieved based on algorithms such as random sample consensus (RANSAC) and iterative closest point (ICP), to calculate 6 degrees of freedom (DoF) positioning deviation and provide guidance for the correction of couch shifts. The evaluation of the system was carried out based on a rigid adult phantom and volunteers’ body, which included positioning error, correlation analysis, and receiver operating characteristic (ROC) analysis. Using Cone Beam CT (CBCT) as the gold standard, the maximum translation and rotation errors of this system were (1.5 ± 0.9) mm along Vrt direction (chest) and (0.7 ± 0.3) ° along Pitch direction (head and neck). The Pearson correlation coefficient between results of system outputs and CBCT verification distributed in an interval of [0.80, 0.84]. Results of ROC analysis showed that the translational and rotational AUC values were 0.82 and 0.85, respectively. In the 4D freedom accuracy test on the human body of volunteers, the maximum translation and rotation errors were (2.6 ± 1.1) mm (Vrt direction, chest and abdomen) and (0.8 ± 0.4)° (Rtn direction, chest and abdomen) respectively. In summary, the positioning system based on structured light body surface imaging proposed in this article can ensure positioning accuracy without surface markers and additional doses, and is feasible for clinical application.

    Release date:2025-04-24 04:31 Export PDF Favorites Scan
  • THE APPLICATION OF DISTALLY BASED FASCIAL PEDICLED ISLAND FLAP TO RAPAIR WOUND OF THE EXTREMITIES

    In order to preserve the major vessels of the extremities in the repair and reconstruction of wounds of the extremities, the distally based fascial pedicled island flap was applied clinically. Its axis and rotatary point were designed along orientation of the major arteries, and the blood supply was from the abundant vascular networks in the deep fascia. Twenty-two cases with exposure of tendon and bone including 10 upper limbs and 12 lower limbs were treated. The flap area of forearm ranged from 7 cm x 8 cm to 12 cm x 9 cm and the ratio of the length to width of the pedicle was 1: 1-2. The flap area of the calf ranged from 10 cm x 6 cm to 16.5 cm x 12 cm and the ratio of the length to width of the pedicle was 2:1. The rotatary angle was 130 degrees-170 degrees. After operation, 18 flaps were survived completely, 2 cases had partial necrosis on the margin, 2 failures received cross-leg flap in the second operation. The patients were followed up with an average of 13.5 months (ranged from 3 months to 2 years). The conclusions were as follows: 1. the blood supply of this type of flap was reliable and the major arteries of the extremities needed not to be sacrificed; 2. the preparation of the flap was easy and the survival rate was satisfactory; 3. the shortcomings of this flap were unsightly incision scar and the limited size of flap and; 4. during the operation, the compression of the pedicle must be avoided.

    Release date:2016-09-01 11:09 Export PDF Favorites Scan
  • Experimental research on the effect of functional residual capacity on the deposition of inhalable particles in human alveoli region

    Research on the deposition of inhalable particles in the alveoli of the lungs is important to the causes, development for common respiratory diseases such as emphysema, and even the optimization of clinical treatment and prevention programs of them. In this paper, an in vitro experimental model was established to simulate the deposition of terminal bronchioles and pulmonary acinus particles. The deposition rate of inhalable particles with different particle sizes in the pulmonary acinus was studied under different functional residual capacity. The results showed that the particle diameter was an important factor affecting the deposition of particles in the lung alveoli. Particles with 1 μm diameter had the highest deposition rate. With the functional residual capacity increasing, particulate deposition rate significantly reduced. The results of this study may provide data support and optimization strategy for target inhalation therapy of respiratory diseases such as emphysema and pneumoconiosis. The established model may also provide a feasible in vitro experimental model for studying the deposition of inhalable particles in the pulmonary alveoli.

    Release date:2018-08-23 05:06 Export PDF Favorites Scan
  • Application of annular ligament reposition and repair via Henry’s approach for Monteggia fracture in children

    ObjectiveTo explore the effectiveness of annular ligament reposition and repair via Henry’s approach for Monteggia fracture in children.MethodsA clinical data of 21 children with Monteggia fractures was retrospectively analysed, who underwent open reduction of the radial head and annular ligament reposition and repair via Henry’s approach between May 2015 and July 2019. There were 11 boys and 10 girls with an average age of 8 years and 1 month (range, 4 years and 5 months to 14 years and 4 months). The fracture was caused by falling in 17 cases and by falling from height in 4 cases. There were 16 fresh fractures and 5 old fractures. The Monteggia fractures were rated as Bado typeⅠin 14 cases and Bado type Ⅲ in 7 cases. Preoperative MRI examination and intraoperative observation confirmed that the annular ligament was intact. After operation, the fracture healing, elbow range of motion (ROM), and complications were recorded, and the effectiveness was evaluated according to the Mackay’s function scoring system.ResultsThe incisions healed by first intention after operation, and there was no complication such as radial nerve injury. All children were followed up 12-25 months, with an average of 15 months. No dislocation or subluxation of the radial head occurred after operation. At last follow-up, the ROM of elbow flexion and extension of the children with old fractures increased from (92.6±11.2)° before operation to (123.6±11.6)°, and the ROM of forearm rotation from (96.8±11.8)° to (129.8±5.9)°; the differences between pre- and post-operation were significant (t=7.672, P=0.002; t=9.487, P=0.001); the ROM of elbow flexion and extension of the children with fresh fractures was 139°-156° (mean, 145°); the ROM of forearm rotation was 158°-168° (mean, 162°). According to Mackay’s criteria, 17 cases were excellent and 4 cases were good, with an excellent and good rate of 100%. X-ray film examination showed no nonunion, heterotopic ossification, or loosening of internal fixation after operation. The ulnar fracture and the ulnar osteotomy healed in all cases.ConclusionThe annular ligament in Monteggia fractures in children is intact. Compared with the reconstruction of the annular ligament, the reposition and repair of the annular ligament via Henry’s approach is closer to the original anatomical state of the annular ligament and has the advantages of less trauma and fewer complications.

    Release date:2021-06-07 02:00 Export PDF Favorites Scan
  • REPAIR OF MEDIAL COLLATERAL LIGAMENT DEFECT OF KNEE JOINT WITH TRANSPOSITION OF GREAT ADDUCTOR MUSCULAR TENDON PEDICLED VESSELS

    BJECTIVE: To study the effect of transposition of great adductor muscular tendon pedicled vessels in repairing the medial collateral ligament defect of knee joint. METHODS: From September 1991 to September 1999, on the basis study of applied anatomy, 30 patients with the medial collateral ligament defect were repaired with great adductor muscular tendon transposition pedicled vessels. Among them, there were 28 males and 2 females, aged 26 years in average. RESULTS: Followed up for 17 to 60 months, 93.3% patients reached excellent or good grades. No case fell into the poor grade. CONCLUSION: Because the great adductor muscular tendon is adjacent to the knee joint and similar to the knee ligament, it is appropriate to repair knee ligament. Transposition of the great adductor muscular tendon pedicled vessels is effective in the reconstruction of the medial collateral ligament defect of knee joint.

    Release date:2016-09-01 10:21 Export PDF Favorites Scan
  • Evaluation of Two Digestive Tract Reconstruction Procedures of Proximal Gastrectomy

    Objective To explore the optimal technique for digestive tract reconstruction of proximal gastrectomy. Methods Fifty-nine patients who underwent proximal subtotal gastrectomy during June 2004 and January 2007 were analyzed retrospectively. All patients were divided into 2 groups according to the styles of reconstruction: one group with gastroesophagostomy (GE group) and the other with accommodation double tract digestive reconstruction of jejunal interposition (GIE group). The reconstruction of GIE group was to interposite a continuous 35 cm jejunum between the gastric stump and the oesophagus, which detail had been reported in our previous literature. The quality of life in 2 groups were evaluated and compared. Results No patient died and there was no anastomotic leakage, dumping syndrome and moderate or severe anemia occurred during perioperative period. There was no significant difference of the following indexes of nutrition between 2 groups 1 month and 6 months after operation: the value of weight, RBC, Hb, Alb, PNI and the indexes versus the preoperative ones (Pgt;0.05), for the exception of the indexes of RBC (P=0.006), Hb (P=0.001) in 1 month after operation versus the preoperative ones. The abdominal and the reflux esophagitis symptoms in GIE group were milder than those in GE group (Plt;0.001). The Visick scoring: most of the GIE group were gradeⅡ (74.2%), and grade Ⅲ (64.3%) in the GE group. There was no delay of the first time of adjuvant chemotherapy in GIE group (Pgt;0.05), and the surgical time was (0.35±0.13) h more than that of GE group (P=0.01). Conclusion The accommodation double tract digestive reconstruction of jejunal interposition for proximal subtotal gastrectomy may be safe and feasible by decreasing residual cancer cells and improving the quality of life of patients with proximal gastric carcinoma who underwent such surgical procedure.

    Release date:2016-09-08 11:47 Export PDF Favorites Scan
  • Relationship Between The Occurrence of Colorectal Cancer and Diet Composition

    ObjectiveTo summarize the current advancement of the relationship between dietary factors and colorectal cancer in recent years, looking for more reasonable prevention measures. MethodsRelated literatures about the relationship between diet composition and the occurrence of colorectal cancer at home and abroad were collected to make a review. ResultsAmong the environmental factors, dietary factors had a close relationship with colorectal cancer, and was easy to control. Nowadays, it was believed that high animal fat, excessive alcohol consumption, consumption of fried, barbecue, and pickles may be positively associated with the occurrence of colorectal cancer. However, high fiber, high vitamin, high folic acid, the amount of minerals and trace elements in diet were negatively correlated with the occurrence of colorectal cancer. ConclusionsColorectal cancer occurs by environmental factors, genetic factors, and other factors. Diet model of people in different areas is not the same, the occurrence rate of colorectal cancer is also different, so it needs further study to explore its mechanism.

    Release date: Export PDF Favorites Scan
22 pages Previous 1 2 3 ... 22 Next

Format

Content