Objective To explore the clinicopathological characteristics which were associated with lymph node metastases in early gastric cancer patients. Methods Clinical data of 187 early gastric cancer patients who received surgical treatment in The Second People’s Hospital of Jiaozuo between January 2009 and January 2016, were retrospectively analyzed, and then exploring the clinicopathological characteristics which were associated with lymph node metastases in early gastric cancer, including age, gender, tumor location, diameter of tumor, number of tumor, depth of invasion, macroscopic type, histological type, venous invasion, and local ulcer. Results In this study, 187 patients with early gastric cancer were included, and lymph node metastasis was detected in 32 patients (17.1%). Results of multivariate logistic regression analysis showed that, lymph node metastasis was significantly closely related with diameter of tumor (OR=2.080,P=0.022), depth of invasion (OR=21.048,P=0.001), histological type (OR=3.507,P=0.018), venous invasion (OR=2.406,P=0.009), and local ulcer (OR=2.738,P=0.001), patients with diameter of tumor larger than 2 cm, infiltration depth of submucosa, histological types of undifferentiated type, vascular infiltration, and local ulcer had higher lymph node metastasis rate. Conclusion The clinicopathological characteristics, including diameter of tumor, depth of invasion, histological type, venous invasion, and local ulcer are risk factors for lymph node metastasis of early gastric cancer patients, which should be paid high attention.
To address the conflict between the “fitness” and “feasibility” of body-fitted stents, this paper investigates the impact of various smoothing design strategies on the mechanical behaviour and apposition performance of stent. Based on the three-dimensional projection method, the projection region was fitted with the least squares method (fitting orders 1–6 corresponded to models 1–6, respectively) to achieve the effect of smoothing the body-fitted stent. The simulation included the crimping and expansion process of six groups of stents in stenotic vessels with different degrees of plaque calcification. Various metrics were analyzed, including bending stiffness, stent ruggedness, area residual stenosis rate, contact area fraction, and contact volume fraction. The study findings showed that the bending stiffness, stent ruggedness, area residual stenosis rate, contact area fraction and contact volume fraction increased with the fitting order's increase. Model 1 had the smallest contact area fraction and contact volume fraction, 77.63% and 83.49% respectively, in the incompletely calcified plaque environment. In the completely calcified plaque environment, these values were 72.86% and 82.21%, respectively. Additionally, it had the worst “fitness”. Models 5 and 6 had similar values for stent ruggedness, with 32.15% and 32.38%, respectively, which indicated the worst "feasibility" for fabrication and implantation. Models 2, 3, and 4 had similar area residual stenosis rates in both plaque environments. In conclusion, it is more reasonable to obtain the body-fitted stent by using 2nd to 4th order fitting with the least squares method to the projected region. Among them, the body-fitted stent obtained by the 2nd order fitting performs better in the completely calcified environment.
Stent migration is one of the common complications after tracheal stent implantation. The causes of stent migration include size mismatch between the stent and the trachea, physiological movement of the trachea, and so on. In order to solve the above problems, this study designed a non-uniform Poisson ratio tracheal stent by combining the size and structure of the trachea and the physiological movement of the trachea to improve the migration of the stent, meanwhile ensuring the support of the stent. In this study, the stent corresponding to cartilage was constructed with negative Poisson's ratio, and the stent corresponding to the circular connective tissue and muscular membrane was constructed with positive Poisson's ratio. And four kinds of non-uniform Poisson's ratio tracheal stents with different link lengths and negative Poisson's ratio were designed. Then, this paper numerically simulated the expansion and rebound process of the stent after implantation to observe the support of the stent, and further simulated the stretch movement of the trachea to calculate the diameter changes of the stent corresponding to different negative Poisson's ratio structures. The axial migration of the stent was recorded by applying different respiratory pressure to the wall of the tracheal wall to evaluate whether the stent has anti-migration effect. The research results show that the non-uniform Poisson ratio stent with connecting rod length of 3 mm has the largest diameter expansion in the negative Poisson ratio section when the trachea was stretched. Compared with the positive Poisson's ratio structure, the axial migration during vigorous breathing was reduced from 0.024 mm to 0.012 mm. The negative Poisson's ratio structure of the non-uniform Poisson's ratio stent designed in this study did not fail in the tracheal expansion effect. Compared with the traditional stent, the non-uniform Poisson's ratio tracheal stent has an anti-migration effect under the normal movement of the trachea while ensuring the support force of the stent.