To investigate the effects of postoperative fusion implantation on the mesoscopic biomechanical properties of vertebrae and bone tissue osteogenesis in idiopathic scoliosis, a macroscopic finite element model of the postoperative fusion device was developed, and a mesoscopic model of the bone unit was developed using the Saint Venant sub-model approach. To simulate human physiological conditions, the differences in biomechanical properties between macroscopic cortical bone and mesoscopic bone units under the same boundary conditions were studied, and the effects of fusion implantation on bone tissue growth at the mesoscopic scale were analyzed. The results showed that the stresses in the mesoscopic structure of the lumbar spine increased compared to the macroscopic structure, and the mesoscopic stress in this case is 2.606 to 5.958 times of the macroscopic stress; the stresses in the upper bone unit of the fusion device were greater than those in the lower part; the average stresses in the upper vertebral body end surfaces were ranked in the order of right, left, posterior and anterior; the stresses in the lower vertebral body were ranked in the order of left, posterior, right and anterior; and rotation was the condition with the greatest stress value in the bone unit. It is hypothesized that bone tissue osteogenesis is better on the upper face of the fusion than on the lower face, and that bone tissue growth rate on the upper face is in the order of right, left, posterior, and anterior; while on the lower face, it is in the order of left, posterior, right, and anterior; and that patients' constant rotational movements after surgery is conducive to bone growth. The results of the study may provide a theoretical basis for the design of surgical protocols and optimization of fusion devices for idiopathic scoliosis.
Humans ; Scoliosis/surgery* ; Spinal Fusion/methods* ; Lumbar Vertebrae/surgery* ; Osteogenesis ; Biomechanical Phenomena/physiology* ; Finite Element Analysis

Objective: To investigate the correlation between carotid plaque vulnerability and MRI imaging markers and overall burden of cerebral small vessel disease (CSVD). Methods: From January 2018 to December 2018, patients with carotid plaque thickness ≥2 mm admitted to the Brain Disease Center, the Affiliated Hospital of Nanjing University of Chinese Medicine was enrolled prospectively. Contrast-enhanced ultrasonography (CEUS) was used to evaluate the vulnerability of carotid plaque. All patients underwent head MRI. Lacunar infarction, white matter hyperintensities, cerebral microbleeds and enlarged perivascular space were recorded and the overall burden of CSDV was calculated. Binary multivariate logistic regression analysis was used to determine the correlation between carotid vulnerable plaque and various imaging markers of CSVD. Ordinal multivariable logistic regression analysis was used to determine the correlation between the carotid vulnerable plaques and the overall burden of CSCD. Results: A total of 112 patients were included, including 61 (54.5%) in vulnerable plaque group and 51 (45.5%) in non-vulnerable plaque group. There were significant differences in the proportion of diabetes mellitus (49.2% vs. 19.6%; χ²=10.580, P<0.001), lacunar infarction (54.1% vs. 31.4%; χ²=5.829, P=0.016) and white matter hyperintensities (41.0% vs. 19.6%; χ²=5.907, P=0.015) between the vulnerable plaque group and the non-vulnerable plaque group. Multivariate logistic regression analysis showed that after adjusting for age, gender, hypertension, diabetes, and hyperlipidemia, there was a significant independent correlation between lacunar infarction (odds ratio [OR] 2.776, 95% confidence interval [CI] 1.139-6.765; P=0.025) and white matter hyperintensities (OR 3.969, 95% CI 1.465-10.753; P=0.007) and carotid vulnerable plaque. There were significant differences in age (F=4.275, P=0.003), past stroke history (χ²=11.100, P=0.025) and vulnerable plaque (χ²=9.829, P=0.043) in different CSVD burden groups. The overall burden of CSVD increased significantly with the increase of CEUS grade of carotid plaque (χ²=28.525, P=0.005). Ordinal multivariable logistic regression analysis showed that after adjusting for age, gender, hypertension, diabetes, coronary heart disease, stroke history, and smoking, there was still a significant independent correlation between the overall burden of CSVD and vulnerable plaques (OR 3.753, 95% CI 1.678-8.392; P=0.001). Conclusions Carotid vulnerable plaques were independently associated with lacunar infarction, white matter hyperintensities, and total burden of CSVD.

【Objective】 To investigate dynamic regional homogeneity (dReHo) abnormality in end-stage renal disease (ESRD) patients by using resting-state functional magnetic resonance imaging (rs-fMRI). 【Methods】 A total of 26 ESRD patients and 26 healthy controls (HC) matched in gender, education level and age were included. Rs-fMRI scanning was performed in all subjects. All the subjects were tested by using auditory verbal learning test Huashan version (AVLT-H) and Montreal Cognitive Assessment (MoCA) to assess cognitive function before collection of MRI data. T-test was used to observe the difference in dReHo at global level between the two groups. Pearson and Spearman correlation analyses were made to estimate the correlation between abnormal brain regions and clinical scales. 【Results】 Compared with HC group, the dReHo value in ESRD patients reduced on the bilateral superior margin gyrus, left insula, left posterior central gyrus, and left putamen (P<0.05, replacement test correction). The dReHo values of left superior margin gyrus (r=-0.534, P=0.005) and left insula in ESRD patients (r=-0.422, P=0.032) were negatively correlated with the LR-S score, and the dReHo value of the left margin was negatively correlated with the SR-S score (r=-0.468, P=0.016). 【Conclusion】 There are abnormal dReHo values in several brain regions in ESRD patients during resting state, which is related to the patients’ cognitive function. The variation of dReHo value provides a new objective imaging basis for evaluating the cognitive function of ESRD patients.