The development and validation of a prediction model for imminent vertebral osteoporotic fracture in postmenopausal women.

PURPOSE: This study aimed to develop and validate a new model that focused on the risk of imminent vertebral fractures in women with osteoporosis. METHODS: Data from 2,048 patients were extracted from three hospitals, of which 1,720 patients passed the inclusion and exclusion screen. The patients from Nanfang Hospital (NFH) were randomized at a 2:1 ratio to create a training cohort (n = 709) and an internal validation cohort (n = 355), with the patients from the other two hospitals (n = 656) used for external validation. The risk factors included in the imminent osteoporotic vertebral compression fractures (OVCFs) prediction model (labelled TVF) were sorted by the least absolute shrinkage and selection operator and constructed by logistic regression. The area under the receiver operating characteristic curve (AUC), the decision curve, and the clinical impact curves of the optimal model were analyzed to verify the model. RESULTS: There were 138 and 161 fresh fractures in NFH and the other two hospitals, respectively. The lowest BMD T value and the history of vertebral fracture were integrated into the TVF model. The prediction power of TVF was demonstrated by the AUCs of 0.788 (95% confidence interval [CI], 0.728-0.849) in the training cohort and 0.774 (95% CI, 0.705-0.842) in the internal validation cohort, and 0.790 (95% CI, 0.742-0.839) and 0.741 (95% CI, 0.668-0.813) in the external validation cohorts. CONCLUSION: The TVF model demonstrated good discrimination to stratify the imminent risk of OVCFs. We therefore consider the model as a pertinent commencement in the search for more accurate imminent OVCFs prediction.

Spatial differentiation of neighborhood climates and their response to surrounding land cover composition: A case study in Beijing, China.

Heterogeneous land cover affects near-surface heat and humidity distribution in urban areas. Effective land cover arrangements can create a more sustainable local thermal environment. However, spatial differentiation in neighborhood climates and their spatial response range to the surrounding land cover composition (LCC) in high-density urban environments remains unclear. In this study, field monitoring of the air temperature (Ta) and relative humidity (Rh) was conducted in summer (August 2016) and winter (December 2016 and January 2017) in a neighborhood in Beijing, China. A multi-radius approach was developed to quantify the effective response range of Ta and Rh at unshaded measuring points to the surrounding LCC. Our results demonstrated that the: (1) spatial distribution of Ta and Rh in a typical neighborhood varies significantly in both summer and winter and is dependent on the local land cover; (2) Ta at measurement points generally increases with growing surrounding vegetation coverage and decreases with less impervious pavement and building coverage, whereas the opposite applies to Rh; (3) response of Ta and Rh to land cover composition is spatially dependent; and (4) Ta and Rh have an effective response range of up to 200-m to surrounding vegetation coverage in both seasons, whereas their response range to pavement coverage is 150- and 100-m in summer and winter, respectively. Overall, LCC within a radius of 100-150-m has a significant impact on the Ta and Rh of the measuring points in a high-density urban neighborhood. These findings elucidate the spatial response of a neighborhood climate to surrounding land cover and demonstrate that landscape infrastructure intervention is an effective means of improving urban thermal environments.

Design and basic research on accuracy of a novel individualized three-dimensional printed navigation template in atlantoaxial pedicle screw placement.

OBJECTIVE: To design and evaluate the accuracy of a novel navigation template suitable for posterior cervical screw placement surgery by using 3D printing technology to improve the existing guiding template design. METHODS: The researchers (including spine surgeons and technicians) used CT to perform thin-slice scanning on 12 cases of normal upper cervical vertebral specimens and defined the screw channels that were completely located in the pedicle without penetrating the cortex as ideal screw channels, then designed the ideal channel of the upper cervical vertebral (atlantoaxial) pedicle screw by computer software which was regarded as the preset values, and recorded the screw entrance point, transverse angle and sagittal angle of the ideal channel. Then, researchers designed the novel navigation templates for placement pedicle screw according to the ideal screw channel preset values and manufactured them with one for every single vertebra by 3D printer. A senior spine surgeon performed the posterior surgery to implant pedicle screw on the specimens by the novel navigation templates, then performed CT thin-slice scanning on the specimens again after removing the screws, and reconstructed the actual screws channel by computer software, recorded the screw entrance point, transverse angle and sagittal angle of the actual channels which were defined as the actual values and evaluated them according to Kawaguchi's pedicle screw evaluation standard finally. The differences between the preoperative preset values of ideal screw channel and the postoperative actual values of actual screw channel were compared by a nonparametric paired rank test. RESULTS: 48 screws were placed on 12 cases of upper cervical vertebral specimens in total. It showed that the grade 0, I, II, III channels in this study were 47, 1, 0, 0, respectively. The grade 0 channels accounted for 97.92% of the total number of channels. There was no significant difference with regard to the screw entrance point, the transverse angle, and the sagittal angle between the preoperative preset values of ideal screw channels and the postoperative actual values of actual screw channels. CONCLUSION: To implant pedicle screw assisted with the novel individually navigation template designed by 3D printed in the posterior cervical surgery can improve accuracy of pedicle screw placement and safety of the surgery.