BACKGROUND:For thoracolumbar spine fractures with developmental stenosis of the vertebral arch,accurate nail placement is difficult using traditional fluoroscopy-assisted techniques.O-arm navigation assistance systems offer higher precision in general vertebral arch nail placement,but there is scarce literature on the application of O-arm navigation-assisted nail placement in thoracolumbar spine fractures with developmental stenosis of the vertebral arch both domestically and abroad. OBJECTIVE:To explore the accuracy of percutaneous vertebral arch nail placement assisted by O-arm navigation in patients with thoracolumbar spine fractures complicated by developmental stenosis of the vertebral arch. METHODS:A retrospective analysis was conducted on 53 patients who underwent percutaneous vertebral arch screw fixation surgery at Department of Orthopedics,General Hospital of Central Theater Command of PLA for thoracolumbar spine fractures complicated by developmental stenosis of the vertebral arch from January 2021 to March 2023.Totally 208 cases of vertebral arch developmental stenosis were found(cases with multiple vertebral arch developmental stenosis were counted separately).Based on the surgical approach,the patients were divided into two groups:O-arm navigation group(n=98)and C-arm fluoroscopy group(n=110).Postoperative imaging data were compared between the two groups,including anatomical perforation score,functional perforation score,actual vs.expected nail trajectory in the horizontal plane,and sagittal plane angle differences. RESULTS AND CONCLUSION:(1)There was no significant difference in the narrowest width of the pedicle isthmus(pow)between the two groups of patients(P>0.05).The proportions of different degrees of narrowing(mild:6 mm≤pow<7 mm,moderate:5 mm≤pow<6 mm,severe:pow<5 mm)were also not significantly different between the two groups(P>0.05).(2)The overall grade and scores of anatomical perforation and functional perforation were lower in the O-arm group compared to the C-arm group,and these differences were statistically significant(P<0.001).In terms of the angular deviation between the actual and planned screw trajectories,the O-arm group had smaller deviations,and these differences were statistically significant(P<0.05).(3)In the mild and moderate narrowing groups,the O-arm group showed significant advantages in anatomical perforation,functional perforation,and angular deviation between actual and planned screw trajectories,and these differences were statistically significant(P<0.001).(4)The O-arm group demonstrated better performance in anatomical perforation and functional perforation,especially in the T12-L2 segment,with more significant advantages.Additionally,the O-arm group had better angular deviations in actual and planned screw trajectories in all segments compared to the C-arm group.(5)Therefore,the use of O-arm navigation-assisted percutaneous screw placement for the treatment of thoracolumbar fractures with developmental pedicle isthmal narrowing provides higher accuracy and safer surgery.

Objective:To evaluate the posterior fixation with inclined-long pedicle screws for the injured vertebra combined with two-level interbody fusion for thoracolumbar burst fractures with severe disc injury.Methods:A retrospective study was conducted to analyze the clinical data of 22 patients who had been treated for thoracolumbar burst fractures with severe disc injury at Department of Orthopaedic, General Hospital of Central Theater Command from June 2016 to June 2021. There were 15 males and 7 females, aged 43.50 (29.75, 52.25) years. By the AO classification, there were 12 cases of type B2, 10 cases of type C3. All the patients were treated by the posterior fixation with inclined-long pedicle screws for the injured vertebra combined with two-level interbody fusion. The visual analogue scale (VAS), Oswestry disability index (ODI), anterior vertebral height ratio (AVHR), kyphosis Cobb angle (KCA), vertebral wedge angle (VWA) and spinal canal encroachment rate (SCER) were compared between pre-surgery, 1 week post-surgery, 3 months post-surgery and the last follow-up. Their neurological function was graded according to the American Spinal Injury Association (ASIA) impairment scale and interbody fusion evaluated according to their 3D CT at the last follow-up.Results:All the 22 patients were followed up for (26.1±1.3) months. In all patients, the VAS and ODI were significantly lower at 1 week post-surgery than the pre-surgery ones ( P<0.05), and then decreased significantly at 3 months post-surgery and at the last follow-up compared with the values at 1 week post-surgery ( P<0.05). For all patients, there were significant improvements in AVHR, KCA, VWA and SCER at 1 week post-surgery, 3 months post-surgery and the last follow-up compared with the pre-surgery values ( P<0.05), and the SCER at the last follow-up was significantly decreased compared with that at 1 week post-surgery ( P<0.05). All patients experienced improved neurological function in different degrees at the last follow-up, and all intervertebral spaces achieved solid bony fusion. Conclusion:In the treatment of thoracolumbar burst fractures with severe disc injury, the posterior fixation with inclined-long pedicle screws for the injured vertebra combined with two-level interbody fusion can lead to satisfactory long-term therapeutic efficacy, because this strategy can effectively reduce spinal canal encroachment, restore the height of the injured vertebra, reconstruct the curvature of the fracture area and ensure reliable intervertebral fusion.

Objective     To evaluate the risk factors for postoperative in-hospital mortality in elderly patients receiving cardiac valvular surgery, and develop a new prediction models using the least absolute shrinkage and selection operator (LASSO)-logistic regression. Methods     The patients≥65 years who underwent cardiac valvular surgery from 2016 to 2018 were collected from the Chinese Cardiac Surgery Registry (CCSR). The patients who received the surgery from January 2016 to June 2018 were allocated to a training set, and the patients who received the surgery from July to December 2018 were allocated to a testing set. The risk factors for postoperative mortality were analyzed and a LASSO-logistic regression prediction model was developed and compared with the EuroSCOREⅡ. Results     A total of 7 163 patients were collected in this study, including 3 939 males and 3 224 females, with a mean age of 69.8±4.5 years. There were 5 774 patients in the training set and 1 389 patients in the testing set. Overall, the in-hospital mortality was 4.0% (290/7 163). The final LASSO-logistic regression model included 7 risk factors: age, preoperative left ventricular ejection fraction, combined coronary artery bypass grafting, creatinine clearance rate, cardiopulmonary bypass time, New York Heart Association cardiac classification. LASSO-logistic regression had a satisfying discrimination and calibration in both training [area under the curve (AUC)=0.785, 0.627] and testing cohorts (AUC=0.739, 0.642), which was superior to EuroSCOREⅡ. Conclusion     The mortality rate for elderly patients undergoing cardiac valvular surgery is relatively high. LASSO-logistic regression model can predict the risk of in-hospital mortality in elderly patients receiving cardiac valvular surgery.

Objectives:To evaluate and predict the risk for in-hospital mortality in elderly patients receiving cardiac valvular surgery preferably,we developed a new prediction model using machine learning. Methods:Clinical data including baseline characteristics,peri-operative data and primary endpoint of 7 163 elderly patients aged 65 years or older undergoing cardiac valvular surgery from January 2016 to December 2018 from 87 hospitals were collected from the Chinese Cardiac Surgery Registry(CCSR).Patients from January 2016 to June 2018 were assigened to the training cohort(n=5 774)and patients from July to December 2018 were assigened to the validation cohort(n=1 389).The primary endpoint was in-hospital mortality.Machine learning algorithms were used to analyze risk factors and develop prediction model. Results:Overall in-hospital mortality was 4.1%.Linear discriminant analysis(LDA),support vector classification(SVC)and logistic regression(LR)models in the training cohort all have high AUCs and low Brier scores,with good discrimination and calibration.In validation cohort,the AUC of LDA,SVC and LR were 0.744,0.744 and 0.746 respectively,which were significantly better than that of 0.642 using the European System for Cardiac Operative Risk Evaluation II(EuroSCORE II)model(P<0.05). Conclusions:The mortality rate for elderly patients undergoing cardiac valvular surgery is relatively high.LDA,SVC and LR can predict the risk for in-hospital mortality in elderly patients receiving cardiac valvular surgery with high accuracy.

Objective To study the mechanical properties of titanium mesh and three-dimensional(3D)-printed metal vertebral body substitutes(VBS)to provide guidance for the selection and structural optimization of artificial vertebral implants in clinical practice.Methods The equivalent elastic modulus,equivalent yield strength,and structural failure mode of titanium mesh and 3D-printed porous,truss,and topologically optimized VBS were systematically investigated using compression tests.Results The elastic modulus of the titanium mesh(2 908.73±287.39 MPa)was only lower than that of the topologically optimized VBS.However,their structural strengths and stabilities were inadequate.The yield strength of the titanium mesh(46.61±4.85 MPa)was only higher than that of the porous VBS and it was the first to yield during compression.The porous VBS was insufficient for use as the vertebral implant owing to its poor mechanical strength(18.14±0.17 MPa-25.79±0.40 MPa).The truss VBS had good elastic modulus(2 477.86±55.19 MPa-2 620.08±194.36 MPa)and strength(77.61±0.50 MPa-88.42±1.07 MPa).However,the structural stability of the truss VBS was insufficient,and instability occurred easily during compression.The topologically optimized VBS had the highest elastic modulus(3 746.28±183.80 MPa)and yield strength(177.43±3.82 MPa)among all the tested VBS types,which could provide improved security and stability for artificial vertebral implant in vivo services.Conclusions Topology optimization results in a high strength and high stability VBS design.Moreover,it provides a large design space and great safety margin to provide increased possibilities for lightweight and new material design of future artificial vertebral implants.

Objective:To investigate the prevalence and associated risk of cardiovascular event of resistant hypertension in treated outpatients.Methods:This study was a nationwide multi-center prospective cohort study. The participants were treated outpatients enrolled in the China Nationwide Ambulatory and Home Blood Pressure Registry study of 42 hospitals in 19 provinces across the country from August 2009 to October 2017. Apparent resistant hypertension was defined as uncontrolled office blood pressure (≥140/90 mmHg, 1 mmHg=0.133 kPa) in spite of the use of three antihypertensive drugs or controlled office blood pressure (<140/90 mmHg) with four antihypertensive drugs or more. Subjects diagnosed with uncontrolled office blood pressure were further subdivided as pseudo-resistant hypertension and true resistant hypertension based on 24 h ambulatory blood pressure monitoring. The primary endpoint was fatal and non-fatal cardiovascular and cerebrovascular events, which was a composite endpoint consisting of cardiovascular and cerebrovascular death, ischemic and hemorrhagic stroke, myocardial infarction, coronary artery revascularization, unstable angina, heart failure, and coronary artery stenosis≥50% confirmed by coronary angiography. Secondary outcomes included fatal and non-fatal stroke or cardiac events. Patients with controlled office blood pressure after taking only 1 or 2 antihypertensive drugs were included as control. Kaplan-Meier survival curves, log-rank test, and Cox proportional risk model were used to evaluate the risk of apparent refractory hypertension in relation to cardiovascular and cerebrovascular prognosis.Results:A total of 2 782 treated hypertensive patients, aged (58.1±12.3) years were enrolled, including 1 403 (50.4%) men. The prevalence of apparent and true resistant hypertension was 15.1% (420/2 782) and 10.5% (293/2 782), respectively. Among patients with apparent resistant hypertension, during a median of 5 years follow-up, the cumulative incidence rate was 28.2, 11.2 and 19.1 per 1 000 person-years for fatal and non-fatal cardiovascular events ( n=58), stroke ( n=24) and cardiac events ( n=40), respectively. The Kaplan-Meier curve and log-rank test showed that those patients with true resistant hypertension, had the highest cumulative incidence rate of fatal and non-fatal cardiovascular events, stroke, and cardiac events. Multivariable Cox regression analyses showed that true resistant hypertension was associated with a significantly higher risk of fatal and non-fatal cardiovascular events ( HR=1.73, 95% CI 1.17-2.56, P=0.006) and stroke ( HR=2.81, 95% CI 1.53-5.17, P=0.001). Conclusion:Resistant hypertension, especially true resistant hypertension, is associated with a higher risk of fatal and non-fatal cardiac and cerebrovascular events.

Humans ; COVID-19 ; Consensus ; SARS-CoV-2 ; China

Objective To propose a quick and low-cost personalized diabetic foot modeling and insole design scheme, so as to reduce the plantar pressure accurately. Methods The foot model of the patient was constructed by scaling the model with foot feature parameters, to make biomechanical analysis on plantar pressure. By means of numerical mapping model of insole elasticity and plantar pressure, the three-dimensional (3D) personalized insole model with gradient modulus was constructed. The insole was then manufactured via 3D printing technology and used for experimental validation. Results The related mechanical parameters from finite element prediction of the foot model constructed by the scaling modeling method were close to those of the CT reconstructed model, and the maximum error was controlled within 15%. Compared with wearing the normal insole, the peak pressure of the personalized insole was effectively reduced by 20%. The time and economic cost of this simplified design was reduced by approximately 90%. Conclusions The design scheme of the diabetes insole shortens the design cycle, and the personalized insole can effectively and accurately reduce the sole pressure, and reduce the risk of foot ulcer, which provides a technical basis for the promotion of the personalized diabetes insole.

Objective Aiming at the clinical problem of the low matching degree with the patient’s anatomical morphology for traditional cervical fusion cage, a cervical fusion cage with the function of adjustable height and the shape matched with the vertebral body was established, and its biomechanical properties were evaluated. Methods A cervical C4-5 segment fusion model was established according to anterior cervical discectomy and fusion (ACDF), so as to simulate different motion conditions, i.e. anterior flexion, posterior extension, left/right lateral flexion, left/right rotation, and stress of the fusion cage and vertebral endplate was calculated. After three-dimensional (3D) printing of the fusion cage, an in vitro mechanical experiment was conducted to explore safety and stability of the fusion cage. ResultsThe fusion cage could keep the range of motion (ROM) of cervical vertebrae at the fusion segment with 1°-2.8° and reduce the ROM to 40%-80% of the natural segment. In the in vitro compression test, the yield load of the fusion cage was (2 721.67±209) N, which met the maximum demand of the physiological load in service state. Conclusions The designed fusion device with adjustable height shows better biomechanical properties and can reduce the selection step in operation.

Objective To analyze the clinical courses and outcomes of COVID-19 cases and the influencing factors in Guangdong province and provide basis for the formulation or adjustment of medical care and epidemic control strategy for COVID-19. Methods We collected demographic data, medical histories, clinical courses and outcomes of 1 350 COVID-19 patients reported in Guangdong as of 4 March 2020 via epidemiological investigation and process tracking. Disease severity and clinical course characteristics of the patients and influencing factors of severe illness were analyzed in our study. Results Among 1 350 cases of COVID-19 cases in Guangdong, 72 (5.3%) and 1049 (77.7%) were mild and ordinary cases, 164 (12.1%) were severe cases, 58 (4.3%) were critical cases and 7 (0.5%) were fatal. The median duration of illness were 23 days ( P 25 - P 75 : 18-31 days) and the median length of hospitalization were 20 days ( P 25 - P 75 : 15-27 days). For severe cases, the median time of showing severe manifestations was on the 12th day after onset ( P 25 - P 75 : 9th to 15th days), and the median time of severe manifestation lasted for 8 days P 25 - P 75 : 4-14 days). Among 1 066 discharged/fetal cases, 36.4% (36/99) and 1.0% (1/99) of the mild cases developed to ordinary cases and severe cases respectively after admission; and 5.2% (50/968) and 0.6% (6/968) of the ordinary cases developed to severe cases, and critical cases respectively after admission. In severe cases, 11.4% developed to critical cases (10/88). The influencing factors for severe illness or worse included male (a HR =1.87, 95% CI : 1.43-2.46), older age (a HR =1.67, 95% CI : 1.51-1.85), seeking medical care on day 2-3 after onset (a HR =1.73, 95% CI : 1.20-2.50) pre-existing diabetes (a HR =1.75, 95% CI : 1.12-2.73) and hypertension (a HR =1.49, 95% CI : 1.06-2.09). Conclusions The course of illness and length of hospitalization of COVID-19 cases were generally long and associated with severity of disease clinical outcomes. The severe cases were mainly occurred in populations at high risk. In the epidemic period, classified management of COVID-19 cases should be promoted according to needs for control and prevention of isolation and treatment for the purpose of rational allocation of medical resources.