BACKGROUND:One of the advantages of clear aligner treatment is molar distalization.However,tooth tilting movement and loss of anterior anchorage may occur during treatment.There are few studies on whether these problems can be improved by selecting clear aligners with different thicknesses and edges to improve the clinical treatment effect.OBJECTIVE:To analyze the control ability of clear aligners with different thickness and edges on the central incisor,lateral incisor,and second molar when pushing the maxillary second molar distally by three-dimensional finite element analysis.METHODS:Three-dimensional finite element analysis models of bilateral maxillary second molar distalization with clear aligner,maxillary dentition,periodontal ligament,and alveolar bone with different thicknesses and margins were established by Mimics,Geomagic Wrap,3-matic and SolidWorks software,respectively.There were 16 combinations of four thicknesses(0.4,0.5,0.625,and 0.75 mm)and four margins(scallop,straight,straight extension 2 mm and straight extension 4 mm).The data were imported into Ansys Workbench software for design and solution.The mean value,peak value and distribution of the periodontal ligament equivalent stress of the second molar,the equivalent stress and the maximum initial displacement of the second molar,and the control ability of each appliance on the second molar,central incisor,and lateral incisor were analyzed.RESULTS AND CONCLUSION:(1)The mean equivalent stress of periodontal ligament of the second molar,the equivalent stress of the second molar and the maximum initial displacement of the second molar increased with the extension of the appliance edge and the increase of the thickness of the appliance in the 16 groups of models.(2)When the thickness of appliances was the same,the maximum equivalent stress of the second molar in the linear appliance group was the highest,and the maximum equivalent stress of the second molar in the linear extended appliance group was greater than that in the scallop appliance group.When the edge of the appliance was the same,the periodontal ligament equivalent stress peak of the second molar increased with the increase of the thickness of the appliance.The equivalent stress distribution in the periodontal ligament of the second molar in the linear extendable appliance group was more uniform than that in the scallop appliance group and the linear appliance group.(3)When the thickness of the appliance was the same,the scallop-shaped appliance had the worst control on the second molar.When the edge of the appliance was the same,with the increase of the thickness of the appliance,the control of the second molar by the linear extender appliance was gradually stronger than that by the linear appliance.The control of the central incisor was stronger and more stable with the linear extended 2 mm appliance,while the control of the lateral incisor was stronger and more stable with the linear appliance.(4)The results showed that when using clear aligners to push molars distally,extending the edge of the appliance could improve the control of the molars and reduce the tilting movement of the teeth.The design of a straight extension margin of 2 mm for the central incisor and a straight edge for the lateral incisor can enhance the control of the anchorage incisor and reduce the labial inclination of the anterior teeth.

BACKGROUND:One of the advantages of clear aligner treatment is molar distalization.However,tooth tilting movement and loss of anterior anchorage may occur during treatment.There are few studies on whether these problems can be improved by selecting clear aligners with different thicknesses and edges to improve the clinical treatment effect.OBJECTIVE:To analyze the control ability of clear aligners with different thickness and edges on the central incisor,lateral incisor,and second molar when pushing the maxillary second molar distally by three-dimensional finite element analysis.METHODS:Three-dimensional finite element analysis models of bilateral maxillary second molar distalization with clear aligner,maxillary dentition,periodontal ligament,and alveolar bone with different thicknesses and margins were established by Mimics,Geomagic Wrap,3-matic and SolidWorks software,respectively.There were 16 combinations of four thicknesses(0.4,0.5,0.625,and 0.75 mm)and four margins(scallop,straight,straight extension 2 mm and straight extension 4 mm).The data were imported into Ansys Workbench software for design and solution.The mean value,peak value and distribution of the periodontal ligament equivalent stress of the second molar,the equivalent stress and the maximum initial displacement of the second molar,and the control ability of each appliance on the second molar,central incisor,and lateral incisor were analyzed.RESULTS AND CONCLUSION:(1)The mean equivalent stress of periodontal ligament of the second molar,the equivalent stress of the second molar and the maximum initial displacement of the second molar increased with the extension of the appliance edge and the increase of the thickness of the appliance in the 16 groups of models.(2)When the thickness of appliances was the same,the maximum equivalent stress of the second molar in the linear appliance group was the highest,and the maximum equivalent stress of the second molar in the linear extended appliance group was greater than that in the scallop appliance group.When the edge of the appliance was the same,the periodontal ligament equivalent stress peak of the second molar increased with the increase of the thickness of the appliance.The equivalent stress distribution in the periodontal ligament of the second molar in the linear extendable appliance group was more uniform than that in the scallop appliance group and the linear appliance group.(3)When the thickness of the appliance was the same,the scallop-shaped appliance had the worst control on the second molar.When the edge of the appliance was the same,with the increase of the thickness of the appliance,the control of the second molar by the linear extender appliance was gradually stronger than that by the linear appliance.The control of the central incisor was stronger and more stable with the linear extended 2 mm appliance,while the control of the lateral incisor was stronger and more stable with the linear appliance.(4)The results showed that when using clear aligners to push molars distally,extending the edge of the appliance could improve the control of the molars and reduce the tilting movement of the teeth.The design of a straight extension margin of 2 mm for the central incisor and a straight edge for the lateral incisor can enhance the control of the anchorage incisor and reduce the labial inclination of the anterior teeth.

Objective To observe the correlations of lumbar bone mineral density(BMD)with serum uric acid(SUA),hepatic fat and abdominal fat based on quantitative CT(QCT).Methods A total of 522 subjects who underwent lumbar QCT were retrospectively enrolled.Subjects with different genders were divided into hyperuricemia(HUA)group and normal SUA group according to SUA levels,and QCT parameters were compared between groups.Meanwhile,subjects with different genders were also divided into normal bone mass group(normal group),osteopenia group and osteoporosis(OP)group,and SUA and QCT parameters were compared among groups.Pearson correlation analyses were performed to explore the correlations of lumbar BMD with age,SUA,visceral adipose tissue(VAT),subcutaneous adipose tissue(SAT)and liver fat content.Results There were 325 males,with 105 ones in HUA group and 220 ones in normal SUA group.There were 197 females,with 26 ones in HUA group and 171 ones in normal SUA group.VAT,SAT and percentage of liver fat content in HUA group of different genders were all higher than those in normal SUA group(all P＜0.05).Among 325 males,there were 196 ones in normal group,105 ones in osteopenia group and 24 ones in OP group among males,and VAT increased successively in the above groups(all P＜0.05).Among 197 females,there were 147 ones in normal group,30 ones in osteopenia group and 20 ones in OP group,and VAT and SAT increased successively in the above groups(all P＜0.05).Lumbar BMD was moderately and weakly negatively correlated with age and VAT in males(r=-0.618,-0.286,both P＜0.001),which was moderately,lowly and weakly negatively correlated with age,VAT and SAT in females,respectively(r=-0.772,-0.451,-0.273,all P＜0.001).Conclusion Increased SUA levels resulted in increased abdominal and liver fat content,and the latter was negatively correlated with lumbar BMD.

Objective To analyze the imaging signs of chondromyxoid fibroma(CMF)and to improve the diagnostic accuracy of CMF.Methods The imaging data of 31 cases of CMF diagnosed by pathology were analyzed retrospectively and the characteristic imaging signs were analyzed.Results Among the 31 CMF patients,the male-to-female ratio was about 1.4∶1,and 75％of cases occurred before the age of 30;20 cases occurred in the long bones:15 cases in the tibia,4 cases in the femur,and 1 case in the fibula;15 cases occurred in the metaphyseal;7 cases occurred in the flat bones,and 4 cases occurred in the bones of the hands and feet.All lesions showed osteolysis with different degrees of expansion,lobulation,clear borders,and sclerotic margins on both X-ray plain film and CT.There was internal mineralization in 17 cases and internal bone ridge in 12 cases.All lesions showed T1 WI low-equal signal,T2WI medium-high signal in MRI,and enhanced scans were dominated by circumferential or nodular enhancement of the margins.Conclusion Multiple imaging examination methods can improve the diagnosis of CMF.

Thoracolumbar spine fracture often leads to severe pain, functional impairments, and neurological deficits, for which open reduction and internal fixation can effectively restore the spinal structural stability. Open decompression and reduction with internal fixation can help relieve spinal cord compression and improve spinal function in cases of concomitant cord injury. Although spinal stability can be restored through surgery, patients often face chronic pain and functional impairments postoperatively. A postoperative rehabilitation program is critical in optimizing therapeutic outcomes, reducing complications, and minimizing the risk of secondary injuries. However, current rehabilitation methods, such as physical therapy, functional training, and pain management, are confronted with problems in clinical practice, including significant variation in efficacy, poor patient adherence, and prolonged rehabilitation period. There is an urgent need for a unified rehabilitation strategy to address these problems. To this end, the Spinal Trauma Group of the Orthopedic Physicians Branch of the Chinese Medical Association and the Spine Health Professional Committee of the Chinese Human Health Technology Promotion Association organized experts from relevant fields to formulate Evidence-based guidelines for rehabilitation treatment after internal fixation of thoracolumbar spine fracture in adults ( version 2025) by integrating evidences from clinical researches and advanced rehabilitation concepts at home and abroad. A total number of 14 recommendations concerning the rehabilitation treatment with multimodal analgesia, psychological intervention, deep vein thrombosis prevention, core muscle and extremity exercise, appropriate use of braces, early weight-bearing, device-aided rehabilitation exercise, neuroregulatory therapy, rehabilitation team were put forward, aiming to standardize the post-operative rehabilitation process following internal fixation, promote the functional recovery, and enhance patients′ quality of life.

Nonunion of osteoporotic vertebral fractures (OVF), predominantly affecting the elderly, can lead to intractable pain, vertebral collapse, progressive kyphotic deformity, and neurological impairment, significantly compromising patients′ quality of life. There exists considerable debate on diagnosis and management of OVF, encompassing key issues such as clinical diagnosis and staging criteria for nonunion, surgical indications and procedure selection, and postoperative rehabilitation planning. Currently, there lacks standardized clinical guideline and expert consensus on the diagnosis and management of OVF nonunion in China. To address this gap, Minimally Invasive Surgery Group of Chinese Orthopedic Association, Osteoporosis Committee of Chinese Association of Orthopedic Surgeons, Prevention and Rehabilitation Committee for Osteoporosis of Chinese Association of Rehabilitation Medicine and Minimally Invasive Orthopedic Surgery Branch of China Association for Geriatric Care jointly organized domestic experts in spinal surgery, endocrinology, and rehabilitation to formulate the Clinical guideline for the diagnosis and treatment for nonunion of osteoporotic vertebral fractures ( version 2025), based on existing literature and clinical experience and adhering to principles of scientific rigor and practicality. The guideline provided 13 evidence-based recommendations encompassing diagnosis and treatment of OVF nonunion, aiming to standardize its clinical management.

Acute symptomatic osteoporotic thoracolumbar compression fracture (ASOTLF) can lead to chronic low back pain, kyphosis deformity, pulmonary dysfunction, loss of mobility, and even life-threatening complications. Vertebral augmentation is currently the mainstream treatment method for this condition. In 2019, the Editorial Board of Chinese Journal of Trauma and the Spinal Trauma Group of Orthopedic Surgeons Branch of Chinese Medical Doctor Association collaboratively led the development of Clinical guideline for vertebral augmentation for acute symptomatic osteoporotic thoracolumbar compression fractures. Six years later, with advances in clinical diagnosis and treatment techniques as well as accumulating evidence in related fields, the 2019 guideline requires updating. To this end, the Spinal Trauma Group of Orthopedic Surgeons Branch of Chinese Medical Doctor Association, the Spinal Health Professional Committee of China Human Health Science and Technology Promotion Association, and the Minimally Invasive Orthopedics Professional Committee of Shaanxi Medical Doctor Association have organized experts in the field to develop the Clinical guideline for vertebral augmentation of acute symptomatic osteoporotic thoracolumbar compression fractures ( version 2025) , based on the latest evidence-based medical researches. This guideline incorporates 3 recommendations retained from the 2019 version with updated strength of evidence, along with 12 new recommendations. It provides recommendations from six aspects of diagnosis, pain management, treatment option selection, prevention of postoperative complications, anti-osteoporosis therapy, and postoperative rehabilitation, aiming to provide a reference for standard treatment of vertebral augmentation for ASOTLF in hospitals at all levels.

Objective:This study aims to provide insights into the clinical features of anti-melanoma differentiation-associated protein-5(MDA5)-positive dermatomyositis (MDA5-DM) patients with fatal outcomes, leveraging pathogenic microbiota metagenomic analysis, to guide the clinical assessment and treatment choices.Methods:From January 2020 to August 2023, deceased patients diagnosed with MDA5-DM were identified at the Department of Rheumatology and Immunology, the Second Affiliated Hospital of Xi ′an Jiaotong University. Clinical data were retrospectively collected and analyzed using Mann Whitney U test and Fisher ′s exact test to summarize risk factors and treatment assessment for MDA5-DM patients with fatal outcomes. Results:①The proportion of male patients was higher than females among MDA5-DM patients with fatal outcomes, which differed from the incidence pattern, possibly associated with smoking and gender proportions (6/11 vs. 0/7, P=0.037). ②94%(17/18) patients presented initially with elevated ferritin levels [(1 350±942)ng/ml] and CRP [(47±36)mg/L]. ③All patients (18/18) exhibited early involvement of the upper lung lobes, including multiple nodules in 9/18, ground-glass opacities in 5/18, and solitary nodules in 4/18. ④Metagenomic next-generation sequencing (mNGS) of bronchoalveolar lavage fluid was negative in 4/16 cases, with cytomegalovirus and pneumocystis jirovecii being the most commonly detected pathogens in 5/16 cases each. ⑤89%(16/18) of patients continued to have lymphocyte counts persistently <0.5×10 9/L irrespective of treatment. Conclusion:Smoking may have adverse effects on male MDA5 patients. Early involvement of the upper lobe of the lungs is more common in MDA5 antibody positive deaths, and persistent lymphocyte depletion is an important factor in poor response. Enhancing mNGS analysis of bronchoalveolar lavage fluid and vigilance towards cytomegalovirusand Pneumocystis jirovecii could provide valuable clinical guidance.

Body weight abnormalities, including overweight, obesity, and underweight, have become a dual public health challenge in Chinese adults: overweight and obesity lead to a variety of chronic complications, while underweight increases the risks of malnutrition, sarcopenia, and organ dysfunction. To systematically address these issues, multidisciplinary experts in endocrinology, sports science, nutrition, and psychiatry from various regions have held multiple weight management seminars. Based on the latest epidemiological data and clinical evidence, they expanded the guideline to include assessment and intervention strategies for underweight, in addition to the core content of obesity management. This guideline outlines the etiological mechanisms, evaluation methods, and multidimensional management strategies for overweight and obesity, covering key areas such as diagnosis and assessment, medical nutrition therapy, exercise prescription, pharmacological intervention, and psychological support. It is intended to provide a scientific and standardized approach to weight management across the adult population, aiming to curb the rising prevalence of obesity, mitigate complications associated with abnormal body weight, and improve nutritional status and overall quality of life.

Objective To investigate the imaging signs of osteoid osteoma(OO)of short tubular bone.Methods A retrospective analysis was conducted on clinical and imaging data from 19 cases pathologically confirmed of OO in short tubular bones,and a com-parision was made with the imaging findings of 67 cases of long tubular bones.Results Among the 19 cases of OO in short tubular bones,73.70%of cases were under 30 years old.There were 16 cases involved the hand's short tubular bones,with 14 cases in the phalanges(1 in the thumb,4 in the index finger,5 in the middle finger,2 in the ring finger,2 in the little finger)and 2 cases in the metacarpals.Three cases involved the short tubular bones of the foot,all in the metatarsals.Five cases reported increased pain at night,three cases experienced relief with nonsteroidal anti-inflammatory drugs,and two cases did not take any medication.All lesions were osteolytic,with mineralisation within the nidus and varying degrees of surrounding bone sclerosis,bone marrow edema,and soft tissue edema.Compared to OO in long tubular bones,OO in short tubular bones more frequently exhibited expansile and discontinu-ous cortical bone features,but the degree and extent of bone sclerosis were less pronounced.Conclusion Short tubular bones are a rare location for OO,often lacking typical clinical symptoms,which can easily lead to misdiagnosis.Therefore,close attention should be paid to its imaging characteristics.