Objective To investigate the post-discharge exercise behavior and factors influencing moderate to vigorous intensity physical activity (MVPA) in patients undergoing lung surgery. Methods A total of 2874 patients from the large prospective, observational perioperative lung symptom study cohort (CN-PRO-Lung 3) in the Department of Thoracic Surgery at Sichuan Cancer Hospital between April 7, 2021, and January 31, 2024, were selected as the survey subjects. A survey was conducted using the Investigation of Exercise Behavior after Lung Surgery questionnaire and the International Physical Activity Questionnaire-Short Form (IPAQ-SF) among patients who underwent lung surgery. Binary logistic regression was used to analyze the factors influencing patients’ engagement in MVPA. Results A total of 702 patients were surveyed, including 252 males and 450 females, with an average age of (52.4±10.2) years. Patients with lung cancer accounted for 85.9%. Only 36.0% of the patients had regular exercise habits, while 42.3% did not engage in any physical activity. The three main barriers for postoperative exercise were physical discomfort (pain, coughing, shortness of breath, etc, 54.7%), lack of professional guidance (41.7%), and concerns about the surgical wound (28.9%). The proportions of patients engaging in vigorous, moderate, and low-intensity physical activity were 5.7%, 28.2%, and 66.1%, respectively. Multivariate analysis showed that patients with a personal annual income ≥50000 yuan (OR=1.52, 95%CI 1.01-2.29, P=0.044), high school education or above (OR=1.92, 95%CI 1.33-2.76, P<0.001), and lobectomy (OR=1.44, 95%CI 1.02-2.03, P=0.037) engaged in more MVPA. Conclusion Patients undergoing lung surgery have inadequate physical activity after discharge, particularly lacking in MVPA. Patients with higher income, higher educational levels, and lobectomy are more frequently engaged in MVPA. Measures such as symptom control, providing exercise guidance, and enhancing education on wound care may potentially improve the inadequate physical activity in lung surgery patients after discharge.

Objective: To study the effect of metformin sensitizing pancreatic cancer cells with radiotherapy, with a focus on elucidating the underlying mechanisms of radiotherapy resistance. In particular, the role of the PERK/P-eIF2/ATF4 signaling pathway in mediating these effects was preliminarily explored. Methods : Pancreatic cancer cell lines(PANC-1 and PANC-2) were categorized into control, radiotherapy, and drug treatment groups. Following the respective treatments, cell proliferation inhibition was assessed using the CCK-8 assay, colony formation assays, and cell death staining. Senescence was quantified by β-galactosidase(SA-β-Gal) staining. The expression of cell cycle regulators(P21, P16, γ-H2AX), apoptosis markers(Bax, Bcl-2, Cleaved caspase-3), and pathway-related proteins(PERK, P-eIF2, ATF4) was evaluated by Western blot and immunofluorescence. To further investigate the role of the PERK/P-eIF2/ATF4 axis in metformin-mediated modulation of pancreatic cancer cell senescence and radiosensitization, selective inhibitors(GSK2606414) and agonists(MK-28) of PERK were employed. Results : Radiotherapy markedly upregulated senescence-associated markers(P21, P16, γ-H2AX, and β-galactosidase activity) in pancreatic cancer cells. Senescent cells exhibited enhanced proliferative activity and increased tumor volume both in vitro and in vivo. Metformin mitigated radiotherapy-induced senescence by reducing the expression of senescence markers and significantly suppressing the clonogenic and proliferative capacity of treated cells. Mechanistically, radiotherapy activated the PERK signaling pathway, leading to increased expression of PERK, P-eIF2, and ATF4, thereby driving cellular senescence. Pharmacological inhibition of PERK reduced β-galactosidase activity, while PERK activation further promoted the expression of senescence-associated proteins—an effect that was reversed by metformin. Conclusion Metformin inhibits the activation of the PERK/P-eIF2/ATF4 signaling pathway in pancreatic cancer cells following radiotherapy, thereby delaying cellular senescence and reducing the associated radiotherapy resistance of senescent cells. This modulation contributes to the sensitization of pancreatic cancer cells to radiotherapy.

Objectives:To analyze the 3D structural characteristics and discuss the clinical significance of pedicle-isthmus complex(PIC)through measuring the anatomical and morphological parameters of normal axis PIC.Methods:The imaging data of 100 patients without high-riding vertebral artery[57 males,43 females,56.1±1.8(18-79)years]undergone CT angiography(CTA)examinations of the cervical spine or neck and admitted to the Affiliated Hospital of Southwest Medical University between January 2022 and December 2022,and another 28 patients[15 males,13 females,55.5±14.6(18-80)years]undergone posterior C2 pedicle screw fixation and examined with CT scan of the cervical spine during the same period were collected.The original CT data were uploaded to Mimics 21.0 software,and bilateral PICs were segmented from the axis to construct a new coordinate axes with multiplanar reconstruction(MPR)technology.The upper,middle and lower faults of the PIC were cut on the new axes,and the front-most,narrowest and back-most parts of the PIC were determined.The widths of the front-most,narrowest and,back-most parts and inclination angles of the upper,middle and lower faults of PIC were measured on 3D images.Based on whether the PIC was punctured or not,the patients implanted with posterior C2 pedicle screws were divided into punctured group and non-punctured group.Using the axis pedicle screw as reference,the image parameters of screw position were measured,including the height from the screw midpoint to the PIC upper wall,the width of the screw midpoint to the PIC inner wall,and the screw inclination angle.Results:There was no statistical difference between the left and right side of PIC parameters in 100 patients.The width of PIC in males was greater than that in females at all levels,and the difference was statistically significant(P＜0.05).The results of PIC width from a coronal perspective showed that the overall width of the upper layer was 9.6±1.3mm,the overall width of the middle layer was 9.5±1.4mm,and the overall width of the lower layer was 8.0±1.1mm.There was no statistical difference between the overall width of the upper layer and the middle layer(P=0.41),while the difference between the other layers was statistically significant(P＜0.05).The overall width of the PIC from the cross-sectional perspective showed that the overall width of the front-most part was 8.8±1.4mm,the overall width of the narrowest part was 7.2±1.3mm,and the overall width of the back-most part was 11.0±1.5mm,with statistical significance among all layers(P＜0.05).The results of PIC inclination showed that the upper layer inclination was 15.1°±8.7°,the middle layer inclination was 19.5°±8.4°,and the lower layer inclination was 26.3°±9.0°,and the differences among all layers were statistically significant(P＜0.05).In the 28 patients fixed with posterior C2 pedicle screw,a total of 50 screws were inserted,with 25 screws each in the punctured group and non-punctured group.The distances from the screw midpoint to PIC upper wall[4.4(3.6-5.3)mm]and PIC inner wall[3.3(2.8-3.8)mm]in the non-punctured group was smaller than those in the punctured group[5.1(4.5-6.0)mm and 4.0(3.1-5.4)mm,P＜0.05].No statistical differences was found between the two groups in the screw inclination angles[17.6°(10.5°-21.5°)vs 16.9°(9.6°-23.1°),P=0.854].Conclusions:The normal PIC without high riding vertebral artery is wide at top and narrow at bottom in the coronal view,and wide at front and back and thin in the middle in the transverse view.The gradual increase of the internal inclination angle from top to bottom indicates that the 3D structure of PIC is distorted.Analyzing the axis PIC as a whole is helpful to better understand its anatomical morphology and change characteristics,and to guide the selection of safe strategies in implanting axial pedicle screws.

Objective:To screen differentially expressed genes in the retinas of mice with experimental autoimmune uveitis (EAU) through transcriptome sequencing.Methods:Twenty 8-week-old SPF grade male C57BL/6J mice were randomly divided into EAU group and control group by random number table method, with 10 mice in each group.In the EAU group, an emulsion of interphotoreceptor retinoid-binding protein 1-20 and complete Freund adjuvant was injected subcutaneously into the inner side of the hind limbs and intravenously into the tail vein of the mice, and pertussis toxin was injected intraperitoneally to establish the EAU model.In the control group, mice were subcutaneously injected with the corresponding volume of phosphate buffer solution.On the 21st day after model establishment, the anterior segment inflammation of the mouse eyes was examined using a slit-lamp microscope.Retinal blood vessels were observed by fundus photography and clinical inflammation was scored.Hematoxylin-eosin staining was used to observe the morphological changes in the retinal tissues of the two groups.Retinal tissues were collected from two groups of mice.RNA was extracted and cDNA libraries were constructed for transcriptome sequencing.The clusterProfiler package in R programming language was used to screen for differentially expressed genes in EAU, and to conduct GO and KEGG enrichment analyses.The expression of core differentially expressed genes in the retinal tissues was then verified using real-time fluorescent quantitative PCR.The breeding and use of experimental animals were in compliance with the relevant regulations of the Animal Ethics Committee of Anhui Medical University.The study protocol was approved by the Ethics Committee of Anhui Medical University (No.LLSC20221208).Results:On the 21st day after model establishment, the clinical score of the EAU group was 2.83±0.94, significantly higher than 1.89±0.93 of the control group, and the difference was statistically significant ( t=2.290, P<0.05). The retinal blood vessels of mice in the EAU group showed tortuosity and dilation.Histopathological examination revealed a large number of inflammatory cell infiltrations in the retina, indicating successful establishment of the EAU mouse model.Transcriptome sequencing of the mouse retinal tissues identified a total of 32 473 genes, and 154 differentially expressed genes were screened out.Among them, 79 genes were up-regulated with Gm38574, Tmem81, Ptpn7 being top three and 75 genes were down-regulated with Gm19802, Fga, Cyp3a11 being top three.GO enrichment analysis showed that the differentially expressed genes were mostly related to immune response and cytokine action.KEGG pathway enrichment analysis showed that the differentially expressed genes were mainly enriched in the Toll-like pathway and cytokine signaling pathway.Compared with the control group, the relative expression levels of Gm38574, Tmem81, and Ptpn7 in the retinal tissues of the EAU group were up-regulated, while the expression levels of Gm19802, Fga, and Cyp3a11 were down-regulated, and the differences were statistically significant ( t=9.755, 5.358, 6.289, 4.312, 6.577, 6.118; all P<0.05). Conclusions:There are significant differences in the key genes Gm38574, Tmem81, Ptpn7, Gm19802, Fga, and Cyp3a11 in the retinal tissues of EAU mice, mainly corelated with the cytokine interaction pathway, Toll-like receptor signaling pathway.

Objective:To report the nationwide surveillance results of pathogenic profiles and antimicrobial resistance patterns of Gram-positive bloodstream infections in China in 2023.Methods:The clinical isolates of Gram-posttive bacteria from blood cultures were collected in member hospitals of National Bloodstream Infection Bacterial Resistant Investigation Collaborative System（BRICS）during January to December 2023. Antimicrobial susceptibility testing was performed using the dilution method recommended by the Clinical and Laboratory Standards Institute（CLSI）. Statistical analyses were conducted using WHONET 5.6 and SPSS 25.0 software.Results:A total of 4 385 Gram-positive bacterial isolates were obtained from 60 participating center. The top five pathogens were Staphylococcus aureus（ n=1 544，35.2%），coagulase-negative Staphylococci（ n=1 441，32.9%）， Enterococcus faecium（ n=574，13.1%）， Enterococcus faecalis（ n=385，8.8%），and α-hemolytic Streptococci（ n=187，4.3%）. The prevalence of methicillin-resistant Staphylococcus aureus（MRSA）and methicillin-resistant coagulase-negative Staphylococci（MRCNS）was 26.2%（405/1 544）and 69.8%（1 006/1 441），respectively. Notably，all Staphylococci remained susceptible to glycopeptide or daptomycin. Staphylococcus aureus demonstrated excellent susceptibility（>97.0%）to cephalobiol，rifampicin，trimethoprim-sulfamethoxazole，linezolid，minocycline，tigecycline，and eravacycline. No Enterococcus exhibiting resistance to linezolid were detected. Glycopeptide resistance was uncommon but more frequent in Enterococcus faecium（resistance to vancomycin and teicoplanin：both 1.7%）compared to Enterococcus faecalis（both 0.3%）. The detection rates of MRSA and MRCNS exhibited significant regional variations across the country（ χ2=17.674 and 148.650，respectively，both P<0.001）. No vancomycin-resistant Enterococci were detected in central China. Institutional comparison demonstrated higher prevalence of MRSA（ χ2=14.111， P<0.001）and MRCNS（ χ2=4.828， P=0.028）in provincial hospitals than that in municipal hospitals. Socioeconomic analysis identified elevated detection rates of both MRSA（ χ2=18.986， P<0.001）and MRCNS（ χ2=4.477， P=0.034）in less developed regions（per capita GDP

Objective:To report the results of bacterial resistant investigation collaborative system（BRICS）on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2023，and provide reference for clinical tretment of bloodstream infections and prevention and control of bacterial resistance.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of BRICS were collected during January 2023 to December 2023. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute（CLSI）. WHONET 5.6 and SPSS 25.0 were used to analyze the data.Results:During the study period，11 492 strains of Gram-negative bacteria were collected from 60 hospitals，of which 10 098（87.9%）were Enterobacterales and 1 394（12.1%）were non-fermentative bacteria. The top 5 bacterial species were Escherichia coli（50.0%）， Klebsiella pneumoniae（26.1%）， Pseudomonas aeruginosa（5.1%）， Acinetobacter baumannii complex（5.0%）and Enterobacter cloacae complex（4.1%）. The ESBL-producing rates in Escherichia coli， Klebsiella pneumoniae and Proteus mirablilis were 46.8%（2 685/5 741），18.3%（549/2 999）and 44.0%（77/175），respectively. The prevalence of carbapenem-resistant Escherichia coli（CREC）and carbapenem-resistant Klebsiella pneumoniae（CRKP）were 1.3%（76/5 741）and 15.0%（450/2 999）；32.9%（25/76）and 78.0%（351/450）of CREC and CRKP were sensitive to ceftazidime/avibactam combination，respectively. 94.7%（72/76）and 90.2%（406/450）of CREC and CRKP were sensitive to aztreonam/avibactam combination. Furthermore，57.9%（44/76）and 79.1%（356/450）were sensitive to imipenem/relebactam combination. The prevalence of carbapenem-resistant Acinetobacter baumannii（CRAB）complex was 64.6%（370/573），while more than 80.0% of CRAB complex was sensitive to tigecycline，eravacycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa（CRPA）was 17.0%（99/581）. There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of important Gram-negative bacteria resistance among different regions in China，with statistically significant differences in the prevalence of CREC，CRKP，CRPA and CRAB complex（ χ2=10.6，28.6，10.8 and 19.3， P<0.05）. The prevalence of ESBL-producing Escherichia coli， CREC，CRAB complex and CRKP were higher in provincial hospitals than those in municipal hospitals（ χ2=12.5，9.8，12.7 and 57.8，all P<0.01）. Conclusions:Gram-negative bacteria are the main pathogens causing bloodstream infections in China，and Escherichia coli is ranked in the top，while the trend of Klebsiella pneumoniae increases continuously with time. CRKP infection shows a slow upward trend，CREC infecton maintains a low prevalence level，and CRAB complex infection continues to exhibit a high prevalence rate. The composition and resistance patterns of pathogens causing bloodstream infections vary to some extent across different regions and levels of hospitals in China.

Objective:To evaluate the efficacy of lamb′s tripe extract and vitamin B 12 capsule (LTEVB 12C) on chronic atrophic gastritis (CAG) at different locations (antrum lesser curvature, antrum greater curvature, gastric angle, corpus lesser curvature, and corpus greater curvature). Methods:From August 2011 to January 2013, 715 patients with CAG in a multicenter, randomized, double-blind, placebo-controlled trial were enrolled from 16 tertiary first-class hospitals across the country, including the First Affiliated Hospital of Air Force Medical University, Nanfang Hospital of Southern Medical University, the First Hospital of Jilin University, West China Hospital of Sichuan University, etc., there were 476 cases in the LTEVB 12C group and 239 cases in the placebo group. The patients of the LTEVB 12C group received LTEVB 12C, and the patients of placebo group received LTEVB 12C mimetic, all the medications were taken 3 capsules each time and 3 times a day after meals, and the treatment course of 2 groups were both 6 months. The efficacy evaluation criteria included the effective rate (a decrease of ≥1 in histopathological score compared with baseline after 6 months of treatment) and the reversal rate (a decrease of ≥ 2 in histopathological score compared with baseline after 6 months of treatment in the patients with moderate to severe CAG). The impact of lesion sites on the therapeutic effects of LTEVB 12C was analyzed by logistic regression analysis. The two-way unordered Cochran-Mantel-Haenszel chi-square test considering the center effect and Pearson chi-square test were used for statistical analysis. Results:The effective rates of chronic inflammation at the antrum greater curvature and corpus greater curvature (23.3%, 110/473 vs. 13.0%, 31/239; 20.3%, 96/472 vs. 12.6%, 30/239), the effective rates of atrophy at the antrum lesser curvature, antrum greater curvature, gastric angle, corpus lesser curvature, and the corpus greater curvature (27.0%, 118/437 vs. 15.7%, 34/216; 29.2%, 126/432 vs. 18.5%, 38/205; 27.8%, 121/435 vs. 16.7%, 36/216; 32.5%, 127/391 vs. 19.8%, 37/187; 33.0%, 119/361 vs. 21.8%, 39/179), and the effective rates of intestinal metaplasia at the antrum lesser curvature, antrum greater curvature, gastric angle, and the corpus lesser curvature (45.0%, 112/249 vs. 29.8%, 31/104; 53.8%, 86/160 vs. 33.9%, 21/62; 45.8%, 103/225 vs. 24.0%, 25/104; 51.9%, 83/160 vs. 28.3%, 17/60) of the LTEVB 12C group were all higher than those of the placebo group, and the differences were statistically significant ( χ2=10.76, 6.39, 9.69, 7.91, 11.05, 9.62, 8.57, 5.20, 7.11, 12.45, and 6.73; all P<0.05). The reversal rates of chronic inflammation at the corpus lesser curvature and corpus greater curvature (5.2%, 12/231 vs. 0, 0/123; 4.7%, 8/170 vs. 0, 0/88), the reversal rates of atrophy at the antrum lesser curvature, antrum greater curvature, corpus lesser curvature, and the corpus greater curvature (6.8%, 22/323 vs. 1.3%, 2/151; 9.2%, 29/315 vs. 1.4%, 2/144; 14.2%, 38/267 vs. 2.5%, 3/121; 20.8%, 35/168 vs. 5.8%, 4/69), and the reversal rates of intestinal metaplasia at the antrum lesser curvature, antrum greater curvature, gastric angle, and the corpus lesser curvature (29.8%, 39/131 vs. 9.1%, 4/44; 41.0%, 32/78 vs. 12.5%, 3/24; 33.3%, 44/132 vs. 4.8%, 3/63; 50.0%, 37/74 vs. 8.7%, 2/23) of the LTEVB 12C group were all higher than those of the placebo group, and the differences were statistically significant ( χ2=6.58, 5.12, 5.60, 8.61, 11.43, 6.59, 7.30, 4.95, 15.92, 7.62; all P<0.05). There were no statistically significant differences in the effective rates and reversal rates of active inflammation at different locations between the LTEVB 12C group and the placebo group (all P>0.05). The results of logistic regression analysis (taking the antrum lesser curvature as the reference) further confirmed that the reversal rates of chronic inflammation ( OR=0.22, 95% confidence interval (95% CI): 0.07 to 0.67; OR=0.24, 95% CI: 0.07 to 0.80), atrophy ( OR=0.28, 95% CI: 0.16 to 0.49; OR=0.28, 95% CI: 0.16 to 0.49), and intestinal metaplasia ( OR=0.42, 95% CI: 0.24 to 0.77; OR=0.20, 95% CI: 0.08 to 0.52) at the corpus lesser curvature and corpus greater curvature were all higher than those at the antrum lesser curvature, and the differences were statistically significant (all P<0.05). There were no statistically siginificant differences in the reversal rates of the aforementioned pathological features between the antrum greater curvature, gastric angle, and the antrum lesser curvature (all P>0.05). Conclusion:LTEVB 12C can achieve good efficacy in the treatment of CAG, and the chronic inflammation, atrophy, and intestinal metaplasia at multiple locations are improved, especially at the corpus lesser curvature and the corpus greater curvature.

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.

For middle-aged and elderly patients with conditions such as spinal fractures and degenerative spinal diseases, spinal internal fixation is a core surgical procedure for reconstructing spinal stability, heavily relying on the biomechanical stability provided by pedicle screw systems. Whereas, these patients are often complicated by osteoporosis that can significantly compromise the stability of the bone-pedicle screw interface, leading to a marked increase in pedicle screw loosening and surgical failure rates. The bone cement-augmented pedicle screw technique, which involves injecting bone cement into the vertebral body or screw trajectory to optimize the mechanical properties of the bone-pedicle screw composite, has been proven to significantly enhance fixation strength and effectively prevent screw-related failures, thereby reducing the incidence of internal fixation failure in high-risk populations undergoing spinal fusion. However, the widespread clinical application of this technique has faced challenges such as inaccurate clinical decision-making (indication and contraindication selection), non-standardized operative practices, and insufficient awareness of complication prevention, resulting in considerable variability in clinical outcomes and even severe complications. To address this, Prof. Luo Fei from First Affiliated Hospital of Army Medical University initiated the project and the Chinese Association Orthopaedic Surgeons organized relevant experts to develop the Evidence-based clinical practice guideline for bone cement-augmented pedicle screw technique ( version 2025), based on current evidence. The guidelines put forward 8 recommendations regarding the clinical value, scope of application, and operational standards of the technique, aiming to provide evidence-based medical support and technical standardization for clinical decision-making.

Objective:To investigate the anatomical characteristics of the atlantoaxial joint associated with nonuniform settlement of the C 2 lateral mass (C 2LM-NUS) and its correlation with atlantoaxial osteoarthritis. Methods:A retrospective analysis was conducted on clinical and imaging data of 522 hospitalized patients (288 males, 234 females; mean age 60.8±11.2 years; range 18-83 years) who underwent CT scans of the head/neck or cervical spine at the Second Affiliated Hospital of Army Medical University between January 1, 2022 and December 31, 2022. Multiplanar reconstruction of CT data was performed to measure the settlement of the C 2 lateral mass (C 2LMS). Patients with a difference in bilateral C 2LMS (d-C 2LMS) >1.4 mm were classified into the C 2LM-NUS group (137 cases; 71 males, 66 females; mean age 63.3±11.6 years), while the normal group included 385 patients (217 males, 168 females; mean age 59.9±11.0 years). Imaging parameters of the atlantoaxial joint were measured, including the C 1, 2 coronal inclination angle (C 1, 2 CI), atlanto-dental interval (ADI), lateral atlanto-dental interval (LADI), coronal deviation angle of the odontoid (Od-CDA), and C 1, 2 relative rotation angle (C 1, 2 RRA). Osteoarthritis prevalence was recorded. A normal C 0-C 3 finite element (FE) model was constructed using CT data from a 48-year-old female in the normal group. A C 2LM-NUS FE model was developed based on anatomical differences between the C 2LM-NUS and normal groups, and stress distribution on the C 2 lateral mass articular surface was analyzed under flexion-extension, lateral bending, and axial rotation torques. Results:The C 2LM-NUS group exhibited asymmetric atlantoaxial joint morphology, with bilateral differences in C 1, 2CI and LADI of 8.5°(5.8°, 11.3°) and 0.8(0.1, 1.4) mm, respectively, significantly greater than those in the normal group [1.7°(0.8°, 2.7°) and 0.2(0.1, 0.5) mm, P<0.05]. Od-CDA and C 1, 2RRA were 3.9°(2.0°, 5.4°) and 7.2°(5.0°, 10.0°) in the C 2LM-NUS group, exceeding the normal group's values [0°(0°, 1.0°) and 0°(0°, 5.5°), P<0.05]. The prevalence of C 2LM-NUS was 37.8% in the atlantoaxial osteoarthritis group, significantly higher than in the non-osteoarthritis group (22.8%, P<0.05). Significant differences were observed in age (68.3±9.4 vs. 58.6±10.8 years), sex distribution (50/69 vs. 238/165), and C 1, 2RRA [5.6°(0°, 8.2°) vs. 3.8°(0°, 6.2°)] between the osteoarthritis and non-osteoarthritis groups ( P<0.05). After adjusting for age, sex, and C 1, 2RRA, binary logistic regression identified C 2LM-NUS as an independent risk factor for atlantoaxial osteoarthritis [ OR=2.024, 95% CI (1.300, 3.150), P<0.001]. FE analysis demonstrated a reduced C 1, 2 range of motion in the C 2LM-NUS model, with elevated stress concentrations on the settled side lateral mass during simulated flexion-extension, lateral bending, and rotation. Conclusions:The study indicated that C 2LM-NUS is associated with asymmetric anatomical changes in the atlantoaxial joint, increasing the risk of osteoarthritis. Stress concentration on the C 2 lateral mass articular surface, caused by C 2LM-NUS, is a biomechanical contributor to this heightened risk.