1.Predictive Modeling of Symptomatic Intracranial Hemorrhage Following Endovascular Thrombectomy: Insights From the Nationwide TREAT-AIS Registry
Jia-Hung CHEN ; I-Chang SU ; Yueh-Hsun LU ; Yi-Chen HSIEH ; Chih-Hao CHEN ; Chun-Jen LIN ; Yu-Wei CHEN ; Kuan-Hung LIN ; Pi-Shan SUNG ; Chih-Wei TANG ; Hai-Jui CHU ; Chuan-Hsiu FU ; Chao-Liang CHOU ; Cheng-Yu WEI ; Shang-Yih YAN ; Po-Lin CHEN ; Hsu-Ling YEH ; Sheng-Feng SUNG ; Hon-Man LIU ; Ching-Huang LIN ; Meng LEE ; Sung-Chun TANG ; I-Hui LEE ; Lung CHAN ; Li-Ming LIEN ; Hung-Yi CHIOU ; Jiunn-Tay LEE ; Jiann-Shing JENG ;
Journal of Stroke 2025;27(1):85-94
Background:
and Purpose Symptomatic intracranial hemorrhage (sICH) following endovascular thrombectomy (EVT) is a severe complication associated with adverse functional outcomes and increased mortality rates. Currently, a reliable predictive model for sICH risk after EVT is lacking.
Methods:
This study used data from patients aged ≥20 years who underwent EVT for anterior circulation stroke from the nationwide Taiwan Registry of Endovascular Thrombectomy for Acute Ischemic Stroke (TREAT-AIS). A predictive model including factors associated with an increased risk of sICH after EVT was developed to differentiate between patients with and without sICH. This model was compared existing predictive models using nationwide registry data to evaluate its relative performance.
Results:
Of the 2,507 identified patients, 158 developed sICH after EVT. Factors such as diastolic blood pressure, Alberta Stroke Program Early CT Score, platelet count, glucose level, collateral score, and successful reperfusion were associated with the risk of sICH after EVT. The TREAT-AIS score demonstrated acceptable predictive accuracy (area under the curve [AUC]=0.694), with higher scores being associated with an increased risk of sICH (odds ratio=2.01 per score increase, 95% confidence interval=1.64–2.45, P<0.001). The discriminatory capacity of the score was similar in patients with symptom onset beyond 6 hours (AUC=0.705). Compared to existing models, the TREAT-AIS score consistently exhibited superior predictive accuracy, although this difference was marginal.
Conclusions
The TREAT-AIS score outperformed existing models, and demonstrated an acceptable discriminatory capacity for distinguishing patients according to sICH risk levels. However, the differences between models were only marginal. Further research incorporating periprocedural and postprocedural factors is required to improve the predictive accuracy.
2.Mechanism of action of bile-gut axis in the development and progression of intrahepatic cholangiocarcinoma
Xue YU ; Tianhao SHEN ; Cheng ZHOU ; Yu LIU ; Wei LI ; Tinghui JIANG ; Yongqiang ZHU ; Yan LIU
Journal of Clinical Hepatology 2025;41(3):588-593
Intrahepatic cholangiocarcinoma is a malignant tumor with an extremely poor prognosis, and its pathogenesis is complex and remains unclear. In recent years, more and more studies have focused on the role of bile-gut axis in the development and progression of intrahepatic cholangiocarcinoma. Bile-gut axis refers to the complex interaction between bile and gut microbiota, including bile salt metabolism, dynamic changes of microbiota, inflammatory response, and immune system regulation. This article elaborates on the potential mechanisms of bile-gut axis in intrahepatic cholangiocarcinoma, especially gut microbiota dysbiosis, abnormal bile salt metabolism, chronic inflammatory response, and immune system interaction, this article aims to provide new perspectives and possible therapeutic targets for future research and promote the early diagnosis and effective treatment of intrahepatic cholangiocarcinoma.
3.Efficacy of Fufang Lingjiao Jiangya Pills with Different Proportions of Goat Horn Replacing Antelope Horn on Spontaneous Hypertensive Rats
Tengjian WANG ; Wanlu ZHAO ; Yang YU ; Yan LIU ; Kun CAO ; Zheyuan LIN ; Yue WU ; Lilan LUO ; Weizhi LAI ; Zhaohuan LOU ; Qiaoyan ZHANG ; Quanlong ZHANG ; Luping QIN
Chinese Journal of Experimental Traditional Medical Formulae 2025;31(9):68-78
ObjectiveTo investigate the optimal ratio of goat horn replacing antelope horn in Fufang Lingjiao Jiangya pills and the blood pressure-lowering mechanism of this medicine. MethodsThe blood pressure-lowering efficacy of Fufang Lingjiao Jiangya pills with varying proportions of goat horn replacing antelope horn was evaluated on spontaneous hypertensive rats (SHR). In this experiment, 50 SHR rats were randomly grouped as follows: model (n=8), captopril (0.01 g·kg-1) (n=6), low-dose blank Fufang Lingjiao Jiangya pills (0.342 g·kg-1) (n=6), high-dose blank Fufang Lingjiao Jiangya pills (0.684 g·kg-1) (n=6), low-dose antelope horn-containing Fufang Lingjiao Jiangya pills (0.378 g·kg-1) (n=6), high-dose antelope horn-containing Fufang Lingjiao Jiangya pills (0.756 g·kg-1) (n=6), low-dose goat horn-containing Fufang Lingjiao Jiangya pills (0.378 g·kg-1) (n=6), and high-dose goat horn-containing Fufang Lingjiao Jiangya pills (0.756 g·kg-1) (n=6). Additionally, 8 WKY rats were used as the normal group. Drugs were administered by gavage for 4 weeks while an equal volume of distilled water was administered for the normal and model groups. Blood pressure was measured before administration, 3 h post administration, and biweekly thereafter. In the experiment for Fufang Lingjiao Jiangya pills with goat horn replacing antelope horn in different proportions, 48 SHR rats were randomly grouped as follows: model, blank Fufang Lingjiao Jiangya pills (0.684 g·kg-1), antelope horn-containing Fufang Lingjiao Jiangya pills (0.756 g·kg-1), 2× goat horn-containing Fufang Lingjiao Jiangya pills (0.824 g·kg-1), 4× goat horn Fufang Lingjiao Jiangya pills (0.969 g·kg-1), and 6× goat horn Fufang Lingjiao Jiangya pills (1.112 g·kg-1). The normal group included 8 WKY rats, and the normal group and model group received an equal volume of distilled water. The treatment lasted for 2 weeks, and blood pressure was recorded at various time points (pre-administration, 3 h post administration, and on days 4, 7, 10, and 14 of administration). Serum levels of angiotensin-converting enzyme (ACE), angiotensin Ⅱ(Ang Ⅱ), renin, and interleukin-6 (IL-6) were measured by enzyme-linked immunosorbent assay. Histopathological changes in the heart, kidney, and thoracic aorta were observed by hematoxylin-eosin staining. The protein levels of ACE2, angiotensin Ⅱ type 1 receptor (AT1R), and angiotensinogen (AGT) in the kidney tissue were determined by Western blot, while the expression of nuclear factor (NF)-κB p65 and Toll-like receptor 4 (TLR4) in the thoracic aorta tissue was assessed by immunohistochemistry. ResultsCompared with the model group, all treatment groups showed lowered blood pressure (P<0.05, P<0.01), and the 6× goat horn-containing Fufang Lingjiao Jiangya pills group showed consistent blood pressure-lowering effect with the antelope horn-containing Fufang Lingjiao Jiangya pills group. Compared with the normal group, the model group showed elevated serum levels of ACE, Ang Ⅱ, renin, and IL-6, while the elevations were declined in the Fufang Lingjiao Jiangya pills groups (P<0.05, P<0.01). Pathological changes in the heart, kidney, and thoracic aorta were alleviated in all the treatment groups, with the 6× goat horn- and antelope horn-containing Fufang Lingjiao Jiangya pills groups exhibited the best effect. Western blot and immunohistochemistry results showed that all the treatment groups exhibited down-regulated protein levels of AT1R, AGT, NF-κB p65, and TLR4 and up-regulated protein levels of ACE2 (P<0.05, P<0.01) compared with model group, with the 6×goat horn- and antelope horn-containing Fufang Lingjiao Jiangya pills groups showcasing the best effect. ConclusionReplacing antelope horn with 6×goat horn in Fufang Lingjiao Jiangya pills can achieve consistent blood pressure-lowering effect with the original prescription. The prescription may exert the effect by inhibiting the renin-angiotensin-aldosterone system (RAAS) and TLR4/NF-κB signaling pathways.
4.Effect of intracellular and extracellular vesicles derived from periodontal ligament stem cells on the osteogenic differentiation ability of periodontal ligament stem cells under an inflammatory microenvironment
LIU Haotian ; YAN Fuhua ; WU Yu ; TONG Xin ; ZHANG Qian
Journal of Prevention and Treatment for Stomatological Diseases 2025;33(4):268-277
Objective:
To examine the effect of intracellular vesicles (IVs) and extracellular vesicles (EVs) that originated from periodontal ligament stem cells (PDLSCs) on the osteogenic differentiation of PDLSCs within a lipopolysaccharide (LPS)-simulated inflammatory microenvironment, and to provide new insights for the application of IVs in the repair and regeneration of periodontal tissue in periodontitis.
Methods:
Ethical approval was obtained from the institution. Human-origin PDLSCs were extracted, and the IVs and EVs from PDLSCs at the 3rd-6th passages were gathered and identified using transmission electron microscopy, nano flow cytometry (Nano FCM) analysis, and Western Blot. The 3rd-6th generations of PDLSCs were categorized into the following groups: Control group, LPS group, LPS + 100 μg/mL EVs group (LPS+EVs group), and LPS + 100 μg/mL IVs group (LPS+IVs group). The effects of the IVs and EVs on the anti-inflammatory and osteogenic differentiation of PDLSCs in an inflammatory microenvironment were assessed by using a Cell Counting Kit-8 (CCK-8), enzyme-linked immunosorbent assay (ELISA), quantitative real-time polymerase chain reaction (qRT-PCR), Western Blot, alkaline phosphatase (ALP) staining, and alizarin red staining (ARS).
Results:
Under transmission electron microscopy, the IVs and EVs derived from PDLSCs displayed a double-layer membrane structure. NanoFCM analysis revealed that the average diameters of the IVs and EVs were 79.6 nm and 82.1 nm, respectively. Western Blot analysis indicated that the surface proteins CD9, CD63, and CD81 of the IVs and EVs were positively expressed, while calnexin was negatively expressed, indicating that IVs and EVs were successfully obtained. Compared with the Control group, the proliferation of PDLSCs in the LPS group was reduced, while the levels of inflammatory cytokine interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in the cell supernatant were increased, the mRNA expressions of osteogenic differentiation-related genes, including osteoblast-related genes runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), osteocalcin (OCN) of PDLSCs were reduced, the protein expressions of RUNX2 and osteopontin (OPN) were also decreased (P<0.05); compared with the LPS group, the proliferation of PDLSCs in the LPS+EVs group and LPS+IVs group were significantly increased, while the levels of IL-6, TNF-α were significantly reduced, and the mRNA expressions of RUNX2, ALP, OCN were significantly increased, the protein expressions of RUNX2 and OPN were also significantly increased (P<0.05). Further, in the inflammatory microenvironment, Compared with EVs, IVs more significantly promote the proliferation of PDLSCs, inhibit TNF-α expression, enhance the expression of RUNX2 mRNA, upregulate the expression of RUNX2 and OPN proteins, increase ALP activity, and promote the formation of mineralized nodules (P<0.05).
Conclusion
IVs and EVs derived from PDLSCs can boost the proliferation of PDLSCs in an inflammatory microenvironment, inhibit the expression of inflammatory factors, and advance the osteogenic differentiation of PDLSCs. The anti-inflammatory and osteogenic effects of IVs are superior to those of EVs.
5.Effect of ultrasound-guided needle-knife release of the ligamentum flavum on the expression of integrin alpha5 and beta1 in degenerative rabbit lumbar intervertebral discs
Can CHEN ; Yu ZHAO ; Binhan HU ; Mengfan DU ; Junning LIU ; Susheng NIU ; Yan ZHANG
Chinese Journal of Tissue Engineering Research 2025;29(2):331-338
BACKGROUND:Needle-knife release of the ligamentum flavum can effectively improve symptoms in patients with lumbar degeneration,and ultrasound guidance can increase the precision of needle-knife release;however,the specific effects of needle-knife release of the ligamentum flavum on the degenerated intervertebral discs and the possible mechanisms remain to be clarified. OBJECTIVE:To investigate the effect of ultrasound-guided needle-knife release of the ligamentum flavum. METHODS:Twenty-four New Zealand rabbits were randomized into control(n=6)and model(n=18)groups.A rabbit model of lumbar disc degeneration model was established in the model group by cutting the supraspinous and interspinous ligaments of the L5/6 and L6/7 segments to maintain a standing posture and apply axial load to the lumbar spine.After successful modeling,the model rabbits were subdivided into a control group,a model group,an ultrasonic needle-knife group,and a sham needle-knife group according to a random number table method,with six animals in each group.The ultrasonic needle-knife group underwent ultrasound-guided needle-knife release of the right yellow ligament of L7/S1,once every week,for a total of four times.The needle-knife approach in the sham needle-knife group was the same as that in the ultrasound needle-knife group,but the ligamentum flavum was not released.At 30 days after the intervention,MRI was used to observe the changes in the signal intensity of the nucleus pulposus within the L7/S1 segment.Hematoxylin-eosin staining was used to observe the morphological changes of the L7/S1 segment.Immunohistochemical staining was used to detect the expression of type I and II collagen in the nucleus pulposus of the L7/S1 segment.RT-PCR and western blot were used to detect the expression of integrin α5 and β1,p38,and nuclear factor κB in the L7/S1 segment. RESULTS AND CONCLUSION:MRI findings indicated that the nucleus pulposus of the intervertebral disc of rabbits in the model group was gray-black in color,and the gray value of the nucleus pulposus was significantly lower than that of the control group(P<0.01).The brightness of the nucleus pulposus of the intervertebral disc of the rabbits in the ultrasonic needle-knife group was elevated compared with that of the model group,and the gray value of the nucleus pulposus was higher than that of the model group(P<0.01).Results from hematoxylin-eosin staining showed that in the model group,the shape of the nucleus pulposus was irregular,the number of nucleus pulposus cells was reduced,the extracellular matrix was compressed,the fibrous ring was ruptured,the structure and boundary of the end plate were unclear,and the chondrocytes were arranged disorderly.Compared with the model group,the ultrasonic needle-knife group showed an increase in the number of the nucleus pulposus,an improvement in the rupture of the fibrous ring,and more regular arrangement of cartilage endplate cells.Results from immunohistochemical staining showed an increase in positive expression of type I collagen(P<0.01)and a decrease in positive expression of type II collagen in the nucleus pulposus of the model group compared with the control group as well as a decrease in positive expression of type I collagen and an increase in positive expression of type II collagen in the nucleus pulposus of the ultrasonic needle-knife group compared with the model group(P<0.01).RT-PCR and western blot assays showed that the mRNA and protein expression of integrin α5,integrin β1,p38,and nuclear factor κB in the intervertebral discs of rabbits in the model group were increased compared with that in the control group(P<0.01);the mRNA and protein expression of integrin α5,integrin β1,p38,and nuclear factor κB in the intervertebral discs of rabbits in the ultrasonic needle-knife group was decreased compared with that in the model group(P<0.01).To conclude,ultrasound-guided needle-knife release of the ligamentum flavum can improve the degree of lumbar disc degeneration in rabbits,which may be related to the inhibition of p38 and nuclear factor-κB expression by modulating integrin α5 and β1 expression.
6.Palpitations, Shortness of Breath, Weakness in Limbs, Edema, and Dyspnea: A Rare Inflammatory Myopathy with Positive Aniti-mitochondrial Antibodies and Cardiac Involvement
Chunsu LIANG ; Xuchang ZHANG ; Ning ZHANG ; Lin KANG ; Xiaohong LIU ; Jiaqi YU ; Yingxian LIU ; Lin QIAO ; Yanli YANG ; Xiaoyi ZHAO ; Ruijie ZHAO ; Na NIU ; Xuelian YAN
Medical Journal of Peking Union Medical College Hospital 2025;16(1):248-255
This article presents a case study of a patient who visited the Geriatric Department of Peking Union Medical College Hospital due to "palpitations, shortness of breath for more than 2 years, limb weakness for 6 months, edema, and nocturnal dyspnea for 2 months". The patient exhibited decreased muscle strength in the limbs and involvement of swallowing and respiratory muscles, alongside complications of heart failure and various arrhythmias which were predominantly atrial. Laboratory tests revealed the presence of multiple autoantibodies and notably anti-mitochondrial antibodies. Following a comprehensive multidisciplinary evaluation, the patient was diagnosed with anti-mitochondrial antibody-associated inflammatory myopathy. Treatment involved a combination of glucocorticoids and immunosuppressants, along with resistance exercises for muscle strength and rehabilitation training for lung function, resulting in significant improvement of clinical symptoms. The case underscores the importance of collaborative multidisciplinary approaches in diagnosing and treating rare diseases in elderly patients, where careful consideration of clinical manifestations and subtle abnormal clinical data can lead to effective interventions.
7.Mid-long term follow-up reports on head and neck rhabdomyosarcoma in children
Chao DUAN ; Sidou HE ; Shengcai WANG ; Mei JIN ; Wen ZHAO ; Xisi WANG ; Zhikai LIU ; Tong YU ; Lejian HE ; Xiaoman WANG ; Chunying CUI ; Xin NI ; Yan SU
Chinese Journal of Pediatrics 2025;63(1):62-69
Objective:To analyze the clinical characteristics of children with head and neck rhabdomyosarcoma (RMS) and to summarize the mid-long term efficacy of Beijing Children′s Hospital Rhabdomyosarcoma 2006 (BCH-RMS-2006) regimen and China Children′s Cancer Group Rhabdomyosarcoma 2016 (CCCG-RMS-2016) regimen.Methods:A retrospective cohort study. Clinical data of 137 children with newly diagnosed head and neck RMS at Beijing Children′s Hospital, Capital Medical University from March 2013 to December 2021 were collected. Clinical characteristic of patients at disease onset and the therapeutic effects of patients treated with the BCH-RMS-2006 and CCCG-RMS-2016 regimens were compared. The treatments and outcomes of patients with recurrence were also summarized. Survival analysis was performed by Kaplan-Meier method, and Log-Rank test was used for comparison of survival rates between groups.Results:Among 137 patients, there were 80 males (58.4%) and 57 females (41.6%), the age of disease onset was 59 (34, 97) months. The primary site in the orbital, non-orbital non-parameningeal, and parameningeal area were 10 (7.3%), 47 (34.3%), and 80 (58.4%), respectively. Of all patients, 32 cases (23.4%) were treated with the BCH-RMS-2006 regimen and 105 (76.6%) cases were treated with the CCCG-RMS-2016 regimen. The follow-up time for the whole patients was 46 (20, 72) months, and the 5-year progression free survival (PFS) and overall survival (OS) rates for the whole children were (60.4±4.4)% and (69.3±4.0)%, respectively. The 5-year OS rate was higher in the CCCG-RMS-2016 group than in BCH-RMS-2006 group ((73.0±4.5)% vs. (56.6±4.4)%, χ2=4.57, P=0.029). For the parameningeal group, the 5-year OS rate was higher in the CCCG-RMS-2016 group (61 cases) than in BCH-RMS-2006 group (19 cases) ((57.3±7.6)% vs. (32.7±11.8)%, χ2=4.64, P=0.031). For the group with meningeal invasion risk factors, the 5-year OS rate was higher in the CCCG-RMS-2016 group (54 cases) than in BCH-RMS-2006 group (15 cases) ((57.7±7.7)% vs. (30.0±12.3)%, χ2=4.76, P=0.029). Among the 10 cases of orbital RMS, there was no recurrence. In the non-orbital non-parameningeal RMS group (47 cases), there were 13 (27.6%) recurrences, after re-treatment, 7 cases survived. In the parameningeal RMS group (80 cases), there were 40 (50.0%) recurrences, with only 7 cases surviving after re-treatment. Conclusions:The overall prognosis for patients with orbital and non-orbital non-parameningeal RMS is good. However, children with parameningeal RMS have a high recurrence rate, and the effectiveness of re-treatment after recurrence is poor. Compared with the BCH-RMS-2006 regimen, the CCCG-RMS-2016 regimen can improve the treatment efficacy of RMS in the meningeal region.
8.Comparison of multiple machine learning models for predicting the survival of recipients after lung transplantation
Lingzhi SHI ; Yaling LIU ; Haoji YAN ; Zengwei YU ; Senlin HOU ; Mingzhao LIU ; Hang YANG ; Bo WU ; Dong TIAN ; Jingyu CHEN
Organ Transplantation 2025;16(2):264-271
Objective To compare the performance and efficacy of prognostic models constructed by different machine learning algorithms in predicting the survival period of lung transplantation (LTx) recipients. Methods Data from 483 recipients who underwent LTx were retrospectively collected. All recipients were divided into a training set and a validation set at a ratio of 7:3. The 24 collected variables were screened based on variable importance (VIMP). Prognostic models were constructed using random survival forest (RSF) and extreme gradient boosting tree (XGBoost). The performance of the models was evaluated using the integrated area under the curve (iAUC) and time-dependent area under the curve (tAUC). Results There were no significant statistical differences in the variables between the training set and the validation set. The top 15 variables ranked by VIMP were used for modeling and the length of stay in the intensive care unit (ICU) was determined as the most important factor. Compared with the XGBoost model, the RSF model demonstrated better performance in predicting the survival period of recipients (iAUC 0.773 vs. 0.723). The RSF model also showed better performance in predicting the 6-month survival period (tAUC 6 months 0.884 vs. 0.809, P = 0.009) and 1-year survival period (tAUC 1 year 0.896 vs. 0.825, P = 0.013) of recipients. Based on the prediction cut-off values of the two algorithms, LTx recipients were divided into high-risk and low-risk groups. The survival analysis results of both models showed that the survival rate of recipients in the high-risk group was significantly lower than that in the low-risk group (P<0.001). Conclusions Compared with XGBoost, the machine learning prognostic model developed based on the RSF algorithm may preferably predict the survival period of LTx recipients.
9.Right ventricular-pulmonary artery connection for palliative treatment of pulmonary atresia with ventricular septal defect in children: A single-center retrospective study
Shuai ZHANG ; Jianrui MA ; Hailong QIU ; Xinjian YAN ; Wen XIE ; Qiushi REN ; Juemin YU ; Tianyu CHEN ; Yong ZHANG ; Xiaohua LI ; Furong LIU ; Shusheng WEN ; Jian ZHUANG ; Qiang GAO ; Jianzheng CEN
Chinese Journal of Clinical Thoracic and Cardiovascular Surgery 2025;32(03):366-371
Objective To compare the benefits and drawbacks of primary patch expansion versus pericardial tube right ventricular-pulmonary artery connection in patients diagnosed with pulmonary atresia with ventricular septal defect (PA/VSD). Methods A retrospective study was conducted on patients diagnosed with PA/VSD who underwent primary right ventricular-pulmonary artery connection surgery at our center between 2010 and 2020. Patients were categorized into two groups based on the type of right ventricular-pulmonary artery connection: a pericardial tube group and a patch expansion group. Clinical data and imaging findings were compared between the two groups. Results A total of 51 patients were included in the study, comprising 31 males and 20 females, with a median age of 12.57 (4.57, 49.67) months. The pericardial tube group included 19 patients with a median age of 17.17 (7.33, 49.67) months, while the patch expansion group consisted of 32 patients with a median age of 8.58 (3.57, 52.72) months. In both groups, the diameter of pulmonary artery, McGoon index, and Nakata index significantly increased after treatment (P<0.001). However, the pericardial tube group exhibited a longer extracorporeal circulation time (P<0.001). The reoperation rate was notably high, with 74.51% of patients requiring further surgical intervention, including 26 (81.25%) patients in the patch expansion group and 12 (63.16%) patients in the pericardial tube group. No statistical differences were observed in long-term cure rates or mortality between the two groups (P>0.005). Conclusion In patients with PA/VSD, both patch expansion and pericardial tube right ventricular-pulmonary artery connection serve as effective initial palliative treatment strategies that promote pulmonary vessel development and provide a favorable foundation for subsequent radical operations. However, compared to the pericardial tube approach, the patch expansion technique is simpler to perform and preserves some intrinsic potential for pulmonary artery development, making it the preferred procedure.
10.Biomechanical effects of postural and cognitive loads on trunk of workers performing assembly tasks at hand functional height
Huishuan WU ; Yu JIN ; Yan LIU ; Siyi ZENG ; Cunwen QIAN ; Kezhi JIN
Journal of Environmental and Occupational Medicine 2025;42(4):392-399
Background The neck, shoulders, and lower back are the primary affected areas of work-related musculoskeletal disorders. In manual tasks, combinations of hand functional height (defined as working height below the waist), awkward postures, and cognitive load are common risk factors. However, there is limited literature documenting how these factors specifically alter biomechanical load on the neck, shoulders, and lower back when working at hand functional height. Objective To explore quantitative differences in biomechanical load on the neck, shoulders, and lower back of workers performing manual tasks at hand functional height under different postures and cognitive load combinations. Methods A 3x2 within-subject design was implemented, with three postures (squat, kneeling, and stoop) and two levels of cognitive load (with cognitive load induced by a 2back task and without cognitive load). Ten male university students were recruited to perform a predetermined assembly task (a sequence of loosening and tightening screws) at hand functional height. Surface electromyography (sEMG) and 3D motion capture system were employed to assess the participants’ trunk biomechanical load in executing the tasks. Additionally, subjective perception, including fatigue, muscle pain, and cognitive load, were evaluated using scales. Results Significant variations in biomechanical load were observed across the three postures (P<0.05). The stoop posture exhibited the lowest muscle activation in most target muscles, except for the sternocleidomastoid, and showed the fastest decline in instantaneous median frequency (IMF) of the erector spinae, with a rate of (-0.050±0.008) Hz per unit time (0.128 s), and the greatest trunk flexion angle (35.14°±4.40°). Performing the task by squatting resulted in the highest muscle activation, especially in the upper trapezius, where maximum voluntary contraction percentage reached 20.07%±1.26%. In addition, the squatting posture also resulted in larger joint angles in the sagittal plane for the neck (−7.03°±2.70°), shoulders (60.20°±7.89°), and lower back (34.42°±4.20°). The kneeling posture showed intermediate muscle activation, the slowest IMF decline for the erector spinae in the lower back (−0.005±0.008) Hz per unit time (0.128s), and the joint angles were closest to neutral. The task performance results were also superior in the kneeling posture. Regarding cognitive load, no significant differences were found for most biomechanical indicators, except for subjective cognitive load scores, neck flexion, and shoulder external rotation angles. Conclusion In assembly tasks performed at hand functional height, kneeling results in moderate biomechanical load on the neck, shoulders, and lower back while also improves task performance compared to squatting and forward bending. Additionally, no significant effects of cognitive load under the 2back condition on biomechanical load are observed.


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