Longitudinal effects of sexual minority stigma on depressive symptoms among young men who have sex with men: Distinguish between and within person effects.

BACKGROUND: Young men who have sex with men (YMSM) may experience high levels of sexual minority stigma (SMS) and depressive symptoms (DS) over the world and in China. However, there is a lack of studies investigating the longitudinal effects of SMS on DS of YMSM, especially focusing on YMSM and separating the between-person and within-person effects. This study aimed to fill the said gaps. METHODS: Study data were derived from a prospective cohort of 349 YMSM from central China (Wuhan, Changsha, Nanchang), the baseline survey was started in 2017 with one follow-up visit every year. SMS and DS were measured three times using valid and reliable instruments. The cross-lagged panel model (CLPM) and the random intercept CLPM (RI-CLPM) were used to examine the between-person and within-person concurrent and lagged effects, respectively. RESULTS: Findings of CLPM revealed bidirectional associations between SMS and DS over time. RI-CLPM suggested that at the between-person level, SMS was significantly associated with DS, echoing the results of CLPM. However, this reciprocal relationship has not been found at the within-person level. CONCLUSION: The associations between SMS and DS among YMSM at the population level is more significant than that at the individual level. We suggest that interventions should be against the adverse effects of cultural marginalization and systemic change the social concepts to reduce the amount of SMS in society.

Design, synthesis and neuroprotective biological evaluation of novel HDAC6 inhibitors incorporating benzothiadiazinyl systems as cap groups.

Histone deacetylase 6 (HDAC6), as the key regulatory enzyme, plays an important role in the development of the nervous system. More and more studies indicate that HDAC6 has become a promising therapeutic target for CNS diseases. Herein we designed and synthesized a series of novel HDAC6 inhibitors with benzothiadiazinyl systems as cap groups and evaluated their activity in vitro and in vivo. Among them, compound 3 exhibited superior selective inhibitory activity against HDAC6 (IC50 = 5.1 nM, about 30-fold selectivity over HDAC1). The results of docking showed that compound 3 can interact well with the key amino acid residues of HDAC6. Compound 3 showed lower cytotoxicity (20 µM to SH-SY5Y cells, inhibition rate = 25.75%) and better neuroprotective activity against L-glutamate-induced SH-SY5Y cell injury model in vitro. Meanwhile, compound 3 exhibited weak cardiotoxicity (10 µM hERG inhibition rate = 17.35%) and possess good druggability properties. Especially, compound 3 could significantly reduce cerebral infarction from 49.87% to 32.18%, and similar with butylphthalide in MCAO model, indicating potential clinical application prospects for alleviating ischemic stroke-induced brain infarction.

Xuanfei Formula inhibited RSV infection by normalizing the SREBP2-mediated cholesterol synthesis process.

Background and aims: Respiratory syncytial virus (RSV) is the major cause of lower respiratory tract infections in children and the elderly, often progressing to pneumonia and severe sequelae. However, there are currently no feasible and cost-effective interventions with proven efficacy for children, making medications with anti-RSV activity urgently needed. Traditional Chinese medicine has shown promising therapeutic efficacy in alleviating viral infection symptoms. Therefore, we aimed to develop effective strategies for RSV treatment based on traditional Chinese medicine. Methods and results: The infection status was assessed in BALB/c mice with or without Xuanfei Formula (XFF) treatment over a one-week period using H&E staining, cytokine assays and RSV titer testing after RSV challenge. Remarkably, on the first day of XFF intervention, both the pro-inflammation cytokine levels in the serum and RSV-N gene copies in the lung of mice were plummeted, compared to the RSV-infected group. This implied that XFF might possess the immune-independent anti-RSV capability. To elucidate the underlying mechanism, we employed transcriptome analysis followed by k-means analysis. The reversal effects of XFF against RSV primarily focused on the processes of innate and adaptive immunity. Additionally, we found that XFF administration corrected the disordered fatty acid and cholesterol metabolism processes during RSV infection. Lipidomics profiling indicated consistent cholesterol abundance with transcriptional changes but not fatty acids. Cholesterol synthesis-related genes mRNA levels and cholesterol synthesis intermediates detection supported XFF's repression upon cholesterol biosynthesis. Aberrantly increased cholesterol production has been reported as necessary for RSV infection. To mimic that, we observed lovastatin treatment inhibited RSV replication and pro-inflammation cytokine expression in vitro. Transcription factor prediction of differentially expressed genes (DEGs) involved in cholesterol synthesis implicated SREBP2. Through network pharmacology, stigmasterol and ß-sitosterol were identified as the effective active ingredients within the XFF, with the help of further molecular docking and mass spectrum detection. In vitro experiments demonstrated ß-sitosterol and stigmasterol reinforced the bonding between SREBP cleavage-activation protein (SCAP) and insulin-induced gene proteins (INSIGs) to inhibit SREBP2 cleavage maturation and consequent RSV infection. Conclusion: Xuanfei Formula (XFF) exhibits excellent anti-RSV efficacy by inhibiting SREBP2-mediated cholesterol synthesis to reduce RSV replication and ameliorate inflammation in the lung of infected mice.

Effects of COVID-19 infection risk perception on depressive symptoms among pregnant women in different periods of the COVID-19 pandemic in China: A mediation model.

OBJECTIVE: The study investigated the mediation mechanisms between coronavirus disease 2019 (COVID-19) infection risk perception and depressive symptoms among pregnant women during the different periods of the COVID-19 pandemic. METHODS: Study data were derived from a sample of 463 pregnant women in Hubei Province, the province with the most severe COVID-19 outbreak in China. Data were collected in two phases (during and after the acute phase of the COVID-19 pandemic) using the COVID-19 infection risk perception scales, the Edinburg Postnatal Depression Scale (EPDS), the Perceived Stress Scale (PSS), and the Peritrauma Distress Inventory (PDI). Mediation model analysis was used for data analysis, overall and by groups. RESULTS: The level of depressive symptoms among pregnant women after the acute phase of the COVID-19 pandemic was moderate (median, 9.00 [25th percentile, 75th percentile = 5.00, 12.00]), higher than the acute group (median, 7.00 [25th percentile, 75th percentile = 4.50, 10.00]). Perceived stress and traumatic stress fully mediated the relationship between infection worry (total indirect effect, 0.39 [95% confidence interval, 0.24-0.54])/infection possibility (total indirect effect, 0.41 [95% confidence interval, 0.22-0.61]) and depressive symptoms among pregnant women during the acute phase of the COVID-19 pandemic, whereas the relationship was only fully mediated by perceived stress after the acute pandemic. CONCLUSIONS: Effects of risk perception on depressive symptoms varied by periods of COVID-19. These findings have important implications for developing effective prevention and early psychoeducational intervention strategies for pregnant women with a high risk of depressive symptoms during different periods of emerging infectious diseases.

Tenascin-C-EGFR activation induces functional human satellite cell proliferation and promotes wound-healing of skeletal muscles via oleanic acid.

Human satellite cells (HuSCs) have been deemed to be the potential cure to treat muscular atrophy diseases such as Duchenne muscular dystrophy. However, the clinical trials of HuSCs were restricted to the inadequacy of donors because of that freshly isolated HuSCs quickly lost the Pax7 expression and myogenesis capacity in vivo after a few days of culture. Here we found that oleanic acid, a kind of triterpenoid endowed with diverse biological functions with treatment potential, could efficiently promote HuSCs proliferation. The HuSCs cultured in the medium supplement with oleanic acid could maintain a high expression level of Pax7 and retain the ability to differentiate into myotubes as well as facilitate muscle regeneration in injured muscles of recipient mice. We further revealed that Tenascin-C acts as the core mechanism to activate the EGFR signaling pathway followed by HuSCs proliferation. Taken together, our data provide an efficient method to expand functional HuSCs and a novel mechanism that controls HuSCs proliferation, which sheds light on the HuSCs-based therapy to treat muscle diseases.

Relationship between adverse childhood experiences, depression and suicidal behaviors in adulthood among young men who have sex with men: A prospective cohort study.

BACKGROUND: Suicidal behaviors have been a crucial public health issue among young men who have sex with men (YMSM). Adverse childhood experiences (ACEs) and depression are important predictors of suicidal behaviors. Few studies have examined the underlying mechanisms. This study aims to examine the mediation mechanism from ACEs to depression and further to suicidal ideation based on a prospective cohort study of YMSM. METHOD: Study data were derived from 499 YMSM recruited from three cities (Wuhan, Changsha and Nanchang) of China from September in 2017 to January in 2018. ACEs (abuse, neglect and household challenges), depressive symptoms and suicidal behaviors (suicidal ideation, suicidal plan and suicidal attempt) were measured at the baseline, the first wave and second wave follow-up survey, respectively. Mediation modeling analysis was used for data analysis only for suicidal ideation due to the low frequency of suicidal plan and attempt. RESULTS: An estimated 17.86% of YMSM reported suicidal ideation, 2.27% ever made a suicidal plan and 0.65% of YMSM had a suicidal attempt in the past six months. The effect of ACEs on suicidal ideation was fully mediated through depressive symptoms (indirect effect [95%CI] = 0.011 [0.004,0.022]). Among the three subconstructs of ACEs, childhood abuse and neglect could increase the risk of suicidal ideation in adulthood by increasing depressive symptoms (indirect effect = 0.020 [0.007,0.042] for childhood abuse, and 0.043 [0.018,0.083] for neglect), but not for household challenges (indirect effect = 0.003 [-0.011,0.018]). CONCLUSIONS: ACEs could affect suicidal ideation through depression, particularly for childhood abuse and neglect. Preventive strategies may focus on the treatment of depression and psychological counseling, especially for YMSM who ever experienced negative experiences in childhood.

Global pattern and determinants of coronavirus disease 2019 (COVID-19) vaccine coverage and progression: a global ecological study.

Background: Understanding and minimizing existing global coronavirus disease 2019 (COVID-19) vaccination disparities is critical to global population health and eliminating health inequities. The study aims to investigate the disparities of vaccination coverage and progression and the associated economic and educational determinants to inform global COVID-19 vaccination strategies. Methods: COVID-19 vaccination coverage data from 206 countries used in the study were derived from "Our World in Data" website. After obtaining the vaccination coverage indicators, we fitted the progression indicators for vaccination. Correlation and multiple linear regression analysis were used to examine the effects of gross domestic product (GDP) per capita, Gini index, education, and their interactions on the coverage and progression of the COVID-19 vaccination. Results: The coverage of COVID-19 vaccination ranged from less than 30 doses to more than 150 doses per hundred people, from less than 15% to more than 75% for proportion of people vaccinated, from less than 15% to more than 60% for proportion of people fully vaccinated. Similarly, the progression of vaccination ranged from less than 0.1 to more than 0.6 for progression of total number of doses, from less than 0.1 to more than 0.3 for progression of proportion of people vaccinated, and from less than 0.1 to more than 0.4 for progression of proportion of people fully vaccinated. GDP per capita and education were positively associated with the coverage and progression, while Gini index was negatively associated with the coverage and progression. Negative interaction between GDP per capita and education was also observed for coverage (ß = -0.012 to -0.011, P < 0.05) and progression (ß = -0.012 to -0.011, P < 0.05). Conclusions: Substantial geographic disparities existed for the coverage and progression of COVID-19 vaccination. Economy and education are two important factors contributing to the disparities. Different countries may adopt varied strategies to promote the national distribution and vaccination of COVID-19 vaccines.

Experimental and numerical analysis of biomechanical effects in cervical spine positioning rotation manipulation.

Unlocking the biomechanical effects of cervical spine positioning rotation manipulation in the treatment of patients with neck pain. In this paper, the safety of the cervical positioning rotation manipulation is analyzed by experimentally obtaining head kinematic data, importing them into a finite element model that has been developed and validated, and calculating and analyzing the angular displacements, disc pressures, and articular surface contact forces in the normal and pathological models. The results show that the cervical spine positioning rotation technique is more effective in adjusting the position and applying force to the cervical spine C5-C6 "tendon out of the groove and bone misalignment" pathological model. Also, the cervical positioning rotation manipulation is applied with less variation in disc nucleus pulposus pressure than in the non-positioning situation. Thus, in patients with disc degeneration, cervical positioning rotational manipulation has a more direct mechanical effect and is safer than non-positioning rotational manipulation. The cervical spine positioning rotation manipulation is a safe method that can effectively treat patients with neck pain. It has been well demonstrated in the computational analysis of the pathological model.

Study on the efficacy and safety of the combination of Shi's manual therapy and percutaneous endoscopic lumbar diskectomy for lumbar disc herniation with radiculopathy: study protocol for a multicenter randomized controlled trial.

BACKGROUND: Lumbar disc herniation (LDH) is a common chronic musculoskeletal disorder that seriously affects quality of life. The percutaneous endoscopic lumbar diskectomy (PELD) technique was developed to address spinal nerve root compression through direct visualization of pathological findings while minimizing tissue destruction upon exposure. It is an effective and safe treatment for LDH. However, recurrent LDH is a major concern after lumbar discectomy for primary LDH. A considerable number of clinical studies have reported that patients with LDH with radiculopathy could benefit from manual therapy. Shi's manual therapy (SMT) was established based on traditional Chinese medicine (TCM) theory and has been shown to have a superior effect in alleviating muscle tension and loosening joints to improve lumbar and leg pain, radiculopathy, stiffness, activity discomfort, and related disorders. However, there is a lack of high-quality clinical evidence to support this conclusion. The purpose of this study is to evaluate the efficacy and safety of the combination of Shi's manual therapy (SMT) and PELD for LDH with radiculopathy. METHODS/DESIGN: A multicenter randomized controlled trial (RCT) with a 1-year follow-up period will be performed. A total of 510 participants with LDH with radiculopathy will be recruited from four clinical centers. The sample size was estimated, and statistical analysis will be performed and supervised by biostatisticians from an independent third-party research institution. Two hundred fifty-five subjects will be randomly allocated to each group. The subjects in the control group will undergo PELD. Participants in the intervention group will be treated with a combination of SMT and PELD. Recurrence rate is the primary endpoint and the survival analysis of recurrence rate is the secondary endpoint, and the primary analysis of recurrence rate is the chi-square test and the secondary analysis of recurrence rate is survival analysis. The primary outcome measure is the recurrence rate of LDH with radiculopathy at the 1-year follow-up after treatment. The secondary outcome measures will be the ODI score, the VAS score for pain for the lumbar spine and lower limbs, the straight leg raise angle, the stability of the operated lumbar segment, and the SF-36 scores. Assessments will occur at baseline, postoperation, and 1 week, 4 weeks, 13 weeks, 26 weeks, and 1 year postoperation. In addition, adverse events related to clinical symptoms and signs and the results of laboratory tests will be documented during the clinical trials. DISCUSSION: This study will provide reliable evidence of the effectiveness and safety of the combination of SMT and PELD for LDH with radiculopathy. If the results are favorable, it is expected that patients with LDH with radiculopathy will benefit from this study, and many patients could gain a good alternative treatment for LDH with radiculopathy. TRIAL REGISTRATION: China Registered Clinical Trial Registration Center ChiCTR2000036515 . Registered on 13 November 2020.

[Manual therapy combined with posterior percutaneous endoscopic cervical decompression for the treatment of cervical spondylotic radiculopathy].

OBJECTIVE: To explore the clinical efficacy and safety of manual therapy combined with posterior percutaneous endoscopic cervical decompression(PECD) in the treatment of intractable cervical spondylotic radiculopathy. METHODS: From May 2016 to May 2018, 23 CSR patients who responded poorly to conservative treatment for at least 6 weeks underwent the combination management. Firstly, the patients received the posterior percutaneous endoscopic cervical decompression routine care for the following 4 weeks and manual therapy for another 4 weeks. A total of 23 patients were followed up, including 14 males and 9 females, the age ranged from 29 to 78 years old with an average of (50.30±12.28) years, the course of disease was 3 to 24 months with an average of (9.74±5.76) months. The lesion segment involved C4,5 in 4 cases, C5,6 in 13 cases, C6,7 in 6 cases. The visual analogue scale (VAS), neck disability index (NDI), changes of cervical physiological curvature and interbody stability, adverse events were observed before and after operation. The follow-up time points were before operation, 1 day after operation and 1, 3 and 6 months after operation. RESULTS: All patients successfully completed the operation and manual treatment for 4 to 8 times. Among the 29 cases, 23 patients were followed up for more than 6 months. There was no spinal cord and nerve root injury during the treatment and follow-up. Operation time was from 80 to 120 min with a median of 90 min;intraoperative blood loss was from 35 to 80 ml with a median of 50 ml. NDI, VAS of neck, shoulder and arm each period after operation were significantly lower than those before PECD(P<0.05), while there were no significant improvement in cervical physiological curvature and target segment intervertebral space height(P>0.05);there was no significant change in interbody stability (P>0.05). After received the manual therapy, NDI significantly decreased (P<0.05), however, there was no significant difference in VAS of neck, shoulder and arm, physiological curvature of cervical spine and intervertebral space height of target segment compared with that before manual treatment (P>0.05);there was no significant change in interbody stability (P>0.05). CONCLUSION: Manual therapy combined with PECD in the treatment of intractable cervical spondylotic radiculopathy can not only quickly improve the symptoms, but also alleviate the residual symptoms after PECD safely and effectively, and can not cause obvious signs of accelerated instability of cervical adjacent segments in the short term.

Posterior cervical full-endoscopic technique for the treatment of cervical spondylotic radiculopathy with foraminal bony stenosis: A retrospective study.

Objective: In the treatment of cervical spondylotic radiculopathy (CSR), spinal endoscopy has been developed vigorously in the past 30 years. However, its effectiveness and subsequent problem of cervical spine stability have always been the controversial hotspots. This study aims to conduct a retrospective study using posterior cervical full-endoscopic technique for the treatment of CSR with foraminal bony stenosis, and evaluate its clinical effect and application value. Methods: All 22 patients treated for CSR with foraminal bony stenosis using posterior cervical full-endoscopic technique were analyzed since Dec 1, 2016, to Apr 30, 2020. The data collection included operation time, length of stay, wound healing, surgical complications, visual analog scale (VAS), Japanese Orthopaedic Association (JOA) scores, intervertebral foramen diameter, intervertebral foramen area and cervical instability. The relevant indicators were observed on admission, at postoperative 1 week and 3 months, and at the last follow-up. Results: The operation time was 141.6 ± 13.7 min. The length of stay was 6.0 ± 2.5 days. VAS and JOA at different time points after operation were decreased compared with before operation (p < 0.05). There were no statistical differences between VAS or JOA at different postoperative time points (p > 0.05). The height, anteroposterior diameter and area of intervertebral foramen after operation were significantly increased compared with before operation (p < 0.05). Conclusion: Posterior cervical full-endoscopic technique shows the advantages of smaller invasion, faster recovery, significant effectiveness and fewer complications in our study. Meanwhile, it has little influence on the ROM and stability of the cervical spine. Therefore, it is a minimally invasive, safe and effective surgical method for the treatment of CSR with foraminal bony stenosis.

Identification of Key Gene Signatures Associated With Bone Metastasis in Castration-Resistant Prostate Cancer Using Co-Expression Analysis.

About 80-90% of castration-resistant prostate cancer (CRPC) patients would develop bone metastasis. However, the molecular mechanisms of bone metastasis are still not clear. This study aimed to detect the differences between the tumor and normal samples in bone after metastatic colonization. Four transcriptional datasets (GSE32269, GSE101607, GSE29650, and GSE74685) were obtained from the GEO database. 1983 differentially expressed genes (DEGs) were first identified between tumor and normal marrow samples in GSE32269. Most of the top 10 up-regulated DEGs are related with prostate cancer, and the top 10 down-regulated DEGs are mainly related with bone development. Seven co-expression modules were then detected based on the 1469 DEGs shared by the four datasets. Three of them were found highly preserved among the four datasets. Enrichment analysis showed that the three modules were respectively enriched in Cell adhesion molecules (CAMs), Leukocyte transendothelial migration and cell cycle, which might play significantly important roles in the tumor development in bone marrow. Ten, 17, and 99 hub genes for each module were then identified. And four genes (C3AR1, IL10RA, LY86, and MS4A6A) were detect to be tightly related to progression of bone metastatic CRPC. ROC curve was plotted and AUC was calculated to distinguish tumor and normal bone marrow samples as well as bone and non-bone metastatic CRPCs. The present study identified key genes and modules involved in bone metastatic CRPCs, which may provide new insights and biomarkers for understanding of the molecular mechanisms of bone metastatic CRPC.

Shi's Daoyin Therapy for Neck Pain: A Randomized Controlled Trial.

OBJECTIVE: To compare the immediate and short term effectiveness of Shi's Daoyin therapy (DT) rather than the Melbourne Protocol (MP) in terms of pain, mobility, and isometric strength of cervical muscles in nonacute nonspecific neck pain patients. MATERIAL AND METHODS: A total of 114 nonacute nonspecific neck pain patients aged 20~50 years were recruited and randomly assigned to be treated by either Shi's DT or the MP. 56 cases and 54 cases received treatment for 3 weeks and were evaluated before and after intervention and at 3-week follow-up in Shi's DT group and MP group, respectively. The outcome measures were Chinese version of the Neck Disability Index (NDI), cervical range of motion (ROM), maximal voluntary isometric force (MVIF), and pain intensity (Numeric Pain Rating Scale, NPRS). RESULTS: All outcomes of both groups showed statistically significant improvements after the intervention and at 3-week follow-up (P < 0.05), while no statistically significant difference was found in NDI between groups. When followed up after 3 weeks, the ROM in axial rotation was significantly greater in the Shi's DT group (P < 0.05), and the NPRS in the Shi's DT group was significantly lower than the MP group (P < 0.05). At the end of the treatment period, the MVIF in lateral bending in the Shi's DT group had a lower value (P = 0.044) than in the MP group, but there was no significant difference in flexion and extension between the two groups. CONCLUSIONS: Both Shi's DT and MP groups demonstrated an obvious reduction in pain intensity and improvements in neck mobility after a short term follow-up period. The improvement of Shi's DT in disability and pain during functional activities is generally similar to that of the MP for the treatment of nonacute nonspecific neck pain.

The Influence of Natural Head Position on the Cervical Sagittal Alignment

Introduction: This study investigated the relationship between the parameters related to the natural head position and cervical segmental angles and alignment of patients with neck pain. Material and Methods: The lateral radiographs of the cervical spine were collected from 103 patients and were used to retrospectively analyze the correlation between the natural head position, cervical local sagittal angles, and alignment. Sagittal measurements were as follows: cervical curvature classification, slope of McGregor's line (McGS), local sagittal angles (C0­C2 angle, C2­C5 angle, C5­C7 angle, and C2­C7 angle), T1 slope, center of gravity of the head to sagittal vertical axis (CG­C7 SVA), and local sagittal alignment (C0­C2 SVA and C2­C7 SVA). Results: McGS was significantly correlated to C0­C2 angle (r = 0.57), C0­C2 SVA (r = −0.53), C2­C7 SVA (r = −0.28), and CG­C7 SVA (r = −0.47). CG­C7 SVA was also significantly correlated to curvature type (r = 0.27), C5­C7 angle (r = −0.37), and C2­C7 angle (r = −0.39). Conclusions: A backward shift with an extended head position may accompany a relatively normal curvature of the cervical spine. The effect of posture control in relieving abnormal mechanical state of the cervical spine needs to be further confirmed by biomechanical analysis.

The Influence of Natural Head Position on the Cervical Sagittal Alignment.

INTRODUCTION: This study investigated the relationship between the parameters related to the natural head position and cervical segmental angles and alignment of patients with neck pain. MATERIAL AND METHODS: The lateral radiographs of the cervical spine were collected from 103 patients and were used to retrospectively analyze the correlation between the natural head position, cervical local sagittal angles, and alignment. Sagittal measurements were as follows: cervical curvature classification, slope of McGregor's line (McGS), local sagittal angles (C0-C2 angle, C2-C5 angle, C5-C7 angle, and C2-C7 angle), T1 slope, center of gravity of the head to sagittal vertical axis (CG-C7 SVA), and local sagittal alignment (C0-C2 SVA and C2-C7 SVA). RESULTS: McGS was significantly correlated to C0-C2 angle (r = 0.57), C0-C2 SVA (r = -0.53), C2-C7 SVA (r = -0.28), and CG-C7 SVA (r = -0.47). CG-C7 SVA was also significantly correlated to curvature type (r = 0.27), C5-C7 angle (r = -0.37), and C2-C7 angle (r = -0.39). CONCLUSIONS: A backward shift with an extended head position may accompany a relatively normal curvature of the cervical spine. The effect of posture control in relieving abnormal mechanical state of the cervical spine needs to be further confirmed by biomechanical analysis.

A finite element study of traditional Chinese cervical manipulation.

PURPOSE: Traditional Chinese cervical manipulation (TCCM) has been claimed as an effective treatment for diseases of the cervical spine, but its biomechanical effects on the vertebral body and intervertebral discs remain unclear. The aim of this study was to develop and validate a detailed finite element model of cervical spine, which was then used to investigate the biomechanical response of the cervical spine to TCCM. METHODS: The model of a C2-T1 cervical spine was constructed based on CT images of a healthy male volunteer and validated against published in vitro studies under different loading conditions. The detailed force-time data of TCCM were measured on the same volunteer through dynamometric diaphragms. The data were applied on the validated finite element model to simulate TCCM. RESULTS: The current model could offer potentials to effectively reflect the behavior of human cervical spine suitable for biomechanics studies of TCCM. Under simulated TCCM condition, the stress distributions in cervical spine and intervertebral discs could not be completely explained through the traditional theory. CONCLUSION: Spinal manipulation, or TCCM, might play no role in reducing intradiscal pressure for treating cervical spondylosis. It could cause less stress concentration in intervertebral discs while operating spinal manipulation or TCCM when the adjustment points was chosen near the root of spinous process than the top of spinous process.

Influence of variations in stiffness of cervical ligaments on C5-C6 segment.

The ligaments of the cervical spine each play a critical role in maintaining stability. Large variations in the mechanical behavior of each ligament have been reported, but it remains unclear how these variations influence cervical biomechanics. The objective of this study was to investigate the mechanical response of the cervical spine to variations in the properties of each cervical ligament. A finite element model of the C5-C6 spine was constructed with the average material properties. The stiffness of each ligament was then changed in turn by increasing or decreasing it per its designated maximum or minimum stiffness. The range of motion (ROM) and intradiscal pressure (IDP) were calculated and compared among the different models under pure moments. The results showed that the capsular ligament with the greatest stiffness caused a lower ROM in all anatomical planes. Varying the stiffness of the anterior longitudinal ligament had the greatest influence on ROM in extension, while the interspinous ligament was the most influential in flexion. During lateral bending or axial rotation, the capsular ligament with the minimum stiffness resulted in a higher IDP, while the capsular ligament with the maximum stiffness resulted in a lower IDP. Varying the capsular ligament stiffness had the greatest role on the C5-C6 ROM and therefore care must be taken to assign appropriate material properties. This study showed a less influence on the intervertebral disc with smaller ROM, especially when the ligaments were relaxed. This suggested that the control of the neck posture may be beneficial for patients with a degenerated cervical spine.

Cervical traction therapy with and without neck support: A finite element analysis.

BACKGROUND: Cervical traction is commonly used for treating neck pain. However, few studies have investigated the biomechanical impact such traction has on soft tissues. OBJECTIVES: To analyze the biomechanics of cervical traction therapy in a supine position with and without neck support (NS and non-NS). METHODS: A finite element model of the cervical spine was constructed to investigate the mechanism behind cervical traction therapy. An axial traction force of 100-N was loaded on the upper surface of C0 to simulate traction weight. Neck support traction was simulated by additionally constraining anterior-posterior motion of the surface of the C4 vertebral lamina. The average von Mises stress, tensile force and motions of related tissues were calculated and compared between the two conditions. Stress in the posterior annulus fibers under flexion was also recorded for comparison. RESULTS: At the C4-C5 and C5-C6 levels, NS traction resulted in less of a decrease in the lordotic angle. At these levels, the highest average stress was distributed in the posterior annulus fibers with non-NS traction and both traction therapies produced greater stress on the posterior annulus fibers than physical flexion. The intradiscal pressure in all intervertebral discs between C4-T1 decreased during both traction therapies. CONCLUSION: Neck support traction therapy produced less tension on the posterior annulus fibers and ligaments posterior to it at the C4-C5 and C5-C6 levels. In order to minimize the potential harm to soft tissue in clinical practice, it may be beneficial to use a neck support according to the targeted level.

[Correlation analysis between position of head, cervical curvature classification and balance of cervical spine through lateral plain radiograph measurement].

OBJECTIVE: To analyze the relationship between position of head, cervical curvature type and associated cervical balance parameters in a neutral looking-forward posture. METHODS: Cervical lateral X-rays of 60 patients with cervical spondylosis were selected from January to December 2015. There were 22 males and 38 females with an average age of (35.5±10.9) years old. The measured parameters included cervical curvature type, McGregor slope, C2 lower end plate slope, T1 slope, center of gravity to C7 sagittal vertical offset (CG-C7 SVA), and C2 to C7 sagittal vertical offset (C2-C7 SVA). The parameters were analyzed using Spearman correlation. RESULTS: The cervical curvature type was significantly correlated with C2 lower endplate slope, C0-C2 angle (total degree of C2 lower endplate slope plus McGregor slope), CG-C7 SVA and T1 slope (P<0.05), but it was not significantly correlated McGregor slope (P>0.05). C2 lower endplate slope and C2-C7 SVA (r=0.87) were significantly (P<0.05) correlated with CG-C7 SVA (P<0.05). CONCLUSIONS: There was certain some relationship among position of head, cervical curvature type and associated cervical balance parameters in a neutral looking-forward posture. The center of gravity of the head would backwards shift following faced upward. A position of extension with posterior-shifting of the head would suggest that it may be accompanied with a relatively normal lordosis of the cervical spine. Some patients with abnormal curvature showed slightly bended head in the natural posture. Health education toward these people would be meaningful to restore the balance of their neck.

[Application of mechanical measurement in assessment of neck pain and manual therapy].

Manual therapy is one of the effective methods in treating neck pain. It has certain advantages in the short term to ease the symptoms of neck pain. In recent years, using different mechanical sensors and imaging equipment with computer software, the researchers found the difference of cervical activity between health adult and patients with neck pain. They also analyzed the kinematics, magnitude of force, stress and strain of the related structure and other mechanical parameters during cervical manipulation. These biomechanical researches revealed the functional anomaly caused by neck pain, reflect the safety of cervical manipulation, explain the abnormal stress of neck pain and the adjusting role of manipulation. Relatively speaking, these studies are too basic, and their analysis also are limited for the stress and strain about internal tissue. Study to aim directly at above problems will have important significance in understanding neck pain and standardizing manipulation therapy.