Study on influencing factors of work-related musculoskeletal disorders in neck-shoulder-back of manufacturing workers / 中国职业医学

{L-End}Objective To investigate the influencing factors of work-related musculoskeletal disorders (WMSDs) that affect neck-shoulder-back among manufacturing workers. {L-End}Methods A total of 8 250 front-line workers from 27 manufacturing enterprises in Henan Province and Hubei Province were selected as the research subjects using cluster sampling method. The Musculoskeletal Disorders Questionnaire was used to investigate the prevalence of neck-shoulder-back (include neck, shoulder, upper back, and lower back) WMSDs in the past year. The log-binomial model, principal component analysis (PCA) and multivariate logistic regression analysis were used to analyze the influencing factors of WMSDs in the neck-shoulder-back. {L-End}Results The prevalence of WMSDs was 77.2%. The prevalence of neck-shoulder-back WMSDs was 50.9%. The prevalence ratios of WMSDs were relatively higher among the neck, shoulder, and upper back (all P<0.05). The results of PCA improved logistic regression analysis showed that the influencing factors of neck-shoulder-back WMSDs were individual factors, biomechanical factors, psychosocial factors and environmental factors. In terms of individual factors, the risk of neck-shoulder-back WMSDs was higher in females than in males (P<0.05). With the increase of age, length of service, and education level, the risk of neck-shoulder-back WMSDs increased among manufacturing workers (all P<0.05). The risk of neck-shoulder-back WMSDs of workers in textile, clothing, shoes and hats manufacturing industry was relatively lower than that in the other nine industries (all P<0.05). In terms of the biomechanical factors, spending a lot of effort to operate tools/machines, sitting for a long time at work,bending greatly bending and turning at the same time, neck leaning forward or maintaining this posture for a long time, neck twisting or maintaining this posture for a long time and uncomfortable position resulting in difficulty exerting exertion were all risk factors of neck-shoulder-back WMSDs among manufacturing workers (all P<0.05) Bending slightly for a long time was a protective factor for neck-shoulder-back WMSDs among manufacturing workers (P<0.05). In terms of the psychosocial factors, doing the same work every day, self-determination in resting time between works staff shortage, and frequent overtime work were risk factors for neck-shoulder-back WMSDs among manufacturing workers (all P<0.05). Adequate resting time was a protective factor for neck-shoulder-back WMSDs among manufacturing workers (P<0.01). In terms of environmental factors, working under cold or fluctuating temperature, having nothings to lean on, and soles slipping or falling at work were all risk factors for neck-shoulder-back WMSDs among manufacturing workers (all P<0.05). {L-End}Conclusion Manufacturing workers are prone to suffer from neck-shoulder-back WMSDs. The influencing factors include individual factors, biomechanical factors (force load and static load), psychosocial factors and environmental factors.

Correlation between Adolescent Scoliosis and Biomechanical Factors / 中国康复理论与实践

Objective To study the relationship between adolescent scoliosis and various biomechanical factors. Methods A total of 637 students in grade four to six in a primary school of Zhaoyang District in Zhaotong,Yunnan,Chi-na were screened for scoliosis in December,2016.Finally,a case control study of 19 patients with idiopathic sco-liosis who had been diagnosed by X-ray was carried out.According to the matching criteria,42 students were col-lected as control group.Then,eleven biomechanical factors were analyzed and evaluated in two groups.Those factors included unequal shoulders,cervical lateral flexion,cervical rotation,thoracic lateral flexion,thoracic ro-tation,lumbar lateral flexion,lumbar rotation,lateral tilt of pelvis,anterior and posterior pelvic tilt,leg inequality and flat foot. Eventually, the biomechanical factors were statistically analyzed with binary Logistic regression analysis. Results and Conclusion The unequal shoulders,thoracic rotation,lateral tilt of pelvis,leg inequality and flat foot were the risk factors for scoliosis(P<0.05).Detailed posture assessment should be carried out to find the biomechani-cal factors leading to abnormal posture,and achieve the goals of the more targeted medical intervention for the patients with spinal asymmetry.

The Effect of Corneal Biomechanical Factors on Ocular Pulse Amplitude in Normal Subjects

PURPOSE: To investigate the influence of corneal biomechanical factors on ocular pulse amplitude measured using dynamic contour tonometry in normal subjects. METHODS: The study population consisted of normal subjects who visited the outpatient clinic from January, 2014 to July, 2014. Ocular pulse amplitude was measured using dynamic contour tonometry and corneal hysteresis (CH) and corneal resistance factor (CRF) were measured using an ocular response analyzer. We applied univariate and multivariate linear regressions to investigate the relationship between ocular pulse amplitude and corneal biomechanical factors and other ocular factors. RESULTS: Fifty eyes of 50 patients (average age 52.8 +/- 17.2 years) were examined. The average ocular pulse amplitude was 2.90 +/- 1.04 mm Hg and the CH and CRF were 10.44 +/- 1.96 mm Hg and 11.03 +/- 2.21 mm Hg, respectively. In univariate linear regression, factors influencing ocular pulse amplitude were ocular pressure based on CRF (beta = 0.280, p = 0.049), Goldmann applanation tonometry (beta = 0.293, p = 0.039), and spherical equivalent (beta = 0.283, p = 0.047), while in multivariate linear regression the only factor influencing ocular pulse amplitude was CRF (beta = 0.686, p = 0.042). CONCLUSIONS: A positive correlation between ocular pulse amplitude reflecting ocular perfusion pressure and CRF reflecting corneal elasticity was observed. Correlations between the 2 factors will be an important aspect in future studies regarding the influences of corneal biomechanical factors on ocular perfusion pressure in glaucoma patients.

Biomechanical Factors Associated with Plantar Fasciitis in Non-obese Patients / 대한스포츠의학회지

The purpose of this study was to identify the biomechanical factors that correlate with plantar fasciitis in non-obese patients whose body mass index were below 25 kg/m2. The subjects were non-obese patients who were diagnosed as plantar fasciitis by clinical appearance, physical examination, and ultrasonographic findings (n=48), and non-obese control persons without clinical diagnosis of plantar fasciitis (n=30). The two groups were compared on fat pad thickness, ankle dorsiflexion range of motion (ROM), resting calcaneal stance position (RCSP), incidence of calcaneal spur, and calcaneal pitch. The results showed that, there were statistically significant differences between two groups in ankle dorsiflexion ROM, RCSP, and calcaneal pitch (p<0.05). Multiple logistic regression analysis showed ankle dorsiflexion ROM and RCSP strongly correlated with presence of plantar fasciitis as independent predictors (p<0.05). In conclusion, reduced ankle dorsiflexion ROM and negative RCSP (valgus tendency in rear foot) may be the biomechanical factors associated with plantar fasciitis in non-obese patients.

Differences in Biomechanical Factors for Fusion Transition Syndrome of Lumbar Spine between Pedicle Screw Fixation and Posterior Lumbar Interbody Fusion Groups

OBJECTIVE: We present the investigation of the biomechanical factors of the degeneration process after lumbar fusion. METHODS: Thirty-five patients underwent L4-5 fusion operation. We measured radius(cm), top angle(TA)(degree), and flexion-extension angle(FEA) at L3-4 joint in pedicle screw fixation(PSF)(n=27) and posterior lumbar interbody fusion(PLIF)(n=8)groups. They were divided into early(3 to 6 months) and late(over 1 year) groups according to post-operative period. RESULTS: The pre-operative radius, TA and FEA in PSF were 6.2+/-0.4, 9.0+/-0.8, and 8.2+/-0.8. The early and late post-operative radius, TA and FEA in PSF were 6.4+/-0.5, 6.9+/-0.8, 6.8+/-0.8, and 5.5+/-0.7, 12.1+/-0.9, 11.0+/-0.9, respectively. The pre-operative radius, TA and FEA in PLIF were 5.4+/-0.5, 8.9+/-0.8, and 9.5+/-1.2. The early and late post-operative Radius, TA and FEA in PLIF were 5.0+/-0.4, 5.8+/-0.9, 5.2+/-0.7, and 5.0+/-0.5, 8.4+/-0.9, 7.6+/-0.8, respectively. In late PSF, TA and FEA were significantly increased(p<0.05)but radius was significantly decreased (p<0.05) compared with pre-operative ones. But in late PLIF, all the factors were decreased compared with pre-operative ones. CONCLUSION: Biomechanical factors of chronic complications were different between PSF and PLIF. Increased FEA seems to be an important factor for post-operative degeneration in PSF, whereas increased stiffness and stress seems more important in PLIF.