On the quantitative relationships between individual/occupational risk factors and low back pain prevalence using nonparametric approaches

A week-long field study of seated pelvis and lumbar spine kinematics during office work

The study objective was to quantify "natural" seated pelvis and lumbar spine kinematics over multiple days of work at individuals' workstations. Twenty participants completed five days of their usual office work while seated time was characterized from a thigh-worn activity monitor. Seated pelvic tilt and lumbar spine flexion-extension were measured from tri-axial accelerometers. Seated time accounted for approximately 90% of participants' workdays. Sitting was characterized by posterior pelvic tilt and lumbar flexion (43-79% of maximum flexion) with an average of 9 shifts and 13 fidgets every 15 min. No significant differences emerged by sex or between days indicating that a single representative day can capture baseline sitting responses in the field. Average field kinematics tended to agree with the laboratory-collected kinematics, but postural variability was larger in the field. These kinematic values could be useful for designing interventions aimed at reducing spine flexion and increasing spine movement in occupational sitting.

Traditional versus dynamic sitting: Lumbar spine kinematics and pain during computer work and activity guided tasks

Dynamic sitting may mitigate low back pain during prolonged seated work. The current study compared pelvis and lumbar spine kinematics, pain, and work productivity, in traditional and dynamic sitting. Sixteen participants completed three 20-min blocks of computer work and activity guided tasks in a traditional office chair or backless and multiaxial rotating seat pan while kinematics were measured from accelerometers on the low back. Pain ratings were recorded on a visual analogue scale every 10 min. Similar pelvis and lumbar kinematics emerged when performing computer work in traditional and dynamic sitting. Pelvis and lumbar sagittal and frontal plane shifts and fidgets were largest for dynamic sitting in the activity guided tasks. Buttocks pain was higher in dynamic sitting, but low back pain and work productivity were unaffected. Dynamic sitting increased spine movement during activity guided tasks, without negatively impacting lumbar kinematics, low back pain, or productivity during seated computer work.

Moving Toward Individual-Specific Automotive Seat Design: How Individual Characteristics and Time Alter the Selected Lumbar Support Prominence

OBJECTIVE

To explore how individual characteristics influence selected lumbar support prominence (LSP), seated lumbar flexion, seatback average pressure, contact area, and center of pressure (CoP) location before and after 1 hr of driving.

BACKGROUND

An LSP can alter posture and may reduce low back pain during prolonged driving. Although LSP preference varies across individuals and may change over time, few investigations have explored the time-varying response to individually selected adjustable seat parameters.

METHOD

Forty individuals selected LSP settings in an automotive seat through a series of systematic adjustment trials. The average LSP setting was fixed for a 1-hr driving simulation, followed by one final adjustment trial. Regressions were performed between individual characteristics and selected LSP, lumbar posture, and measures of seatback pressure from the initial adjustment trials. ANOVAs were performed to determine the effect of time and sex on these dependent variables. Discomfort was also monitored throughout the protocol.

RESULTS

Individual's standing lumbar lordosis, selected LSP, and height and mass were significant predictors for seated lumbar flexion, seatback average pressure, and contact area, respectively. Discomfort levels remained low; however, following the driving protocol, individuals altered their posture to decrease lumbar flexion and increase seatback average pressure without significant adjustments to the LSP.

CONCLUSION

These findings highlight individual characteristics to consider in automotive seat design and that the method for determining LSP settings may facilitate appropriate LSP selection.

APPLICATION

A systematic method to determine LSP settings may reduce discomfort and automate seat adjustments, such that only short-term postural adjustments may be required.

Defining the lumbar and trunk-thigh neutral zone from the passive stiffness curve: application to hybrid sit-stand postures and chair design

Minimal data exist on the neutral position for the lumbar spine, trunk, and thighs when adopting a hybrid posture. This study examined sex differences in the neutral zone lumbar stiffness and the lumbar and trunk-thigh angle boundaries of the neutral zone, and determined if the standing lumbar angle fell within the neutral zone. Passive lumbar flexion and extension moment-angle curves were generated for 31 participants (13 M, 18 F), pooled from two datasets, with trunk-thigh angles available for 10 participants. The neutral zone was defined as the low stiffness zone from both the flexion and extension curves. Males demonstrated significantly greater extensor stiffness. Neutral lumbar and trunk-thigh angles ranged on average -22.2 to 0.2° and 124.2 to 159.6° for males and -17.8 to -1.3° and 143.2 to 159.5° for females, respectively. Standing lumbar angles fell outside the neutral zone for 44% of participants. These neutral zone boundaries may inform kinematics for hybrid chair designs.Practitioner summary: Adoption of a neutral spinal posture may be achieved through hybrid chair design, yet minimal data exists on a physiologically defined neutral zone. Using measures of in vivo lumbar stiffness, the lumbar and trunk-thigh angular boundaries of the neutral zone were defined for both males and females.Abbreviations: EMG: electromyography; MVC: maximal voluntary contraction.

Does sitting on a stability ball increase fall risk during ergonomic reaching tasks?

Although sitting on a stability ball has become an alternative to using an office chair, little is known about the increased potential for a fall on the deformable seat. This study examined differences in stability between sitting on a seat pan of a backless office chair and a stability ball during reaching tasks. Sixteen participants performed forward and lateral reaching tasks on a backless and armless office chair and stability ball while whole-body motion and force data under the seat were recorded. Even with participants placing their feet 16.5 cm wider when seated on the ball, the perceived fall risk was significantly greater. Centre of pressure displacement tended to be smaller under the ball for lateral reach directions, but larger during far anterior reaches. While not statistically significant, the medial-lateral margin of stability was on average 3.4 cm smaller on the ball. Despite attempts to increase stability by widening their stance, stability ball fall risk remained higher.

Is it possible to discriminate workers with a higher prevalence of low back pain considering daily exposure time in a work-related lumbar posture? A diagnostic accuracy study

The study aimed to develop and validate a cut-off for daily postures to discriminate workers with low back pain. The self-reported episode of low back pain in the last year and during the previous week and the total spent time in occupational postures of 529 workers were used to screen workers who more likely would report low back pain. The receiver operating characteristics curve verified the ability of daily time in each posture in discriminating workers with low back pain in a training sample. Then, the chi-squared test and measurements of the diagnostic accuracy were performed in the testing sample. The daily time spent in a given posture was not able to accurately discriminate against workers with low back pain. Total time spent walking was the only daily posture that discriminated workers with low back pain in the last year in the testing sample, albeit with low accuracy. Practitioner Summary: The daily time spent in a given posture was not able to accurately distinguish workers with low back pain. Total spent time in walking presented modest diagnostic accuracy and should be interpreted cautiously. The spent time in a particular posture did not detect workers with LBP in the last week.

The relationship between low back pain and the basic lumbar posture at work: a retrospective cross-sectional study

PURPOSE

This study aimed to analyze the relationship between work-related lumbar posture (sitting, standing, walking, alternating posture) and LBP in workers.

METHODS

This is a retrospective study comprising 529 records of adult workers from a database of a private company. Predominant work-related lumbar posture was classified based on time spent in each posture. A total of 22 personal, occupational, clinical, and psychosocial covariates were evaluated. LBP symptoms in the last 12 months and during the last 7 days were the outcomes of the study. The multivariate analysis model evaluated the independent relationship between the work-related lumbar posture classification and other potential exposure factors with LBP.

RESULTS

The adjusted logistic regression model indicated that predominant walking reduced the likelihood to report LBP during the last 12 months when compared to standing (OR = 0.54; 95% CI 0.30, 0.99; p = 0.048), but there is no association between work-related postures and recent LBP. The adjusted analyses also revealed an association between LBP during the last 12 months and female sex, blue-collar task, frequently feeling tiredness, pain at any other body region previous 12 months, previous LBP, and monotonous work. Recent LBP was associated with female sex, pain at any other body region last 7 days, and previous LBP.

CONCLUSIONS

Standing posture increases the likelihood to report LBP during the last 12 months when compared to walking. LBP over previous year and during the previous 7 days was associated with personal and clinical factors.

When driving hurts: characterizing the experience and impact of driving with back pain

OBJECTIVES

Driving is one of the most widespread aspects of daily living to people in the United States and is an active process that requires various cognitive functions, such as attention. Chronic low back pain (CLBP) is one of the more prevalent and costly health conditions in the world, with individuals who report CLBP also reporting significant impairment across different domains of daily life both physically and cognitively. However, despite the prevalence of these two constructs, research detailing the experience of driving in pain remains largely underrepresented. This cross-sectional study sought to characterize the driving experience of people who experience CLBP, focusing on the psychological constructs related to chronic pain like pain catastrophizing, affective responses (irritability, anxiety, fear), and self-reported driving behaviors and outcomes.

METHODS

This study distributed an online questionnaire measuring pain, disability, and other psychological constructs commonly associated with CLBP like pain catastrophizing through M-turk to 307 U.S. participants with recurring CLBP and regular driving activity. Participants also answered questions regarding driving in pain, affective responses to driving in pain (i.e., irritability, anxiety, and fear), driving behaviors and violations, driving avoidance habits as a result of pain, opioid use, using pain medication while driving, and recent vehicle collisions within the past three years. Bivariate correlations were used to compare study variables, and one-way ANOVA's were used to compare means between participants with and without a collision history within the past three years.

RESULTS

Findings demonstrated significant positive associations not only between the psychological factors commonly associated with chronic pain, such as pain intensity, pain disability, pain catastrophizing, and the cognitive intrusion by pain, but also statistically significant relationships between these measures and pain intensity while driving, affective responses to driving in pain, driving violations, and driving avoidance habits. Additionally, in comparison to participants with no collision history within the past three years, participants who had been driving during a vehicle collision reported greater pain catastrophizing and cognitive intrusion by pain scores.

CONCLUSIONS

To our knowledge, the current study is the first to characterize driving experience specifically among individuals with CLBP, with attention to the relationship among key sensory, affective, and cognitive psychological metrics as well as self-reported driving history and behavior. The current findings reinforce multiple associations between pain and cognitive-affective variables that have been observed in literature outside the driving context, including pain intensity, anger, inattention, and behavioral disruption. Given that driving is a pervasive, potentially risky behavior that requires some form of cognitive focus and control, the current findings point to a continued need to examine these associations within this specific life context. We believe we have laid a groundwork for research considering the role of psychological pain variables in a driving performance. However, the nature of our analyses prevents any sort of causality from being inferred, and that future experimental research is warranted to better understand and explain these mechanisms underlying driving in pain while accounting for participant bias and subject interpretation.

A kinematic posture analysis of neurological assistants in their daily working practice-a pilot study

Background

The aim of this pilot study was to analyze postures during the work of neurologists with respect to their occupational activities.

Methods

A total data material of 64.8 h (3885.74 min) of nine (three m/six f) neurologists (assistant physicians) was collected. Kinematic data were collected using the CUELA system (electro-goniometry). In addition, the occupational tasks performed on-site were subject to a detailed objective activity analysis. All activities were assigned to the categories “Office activities” (I), “Measures on patients” (II) and “Other activities” (III). The angle values of each body region (evaluation parameters) were evaluated according to ergonomic ISO standards.

Results

Only 3.4% of the working hours were spent with (II), while 50.8% of time was spent with (I) and 45.8% with (III). All tasks of category (II) revealed an increased ergonomic risk to the head, neck, trunk and back areas. During category (I) especially neck and back movements in the sagittal plane showed higher ergonomic risk levels.

Conclusion

Despite frequently performed awkward body positions in (II), the ergonomic risk is considered as rather low, since the percentage time share totaled only 3.4%. As a result, “Office activities” have been detected as high predictor to cause stress load on the musculoskeletal system in the daily work of neurologists.

Partitioning the total seatback reaction force amongst the lumbar spine motion segments during simulated rear-impact collisions

Purpose. This study aimed to determine how the seatback force is distributed across lumbar spine motion segments during a simulated low-velocity rear-impact collision with and without the application of mechanical lumbar support. Methods. A ferroresistive pressure-sensing system was used during simulated rear-impact collisions (ΔV = 7.66 km/h). Total seatback reaction force was derived from pressure recordings as the product of calibrated pressure outputs and sensel areas. The three-dimensional position of the pressure mat and the lumbar spinous processes were tracked and then used to extract the seatback force that was applied to the lumbar motion segments. Results. On average, 77% (637 N) and 53% (430 N) of the total seatback force was applied directly to the lumbar spine with and without lumbar support, respectively (p < 0.001). In addition to four of five individual motion segments bearing a greater force with lumbar support (p < 0.029), the distribution of the total lumbar force was found to be significantly different between support type conditions. Conclusions. Although lumbar supports can alter the magnitude and distribution of shear force applied to the lumbar spine during low-velocity rear-impact collisions, they do not appear to elevate the injury risk.

Prevalence and factors associated with low back pain among Malaysian army personnel stationed in Klang Valley

Study aim: The aims of this study were to examine the prevalence of low back pain (LBP) and explore possible factors associ­ated with LBP among Malaysian army personnel deployed in Klang Valley in the year 2018. Material and methods: A self-administered questionnaire on sociodemographic data, occupational background, occupational exposure and LBP evaluation was used in this study. A total of 330 respondents participated in this study and 321 (97%) of them completed and returned the questionnaires. Results: One hundred and fifty-seven respondents complained of LBP, giving a prevalence of 48.9%. LBP was found to be associated with smoking status, history of LBP, history of accident, military rank, category of regiment, lifting weights, push­ing weights, pulling weights and job-related physical activity. Logistic regression analysis identified four associated risk fac­tors of LBP: history of accident (OR = 4.42, 95% 2.29-8.55), history of LBP (OR=1.92, 95% 1.11-3.31), combat regiment (OR = 1.97, 95% 1.14-3.42) and high job-related physical activity (OR = 2.35, 95% 1.31-4.20). Conclusion: Almost half of Malaysian army personnel stationed in Klang Valley reported LBP symptoms. Smoking status, history of LBP, history of accident, junior non-commissioned officers (NCOs), combat regiments, manual handling of objects and moderate/high job-related physical activity are associated with LBP, but there is no evidence of a temporal relationship in the current study. Further exploration with a longitudinal study is needed to identify a cause and effect relationship between occupational exposure and LBP among Malaysian army personnel.

Low back pain and disability in military police: an epidemiological study

Abstract Introduction: The low back pain is a major public health problem in industrialized societies, commonly affecting the adult population. The occupation is considered as a risk factor, especially those functions that require physical effort, we have as example the job of the military police, who are exposed to several risk factors, both those who perform administrative activities, and those who perform the ostensive policing. Objective: The aim of this study was to evaluate the prevalence of low back pain among military police, as well the presence of disability and associated factors. Methods: This is an analytical cross-sectional study. Was evaluated the level of disability, pain before and after the work shift, flexibility, postural alterations and anthropometric measures. It was used the regression analysis, considering 95% CI and p < 0.05. Were interviewed 97 military police with mean age of 39.30 (± 5.33), all males. Results: The complaint of low back pain was significantly larger after the work shift, and 82.5% reported difficulties in daily life activities due to low back pain. Conclusion: There is a high prevalence of low back pain and impairment in daily life activities because of military police. The data presented reinforce the need to consider low back pain as a public health problem that affects the whole population, especially the military police.

Ultrasonographic Evaluation of the Effect of Osteopathic Manipulative Treatment on Sacral Base Asymmetry

Context

Patients with low back pain (LBP) may receive osteopathic manipulative treatment (OMT) to resolve or manage their pain. The indication for OMT for patients with LBP is the presence of somatic dysfunction, diagnosed using palpatory examination. Because palpatory findings commonly have poor interexaminer reliability, the current study used ultrasonography (US) to establish pre-OMT and post-OMT musculoskeletal measurements of relative asymmetry between pelvic and sacral bony landmarks.

Objective

To document objective musculoskeletal changes that occur in response to OMT using US and to compare palpatory assessment of landmark asymmetry with US assessment.

Methods

Sixty men and women aged 20 to 55 years with at least 1 episode of LBP in the past 2 weeks were assigned to a seated control, walking control, or OMT group (20 participants per group). Participants received an initial, bilateral US measurement of the skin to posterior superior iliac spine (SPSIS), skin to sacral base position (SBP), and sacral sulcus depth (SSD). Participants in seated control and OMT groups received a palpatory assessment of SBP and SSD prior to initial US assessment. After assessment, the seated control group sat in a waiting room for 30 minutes, the walking control group walked for 5 minutes, and the OMT group received OMT to address sacral base asymmetry using predominantly direct techniques for a maximum of 20 minutes. Participants then received a second US assessment of the same structures.

Results

Body mass index (BMI) was correlated with SPSIS (r=0.5, P=.001) and SBP (r=0.6, P<.001). More participants in seated control (75%) and OMT (65%) groups had an increase in asymmetry from first to second US assessment for SPSIS compared with participants in the walking control group (35%, P=.05). No significant differences were found between groups for absolute asymmetry or total change in asymmetry (all P>.10). The κ was −0.1 (95% CI, −0.2 to 0.03) for SBP and −0.01 (95% CI, −0.1 to 0.1) for SSD.

Conclusion

Musculoskeletal changes in SPSIS and SBP measurements related to OMT could not be readily identified using US. The SPSIS and SBP measurements were dependent on BMI, which may have affected the accuracy of US to detect small changes in asymmetry. Qualitative palpatory assessments did not correlate with US measurements. Further study is needed to identify US measurements that demonstrate change with OMT. (ClinicalTrials.gov number NCT02820701)

Prediction Effects of Personal, Psychosocial, and Occupational Risk Factors on Low Back Pain Severity Using Artificial Neural Networks Approach in Industrial Workers

OBJECTIVES

This study aimed to provide an empirical model of predicting low back pain (LBP) by considering the occupational, personal, and psychological risk factor interactions in workers population employed in industrial units using an artificial neural networks approach.

METHODS

A total of 92 workers with LBP as the case group and 68 healthy workers as a control group were selected in various industrial units with similar occupational conditions. The demographic information and personal, occupational, and psychosocial factors of the participants were collected via interview, related questionnaires, consultation with occupational medicine, and also the Rapid Entire Body Assessment worksheet and National Aeronautics and Space Administration Task Load Index software. Then, 16 risk factors for LBP were used as input variables to develop the prediction model. Networks with various multilayered structures were developed using MATLAB.

RESULTS

The developed neural networks with 1 hidden layer and 26 neurons had the least error of classification in both training and testing phases. The mean of classification accuracy of the developed neural networks for the testing and training phase data were about 88% and 96%, respectively. In addition, the mean of classification accuracy of both training and testing data was 92%, indicating much better results compared with other methods.

CONCLUSION

It appears that the prediction model using the neural network approach is more accurate compared with other applied methods. Because occupational LBP is usually untreatable, the results of prediction may be suitable for developing preventive strategies and corrective interventions.

Low back pain characterized by muscle resistance and occupational factors associated with nursing

Objective

to identify the occupational factors associated with low back pain using a surveillance tool and to characterize the low back pain by the resistance of the extensor muscles of the vertebral column among nursing professionals at an Intensive Care Unit.

Methods

Cross-sectional study. The workers answered a questionnaire about occupational factors and participated in a resistance test of the extensor muscles of the vertebral column. Associations were established through Student's T-test or Mann-Whitney's U-test and correlations using Pearson's test.

Results

Out of 48 participants, 32 (67%) suffered from low pain. For the resistance test, the subjects suffering from low back pain endured less time in comparison with asymptomatic subjects, but without significant differences (p=0.147). The duration of the pain episode showed a significant negative correlation (p=0.016) with the results of the resistance test though. The main factors identified as causes of low back pain were biomechanical and postural elements, conditions of the muscle structure and physical and organizational conditions.

Conclusions

the main occupational factors associated with the low back pain were the posture and the characteristics of the physical and organizational conditions. In addition, the extensor muscles of the column showed a trend towards lesser resistance for workers in pain. This evidence is important when considering prevention and treatment strategies.

Reliability and Validity Measurement of Sagittal Lumbosacral Quiet Standing Posture with a Smartphone Application in a Mixed Population of 183 College Students and Personnel

Accurate recording of spinal posture with simple and accessible measurement devices in clinical practice may lead to spinal loading optimization in occupations related to prolonged sitting and standing postures. Therefore, the purpose of this study was to establish the level of reliability of sagittal lumbosacral posture in quiet standing and the validity of the method in differentiating between male and female subjects, establishing in parallel a normative database. 183 participants (83 males and 100 females), with no current low back or pelvic pain, were assessed using the “iHandy Level” smartphone application. Intrarater reliability (3 same-day sequential measurements) was high for both the lumbar curve (ICC_2,1: 0.96, SEM: 2.13°, and MDC_95%: 5.9°) and the sacral slope (ICC_2,1: 0.97, SEM: 1.61°, and MDC_95%: 4.46°) sagittal alignment. Data analysis for each gender separately confirmed equally high reliability for both male and female participants. Correlation between lumbar curve and sacral slope was high (Pearson's r = 0.86, p < 0.001). Between-gender comparisons confirmed the validity of the method to differentiate between male and female lumbar curve and sacral slope angles, with females generally demonstrating greater lumbosacral values (p < 0.001). The “iHandy Level” application is a reliable and valid tool in the measurement of lumbosacral quiet standing spinal posture in the sagittal plane.

Modifying beliefs about back pain: A pilot study among healthcare professionals

OBJECTIVES

This study aimed to explore whether a preventive intervention based on the non-injury model and the biopsychosocial model of back pain succeeded in shifting beliefs toward less negative representations and in decreasing fear-avoidance beliefs related to back pain.

METHODS

One hundred and one healthcare professionals took part in a 10-h educational program held over 2 consecutive days, based on the key messages of the "Back Book." Baseline values were measured 6 weeks before the intervention and when it started. Follow-up was performed at the end of the intervention and six months later.

RESULTS

No significant changes were observed between baseline values and values measured at the beginning of the intervention, but participants' beliefs about LBP changed significantly after the program. The benefit remained at 6 months follow-up.

CONCLUSION

A prevention program based on the non-injury and bio-psychosocial models of LBP, introducing empowerment and problem-solving strategies, significantly reduced fear-avoidance and negative beliefs about LBP. The change was clinically relevant and thus could decrease direct and indirect healthcare costs.

Frequency and severity of low back pain in nurses working in intensive care units and influential factors

Objective: The purpose of this research was to determine the frequency and severity of low back pain and influencing factors in nurses working in intensive care units.

Methods: This research was conducted as a cross-sectional study with 114 nurses working in the intensive care units in the province of Gaziantep, Turkey. Study data were collected using a questionnaire form and visual analogue scale.

Results: It was found that 84.2% of the nurses experienced low back pain, and 66.7% of the nurses evaluated this pain as “a pain with moderate severity”. It was determined that nurses who had not received any education on low back pain, who remained standing for long periods of time, who performed interventions that required bending forward, who lifted and repositioned patients, and who did not use any aiding equipment during interventions, experienced more pain and had higher average pain scores. In addition, average pain scores were higher among nurses with master’s and doctorate degrees, and those working in internal medicine and pediatric intensive care units and working in shifts.

Conclusion: It was observed that many of the nurses working in intensive care units experienced low back pain, and especially those working in internal medicine and pediatric intensive care units and working in shifts had higher average pain scores.

Influence of automobile seat lumbar support prominence on spine and pelvic postures: a radiological investigation

BACKGROUND

The use of lumbar supports has been associated with decreased reports of low back pain during driving exposures. However, there has been limited work investigating whether lumbar supports actually change spine and pelvic postures at the level of the vertebrae.

PURPOSE

To investigate the effectiveness of a lumbar support in changing radiological measures of lumbar spine and pelvic postures and to examine the impact of support excursion magnitudes on these postures.

METHODS

Eight male subjects were recruited with no history of back injury, pathologies or low back pain within the past 6 months. Radiographs were taken in four postures: standing, and sitting with 0 cm, 2 cm and 4 cm lumbar support prominence (LSP).

RESULTS

Lumbar lordosis angle increased from 20° with no support to 25° with 2 cm support and 30° with 4 cm support. Lumbar lordosis angles were significantly different between 0 cm support and 4 cm support (p < 0.0001) and between 2 cm support and 4 cm support (p = 0.0256). Increasing lumbar support reduced the flexion at intervertebral disc joints throughout the lumbar spine, however, these remained significantly different from upright standing (p > 0.001) with the exception of L1/L2 in 4 cm support (p = 0.1381) and L5/S1 for all seated postures (p = 0.0687). All measures of pelvic posture were significantly different in sitting compared to standing (p < 0.0001), however, the lumbar support had no significant impact on seated pelvic posture.

CONCLUSIONS

Lumbar supports were shown to impact the vertebral rotations of the lumbar spine yet had no effect on pelvis postures. Increasing support from the current maximum of 2 cm-4 cm resulted in increased lumbar lordosis. The changes were mostly imparted at the upper lumbar spine joints with the most marked change being exhibited at the approximate level of the lumbar support apex: in the L2/L3 joint.