Intratester and intertester reproducibility of the lumbar motion monitor as a measure of range, velocity and acceleration of the thoracolumbar spine

Comparisons of Trunk Motions and Low Back Injury Risk between Alternative Hotel Room Cleaning Methods

Hotel room cleaners frequently report job-related pain, with high rates of work-related musculoskeletal disorder injuries established for this group of workers. Surprisingly, there is limited published research documenting the impact of interventions to reduce ergonomic-related injury risks specific to hotel room cleaners' job tasks. In this study focused on hotel bathroom-cleaning and furniture-dusting tasks, twelve experienced hotel room cleaners used their standard method and a risk-reduction method-a tool with a handle that could extend, to perform these tasks. The female study participants' average age was 45.3 (SD 8.7) years with an average of 10 years of work experience as cleaners (range: 0.8-26.0 years). Trunk kinematics and a low back injury risk assessment were measured using the Lumbar Motion Monitor. All study metrics were significantly reduced when cleaning tasks involved use of adjustable, long-handled tools (p < 0.05). This study demonstrated that commonly available cleaning and dusting tools with extendable handles can significantly reduce low back injury risk among hotel room cleaners and potentially reduce injury risk to other body parts known to be the site of musculoskeletal disorders in this workforce. The study findings suggest that cleaning or housekeeping jobs in other industries where these same tasks are performed could benefit from use of extended-handle tools like those investigated here.

Comparison of three validated systems to analyse spinal shape and motion

The assessment of spinal shape and mobility is of great importance for long-term therapy evaluation. As frequent radiation should be avoided, especially in children, non-invasive measurements have gained increasing importance. Their comparability between each other however stays elusive. Three non-invasive measurement tools have been compared to each other: Idiag M360, raster stereography and Epionics SPINE. 30 volunteers (15 females/15 males) have each been assessed by each system, investigating lumbar lordosis, thoracic kyphosis and spinal range-of-motion in the sagittal plane. Lumbar lordosis differed significantly (p < 0.001) between measurement devices but correlated significant to each other (Pearson’s r 0.5–0.6). Regarding thoracic kyphosis no significant difference and a high correlation (r = 0.8) could be shown between Idiag M360 and raster stereography. For lumbar mobility resulting measurements differed significantly and correlated only moderate between Idiag M360 and Epionics SPINE. Although the different measurement systems are moderate to high correlated to each other, their absolute agreement is limited. This might be explained by differences in their angle definition for lordotic and kyphotic angle, their measurement placement, or their capturing of mobility (static vs. dynamic assessment). Therefore, for long-term evaluation of the back profile, inter-modal comparison of values between different non-invasive devices should be avoided.

A Mobile Application to Measure Trunk Flexion Angles in Lifting Tasks

Occupational Abstract The aim of this project was to develop and test an application capable of quickly and repeatedly measuring trunk flexion angles during sagittal plane lifting tasks. The developed application uses the built-in accelerometer in mobile devices to approximate trunk flexion angle, as the user follows an operator as they perform a lift. A black line is superimposed over the camera feed, allowing the user to approximate the angle of inclination of a line connecting the operator's seventh cervical and first sacral vertebrae-thereby estimating the trunk flexion angle. The magnitude of this angle and its velocity have been linked to the development of occupational low back pain; thus the application provides ergonomists a more refined means of screening tasks beyond currently available survey tools.

Using visual aids to influence manual lifting techniques: acute effects of viewing static images on spine motion

Purpose. This study aimed to determine whether untrained observers alter their spine as directed via static images of different lifting techniques. Methods. Ten men and eight women, who had no lifting or visual observation training, performed box lifts. Following a self-selected lifting technique trial, participants performed four experimental lifting trials (in randomized order) wherein they were instructed to execute lifts in accordance with the techniques pictured. These techniques differed by the amount of knee, trunk and spine flexion modeled. Peak lumbar flexion angles and flexion/extension velocities were quantified, and then statistically analyzed via general linear models with two within-participant factors (condition = technique; phase = lift/lower). Results. Lumbar flexion angles and flexion/extension velocities differed between conditions (p < 0.001), although the effects depended on the combination of postural characteristics pictured. A main effect of phase was observed for peak lumbar flexion velocity only (p = 0.001). No condition × phase interaction effects were detected for any dependent variables (p > 0.050). Conclusions. Acute changes in lifting mechanics can be elicited via visual observation of pictured techniques. However, if using pictures to attenuate peak lumbar flexion displacements and velocities when lifting, auxiliary instruction may be needed to direct observers' attention to the spine curvature displayed.

Lumbar axial rotation kinematics in men with non-specific chronic low back pain

BACKGROUND

Lumbar flexion, coupled with rotation, is a dominant factor in the etiology and exacerbation of low back pain. Yet, no study has examined its kinematics in patients with non-specific chronic low back pain (NSCLBP). The aim of the study was to evaluate the lumbar rotation kinematics in neutral standing and with full flexion in men with NSCLBP.

METHODS

ROM, average velocity, maximum velocity and maximal acceleration of lumbar rotation in neutral standing and with full flexion were measured using an industrial lumbar motion monitor in 50 men (25 with NSCLBP and 25 controls). VAS and Rolland Morris questionnaire were also included.

FINDINGS

All examined kinematical parameters were significantly lower in men with NSCLBP compared with controls (↓ROM = 29%-45%; ↓AV = 40%-68%; ↓MV = 25%-50%; ↓MA = 20%-37%). Left rotation manifested smaller kinematic values (except for MA) than right rotation (Δ ROM = 35%; Δ AV = 66%; Δ MV = 19%) in NSCLBP. Most kinematical parameters significantly decreased from neutral standing to standing with flexion (right rotation: ↓ROM = 43%-45%, ↓AV = 38%-45%, ↓MV = 24%-27%, ↓MA for the NSCLBP group = 21%; left rotation: ↓ROM = 25%-38%, ↓AV in the control group: =34%, ↓MV in the control group: =23%, ↓MA in the control group = 25%). No correlations were found between all measured kinematical parameters, VAS and RMQ total score in the NSCLBP group.

INTERPRETATION

The kinematic parameters of lumbar rotation were reduced in men with NSCLBP compared with controls both in neutral standing and with fully forward bending. Most lumbar rotation kinematics decreased from neutral standing to standing with flexion.

Reliability and measurement error of frontal and horizontal 3D spinal motion parameters in 219 patients with chronic low back pain

Background

In order for measurements to be clinically useful, data on psychometric conditions such as reliability should be available in the population for which the measurements are intended to be used. This study comprises a test-retest design separated by 7 to 14 days, and evaluates the intra and interrater reliability of regional frontal and horizontal spinal motion in 219 chronic LBP patients using the CA6000 Spine Motion Analyzer. In addition, it compares these results on the frontal and horizontal plane with previously published results on the sagittal plane. 219 individuals with chronic mechanical LBP, classified as either Quebec Task Force group 1, 2, 3 or 4 were included, and kinematics of the lumbar spine were sampled during standardized spinal lateral flexion and rotation motion using a 6-df instrumented spatial linkage system. Test-retest reliability and measurement error were evaluated using intraclass correlation coefficients ICC_(1,1) and Bland-Altman limits of agreement (LOAs).

Results

The reliability analysis based on the whole study sample showed ICC_(1,1) coefficients varying between 0.68 and 0.73 for the frontal plane and 0.33 and 0.49 for the horizontal plane. Relatively wide LOAs were observed for all parameters. Reliability measures in patient subgroups ICC_(1,1) ranged between 0.55 and 0.81 for the frontal plane and 0.28 and 0.69 for the horizontal plane. Greater ICC_(1,1) coefficients and smaller LOA were observed when patients were examined by the same examiner, had a stable pain level between tests, and were male. ROM measurements were more reliable in patients with a BMI higher than 30, and measurements on patients with LBP and leg pain showed higher reliability and smaller measurement error in all parameters except for the jerk index.

Conclusion

Frontal plane measurements obtained using the CA6000 Spine Motion Analyzer are sufficiently reliable to be used for group comparisons but not individual comparisons. Measurements in the horizontal plane can be used for neither group nor individual comparisons.

A comparison of instrumentation methods to estimate thoracolumbar motion in field-based occupational studies

The performance of an inertial measurement unit (IMU) system for directly measuring thoracolumbar trunk motion was compared to that of the Lumbar Motion Monitor (LMM). Thirty-six male participants completed a simulated material handling task with both systems deployed simultaneously. Estimates of thoracolumbar trunk motion obtained with the IMU system were processed using five common methods for estimating trunk motion characteristics. Results of measurements obtained from IMUs secured to the sternum and pelvis had smaller root-mean-square differences and mean bias estimates in comparison to results obtained with the LMM than results of measurements obtained solely from a sternum mounted IMU. Fusion of IMU accelerometer measurements with IMU gyroscope and/or magnetometer measurements was observed to increase comparability to the LMM. Results suggest investigators should consider computing thoracolumbar trunk motion as a function of estimates from multiple IMUs using fusion algorithms rather than using a single accelerometer secured to the sternum in field-based studies.

Reliability and measurement error of sagittal spinal motion parameters in 220 patients with chronic low back pain using a three-dimensional measurement device

BACKGROUND CONTEXT

A basic premise for any instrument measuring spinal motion is that reliable outcomes can be obtained on a relevant sample under standardized conditions.

PURPOSE

The purpose of this study was to assess the overall reliability and measurement error of regional spinal sagittal plane motion in patients with chronic low back pain (LBP), and then to evaluate the influence of body mass index, examiner, gender, stability of pain, and pain distribution on reliability and measurement error.

STUDY DESIGN/SETTING

This study comprises a test-retest design separated by 7 to 14 days.

PATIENT SAMPLE

The patient cohort consisted of 220 individuals with chronic LBP.

OUTCOME MEASURES

Kinematics of the lumbar spine were sampled during standardized spinal extension-flexion testing using a 6-df instrumented spatial linkage system.

METHODS

Test-retest reliability and measurement error were evaluated using interclass correlation coefficients (ICC(1,1)) and Bland-Altman limits of agreement (LOAs).

RESULTS

The overall test-retest reliability (ICC(1,1)) for various motion parameters ranged from 0.51 to 0.70, and relatively wide LOAs were observed for all parameters. Reliability measures in patient subgroups (ICC(1,1)) ranged between 0.34 and 0.77. In general, greater (ICC(1,1)) coefficients and smaller LOAs were found in subgroups with patients examined by the same examiner, patients with a stable pain level, patients with a body mass index less than below 30 kg/m(2), patients who were men, and patients in the Quebec Task Force classifications Group 1.

CONCLUSIONS

This study shows that sagittal plane kinematic data from patients with chronic LBP may be sufficiently reliable in measurements of groups of patients. However, because of the large LOAs, this test procedure appears unusable at the individual patient level. Furthermore, reliability and measurement error varies substantially among subgroups of patients.

The effects of the Mulligan Sustained Natural Apophyseal Glide (SNAG) mobilisation in the lumbar flexion range of asymptomatic subjects as measured by the Zebris CMS20 3-D motion analysis system

Background

Mulligan's mobilisation techniques are thought to increase the range of movement (ROM) in patients with low back pain. The primary aim of this study was to investigate the application of the Mulligan's Sustained Natural Apophyseal Glide (SNAG) technique on lumbar flexion ROM. The secondary aim was to measure the intra- and inter-day reliability of lumbar ROM employing the same procedure.

Methods

49 asymptomatic volunteers participated in this double-blinded study. Subjects were randomly assigned to receive either SNAG mobilisation (n = 25), or a sham mobilisation (n = 24). The SNAG technique was applied at the L₃and L₄ spinal levels with active flexion in sitting by an experienced manual therapist. Three sets of 10 repetitions at each of the two spinal levels were performed. The sham mobilisation was similar to the SNAG but did not apply the appropriate direction or force. Lumbar ROM was measured by a three dimensional electronic goniometer (Zebris CMS20), before and after each technique. For the reliability, five measurements in two different days (one week apart) were performed in 20 healthy subjects.

Results

When both interventions were compared, independent t tests yielded no statistically significant results in ROM between groups (p = 0.673). Furthermore no significant within group differences were observed: SNAG (p = 0.842), sham (p = 0.169). Intra- and inter-day reliability of flexion measurements was high (ICC_1,1 > 0.82, SEM < 4.0°, SDD<16.3%) indicating acceptable clinical applicability.

Conclusion

While the Zebris proved to be a reliable device for measuring lumbar flexion ROM, SNAG mobilisation did not demonstrate significant differences in flexion ROM when compared to sham mobilisation.

Trial registration

Current Controlled Trials NCT00678093.

Development of a fibre optic goniometer system to measure lumbar and hip movement to detect activities and their lumbar postures

If sitting postures influence the risk of developing low back pain then it is important that quantification of sedentary work activities and simultaneous measurement of lumbar postural characteristics takes place. The objective of this study was to develop a system for identifying activities and their associated lumbar postures using fibre optic goniometers (FOGs). Five student subjects wore two FOGs attached to the lumbar spine and hip for 8 min while being recorded using a video camera when sitting, standing and walking. Observer Software was used to code the video recording, enabling the sagittal movement characteristics of each FOG to be described for individual activities. Results indicated that each activity produced unique data, and could be independently identified from their motion profiles by three raters (k = 1). The data will be used to develop algorithms to automate the process of activity detection. This system has the potential to measure behaviour in non-clinical settings.

Effect of pregnancy on trunk range of motion when sitting and standing

BACKGROUND

During pregnancy, apposition of body segments and changes in trunk mobility and motion control due to increased mass and dimensions may reduce the functional range of motion of the trunk segments. Although static postures have been investigated, dynamic trunk motion during pregnancy in sitting and standing has had very limited investigation.

METHODS

Included in the study was a volunteer sample of convenience of nine primiparous and multiparous women. Twelve nulliparous females formed a control group. The subjects were filmed while performing maximum seated and standing trunk forward flexion, side-to-side flexion and seated axial rotation. A repeated measures anova was used to investigate systematic changes in the motion of the pelvic and thoracic segments and the thoracolumbar spines during pregnancy.

RESULTS

As pregnancy progressed, there was no significant decrease in the range of side-to-side flexion. For forward flexion and axial rotation, motion of the thoracic segment and the thoracolumbar spine was significantly reduced. Movement of the pelvis was less affected. Base of support width was increased for forward flexion and side-to-side flexion.

CONCLUSIONS

In late pregnancy, strategies such as increasing the width of the base of support and reducing obstruction from other body parts were used to minimize the effects of increased trunk mass and girths. Not all trunk segment motion was affected equally. The differing effect on individual trunk segment motion may lead to altered movement patterns during functional tasks.

Thoracolumbar proprioception in individuals with and without low back pain: intratester reliability, clinical applicability, and validity

STUDY DESIGN

Repeated measures design of active spinal position sense in individuals with and without low back pain (LBP).

OBJECTIVES

Reproducibility and validity evaluation of thoracolumbar proprioception measurement.

BACKGROUND

Proprioception studies in peripheral joints and the spine suggest that there may be proprioception deficits due to injury, pain, or degeneration. Kinesthetic retraining may be useful in rehabilitation of patients with LBP, but appropriate measures are required to objectively quantify spinal proprioception.

METHODS AND MEASURES

Active-target reproduction in the sagittal, horizontal, and coronal planes was assessed (3 separate occasions for 18 asymptomatic volunteers and 2 occasions for 62 patients with LBP). Repositioning accuracy was expressed as absolute errors (AE) and variable errors (VE). Reliability was analyzed with intraclass correlation coefficient (ICC) and precision with standard error of measurement (SEM) and calculation of the smallest detectable difference (SDD) index. Repeated measures ANOVA and correlations were used for within-group comparisons and discriminant analysis for between-group comparisons.

RESULTS

Reproducibility was better for the asymptomatic group, with AE for flexion and rotation being the most reliable (ICC = 0.76-0.80, SEM = 0.91 degrees-1.34 degrees). SDDs were high for all tests, suggesting limited clinical applicability. Reproducibility for the same tests was poor-moderate (ICC = 0.31-0.64, SEM = 0.45 degrees-3.90 degrees) for the patient group. AE for right-side rotation could discriminate between subject groups with 83.3% specificity but only 54.8% sensitivity.

CONCLUSIONS

Proprioception testing, with the methods employed, did not demonstrate good measurement properties in a sample of patients with recurrent LBP. Neither could it sufficiently discriminate between individuals with and without LBP. Possible reasons for these findings are discussed.

The reproducibility of multi-joint isokinetic and isometric assessments in a healthy and patient population

DESIGN

Test re-test reliability design.

OBJECTIVE

To determine a reproducible protocol for lower limb simultaneous multi-joint assessments on a healthy group of subjects and a patient group with patellofemoral pain syndrome.

BACKGROUND

Although single joint assessment with isokinetic dynamometers has been utilised for many years in knee rehabilitation, simultaneous multi-joint assessment has not attracted comparable attention.

METHODS

Twenty healthy volunteers mean age 30.6 years and 16 patients with patellofemoral pain syndrome mean age 29.6 years performed isometric maximum voluntary contractions and concentric isokinetic contractions of the lower limb. Data were collected on three separate days for resultant extension/flexion peak torque, average power and total work which were analysed using intraclass correlation coefficients with a 95% level of confidence.

RESULTS

In healthy subjects, intraclass correlation coefficients estimates were > or =0.75 for isokinetic peak torque and >0.83 for average power and total work. The intraclass correlation coefficients estimate for isometric peak torque extension was 0.82. In the patient group, intraclass correlation coefficients estimates were >0.82 for isokinetic peak torque and > or =0.75 for average power and total work. The intraclass correlation coefficients estimate for isometric peak torque extension was 0.89. Discarding the first session's data for both groups improved the intraclass correlation coefficients estimates for virtually all assessments.

CONCLUSIONS

This study has demonstrated high reproducibility of lower limb multi-joint testing for peak torque, average power, and total work on healthy subjects and then has employed the protocol to demonstrate similarly high reliability on a patient group. It has also highlighted the need for a practice session before the data can be said to be reliable.

RELEVANCE

Reliability studies often use healthy subject groups, which although useful, have limited relevance to patient populations. This study has not only gained comprehensive reproducibility data on multi-joint assessment in healthy subjects, it has also shown that multi-joint testing can be used safely and reliably in patients with patellofemoral pain syndrome. Clinicians may now be able to measure objectively lower limb function in this patient group both pre and post treatment.

Prospective validation of a low-back disorder risk model and assessment of ergonomic interventions associated with manual materials handling tasks

The evaluation of low-back disorder risk associated with materials handling tasks can be performed using a variety of assessment tools. Most of these tools vary greatly in their underlying logic, yet few have been assessed for their predictive ability. It is important to document how well an assessment tool realistically reflects the job's injury risk, since only valid and accurate tools can reliably determine whether a given ergonomic intervention will result in a future reduction in back injuries. The goal of this study was to evaluate how well a previously reported low-back disorder (LBD) risk assessment model (Marras et al. 1993) could predict changes in LBD injury rates as the physical conditions to which employees are exposed were changed. Thirty-six repetitive materials handling jobs from 16 different companies were included in this prospective cohort study. Of these 36 jobs, 32 underwent an ergonomic intervention during the observation period, and four jobs in which no intervention occurred served as a comparison group. The trunk motions and workplace features of 142 employees performing these jobs were observed both before and after workplace interventions were incorporated. In addition, the jobs' LBD rates were documented for these pre- and post-intervention periods. The results indicated that a statistically significant correlation existed between changes in the jobs' estimated LBD risk values and changes in their actual low-back incidence rates over the observation period. Linear and Poisson regression models also were developed to predict a change in a job's incidence rate and the number of LBD on ajob respectively, as a function of the job's risk change using this assessment model. Finally, this prospective study showed which ergonomic interventions consistently reduced the jobs' mean low-back incidence rates. These results support use of the LBD risk model to assess accurately a job's potential to lead to low-back injuries among its employees.

Patient handling with and without slings: an analysis of the risk of injury to the lumbar spine

Health professionals handling patients are known to be at risk of sustaining work related low back injuries. It is not known whether the use of lifting slings reduces the risk of injury to the lumbar spine for patient handlers. This study used kinematic variables and subjective ratings of body part stress and lifter preference as measures of relative risk for three two-person techniques for carrying a patient from one chair to another chair. The techniques used no slings, one and two slings respectively. Twenty-two nurses performed five trials each of the three techniques. Kinematic measures of angular displacement, velocity and acceleration were obtained using the lumbar motion monitor and visual analogue scales were used to obtain measures of body part stress for seven body parts. Angular displacement, velocity and acceleration were significantly greater (p < 0.05) in the frontal, sagittal and transverse planes for the no sling technique compared to techniques using slings. Comparatively small yet significant differences between techniques using slings were recorded for sagittal flexion and rotation. There was no significant difference between one and two sling techniques for other dependent variables. Mean total body stress rating was higher for the no sling technique and all subjects indicated that their first preference was for slings. Although all three measures of risk rated the no sling technique as carrying a higher level of risk than the techniques using slings. No single measure adequately captured all aspects of relative risk. The elimination of manual patient handling is thought to be the best option for the reduction of work related back injuries in patient handlers. Where resources or technology are not yet adequate to provide practical alternatives and where the use of manual technique for a seat to seat task is unavoidable, the use of patient handling slings will reduce the risk.

Trunk proprioception: enhancement through lumbar bracing

OBJECTIVES

To examine the effects of a neoprene lumbar brace on the proprioceptive ability of subjects without pathology and to determine whether those with poorer proprioception were more affected by the brace.

STUDY DESIGN

Randomized 2 x 2 Latin square cross-over design.

SETTING

Laboratory in an educational institution.

SUBJECTS

Forty asymptomatic subjects matched by gender, age, weight, and height.

METHOD

Blindfolded subjects performed a position matching task in which they flexed the trunk in the sagittal plane. Six positions across the range of motion were examined. Angular data were recorded by a lumbar motion monitor secured by straps to the subject's trunk.

MAIN OUTCOME MEASURE

Absolute, constant, and variable errors in braced and unbraced conditions.

RESULTS

The mean absolute, constant, and variable errors were 3.6 degrees, .45 degrees, and 4.4 degrees, respectively. Absolute, constant, and variable errors were significantly decreased when wearing a brace. However, the magnitude of the decreases were small (<1.0 degrees) for all errors when wearing a brace. The high error group's absolute error improved significantly (p < .05), from 6.0 degrees when unbraced to 4.0 degrees when braced. In contrast, absolute error measurements for subjects in the low error group were unchanged, with an error of 2.0 degrees when unbraced and 2.3 degrees when braced.

CONCLUSIONS

The findings suggest that a neoprene lumbar brace improves the somatosensory information received by the central nervous system and results in less error in trunk positioning. Persons with less ability to match trunk position will benefit more from wearing a neoprene brace than will those who are already adept at the task.