Validity and reliability of measures obtained from the OSI CA-6000 Spine Motion Analyzer for lumbar spinal motion

Normative values of cervical range of motion for both children and adults: A systematic review

STUDY DESIGN

Systematic review.

OBJECTIVE

To synthesize studies reporting normative values of active cervical range of motion (ROM) in healthy children and adults.

SUMMARY OF BACKGROUND DATA

Evaluating active cervical ROM is part of routine assessment of patients with neck pain. Interpretation of outcomes necessitates having normative data per age category. Currently available normative values differ across studies, perhaps due to (the measurement properties of) the devices used.

METHODS

A systematic review according to PRISMA guidelines was conducted. Electronic searches included EMBASE, MEDLINE, Web of Science, Cochrane, CINAHL and Google Scholar databases from inception to August 2018. Included studies had to involve healthy subjects in which active cervical ROM was assessed or when determining normative values was the aim of the study. Methodological quality of the included studies was assessed using an adapted version of the QUADAS. A mean value was re-calculated for the total group in case data were presented per gender per age-category only. When possible, data were pooled.

RESULTS

From 2151 unique hits, 217 articles were selected for full text assessment, after which 162 articles were excluded. Data were extracted from 55 articles using 16 different measurement devices. Twenty-five studies were rated as being of "low risk of bias". Only data from studies evaluating the CROM device and Zebris could be pooled.

CONCLUSIONS

This systematic review revealed that although a large number of studies assessed normative data for active cervical ROM, the methodological quality of most studies was low and the heterogeneity between studies was high. Only the normative data for active cervical ROM using the CROM device seems to be useful. Overall, reference values for measuring active cervical ROM is unclear for most measurement devices. Normative values of cervical range of motion for both children and adults: a systematic review.

Validity of flexicurve for the assessment of spinal flexibility in asymptomatic individuals

Abstract Introduction: Spine problems are common, and assessment of spine flexibility provides relevant information; however, alternative evaluation methods need to be validated. Objective: To evaluate the concurrent validity of the Flexicurve using 3D videogrammetry as a reference value to assess spinal flexion and extension in the lumbar and thoracic regions. Method: The consecutive sample consisted of 39 individuals aged between 18 and 50 years. Two consecutive evaluations were performed by the same rater on the same day and at the same location: (1) Flexicurve and (2) 3D videogrammetry. The assessments were performed with the spine in the neutral position, followed by maximum flexion and extension. The range of motion (ROM) in the maximum flexion and extension positions was calculated in MATLAB® and defined as the difference between the maximum flexion or extension angle and that of the neutral position. Statistical analyses used were the Pearson Product-Moment Correlation coefficient, RMS error and Bland-Altman plot (α < 0.05). Results: The ROM between instruments was similar, with high correlations for thoracic flexion (r = 0.751), extension (r = 0.814) and lumbar flexion (r = 0.853), and RMS errors under 8°. The correlation for lumbar extension was moderate (r = 0.613) and the RMS error was more than 10°. The limits of agreement varied between ± 10º and ± 21º. Conclusion: The Flexicurve is valid for assessing maximum flexion and extension of the thoracic spine, and maximum flexion of the lumbar spine. We suggest caution in evaluating the maximum extension of the lumbar spine.

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.

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.

Associations of self-report measures with gait, range of motion and proprioception in patients with lumbar spinal stenosis

INTRODUCTION

Spinal stenosis is defined as neurogenic claudication due to narrowing of the spinal canal lumen diameter. As the disease progresses, ambulation and gait may be impaired. Self-report measures are routinely used in the clinical setting to capture data related to lumbar pain symptoms, function and perceived disability. The associations between self-report measures and objective measures of physical function in patients with lumbar spinal stenosis are not well characterized. The purpose of this study was to determine the correlation between self-reported assessments of function with objective biomechanical measures of function.

METHODS

25 subjects were enrolled in this study. Subjects completed self-report questionnaires and biomechanical assessments of gait analysis, lumbar 3D ROM and lumbar proprioception. Correlations were determined between self-report measures and biomechanical data.

RESULTS

The Oswestry Disability Index (ODI) was strongly correlated with stride length and gait velocity and weakly correlated with base of support. ODI was also weakly correlated with left lateral bending proprioception but not right lateral bending. The SF12 was not significantly correlated with any of the biomechanical measurements. Pain scores were weakly correlated with velocity, and base of support, and had no correlation any of the other biomechanical measures.

DISCUSSION

There is a strong correlation between gait parameters and functional disability as measured with the ODI. Quantified gait analysis can be a useful tool to evaluate patients with lumbar spinal stenosis and to assess the outcomes of treatments on this group of patients.

Validation of a novel spinal posture monitor: comparison with digital videofluoroscopy

PURPOSE

A novel, minimally invasive posture monitor which can monitor lumbar postures outside the laboratory has demonstrated excellent reliability, as well as concurrent validity compared to a surface marker-based motion analysis system. However, it is unclear if this device reflects underlying vertebral motion.

METHODS

Twelve participants performed full range sagittal plane lumbo-pelvic movements during sitting and standing. Their posture was measured simultaneously using both this device (BodyGuard™) and digital videofluoroscopy.

RESULTS

Strong correlations were observed between the two methods (all r (s) > 0.88). Similarly, the coefficients of determination were high (all r (2) > 0.78). The maximum mean difference between the measures was located in the mid-range of motion and was approximately 3.4° in sitting and 3.9° in standing.

CONCLUSION

The BodyGuard™ appears to be a valid method for analysing vertebral motion in the sagittal plane and is a promising tool for long-term monitoring of spinal postures in laboratory and clinical settings in people with low back pain.

Towards monitoring lumbo-pelvic posture in real-life situations: concurrent validity of a novel posture monitor and a traditional laboratory-based motion analysis system

Many factors are associated with low back pain (LBP), including provocative spinal postures. Consequently, lumbo-pelvic posture is commonly assessed in LBP patients. A novel wireless monitor (BodyGuard™) can monitor lumbo-pelvic sagittal plane movements reliably, and has demonstrated concurrent validity during non-functional tasks. This study evaluated the concurrent validity of this monitor during functional tasks, as a precursor to LBP field studies. Twelve painfree participants performed a series of postural tasks (in sitting and standing) three times. Simultaneous postural measurements were obtained by the wireless monitor and a laboratory-based system (CODA™). Postural measurements were strongly correlated (r(s) = 0.88, r(2) = 0.78). The mean difference observed was small (<10% lumbo-pelvic ROM), however some tasks displayed greater error. The results support the concurrent validity of the wireless monitor for analysing lumbo-pelvic posture during functional tasks. Specific limitations of the monitor for certain postural tasks were identified, and should be considered before implementation in future field studies.

Supervised exercise, spinal manipulation, and home exercise for chronic low back pain: a randomized clinical trial

BACKGROUND CONTEXT

Several conservative therapies have been shown to be beneficial in the treatment of chronic low back pain (CLBP), including different forms of exercise and spinal manipulative therapy (SMT). The efficacy of less time-consuming and less costly self-care interventions, for example, home exercise, remains inconclusive in CLBP populations.

PURPOSE

The purpose of this study was to assess the relative efficacy of supervised exercise, spinal manipulation, and home exercise for the treatment of CLBP.

STUDY DESIGN/SETTING

An observer-blinded and mixed-method randomized clinical trial conducted in a university research clinic in Bloomington, MN, USA.

PATIENT SAMPLE

Individuals, 18 to 65 years of age, who had a primary complaint of mechanical LBP of at least 6-week duration with or without radiating pain to the lower extremity were included in this trial.

OUTCOME MEASURES

Patient-rated outcomes were pain, disability, general health status, medication use, global improvement, and satisfaction. Trunk muscle endurance and strength were assessed by blinded examiners, and qualitative interviews were performed at the end of the 12-week treatment phase.

METHODS

This prospective randomized clinical trial examined the short- (12 weeks) and long-term (52 weeks) relative efficacy of high-dose, supervised low-tech trunk exercise, chiropractic SMT, and a short course of home exercise and self-care advice for the treatment of LBP of at least 6-week duration. The study was approved by local institutional review boards.

RESULTS

A total of 301 individuals were included in this trial. For all three treatment groups, outcomes improved during the 12 weeks of treatment. Those who received supervised trunk exercise were most satisfied with care and experienced the greatest gains in trunk muscle endurance and strength, but they did not significantly differ from those receiving chiropractic spinal manipulation or home exercise in terms of pain and other patient-rated individual outcomes, in both the short- and long-term.

CONCLUSIONS

For CLBP, supervised exercise was significantly better than chiropractic spinal manipulation and home exercise in terms of satisfaction with treatment and trunk muscle endurance and strength. Although the short- and long-term differences between groups in patient-rated pain, disability, improvement, general health status, and medication use consistently favored the supervised exercise group, the differences were relatively small and not statistically significant for these individual outcomes.

The between-day and inter-rater reliability of a novel wireless system to analyse lumbar spine posture

Lumbar posture is commonly assessed in non-specific chronic low back pain (NSCLBP), although quantitative measures have mostly been limited to laboratory environments. The BodyGuard™ is a spinal position monitoring device that can monitor posture in real time, both inside and outside the laboratory. The reliability of this wireless device was examined in 18 healthy participants during usual sitting and forward bending, two tasks that are commonly provocative in NSCLBP. Reliability was determined using intraclass correlation coefficients (ICC), the standard error of measurement (SEM), the mean difference and the minimal detectable change (MDC90). Between-day ICC values ranged from 0.84 to 0.87, with small SEM (5%), mean difference (<9%) and MDC90 (<14%) values. Inter-rater ICC values ranged from 0.91 to 0.94, with small SEM (4%), mean difference (6%) and MDC90 (9%) values. Between-day and inter-rater reliability are essential requirements for clinical utility and were excellent in this study. Further studies into the validity of this device and its application in clinical trials in occupational settings are required. STATEMENT OF RELEVANCE: A novel device that can analyse spinal posture exposure in occupational settings in a minimally invasive manner has been developed. This study established that the device has excellent between-day and inter-rater reliability in healthy pain-free subjects. Further studies in people with low back pain are planned.

Nucleus pulposus deformation in response to lumbar spine lateral flexion: an in vivo MRI investigation

Whilst there are numerous studies examining aspects of sagittal plane motion in the lumbar spine, few consider coronal plane range of motion and there are no in vivo reports of nucleus pulposus (NP) displacement in lateral flexion. This study quantified in vivo NP deformation in response to side flexion in healthy volunteers. Concomitant lateral flexion and axial rotation range were also examined to evaluate the direction and extent of NP deformation. Axial T2- and coronal T1-weighted magnetic resonance images (MRI) were obtained from 21 subjects (mean age, 24.8 years) from L1 to S1 in the neutral and left laterally flexed position. Images were evaluated for intersegmental ranges of lateral flexion and axial rotation. A novel methodology derived linear pixel samples across the width of the disc from T2 images, from which the magnitude and direction of displacement of the NP was determined. This profiling technique represented the relative hydration pattern within the disc. The NP was displaced away from the direction of lateral flexion in 95/105 discs (p < 0.001). The extent of NP displacement was associated strongly with lateral flexion at L2-3 (p < 0.01). The greatest range of lateral flexion occurred at L2-3, L3-4 and L4-5. Small intersegmental ranges of axial rotation occurred at all levels, but were not associated with NP displacement. The direction of NP deformation was highly predictable in laterally flexed healthy lumbar spines; however, the magnitude of displacement was not consistent with the degree of intersegmental lateral flexion or rotation.

Validation of spinal motion with the spine reposition sense device

Background

A sagittal plane spine reposition sense device (SRSD) has been developed. Two questions were addressed with this study concerning the new SRSD: 1) whether spine movement was occurring with the methodology, and 2) where movement was taking place.

Methods

Sixty-five subjects performed seven trials of repositioning to a two-thirds full flexion position in sitting with X and Y displacement measurements taken at the T4 and L3 levels. The thoracolumbar angle between the T4 and the L3 level was computed and compared between the positions tested. A two (vertebral level of thoracic and lumbar) by seven (trials) mixed model repeated measures ANOVA indicated whether significant differences were present between the thoracic (T4) and lumbar (L3) angular measurements.

Results

Calculated thoracolumbar angles between T4 and L3 were significantly different for all positions tested indicating spinal movement was occurring with testing. No interactions were found between the seven trials and the two vertebral levels. No significant findings were found between the seven trials but significant differences were found between the two vertebral levels.

Conclusion

This study indicated spine motion was taking place with the SRSD methodology and movement was found specific to the lumbar spine. These findings support utilizing the SRSD to evaluate changes in spine reposition sense during future intervention studies dealing with low back pain.

The in vivo three-dimensional motion of the human lumbar spine during gait

Lumbar spine pathology accounts for billions of dollars in societal costs each year. Although the symptomatology of these conditions is relatively well understood, the mechanical changes in the spine are not. Previous direct measurements of lumbar spine mechanics have mostly been performed on cadavers. The methods for in vivo studies have included imaging, electrogoniometry, and motion capture. Few studies have directly measured in vivo lumbar spine kinematics with in-dwelling bone pins. This study tracked the in vivo three-dimensional motion of the entire lumbar spine (L1 [corrected] to S1) in 10 healthy, young-adult subjects. Two 1.55 mm (0.062 in.) diameter Kirshner wires were inserted into each vertebra's spinous process under anesthesia. Motion capture cameras were used to track a triad of passive markers attached to the wires. Offsets between anatomical landmarks and tracking markers were established with a CT scan for each individual vertebra. Subjects were asked to perform various exercises including walking and voluntary range of motion. Subjects were able to complete all of the exercises. All subjects reported being adequately informed of all of the procedures and there were no neurological or orthopaedic complications. The range of the average inter-segmental range of motion was 4.26 degrees -4.38 degrees in the sagittal plane, 2.61 degrees -4.00 degrees in the coronal plane, and 4.11 degrees -5.24 degrees in the transverse plane. Using a direct (pin-based) in vivo measurement method, the motion of the human lumbar spine during gait was found to be triaxial. This appears to be the first three-dimensional motion analysis of the entire lumbar spine using indwelling pins. The results were similar to previously published data derived from a variety of experimental methods.

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.

Kinematic and temporal interactions of the lumbar spine and hip during trunk extension in healthy male subjects

Kinematic properties of trunk extension are considered sensitive differentiators of movement between asymptomatic and low back pain subjects. The aim of this study was to quantify the continuous interaction of the hip and lumbar spine kinematics and temporal characteristics as a function of direction during the task of trunk bending backwards and returning to the upright position in healthy young subjects. The sagittal hip and lumbar spine kinematics during the extension task were examined in 18 healthy male subjects. Five trials of trunk extension were recorded for each subject and paired t-tests were then used to determine significant differences (P < 0.05) between the mean lumbar and the hip time-normalized kinematic and temporal variables. The data from the full cycle of trunk extension was analyzed with respect to movement initiation, time to reach peak velocity and peak angular displacement during the full cycle of trunk extension. Three distinct phases of movements were identified based on the continuous movement trajectories of velocity and angular displacement in the lumbar spine and hip; that of extension, return and, a terminal overcorrection phase. There were significant differences identified in the respective mean peak angular velocities of the lumbar spine (21.7 +/- 8.6, 37.0 +/- 14.7, 8.3 +/- 5.0 deg/s) when compared with those of hip (14.6 +/- 6.1, 21.7 +/- 8.5, 5.4 +/- 3.5 deg/s) in each of these three phases. The lumbar spine initiated the movement of trunk extension when bending backwards and returning to the upright position significantly early than that of the hip. These results highlight that in normal healthy adults there is the tendency for the lumbar spine to dominate over the hip during the task of backward trunk bending in terms of the amount and velocity of movement. At the end of extension the kinematics of the lumbar spine and hip kinematic are characterized by a terminal overcorrection phase marking the completion of the movement.

Agreement of measures obtained radiographically and by the OSI CA-6000 Spine Motion Analyzer for cervical spinal motion

The purpose of this study was to determine the agreement between angular measures of cervical spinal motion obtained from radiographs and from measures recorded by the OSI CA 6000 Spine Motion Analyzer (OSI SMA) in asymptomatic subjects. Fourteen subjects performed each of the following motions two times while wearing the OSI SMA: cervical flexion, extension, side bending to the right and left. Each motion was performed once for the cervical radiograph. The difference between the values obtained by the two methods was plotted against the average of those values for each subject to illustrate the level of agreement of the two methods. The plotted points were widely scattered, with a large range between the limits of agreement. Range of motion values taken from the OSI SMA were not similar to those obtained from radiographs for the motions of the cervical spine.

Palpation identification of spinous processes in the lumbar spine

The purpose of this study was to determine the accuracy of manipulative physiotherapists in palpating radiologically identified lumbar spinous processes (SPs). Five experienced manipulative physiotherapists were each allocated a cohort of 15 consecutive low back pain (LBP) patients presenting for X-rays and were asked to use surface palpation to identify the L1, L3 and L5 SPs. Spherical radio-opaque markers were taped to the skin over these palpated points and standard lateral radiographs taken. Measurements were made to determine the proximity of these nominated markers to identified SPs. Seventy-two percent of markers were either placed accurately over the nominated SP or consistently within one SP of the nominated level. Forty-seven percent were accurately placed over the nominated SPs. A greater SP height at L3 and L5, and decreased soft tissue thickness over L5, were associated with an increase in palpation accuracy levels, yet the patient variables of age, sex and body mass index (BMI) had no effect. The strongest effect on accuracy was between-therapist variability. The manipulative physiotherapists used in this study appear to be moderately successful in either palpating a nominated SP or being no more than one spinal level in error. Further research will focus on the choice of palpation procedure and a larger sample.

Spinal manipulation, epidural injections, and self-care for sciatica: a pilot study for a randomized clinical trial

OBJECTIVE

To assess the feasibility of recruiting sciatica patients and to evaluate their compliance in preparation for a full-scale randomized clinical trial. We also aimed to determine the responsiveness of key outcome measures.

METHODS

Thirty-two subjects were randomly assigned to spinal manipulation (n=11), epidural steroid injections (n=11), or self-care education (n=10). No between-group comparisons were planned because of the small sample size.

RESULTS

At week 12 (the end of the treatment phase), the outcome measures indicating the most improvement/change were the Oswestry disability score (mean, 22.9; SD, 19.9; effect size [ES], 1.8), leg pain severity (mean, 2.9; SD, 1.7; ES, 1.7), and if the symptoms were bothersome (mean, 25.2; SD, 16.0; ES, 1.6). Twenty-four patients were either "very satisfied" or "completely satisfied," and 22 of 32 patients reported 75% or 100% improvement. After 52 weeks, the outcome measure showing the most improvement/change was leg pain severity (mean, 2.3; SD, 2.6; ES, 1.35), followed by the Oswestry disability score (mean, 15.6; SD, 20; ES, 1.2) and if symptoms were bothersome (mean, 18.1; SD, 22.6; ES, 1.1). Eighteen patients were either "very satisfied" or "completely satisfied," and 15 of 32 patients reported 75% or 100% improvement.

CONCLUSIONS

The results of this pilot study suggest that it is feasible to recruit subacute and chronic sciatica patients and to obtain their compliance for a full-scale randomized clinical.

A new skin-surface device for measuring the curvature and global and segmental ranges of motion of the spine: reliability of measurements and comparison with data reviewed from the literature

There is an increasing awareness of the risks and dangers of exposure to radiation associated with repeated radiographic assessment of spinal curvature and spinal movements. As such, attempts are continuously being made to develop skin-surface devices for use in examining the progression and response to treatment of various spinal disorders. However, the reliability and validity of measurements recorded with such devices must be established before they can be recommended for use in the research or clinical environment. The aim of this study was to examine the reliability of measurements using a newly developed skin-surface device, the Spinal Mouse. Twenty healthy volunteers (mean age 41 +/- 12 years, nine males, 11 females) took part. On 2 separate days, spinal curvature was measured with the Spinal Mouse during standing, full flexion, and full extension (each three times by each of two examiners). Paired t-tests, intraclass correlation coefficients (ICC), and standard errors of measurement (SEM) with 95% confidence intervals were used to characterise between-day and interexaminer reliability for: standing sacral angle, lumbar lordosis, thoracic kyphosis, and ranges of motion (flexion, extension) of the thoracic spine, lumbar spine, hips, and trunk. The between-day reliability for segmental ranges of flexion was also determined for each motion segment from T1-2 to L5-S1. The majority of parameters measured for the 'global regions' (thoracic, lumbar, or hips) showed good between-day reliability. Depending on the parameter of interest, between-day ICCs ranged from 0.67 to 0.92 for examiner 1 (average 0.82) and 0.57 to 0.95 for examiner 2 (average 0.83); for 70% of the parameters measured, the ICCs were greater than 0.8 and generally highest for the lumbar spine and whole trunk measures. For lumbar spine range of flexion, the SEM was approximately 3 degrees. The ICCs were also good for the interexaminer comparisons, ranging from 0.62 to 0.93 on day 1 (average 0.81) and 0.70 to 0.94 on day 2 (average 0.86), although small systematic differences were sometimes observed in their mean values. The latter were still evident even if both examiners used the same skin markings. For segmental ranges of flexion, the ICCs varied between vertebral levels but overall were lower than for the global measures (average for all levels in all analyses, ICC 0.6). For each examiner, the average between-day SEM over all vertebral levels was approximately 2 degrees. For 'global' regions of the spine, the Spinal Mouse delivered consistently reliable values for standing curvatures and ranges of motion which compared well with those reported in the literature. This suggests that the device can be reliably implemented for in vivo studies of the sagittal profile and range of motion of the spine. As might be expected for the smaller angles being measured, the segmental ranges of flexion showed lower reliability. Their usefulness with regard to the interpretation of individual results and the detection of 'real change' on an individual basis thus remains questionable. Nonetheless, the group mean values showed few between-day differences, suggesting that the device may still be of use in providing clinically interesting data on segmental motion when examining groups of individuals with a given spinal pathology or undergoing some type of intervention.

The influence of initial resting posture on range of motion of the lumbar spine

The aim of this study was to investigate the influence of initial resting posture on range of motion of the lumbar spine in 18 normal subjects. Subjects resting posture and active range of motion was measured using the CA-6000 Spinal Motion Analyser (OSI, USA) in five test positions, namely in flat standing and with a variety of heel raises. Analysis showed that there was no significant correlation between subject's normal resting posture and active range of motion. However, when subjects resting posture was artificially altered with heel raises, significant effects on the active range of motion were demonstrated. Increasing heel height significantly influenced resting posture in the sagittal plane only. As heel height increased, the lumbar lordosis decreased and a significant reduction in the range of lumbar spine flexion (P<0.001) was observed. Simulating pelvic asymmetry influenced resting posture in the frontal plane and significant effects on the range of lateral flexion (P<0.05) were observed. These results have important clinical implications in terms of using range of motion of the lumbar spine as an examination tool and suggest that studies using range of motion as an outcome measure should consider initial resting posture.

Reliability of cervical range of motion using the OSI CA 6000 spine motion analyser on asymptomatic and symptomatic subjects

Cervical range of motion (ROM) is evaluated in both clinical and research settings. This study's purpose was to determine if ROM data obtained with the OSI CA 6000 Spine Motion Analyser (SMA) from asymptomatic and symptomatic cervical subjects were reliable within and between testers. Cervical ROM was measured in all three planes in 30 adult asymptomatic and 20 adult symptomatic subjects. A standardized protocol was used to fit each subject with the OSI SMA cervical hardware. Subjects were tested in a seated position with the trunk stabilized. Subjects performed four trials of each pain-free cervical motion during testing. The hardware was completely removed and replaced by the same tester and ROM trials in all three planes were repeated for intratester asymptomatic and symptomatic reliability. The same procedure was completed by a second tester for asymptomatic intratester and intertester reliability. Repeated measures analysis of variance and intraclass correlation coefficients (ICC [2,1 and 2 k]) were used to analyse intra- and intertester reliability data. Intratester ICCs were 0.85 or higher (except for flexion 0.76) for asymptomatic subjects and 0. 87 or higher (except for flexion 0.68) for symptomatic subjects for all motions. Intertester ICCs were 0.88 or higher for all motions. Standard error of measurements were less than 3.92 degrees for all motions. Measures of cervical spinal ROM obtained with the OSI SMA showed good intertester reliablity for all motions, and good intratester reliability for all motions with the exception of the motion of flexion for one of the examiners, which showed moderate reliability.

A comparison of two motion analysis devices used in the measurement of lumbar spinal mobility

OBJECTIVE. The aim of the study was to compare lumbar range of motion determined using two computerised dynamic motion analysis devices.

BACKGROUND

Measures of spinal motion are currently used in biomechanical, epidemiological and clinical studies of the low back. It is essential that the various devices used to measure mobility yield similar results, particularly when the absolute values are to be used to assess job suitability, the extent of injury or the need for rehabilitation.

METHODS

Eleven volunteers took part. The ranges of lumbar flexion, extension, lateral bending and axial rotation were measured using the CA6000 Spine Motion Analyser and the Polhemus Fastrak system, using standardised protocols.

RESULTS

Each device showed good test-retest reliability in itself (R0.82). The absolute values for range of flexion in a standing posture were significantly higher with the CA6000 than with the Fastrak (though well correlated); those recorded in sitting were comparable for the two devices. Values for lateral bending using the two devices were well correlated, although small (but significant) differences in the absolute values were found. For extension and axial rotation, the devices gave significantly different values that were also poorly correlated. The 'limits of agreement' for the two devices (calculated to examine whether they could be used interchangeably) were rather wide, especially for extension and axial rotation.

CONCLUSION

The two devices do not always yield comparable measures for spinal mobility. The accuracy of each, in relation to true angular movements of the vertebrae, remains unknown.

RELEVANCE

The two computerised motion analysis devices can each be used reliably in longitudinal studies. However, if 'normal' values for spinal mobility are to be established, they must be considered device-specific.