Can the computerized physical examination differentiate normal subjects from abnormal subjects with benign mechanical low back pain?

Is there evidence to use kinematic/kinetic measures clinically in low back pain patients? A systematic review

BACKGROUND

Currently, there is a widespread reliance on self-reported questionnaires to assess low back pain patients. However, it has been suggested that objective measures of low back pain patients' functional status should be used to aid clinical assessment. The aim of this study is to systematically review which kinematic /kinetic parameters have been used to assess low back pain patients against healthy controls and to propose clinical kinematic/kinetic measures.

METHODS

PubMed, Embase and Scopus databases were searched for relevant studies. Reference lists of selected studies and hand searches were performed. Studies had to compare people with and without non-specific low back pain while performing functional tasks and report body segment/joint kinematic and/or kinetic data. Two reviewers independently identified relevant papers.

FINDINGS

Sixty-two studies were included. Common biases identified were lack of assessor blinding and sample size calculation, use of samples of convenience, and poor experimental protocol standardization. Studies had small sample sizes. Range of motion maneuvers were the main task performed (33/62). Kinematic/kinetic data of different individual or combination of body segments/joints were reported among the studies, commonest was to assess the hip joint and lumbar segment motion (13/62). Only one study described full body movement. The most commonly reported outcome was range of motion. Statistically significant differences between controls and low back pain groups were reported for different outcomes among the studies. Moreover, when the same outcome was reported disagreements were noted.

INTERPRETATION

The literature to date offers limited and inconsistent evidence of kinematic/kinetic measures in low back pain patients that could be used clinically.

Multi-segment kinematic model to assess three-dimensional movement of the spine and back during gait

BACKGROUND

Relatively little is known about spine during gait compared to movement analysis of the lower extremities. The trunk is often regarded and analysed as a single rigid segment and there is a paucity of information on inter-segmental movement within the spine and its relationship to pelvis and lower limbs.

OBJECTIVES

To develop and validate a new multi-segment kinematic model to assess regional three-dimensional movement of the lumbar, lower thoracic and upper thoracic spine during gait.

STUDY DESIGN

Observational study.

METHODS

The study was conducted in two parts: (1) to provide validation measures on the kinematic model built in commercially available software and (2) to apply the marker configuration to the spine at T3, T8 and L3 during gait analysis on 10 healthy male volunteers.

RESULTS

Proposed model revealed excellent concurrent validation measures between an applied input angle to the recorded output angle from the kinematic model. A high reliability was observed during gait analysis, both during a single session and between sessions for all participants.

CONCLUSION

The thoracic region of the spine should not be modelled as a single rigid segment and the proposed three-dimensional cluster is reliable and repeatable to assess the inter-segmental movement of the spine.

CLINICAL RELEVANCE

Reliable kinematic data can be collected using the three-dimensional cluster technique, thus, allowing researchers to accurately distinguish between movement patterns of healthy individuals to those with a clinical condition, and provide confidence in data acquisition during the monitoring process of an implemented rehabilitation intervention programme.

Lumbopelvic rhythm during forward and backward sagittal trunk rotations: combined in vivo measurement with inertial tracking device and biomechanical modeling

BACKGROUND

The ratio of total lumbar rotation over pelvic rotation (lumbopelvic rhythm) during trunk sagittal movement is essential to evaluate spinal loads and discriminate between low back pain and asymptomatic population.

METHODS

Angular rotations of the pelvis and lumbar spine as well as their sagittal rhythm during forward flexion and backward extension in upright standing of eight asymptomatic males are measured using an inertial tracking device. The effect of variations in the lumbopelvic ratio during trunk flexion on spinal loads is quantified using a detailed musculoskeletal model.

FINDINGS

The mean of peak voluntary flexion rotations of the thorax, pelvis, and lumbar was 121° (SD 9.9), 53.0° (SD 5.2), and 60.2° (SD 8.6), respectively. The mean lumbopelvic ratios decreased from 2.51 in 0-30° of trunk flexion to 1.34 in 90-120° range during forward bending while it increased from 1.23 in 90-120° range to 2.86 in 0-30° range during backward extension. Variations in the lumbopelvic ratio from 0.5 to 3 (with an interval of 0.25) at any trunk flexion angle generally reduced the L5-S1 compression and shear forces by up to 21 and 45%, respectively. The measured lumbopelvic ratios resulted overall in near-optimal (minimal) L5-S1 compression forces.

INTERPRETATION

A simultaneous rhythm between the lumbar and pelvis movements was found during both forward and backward trunk movements. While the lumbar spine contributed more to the trunk rotation during early and final stages of forward flexion and backward extension, respectively, the pelvis contributed more during final and early stages of forward flexion and backward extension, respectively. Our healthy subjects adapted a lumbopelvic coordination that diminished L5-S1 compression force.

The relationship between work function and low back pain history in occupationally active individuals

PURPOSE

To investigate the relationship between work function and low back pain (LBP) history.

STUDY DESIGN

Cross-sectional study.

BACKGROUND

In some countries, traditional medical examinations do not assess work performance in people who continue working despite a history of LBP, although such assessment may be required.

METHODS

A total of 100 industrial metal workers were assigned to groups with and without LBP history. Logistic regression and t-tests examined the associations between physical work performance (represented by dynamic strength evaluation) and the group, and compared worker performance between the two groups. Similar tests examined potentially confounding effects on group assignment.

RESULTS

Work performance was significantly associated with the group in dynamic strength sub-tests assessing weight lifting and carrying. The weights handled were lower in the group with LBP history (p < 0.05). Only the workers' country of origin affected group assignment; adjustment for this factor, as well as for age and education improved the associations between work performance and the group.

CONCLUSIONS

Workers with a history of LBP display decreased physical performance at work, which should be subject to further research and treated as a health-related problem in accordance with the ICF model.

Disability measurement in persons with back pain: a validity study of spinal range of motion and velocity

OBJECTIVE

To evaluate the criterion validity and responsiveness to change of spine kinematic variables to assess disability in patients with low back pain.

DESIGN

Blinded comparison between spine kinematic variables, Oswestry disability questionnaire scores, and work status.

SETTING

Multidisciplinary occupational rehabilitation clinic of a university hospital.

PATIENTS

Population-based cohort of 111 patients with subacute work-related back pain who were absent from regular work for more than 4 weeks because of back pain.

INTERVENTIONS

This study was part of a population-based randomized clinical trial. Patients were randomized to 4 different methods of management: usual care, rehabilitation, ergonomics, or rehabilitation and ergonomics.

MAIN OUTCOME MEASURES

Oswestry disability questionnaire, kinematic analysis of the spine during flexion and extension of the trunk, and work status were collected at weeks 4, 12, 24, and 52 after the back accident.

RESULTS

Kinematic variables were poorly to moderately related to work status and Oswestry questionnaire scores. Kinematic variables were also unresponsive to change in work status and Oswestry questionnaire scores over time.

CONCLUSION

Spine kinematics during flexion and extension of the trunk do not appear to be a valid measure of disability in patients with subacute and chronic back pain.

Relationship between functional evaluation measures and self-assessment in nonacute low back pain

STUDY DESIGN

The correlations between objective biomechanical indicators of function and self-assessment scores were examined retrospectively for 91 subjects with nonacute low back pain.

OBJECTIVES

To examine the correlation between self-assessment, trunk range of motion (ROM), velocity, and complex mechanical coordination patterns of the spine in nonacute low back pain.

SUMMARY OF BACKGROUND DATA

In low back pain, there is often little concordance between pain, physical impairment, and disability. Use of range of motion and velocity to enhance objectivity in impairment evaluations has been ineffectual. In this study, two hypotheses were examined: range of motion and velocity are controllable and inherently correlated with self-assessment; complex spinal coordination patterns such as range of lordosis cannot be controlled and are independent of self-assessment.

METHODS

Self-assessment questionnaires were administered, and indexes of spinal motion and coordination were measured through skin marker kinematics. The correlation between self-assessments and biomechanical measures was determined.

RESULTS

Self-assessments of function were significantly correlated with parameters prone to regulation: range of motion, velocity, and load lifted. In contrast, little correlation was found with measures of complex spinal coordination less susceptible to conscious or affective regulation, namely, range of lordosis and estimated segmental mobility. This effect was magnified with increased load. Self-assessment scores were significantly poorer among insurance referrals, regardless of functional status.

CONCLUSIONS

Simple parameters of the functional examination, such as range of motion and velocity, are strongly correlated with cognitive state, and thus the information they supply is less than ideal. Complex spinal coordination is a better indicator of the degree of spinal dysfunction and enhances the process of differentiating between pain, disability, and functional impairment.

The effect of load on the coordination of the trunk for subjects with and without chronic low back pain during flexion-extension and lateral bending tasks

OBJECTIVE

To evaluate if patients move their trunk sections differently than normal subjects and to determine if these differences increase when lifting a load.

DESIGN

Comparative study using a repeated measures design.

BACKGROUND

Many studies demonstrate a modification of the lumbar-pelvic rhythm for chronic low back pain patients but the large variability of the results impair the discrimination power. It was hypothesized that the lifting of a load would magnify the manifestation of lumbar impairments.

METHODS

Fifteen chronic low back pain patients and 18 normal subjects performed maximal flexion-extension and lateral bending of the trunk with and without a 12 kg load. The pelvic, lumbar and thoracic motions were measured with a motion analysis system.

RESULTS

During flexion-extension tasks, a significant decrease in lumbar flexion and increase in thoracic flexion were observed for the patients. The load effect was significant for all trunk sections but did not allow a better discrimination between groups.

CONCLUSIONS

Lifting a 12 kg load during flexion-extension of the trunk did confirm alteration in trunk section coordination but did not help to better discriminate patients from normal subjects. However, it was demonstrated for the first time that chronic low back pain patients compensate for a loss of lumbar flexion by increasing their thoracic flexion.

RELEVANCE

The lumbar-pelvic rhythm is routinely used to evaluate low back impairments. The use of kinematic measures enhance the objectivity of the examination but the large variability of the results impair the discrimination power. Lifting a load during such an evaluation might magnify the low back impairments and increase the discrimination power of this measure.

Lumbar-pelvic coordination is influenced by lifting task parameters

STUDY DESIGN

Low back kinematics, including relative lumbar and pelvic motions, were quantified during controlled lifting tasks.

OBJECTIVES

To evaluate the influence of load and lifting velocity on lumbar-pelvic (LP) coordination.

SUMMARY OF BACKGROUND DATA

Sagittal trunk extension is achieved through the coordinated motion of the pelvis and lumbar spine. There are no data to indicate whether lifting task design influences lumbar-pelvic coordination.

METHODS

Lumbar and pelvic motions were recorded from 18 healthy subjects while performing isokinetic lifting tasks of 0.1 kg and 10 kg. Coordinated motions of the pelvis (sacral spine) and low-thoracic spine were evaluated using eigenvector analyses and a ratio of lumbar and pelvic angles (L/P).

RESULTS

Eigenvector models of the lumbar-pelvic coordination accurately represented empirical coordination profiles. Weight significantly influenced lumbar-pelvic coordination. Trunk extension velocity demonstrated a small but statistically significant influence on lumbar-pelvic coordination. Weight and trunk flexion angle significantly influenced lumbar/pelvic angle ratios.

CONCLUSIONS

Trunk extension was achieved through simultaneous but nonlinear contributions from both the pelvis and lumbar spine throughout the range of motion. The lumbar spine accounted for 70% of the total, with increased pelvic contributions in flexed postures. Task weight increased the lumbar contribution to total trunk motion. When performing clinical evaluations of spinal kinematics, it is necessary to recognize that unloaded motions may not fully represent loaded behavior of spinal coordination.

Improving the evaluation of benign low back pain

STUDY DESIGN

A prospective, blind study was conducted to investigate the factors underlying the decisions of expert clinicians in diagnosis of acute, benign low back pain, compared with results obtained with an automated physical examination by machine. From the results, a strategy to significantly improve clinical diagnosis in cases of discordance was determined.

OBJECTIVES

To identify factors in the clinical assessment of low back pain that indicate when independent diagnostic testing would be useful.

SUMMARY OF BACKGROUND DATA

The clinical evaluation of low back pain is often dominated by subjective reports of pain. Published medical literature has underscored several inherent weaknesses of the clinical examination, and concerns have been raised about its effectiveness for assessing patients with low back pain. Thus, it has been proposed that objective measures to complement the clinician's examination would be beneficial in the formulation of dependable diagnoses.

METHODS

Randomly designated subjects, who in describing their conditions were objective or role playing, were assessed by clinicians and a machine for diagnosis of low back pain assessment versus normal backs. Each subject's pain assessment was compared with a gold standard that was established by experts in low back pain. Components of the clinical examination were analyzed to assess which were the most informative in making a reliable diagnosis. The information content of the machine assessment was also analyzed and a strategy to complement the clinical diagnosis with the machine diagnosis determined.

RESULTS

Discordance among the various components of the clinical examination was a strong indicator of when the efficacy of the clinical examination dropped below a random level of decision making. When there was discordance, incorporating the functional evaluation by machine into the clinical diagnosis improved the performance of the clinician. Notably, in nonobjective subjects, the accuracy of diagnosis was enhanced by as much as 69%.

CONCLUSIONS

It is possible to improve the accuracy of clinical diagnosis by incorporating a functional evaluation by machine when there is discordance between physical examination findings and reported pain.

Evaluation of clinician and machine performance in the assessment of low back pain

STUDY DESIGN

A prospective blind study to test and compare the performance of clinicians (evaluators) with that of an automated machine (the Spinoscope) in conducting an examination on randomly designated simulators/dissimulators and honest subjects to assess acute benign low back pain.

OBJECTIVES

To test the impact of reported pain and history on the clinical examination and to compare the ability of clinicians and the machine to recognize normal findings in a controlled group of subjects with and without benign low back pain.

BACKGROUND

The literature raises serious questions regarding the efficacy of the clinical examination for patients with low back pain.

METHODS

A "gold standard" (clinical examination by experts in low back pain) was established against which the clinical examination by the evaluators and the machine assessment (incorporating weight-lifting ability) of honest subjects and simulators/dissimulators were compared using the receiver operating characteristic technique. The selection of subjects was performed according to strict inclusion and exclusion criteria.

RESULTS

The evaluators were more accurate with the honest subjects, the machine more accurate with the simulators/dissimulators, and, for the entire population tested, the they were equivalent in accuracy (71% vs. 72% concordance). Results from the machine's expert system and from clinician readers of the machine data compared favorably. The machine's concordance with the gold standard increased with increasing loads lifted by the subject.

CONCLUSION

By relying primarily on the subject's self-presentation, often to the exclusion of objective findings, the clinician may err in evaluating low back function when the patient does not report his or her true condition. The additional functional analysis provided by the machine offers the clinician objective, pertinent information to complement the findings from the clinical examination.

The impact of inefficient clinical diagnosis on the cost of managing low back pain

The clinical examination remains the pivotal factor in evaluating low back pain (LBP) for decisions concerning compensation and rehabilitation. Many practitioners believe it to be highly reliable, even though existing literature does not support this belief. Not only are there no data supporting the efficacy of clinical diagnosis for LBP, but also published data underscore its many inherent weaknesses. Healthcare risk managers need accurate clinical information to make decisions. If current clinical information is unreliable, then healthcare risk management strategies for LBP must be revised. This article reviews the work of many researchers in their attempts to unravel the problem of diagnosing LBP. The following conclusions were reached: The problem is significant and continues to increase. The problem is rooted in the clinician's strong dependency on reported pain, which may not always be a reliable source of objective information. Quantification of the impact of the objectivity of reported pain on clinical performance demonstrates the need for a independent source of functional data that can improve the diagnosis. Technology exists to complement the clinical examination, improve clinical performance, and thus reduce the cost associated with LBP management. The research results presented in this article unveil disturbing findings for healthcare risk managers. The strong bias clinicians reserve for reported pain may lead them to overrate pathology, treat patients inappropriately, prescribe unnecessary imaging tests, and generate unfounded medical opinions that are responsible for many disputes. Data are presented to demonstrate the financial benefits that result from the introduction of systematic objective controls via technology. These sound management principles allow the risk manager to determine the validity of claims and treatment proposals. Risk managers can then make informed decisions on contentious claims and regulate the large number of clinician-supported disability cases--decisions that represent significant savings.