Are Lumbar Repositioning Errors Larger Among Patients With Chronic Low Back Pain Compared With Asymptomatic Subjects?

The associations between lumbar proprioception and postural control during and after calf vibration in people with and without chronic low back pain

The relationships of lumbar proprioception with postural control have not been clarified in people with chronic low back pain. This study aimed to compare the associations between lumbar proprioception and postural control in response to calf vibration in individuals with and without chronic low back pain. In this study, we recruited twenty patients with chronic low back pain (CLBP group) and twenty healthy control subjects (HC group) aged between 18 and 50 years. This study was a cross-sectional study and completed from May 2022 to October 2022. The passive joint repositioning sense (PJRS) test for two positions (15° and 35°) were used to assess lumbar proprioception and expressed as the mean of reposition error (RE). Postural control was tested by adding and removing calf vibration while standing on a stable force plate with eyes closed. The sway velocity in the anterior-posterior (AP) direction of center of pressure (COP) data with a window of 15s epoch at baseline, during and after calf vibration was used to evaluate postural control. Mann-Whitney U-tests were used to compare the difference of lumbar proprioception between two groups, and the independent t-tests were used to compare the difference of postural control at baseline and during vibration, and a mixed design ANOVA was used to compare the difference of postural control during post-perturbation. In addition, to explore the association between postural control and lumbar proprioception and pain intensity, Spearman's correlations were used for each group. The major results are: (1) significantly higher PJRS on RE of 15° (CLBP: 95% CI [2.03, 3.70]; HC: 95% CI [1.03, 1.93]) and PJRS on RE of 35° (CLBP: 95% CI [2.59, 4.88]; HC: 95% CI [1.07, 3.00]) were found in the CLBP group; (2) AP velocity was not different between the CLBP group and the HC group at baseline and during calf vibration. However, AP velocity was significantly larger in the CLBP group compared with the HC group at epoch 2-14 after calf vibration, and AP velocity for the CLBP group took a longer time (23 epochs) to return to the baseline after calf vibration compared with the HC group (9 epochs); (3) lumbar proprioception represented by PJRS on RE of 15°correlated negatively with AP velocity during and after vibration for the HC group. Within the CLBP group, no significant relationships between PJRS on RE for two positions (15° and 35°) and AP velocity in any postural phases were found. In conclusion, the CLBP group has poorer lumbar proprioception, slower proprioceptive reweighting and impaired postural control after calf vibration compared to the HC group. Lumbar proprioception offers different information on the control strategy of standing control for individuals with and without CLBP in the situations with proprioceptive disturbance. These results highlight the significance of assessing lumbar proprioception and postural control in CLBP patients.

The effects of proprioceptive weighting changes on posture control in patients with chronic low back pain: a cross-sectional study

Introduction

Patients with chronic low back pain (CLBP) exhibit changes in proprioceptive weighting and impaired postural control. This study aimed to investigate proprioceptive weighting changes in patients with CLBP and their influence on posture control.

Methods

Sixteen patients with CLBP and 16 healthy controls were recruited. All participants completed the joint reposition test sense (JRS) and threshold to detect passive motion test (TTDPM). The absolute errors (AE) of the reposition and perception angles were recorded. Proprioceptive postural control was tested by applying vibrations to the triceps surae or lumbar paravertebral muscles while standing on a stable or unstable force plate. Sway length and sway velocity along the anteroposterior (AP) and mediolateral (ML) directions were assessed. Relative proprioceptive weighting (RPW) was used to evaluate the proprioception reweighting ability. Higher values indicated increased reliance on calf proprioception.

Results

There was no significant difference in age, gender, and BMI between subjects with and without CLBP. The AE and motion perception angle in the CLBP group were significantly higher than those in the control group (JRS of 15°: 2.50 (2.50) vs. 1.50 (1.42), JRS of 35°: 3.83 (3.75) vs. 1.67 (2.00), p_JRS < 0.01; 1.92 (1.18) vs. 0.68 (0.52), p_TTDPM < 0.001). The CLBP group demonstrated a significantly higher RPW value than the healthy controls on an unstable surface (0.58 ± 0.21 vs. 0.41 ± 0.26, p < 0.05). Under the condition of triceps surae vibration, the sway length (p_stable < 0.05; p_unstable < 0.001), AP velocity (p_stable < 0.01; p_unstable < 0.001) and ML velocity (p_unstable < 0.05) had significant group main effects. Moreover, when the triceps surae vibrated under the unstable surface, the differences during vibration and post vibration in sway length and AP velocity between the groups were significantly higher in the CLBP group than in the healthy group (p < 0.05). However, under the condition of lumbar paravertebral muscle vibration, no significant group main effect was observed.

Conclusion

The patients with CLBP exhibited impaired dynamic postural control in response to disturbances, potentially linked to changes in proprioceptive weighting.

Relationship between Trunk Position Sense and Trunk Control in Children with Spastic Cerebral Palsy: A Cross-Sectional Study

METHODS

In this study, 24 children with spastic CP aged between 8 and 15 years were recruited. They were classified based on their functional performance using Gross Motor Function Classification System (GMFCS). Trunk control and trunk position sense were assessed using the trunk control measurement scale (TCMS) and digital goniometer, respectively. The correlation between these variables was tested using Spearman's correlation coefficient.

RESULTS

Significant negative correlation was found between trunk position sense and TCMS score. Similarly, a significant moderate correlation was found between trunk position sense and GMFCS. A strong negative correlation was also found between GMFCS and TCMS.

CONCLUSION

Children with spastic CP with better trunk position sense had better trunk control. Similarly, children with higher functional performance had better trunk control and lesser error in trunk position sense. The current findings imply the relevance of proprioceptive training of the trunk for enhancing trunk motor control in children with spastic CP.

Intra-rater and inter-rater reliability of neutral and target lumbar positioning tests in subjects with and without non-specific lower back pain

BACKGROUND

Proprioception, one's sense of movement and position, is a common term used in back rehabilitation. Kinesthetic rehabilitation may be useful in managing lower back pain; however, reliable measures are required to quantify lumbar proprioception sense.

OBJECTIVE

To investigate intrarater and interrater reliability of neutral lumbar positioning (NLP) and target lumbar positioning (TLP) tests and compare the position sense errors in subjects with non-specific low back pain and healthy controls.

METHODS

Intrarater (between-day) and interrater (within-day) reliability of NLP and TLP tests were assessed in 30 subjects with low back pain and 30 healthy subjects using a digital inclinometer. NLP is evaluated when the subject is repositioned to neutral from flexion, while TLP is evaluated in lumbar flexion, by bending laterally left and right.

RESULTS

Intrarater reliability for NLP tests had ICC values of 0.85 and 0.89 and TLP tests had 0.78 and 0.92. Likewise, interrater reliability for NLP had ICC values of 0.75 and 0.85, and for the TLP test, the interrater reliability had 0.78 and 0.93. Subjects with back pain had significantly larger neutral and target lumbar proprioceptive errors compared to healthy controls (p< 0.001).

CONCLUSIONS

Intrarater and interrater reliability showed good agreement for both NLP and TLP tests of lumbar proprioception. Subjects with nonspecific low back pain have impaired lumbar proprioceptive sense.

Lumbo-pelvic proprioception in sitting is impaired in subgroups of low back pain-But the clinical utility of the differences is unclear. A systematic review and meta-analysis

BACKGROUND

Altered spinal postures and altered motor control observed among people with non-specific low back pain have been associated with abnormal processing of sensory inputs. Evidence indicates that patients with non-specific low back pain have impaired lumbo-pelvic proprioceptive acuity compared to asymptomatic individuals.

OBJECTIVE

To systematically review seated lumbo-pelvic proprioception among people with non-specific low back pain.

METHODS

Five electronic databases were searched to identify studies comparing lumbo-pelvic proprioception using active repositioning accuracy in sitting posture in individuals with and without non-specific low back pain. Study quality was assessed by using a modified Downs and Black's checklist. Risk of bias was assessed using an adapted tool for cross-sectional design and case-control studies. We performed meta-analysis using a random effects model. Meta-analyses included subgroup analyses according to disability level, directional subgrouping pattern, and availability of vision during testing. We rated the quality of evidence using the GRADE approach.

RESULTS

16 studies met the eligibility criteria. Pooled meta-analyses were possible for absolute error, variable error, and constant error, measured in sagittal and transverse planes. There is very low and low certainty evidence of greater absolute and variable repositioning error in seated tasks among non-specific low back pain patients overall compared to asymptomatic individuals (sagittal plane). Subgroup analyses indicate moderate certainty evidence of greater absolute and variable error in seated tasks among directional subgroups of adults with non-specific low back pain, along with weaker evidence (low-very low certainty) of greater constant error.

DISCUSSION

Lumbo-pelvic proprioception is impaired among people with non-specific low back pain. However, the low certainty of evidence, the small magnitude of error observed and the calculated "noise" of proprioception measures, suggest that any observed differences in lumbo-pelvic proprioception may be of limited clinical utility.

PROSPERO-ID

CRD42018107671.

Trunk control during repetitive sagittal movements following a real-time tracking task in people with chronic low back pain

Precision of trunk movement has commonly been examined by testing relocation accuracy rather than evaluating accuracy of tracking dynamic movement. In this study we used a 3-D motion capture system to provide a novel real-time tracking task to assess trunk motor control at varying movement speeds between people with and without chronic non-specific low back pain (LBP). Eleven asymptomatic volunteers and 15 participants with chronic non-specific LBP performed 12 continuous cycles of trunk flexion-extension following real time visual feedback, during which, trunk motion was measured using eight optoelectronic infrared cameras. Significant time differences between the feedback and actual trunk motion were found between groups (P = 0.001). Both groups had similar variability of tracking accuracy when following the feedback (P > 0.05). However, tracking variability at a slow speed correlated (P = 0.03; r = 0.55) with the Fear-Avoidance Beliefs Questionnaire (FABQ) scores in those with LBP. This study shows that both asymptomatic people and individuals with LBP displayed anticipatory behaviour, however, the response of those with LBP was consistently delayed in tracking the visual feedback compared to the asymptomatic group. Additionally, the extent of variability of tracking accuracy over repeated tracking cycles was associated with the degree of fear of movement in people with LBP.

Differences in Proprioception Between Young and Middle-Aged Adults With and Without Chronic Low Back Pain

Introduction: While young adults with chronic low back pain (CLBP) exhibit impaired lumbar proprioception, it remains unclear if the same phenomenon is observed in middle-aged adults with CLBP. Objectives: This study aimed to investigate whether young or middle-aged adults with CLBP displayed different proprioception ability as compared to age-matched asymptomatic controls. Methods: Sixty-four young adults with [median age:34 [interquartile range (IQR): 29-37] years] and without [median age:29 (IQR; 23-34) years] CLBP, and 87 middle-aged adults with [median age:53 (IQR: 49-58) years] and without [median age: 54 (IQR: 45-64) years] CLBP underwent postural sway tests on a force-plate with (unstable surface) and without a foam (stable surface), while bilateral L5/S1 multifidi and triceps-surae were vibrated separately. An individual's proprioception reweighting ability was estimated by relative proprioceptive reweighting (RPW). Higher RPW values indicate less reliance on lumbar multifidus proprioceptive signals for balance. Participants also underwent lumbar repositioning tests in sitting to determine repositioning errors in reproducing target lumbar flexion/extension positions. Results: Young adults with CLBP demonstrated significantly higher median RPW values than age-matched asymptomatic controls for maintaining standing balance [stable surface: CLBP: 0.9 (IQR: 0.7-0.9), asymptomatic: 0.7 (IQR: 0.6-0.8), p < 0.05; unstable surface: CLBP: 0.6 (IQR: 0.4-0.8), asymptomatic: 0.5 (IQR: 0.3-0.7), p < 0.05]. No significant differences in repositioning error were noted between young or middle-aged adults with and without CLBP (p > 0.05). RPW values were unrelated to repositioning errors in all groups (p > 0.05). Conclusion: Young adults with CLBP, and middle-aged adults with and without CLBP had inferior proprioceptive reweighting capability. This finding may indicate potential age-related deterioration in central and peripheral processing of lumbar proprioceptive signals. Future studies should use advanced imaging and/or electroencephalogram to determine mechanisms underlying changes in proprioceptive reweighting in middle-aged adults.

Short-term effect of kinesiology taping on pain, functional disability and lumbar proprioception in individuals with nonspecific chronic low back pain: a double-blinded, randomized trial

Background

This study aimed to evaluate the effect of kinesiology taping (KT) on lumbar proprioception, pain, and functional disability in individuals with nonspecific chronic low back pain (CLBP).

Methods

Thirty individuals with nonspecific CLBP participated in this double-blinded, randomized clinical trial from July 2017 to September 2018. The participants were randomized into two groups: KT (n = 15) and placebo group (n = 15). KT was applied with 15–25% tension for 72 h, and placebo taping was used without tension. Lumbar repositioning error was measured by a bubble inclinometer at three different angles (45° and 60° flexion, and 15° extension) in upright standing. Pain and disability were assessed by the Short-Form McGill Pain Questionnaire and Oswestry Disability Index, respectively. All measurements were recorded at baseline and 3 days after taping.

Results

Pain and disability scores reduced 3 days after taping in the KT group with large effect sizes (p < 0.05). Only the total score of pain was significantly different between the groups 3 days after taping and improved more in the KT group with a large effect size (p < 0.05). However, lumbar repositioning errors were similar between the groups after 3 days (p > 0.05). Also, only constant error of 15° extension showed a moderate correlation with disability (r = 0.39, p = 0.02).

Conclusion

KT can decrease pain and disability scores after 3 days of application. Although placebo taping can reduce pain, the effect of KT is higher than placebo taping. The findings do not support the therapeutic effect of KT and placebo taping as a tool to enhance lumbar proprioception in patients with nonspecific CLBP.

Trial registration

The study prospectively registered on 21.05.2018 at the Iranian Registry of Clinical Trials: IRCT20090301001722N20.

Effect of a Spinomed orthosis on balance performance, spinal alignment, joint position sense and back muscle endurance in elderly people with hyperkyphotic posture: A randomized controlled trial

BACKGROUND

Hyperkyphosis may cause balance impairment in elderly people. Although the effectiveness of orthoses for improving balance in hyperkyphotic elderly people has received much attention, the mechanisms by which devices affect balance remain unknown.

OBJECTIVES

The objective of this study was to evaluate changes in balance performance, thoracic kyphosis angle, craniovertebral angle, back muscle endurance and joint position sense after 3 months of wearing a Spinomed orthosis. The study also included a secondary exploratory analysis to determine whether changes in any of the above-mentioned outcome measures can predict balance performance improvement in elderly people with hyperkyphosis.

STUDY DESIGN

Parallel group randomized controlled trial.

METHODS

In total, 44 hyperkyphotic elderly people were randomly allocated to an experimental group, who wore a Spinomed orthosis and a control group, who did not. No other treatment or change in physical activity was permitted during the study. A blinded assessor evaluated thoracic kyphosis angle, joint position sense, craniovertebral angle, back muscle endurance, Timed Up and Go Test time and Berg Balance Scale score at baseline and after 5, 9 and 13 weeks. All dependent variables were measured without the orthosis and analyzed separately using a 2 × 4 (time × group) mixed model analysis of variance. Based on the results of correlation analysis, thoracic kyphosis angle, back muscle endurance and joint position sense were selected as independent variables in a stepwise multiple regression model.

RESULTS

The two-way (group × time) interactions were significant in terms of Berg Balance Scale (F = 11.6, P ⩽ 0.001, ηp2=0.59), Timed Up and Go Test (F = 3.74, P = 0.013, ηp2=0.46), thoracic kyphosis angle (F = 43.39, P ⩽ 0.001, ηp2=0.96), craniovertebral angle (F = 5.245, P = 0.002, ηp2=0.59) and joint position sense (F = 4.44, P = 0.005, [Formula: see text]). The two-way interaction was not significant in terms of back muscle endurance; however, the main effect of group was significant for this variable (F = 3.85, P = 0.025). Stepwise multiple regression showed that thoracic kyphosis angle and joint position sense were significant determinants of Timed Up and Go Test time (R² = 0.155, P = 0.037 and R² = 0.292, P = 0.012, respectively).

CONCLUSION

Wearing a Spinomed orthosis for 3 months improved the posture, position sense and muscle performance of hyperkyphotic elderly people. Orthoses may improve balance performance by correcting spinal alignment and increasing proprioceptive information.

Balance Control in Patients with Subacute Non-Specific Low Back Pain, with and without Lumbar Instability: A Cross-Sectional Study

BACKGROUND

Patients with low back pain (LBP) have poorly coordinated neuromuscular control, which may alter the normal postural stability of the spine. Altered movement control may occur at any stage of LBP.

PURPOSE

(1) To identify differences in balance control and proprioceptive sense between subacute non-specific LBP (NSLBP) patients with and without lumbar instability (LI) and healthy subjects and (2) to investigate the correlation between factors of motor control deficits and balance.

PATIENTS AND METHODS

Thirty-six participants matched by gender, age, and body mass index (BMI) were allocated into three groups of 12: subacute NSLBP patients with LI, subacute NSLBP patients without LI, and healthy subjects. Balance, proprioceptive sense, pain, functional disability, and fear of movement were evaluated.

RESULTS

Subacute NSLBP patients with LI exhibited greater impairments in balance control, proprioceptive sense, and functional ability than patients without LI (p<0.05). Subacute NSLBP patients showed more impairments in balance control, proprioceptive sense, and fear of movement than healthy subjects (p<0.001), with the following effect sizes (partial η2) for static balance on stable and unstable surface: 0.597 and 0.560, anticipatory balance: 0.417, and dynamic balance: 0.536; proprioceptive sense: 0.676; and fear of movement: 0.379. Significant fair correlations were found between (1) static balance and proprioceptive sense, functional disability, and fear of movement; (2) functional reach test (FRT) and pain; and (3) the five times sit to stand test (FTSTS) and functional disability.

CONCLUSION

Subacute NSLBP patients with LI showed greater impairment in balance control than patients without LI. Reduced proprioceptive sense, increased pain, functional disability, and fear of movement were fairly related to impaired balance.

Effect of sustained experimental muscle pain on joint position sense

Introduction:

Joint position sense (JPS) is impaired in clinical musculoskeletal pain conditions, but when this impairment develops in the transition from initial to prolonged pain is not known.

Objectives:

This study assessed whether progressively developing sustained experimentally induced muscle pain impacts JPS in healthy individuals.

Methods:

Twenty-eight healthy individuals received injection of nerve growth factor (NGF) into the right extensor carpi radialis brevis muscle on days 0 and 2 to induce sustained pain and hyperalgesia. Wrist JPS was assessed 2 days before day 0 (day −2), before the injection on days 0 and 2, and on days 4 and 14. Joint position sense was quantified as the ability to return the wrist to a neutral position following movements in the direction of radial and ulnar deviation. A 3-dimensional motion analysis system was used to calculate absolute, relative, and joint-angle repositioning errors. Numerical rating scale scores of pain intensity, body chart pain drawings, and pressure pain thresholds (PPTs) were recorded on each day.

Results:

Compared with baseline, pressure pain thresholds decreased while pain intensity and area increased at day 2 (P < 0.001) and day 4 (P < 0.001) before returning to baseline on day 14 (P > 0.13). Relative to day 0, there was no change in wrist JPS at day 2, 4, and 14 following movements in either target direction (P > 0.05).

Conclusion:

Despite the presence of sustained muscle pain and hyperalgesia for 4 days at the elbow, no statistical change in wrist joint position error was observed. These findings suggest that pain and hyperalgesia lasting as long as 4 days does not impair JPS.

Relationship Between Proprioception and Pain and Disability in People With Non-Specific Low Back Pain: A Systematic Review With Meta-Analysis

STUDY DESIGN

Systematic review with meta-analysis.

OBJECTIVE

To examine the association between proprioception and pain and disability in people with non-specific low back pain (NSLBP) and the impact of potential moderators on the strength of the association.

SUMMARY OF BACKGROUND DATA

NSLBP is a common musculoskeletal disorder and a leading cause of disability. Proprioception deficit has been associated with low back pain and correlated with pain and disability; however, the correlation coefficients presented are conflicting.

METHODS

Systematic literature search was performed in eight databases and Google scholar. Two independent reviewers assessed the literature and extracted data. Data of interest included participant characteristics of NSLBP group, pain and disability, proprioception test protocol, and the correlation coefficient between proprioception and pain/disability. Meta-analysis of data from homogeneous studies was performed according to proprioception test methods. Subgroup of movement directions was analyzed. The methodological quality of studies was assessed.

RESULTS

The literature search identified 3067 records of which 14 studies were included for meta-analysis. Proprioception was measured by active joint repositioning sense (AJRS), passive joint repositioning sense (PJRS), and threshold to detect passive motion (TTDPM). Meta-analysis revealed no significant correlation coefficient between any proprioception measures and pain or disability (P > 0.05). The subgroup analysis showed little correlation between absolute error (AE) of passive lumbar flexion and pain (r = 0.225, 95% CI 0.040-0.395), and between AE of passive lumbar extension and disability (r = 0.196, 95%CI 0.010-0.369).

CONCLUSION

AJRS and TTDPM are not correlated with pain and disability in people with NSLBP. The AE of passive lumbar movement is correlated to a small degree with pain and disability. However, the degree of correlation is small and should be interpreted with caution. Therefore, the differences in proprioception observed between people with pain and people without pain seem to be independent of the symptoms.

LEVEL OF EVIDENCE

1.

Anteroposterior perception of the trunk position while seated without the feet touching the floor

[Purpose] The purpose of this study was to investigate the trunk position perception in the anteroposterior direction in young participants sitting without their feet touching the floor to avoid the influence of the hamstrings tension and the feet pressure on the perception. [Subjects and Methods] Fourteen healthy volunteers were seated on a chair fitted with an original manual goniometer. There were 7 reference positions set at 5° increments, from −15° to 15°, and reproductions of each position were conducted 5 times. Trunk position perception was evaluated by the absolute error between the reproduced trunk angle and the reference position angle. [Results] The results revealed a significant effect of reference position on the absolute error. The absolute error at the −5° reference position was significantly larger than at the −15° and 15° positions, and the absolute error at the 0° position was significantly larger than at the −15°, 10°, and 15° positions. [Conclusion] These results suggest that the perception of extreme forward- and backward-leaning trunk positions while sitting without the feet touching the floor would be higher than in a neutral sitting position. The relationship between the stability of the posture and the perception may be involved in the sitting position.

Is There a Relationship Between Lumbar Proprioception and Low Back Pain? A Systematic Review With Meta-Analysis

OBJECTIVE

To systematically review the relationship between lumbar proprioception and low back pain (LBP).

DATA SOURCES

Four electronic databases (PubMed, EMBASE, CINAHL, SPORTDiscus) and reference lists of relevant articles were searched from inception to March-April 2014.

STUDY SELECTION

Studies compared lumbar proprioception in patients with LBP with controls or prospectively evaluated the relationship between proprioception and LBP. Two reviewers independently screened articles and determined inclusion through consensus.

DATA EXTRACTION

Data extraction and methodologic quality assessment were independently performed using standardized checklists.

DATA SYNTHESIS

Twenty-two studies (1203 participants) were included. Studies measured lumbar proprioception via active or passive joint repositioning sense (JRS) or threshold to detection of passive motion (TTDPM). Data from 17 studies were pooled for meta-analyses to compare patients with controls. Otherwise, descriptive syntheses were performed. Data were analyzed according to measurement method and LBP subgroup. Active JRS was worse in patients compared with controls when measured in sitting (standard mean difference, .97; 95% confidence interval [CI], .31-1.64). There were no differences between groups measured via active JRS in standing (standard mean difference, .41; 95% CI, -.07 to .89) or passive JRS in sitting (standard mean difference, .38; 95% CI, -.83 to 1.58). Patients in the O'Sullivan flexion impairment subgroup had worse proprioception than the total LBP cohort. The TTDPM was significantly worse in patients than controls. One prospective study found no link between lumbar proprioception and LBP.

CONCLUSIONS

Patients with LBP have impaired lumbar proprioception compared with controls when measured actively in sitting positions (particularly those in the O'Sullivan flexion impairment subgroup) or via TTDPM. Clinicians should consider the relationship between sitting and proprioception in LBP and subgroup patients to guide management. Further studies focusing on subgroups, longitudinal assessment, and improving proprioception measurement are needed.

Lumbar repositioning error in sitting: healthy controls versus people with sitting-related non-specific chronic low back pain (flexion pattern)

Studies examining repositioning error (RE) in non-specific chronic low back pain (NSCLBP) demonstrate contradictory results, with most studies not correlating RE deficits with measures of pain, disability or fear. This study examined if RE deficits exist among a subgroup of patients with NSCLBP whose symptoms are provoked by flexion, and how such deficits relate to measures of pain, disability, fear-avoidance and kinesiophobia. 15 patients with NSCLBP were matched (age, gender, and body mass index) with 15 painfree participants. Lumbo-pelvic RE, pain, functional disability, fear-avoidance and kinesiophobia were evaluated. Participants were asked to reproduce a target position (neutral lumbo-pelvic posture) after 5 s of slump sitting. RE in each group was compared by evaluating constant error (CE), absolute error (AE) and variable error (VE). Both AE (p = 0.002) and CE (p = 0.006) were significantly larger in the NSCLBP group, unlike VE (p = 0.165) which did not differ between the groups. There were significant, moderate correlations in the NSCLBP group between AE and functional disability (r = 0.601, p = 0.018), and between CE and fear-avoidance (r = -0.577, p = 0.0024), but all other correlations were weak (r < 0.337, rs < 0.377) or non-significant (p > 0.05). The results demonstrate increased lumbo-pelvic RE in a subgroup of NSCLBP patients, with the selected subgroup undershooting the target position. Overall, RE was only weakly to moderately correlated with measures of pain, disability or fear. The deficits observed are consistent with findings of altered motor control in patients with NSCLBP. The mechanisms underlying these RE deficits, and the most effective method of addressing these deficits, require further study.

Effect of spinal manipulation on sensorimotor functions in back pain patients: study protocol for a randomised controlled trial

Background

Low back pain (LBP) is a recognized public health problem, impacting up to 80% of US adults at some point in their lives. Patients with LBP are utilizing integrative health care such as spinal manipulation (SM). SM is the therapeutic application of a load to specific body tissues or structures and can be divided into two broad categories: SM with a high-velocity low-amplitude load, or an impulse "thrust", (HVLA-SM) and SM with a low-velocity variable-amplitude load (LVVA-SM). There is evidence that sensorimotor function in people with LBP is altered. This study evaluates the sensorimotor function in the lumbopelvic region, as measured by postural sway, response to sudden load and repositioning accuracy, following SM to the lumbar and pelvic region when compared to a sham treatment.

Methods/Design

A total of 219 participants with acute, subacute or chronic low back pain are being recruited from the Quad Cities area located in Iowa and Illinois. They are allocated through a minimization algorithm in a 1:1:1 ratio to receive either 13 HVLA-SM treatments over 6 weeks, 13 LVVA-SM treatments over 6 weeks or 2 weeks of a sham treatment followed by 4 weeks of full spine "doctor's choice" SM. Sensorimotor function tests are performed before and immediately after treatment at baseline, week 2 and week 6. Self-report outcome assessments are also collected. The primary aims of this study are to 1) determine immediate pre to post changes in sensorimotor function as measured by postural sway following delivery of a single HVLA-SM or LVVA-SM treatment when compared to a sham treatment and 2) to determine changes from baseline to 2 weeks (4 treatments) of HVLA-SM or LVVA-SM compared to a sham treatment. Secondary aims include changes in response to sudden loads and lumbar repositioning accuracy at these endpoints, estimating sensorimotor function in the SM groups after 6 weeks of treatment, and exploring if changes in sensorimotor function are associated with changes in self-report outcome assessments.

Discussion

This study may provide clues to the sensorimotor mechanisms that explain observed functional deficits associated with LBP, as well as the mechanism of action of SM.

Trial registration

This trial is registered in ClinicalTrials.gov, with the ID number of NCT00830596, registered on January 27, 2009. The first participant was allocated on 30 January 2009 and the final participant was allocated on 17 March 2011.

Spine stability: lessons from balancing a stick

This paper introduces control concepts that are important for ensuring stability. To clarify these concepts, a series of experiments using a simple task of stick balancing will be performed. The lessons from these experiments will be applied to the spine system and illustrated with clinical examples. Insight into the following will be gained: what information is used to stabilize the spine, how does noise in control affect spine performance, how has the spine evolved to allow it to be stabilized and controlled in a metabolically efficient way, how do delays in control affect spine performance, and how do different goals (i.e., maximizing performance versus minimizing fatigue) affect the logic for controlling the spine?

Discrimination of Amount of Spinal Flexion for Movements Made with and without Vision after Lumbar Disc Replacement

Discrimination of differences between small lumbar flexion movements made when standing may differ depending on whether vision is available. Dependence on general vision during trunk movements may be increased following surgery, in which an intervertebral disc is replaced with a prosthetic disc. This study investigated whether the availability of vision changed discrimination of small differences in lumbar forward flexion movement when standing for patients with lumbar disc replacement and healthy peers. 20 volunteers without a history of back pain and 20 with disc replacement undertook a 100-trial sequence of forward flexion movements to a set of physical stops, making an absolute judgement as to the position after each movement. General (nontarget) vision during the movement was available or removed randomly trial by trial. Availability of vision did not affect discrimination of flexion movements of the lumbar spine either in normal healthy individuals or those with disc replacement.

Comparison of trunk proprioception between patients with low back pain and healthy controls

OBJECTIVE

To determine whether proprioceptive impairments exist in patients with low back pain (LBP). We hypothesized that patients with LBP would exhibit larger trunk proprioception errors than healthy controls.

DESIGN

Case-control study.

SETTING

University laboratory.

PARTICIPANTS

24 patients with nonspecific LBP and 24 age-matched healthy controls.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

We measured trunk proprioception in all 3 anatomical planes using motion perception threshold, active repositioning, and passive repositioning tests.

RESULTS

LBP patients had significantly greater motion perception threshold than controls (P<.001) (1.3+/-0.9 degrees vs 0.8+/-0.6 degrees ). Furthermore, all subjects had the largest motion perception threshold in the transverse plane (P<.001) (1.2+/-0.7 degrees vs 1.0+/-0.8 degrees for all other planes averaged). There was no significant difference between LBP and healthy control groups in the repositioning tasks. Errors in the active repositioning test were significantly smaller than in the passive repositioning test (P=.032) (1.9+/-1.2 degrees vs 2.3+/-1.4 degrees ).

CONCLUSIONS

These findings suggest that impairments in proprioception may be detected in patients with LBP when assessed with a motion perception threshold measure.

Low back pain history and postural sway in unstable sitting

STUDY DESIGN

A cross-sectional study comparing subjects with self-reported low back pain, recent low back, and no low back pain.

OBJECTIVE

To determine differences in trunk postural control between groups.

SUMMARY OF BACKGROUND DATA

Poor postural control has been demonstrated in patients with low back pain, but the cause of this is unknown.

METHODS

A total of 331 participants of a longitudinal study participated in a seated balancing task. Based on a questionnaire, subjects were subdivided in 3 groups: current-LBP, recent-LBP (last 12 months), no-LBP. Subjects balanced on a seat mounted over a hemisphere during three 30-second trials. Sway amplitudes (RMS), mean power frequency (MPF), short-term diffusion coefficients (DS), and critical point (CP) coordinates of sway were calculated.

RESULTS

RMS values differed significantly between groups, with smaller values in recent-LBP than in no-LBP. MPF values were lowest in current-LBP. DS values were highest in no-LBP, with significant differences between this group and recent-LBP only. CP values were generally lower for recent-LBP than both other groups.

CONCLUSION

In contrast with previous findings, postural sway amplitudes in unstable sitting were not different between LBP and healthy subjects, while subjects with a recent history of LBP showed smaller amplitudes. Higher DS values in subjects without LBP indicated more stochastic sway. These findings may be explained by the disturbing effect of current pain on postural control causing low sway frequencies and by lower effort in balancing in healthy subjects causing high sway amplitudes and diffusion coefficients.

Postural control in patients with lumbar disc herniation in the early postoperative period

Chronic spinal disc disease leads to disorders in postural movement coordination. An incorrect asymmetrical movement pattern for the lower limbs loading impairs proprioception and deteriorates postural stability, particularly when the vision is occluded. The standard surgical treatment improves biomechanical conditions in the lumbar spine, reduces pain, yet does it reduce the stability deficit in the upright position? An answer to the latter question would help work out targeted therapy to improve postural stability. We hypothesized that the standard surgical treatment would improve postural stability reflected by decreased sway variability accounting for better use of proprioceptive inputs postoperatively. Thirty-nine patients with lumbar disc herniation participated in the study. Their postural sway was recorded in anterior/posterior and medial/lateral planes with their eyes open or closed (EC) before and after surgery. The variability, range, mean velocity of the recorded time series and the area of the ellipse enclosed by the statokinesiogram were used as measures of postural stability. Preoperatively, EC condition resulted in an increased variability and mean velocity of postural sway, while postoperatively it caused an increase in sway mean velocity and sway area only with no effect on sway variability and range. The comparison of the balance before and after the surgery in the EC condition showed significant decrease in all parameters. In the early postoperative period, the patients recover the ability to control their postural sway in EC within normal limits, however, at the expense of significantly increased frequency of corrective torques. It is probably a transient short-term strategy needed to compensate for the recovery phase when the normal weighting factors for all afferents are being reestablished. We propose that this transient postoperative period may be the best timing of therapeutic intervention targeted at facilitating and reinforcing the acquisition of correct motor patterns.

The effects of stochastic resonance stimulation on spine proprioception and postural control in chronic low back pain patients

STUDY DESIGN

Spine proprioception and postural control in unstable sitting were compared in 18 chronic low back pain patients using a repeated measures design.

OBJECTIVE

The study objective was to determine if stochastic resonance (SR) stimulation of the paraspinal muscles improves spine proprioception and trunk postural control.

SUMMARY OF BACKGROUND DATA

Decreased spine proprioception and larger postural sway have been found in low back pain patients, although several studies have also shown no differences in spine proprioception.

METHODS

Spine proprioception, measuring subjects' sensitivity to change in position, was assessed in 3 orthopaedic planes. Postural control was assessed using an unstable seat with a hemisphere attached to the bottom. Subjects balanced with eyes closed on the most challenging size hemisphere they could manage while center-of-pressure was recorded with a force plate beneath the seat. Both tasks were performed with SR stimulation randomized at 0%, 25%, 50%, and 90% intensity levels.

RESULTS

No significant differences in spine proprioception were observed between SR stimulation levels for any of the 3 orthopaedic planes. SR stimulation significantly improved postural control, but only in the lateral plane. No differences in postural control were observed between stimulation levels 25%, 50%, and 90% in the lateral plane. There was no correlation between spine proprioception and postural control.

CONCLUSION

Results suggest that SR stimulation to the paraspinal muscles can improve postural control; however, this improvement cannot be attributed to improved spine proprioception based on the current study. People with compromised neuromuscular control or those exposed to unstable environments may benefit from SR stimulation.

Movement control tests of the low back; evaluation of the difference between patients with low back pain and healthy controls

BACKGROUND

To determine whether there is a difference between patients with low back pain and healthy controls in a test battery score for movement control of the lumbar spine.

METHODS

This was a case control study, carried out in five outpatient physiotherapy practices in the German-speaking part of Switzerland. Twelve physiotherapists tested the ability of 210 subjects (108 patients with non-specific low back pain and 102 control subjects without back pain) to control their movements in the lumbar spine using a set of six tests. We observed the number of positive tests out of six (mean, standard deviation and 95% confidence interval of the mean). The significance of the differences between the groups was calculated with Mann-Whitney U test and p was set on <0.05. The effect size (d) between the groups was calculated and d>0.8 was considered a large difference.

RESULTS

On average, patients with low back pain had 2.21(95%CI 1.94-2.48) positive tests and the healthy controls 0.75 (95%CI 0.55-0.95). The effect size was d = 1.18 (p < 0.001). There was a significant difference between acute and chronic (p < 0.01), as well as between subacute and chronic patient groups (p < 0.03), but not between acute and subacute patient groups (p > 0.7).

CONCLUSION

This is the first study demonstrating a significant difference between patients with low back pain and subjects without back pain regarding their ability to actively control the movements of the low back. The effect size between patients with low back pain and healthy controls in movement control is large.

Lumbar position sense and the risk of low back injuries in college athletes: a prospective cohort study

Background

Impaired proprioception in the lumbar spine has often been reported in people with low back pain. However, no prospective studies exist to assert the cause and effect of this association. We hypothesized that athletes with a history of low back injury (LBI) would demonstrate poorer lumbar position sense (PS) than athletes without a history of LBI, and that this deficit would be a risk factor for future LBI.

Methods

This was a prospective cohort study with 2–3 year follow-up. Lumbar spine PS in the transverse plane was evaluated in 292 athletes using three tests: 1) passive and 2) active trunk repositioning, and 3) motion perception threshold. Mean absolute (accuracy) and variable (precision) errors were computed.

Results

There were no significant differences in the repositioning errors or motion perception threshold between athletes with and without a history of LBI or between those who did and did not get injured during the follow-up. Active trunk repositioning resulted in smaller errors than passive repositioning (1.6°± 0.8°) versus 2.1°± 1.0°) and 1.7°± 0.8°) versus 2.3°± 1.1°) for the absolute and relative errors, respectively).

Conclusion

Poor trunk PS in transverse plane is not associated with LBI in athletes, nor does it appear that poor trunk PS predisposes athletes to LBI.