title: Evaluation of the Quality of Prognosis Studies in Systematic Reviews Effect of Core Stability Exercises on Feed-Forward Activation of Deep Abdominal Muscles in Chronic Low Back Pain: A Randomized Controlled Trial AMSTAR is a reliable and valid measurement tool to assess the methodological quality of systematic reviews. Changes in recruitment of transversus abdominis correlate with disability in people with chronic low back pain Experimental muscle pain changes feedforward postural responses of the trunk muscles Long-Term Effects of Specific Stabilizing Exercises for First-Episode Low Back Pain Preliminary Investigation of the Mechanisms Underlying the Effects of Manipulation: Exploration of a Multivariate Model Including Spinal Stiffness, Multifidus Recruitment, and Clinical Findings Altered trunk muscle recruitment in people with low back pain with upper limb movement at different speeds. Course and prognosis of recovery for chronic non-specific low back pain: design, therapy program and baseline data of a prospective cohort study Lumbar multifidus muscle thickness does not predict patients with low back pain who improve with trunk stabilization exercises. Changes in the Cross-Sectional Area of Multifidus and Psoas in Patients With Unilateral Back Pain: The Relationship to Pain and Disability Asymmetric Atrophy of Multifidus Muscle in Patients With Unilateral Lumbosacral Radiculopathy Critical Appraisal of Clinical Prediction Rules That Aim to Optimize Treatment Selection for Musculoskeletal Conditions High Fear-Avoiders of Physical Activity Benefit From an Exercise Program for Patients With Back Pain Rehabilitative ultrasound measurement of select trunk muscle activation during induced pain. The relationship between EMG and change in thickness of transversus abdominis. Association between changes in electromyographic signal amplitude and abdominal muscle thickness in individuals with and without lumbopelvic pain. Spine stabilisation exercises in the treatment of chronic low back pain: a good clinical outcome is not associated with improved abdominal muscle function Publication bias in clinical research Covariate adjustment increased power in randomized controlled trials: an example in traumatic brain injury. Intra-abdominal pressure increases stiffness of the lumbar spine. Trunk muscle stabilization training plus general exercise versus general exercise only: randomized controlled trial of patients with recurrent low back pain. A Controlled Examination of Medical and Psychosocial Factors Associated With Low Back Pain in Combination With Widespread Musculoskeletal Pain Association between changes in abdominal and lumbar multifidus muscle thickness and clinical improvement after spinal manipulation.
abstract: Prognosis studies are investigations of future events or the evaluation of associations between risk factors and health outcomes in population s of patients ( 1 ) . The results of such studies improve our underst and ing of the clinical course of a disease and assist clinicians in making informed decisions about how best to manage patients . Prognostic research also informs the design of intervention studies by helping define subgroups of patients who may benefit from a new treatment and by providing necessary information about the natural history of a disorder ( 2 ) . There has recently been a rapid increase in the use of systematic review methods to synthesize the evidence on research questions related to prognosis . It is essential that investigators conducting systematic review s thoroughly appraise the method ologic quality of included studies to be confident that a study 's design , conduct , analysis , and interpretation have adequately reduced the opportunity for bias ( 3 , 4 ) . Caution is warranted , however , because inclusion of method ologically weak studies can threaten the internal validity of a systematic review ( 4 ) . This follows abundant empirical evidence that inadequate attention to biases can cause invalid results and inferences ( 5 - 9 ) . However , there is limited consensus on how to appraise the quality of prognosis studies ( 1 ) . A useful framework to assess bias in such studies follows the basic principles of epidemiologic research ( 10 , 11 ) . We focus on 6 areas of potential bias : study participation , study attrition , prognostic factor measurement , confounding measurement and account , outcome measurement , and analysis . The main objectives of our review of review s are to describe methods used to assess the quality of prognosis studies and to describe how well current practice s assess potential biases . Our secondary objective is to develop recommendations to guide future quality appraisal , both within single studies of prognostic factors and within systematic review s of the evidence . We hope this work facilitates future discussion and research on biases in prognosis studies and systematic review s. Methods Literature Search and Study Selection We identified systematic review s of prognosis studies by search ing MEDLINE ( 1966 to October 2005 ) using the search strategy recommended by McKibbon and colleagues ( 12 ) . This strategy combines broad search terms for systematic review s ( systematic review .mp ; meta- analysis .mp ) and a sensitive search strategy for prognosis studies ( cohort , incidence , mortality , follow-up studies , prognos * , predict * , or course ) . We also search ed the reference lists of included review s and method ologic papers to identify other relevant publications . We restricted our search to English- language publications . One review er conducted the search and selected the studies . Systematic review s , defined as review s of published studies with a comprehensive search and systematic selection , were included if they assessed the method ologic quality of the included studies by using 1 or more explicit criteria . We excluded studies if they were meta-analyses of independent patient data only , if their primary goal was to investigate the effectiveness of an intervention or specific diagnostic or screening tests , or if they included studies that were not done on humans . Data Extraction and Synthesis Individual items included in the quality assessment of the systematic review s were recorded as they were reported in the publication ( that is , the information that would be available to readers and future review ers ) . We review ed journal Web sites and contacted the authors of the systematic review s for additional information when authors made such an offer in their original papers . When review s assessed different study design s by using different sets of quality items , we extracted only those items used to assess cohort studies . We constructed a comprehensive list of distinct items that the review s used to assess the quality of their included studies . The full text of each review was screened . All items used by the review authors to assess the quality of studies were extracted into a computerized spreadsheet by 1 review er . Two experienced review ers , a clinical epidemiologist and an epidemiologist , independently synthesized the quality items extracted from the prognosis review s to determine how well the systematic review s assessed potential biases . We did this in 3 steps : 1 ) identified distinct concepts or domains addressed by the quality items ; 2 ) grouped each extracted quality item into the appropriate domain or domains ; and 3 ) identified the domains necessary to assess potential biases in prognosis studies . We then used this information to assess how well the review s ' quality assessment included items from the domains necessary to assess potential biases . After completing each of the first 3 steps , the review ers met to attempt to reach a consensus . The consensus process involved each review er presenting his or her observations and results , followed by discussion and debate . A third review er was available in cases of persistent disagreement or uncertainty . In the first step , all domains addressed by the quality items were identified . The first review er iteratively and progressively defined the domains as items were extracted from the included review s. The second review er defined domains from a r and om list of all extracted quality items . Limited guidance was provided to the review ers so that their assessment s and definitions of domains would be independent . The review ers agreed on a final set of domains that adequately and completely defined all of the extracted items . In the second step , review ers independently grouped each extracted item into the appropriate domains . Review ers considered each extracted item by asking , What is each particular quality item addressing ? or What are the review 's authors getting at with the particular quality assessment item ? . Items were grouped into the domain or domains that best represented the concepts being addressed . For example , the extracted items at least 80 % of the group originally identified was located for follow-up and follow-up was sufficiently complete or does n't jeopardize validity were each independently classified by both review ers as assessing the domain completeness of follow-up adequate , whereas the extracted item quantification and description of all subjects lost to follow-up was classified as assessing the domain completeness of follow-up described . In the third step , we identified the domains necessary to assess potential biases . Each review er considered the ability of the identified domains to adequately address , at least in part , 1 of the following 6 potential biases : 1 ) study participation , 2 ) study attrition , 3 ) prognostic factor measurement , 4 ) confounding measurement and account , 5 ) outcome measurement , and 6 ) analysis . Domains were considered to adequately address part of the framework if information garnered from that domain would inform the assessment of potential bias . For example , both review ers judged that the identified domain study population represents source population or population of interest assessed potential bias in a prognosis study , whereas the domain research question definition did not , although the latter is an important consideration in assessing the inclusion of studies in a systematic review . Finally , on the basis of our previous ratings , we looked at whether each review included items from the domains necessary to assess the 6 potential biases . We calculated the frequency of systematic review s by assessing each potential bias and the number of review s that adequately assessed bias overall . From this systematic synthesis , we developed recommendations for improving quality appraisal in future systematic review s of prognosis studies . We used Microsoft Access and Excel 2002 ( Microsoft Corp. , Redmond , Washington ) for data management and SAS for Windows , version 9.1 ( SAS Institute , Inc. , Cary , North Carolina ) for descriptive statistics . Role of the Funding Sources The funding sources , the Canadian Institutes of Health Research , the Canadian Chiropractic Research Foundation , the Ontario Chiropractic Association , and the Ontario Ministry of Health and Long Term Care , did not have a role in the collection , analysis , or interpretation of the data or in the decision to su bmi t the manuscript for publication . Results We identified 1384 potentially relevant articles . Figure 1 shows a flow chart of studies that were included and excluded . Figure 2 shows the number of review s identified by year of publication . We excluded 131 systematic review s of prognosis studies that did not seem to include any quality assessment of the included studies ; this represented 44 % of prognosis review s. We included 163 review s of prognosis studies in our analysis ( 13 - 175 ) . The most common topics were cancer ( 15 % ) , musculoskeletal disorders and rheumatology ( 13 % ) , cardiovascular ( 10 % ) , neurology ( 10 % ) , and obstetrics ( 10 % ) . Other review s included a wide range of health and health care topics . Sixty-three percent of the review s investigated the association between a specific prognostic factor and a particular outcome ; the remainder investigated multiple prognostic factors or models . The number of primary studies included in each systematic review ranged from 3 to 167 ( median , 18 [ interquartile range , 12 to 31 ] ) . A complete description of the included review s is available from the authors on request . Figure 1 . Flow diagram of inclusion and exclusion criteria of systematic review s. Figure 2 . Number of systematic review s of prognosis studies identified over time . Quality Items One hundred fifty-three review s provided adequate detail to allow extraction of quality items . Eight hundred eighty-two distinct quality items were extracted from the review s. Most review s developed their own set of quality items , with only a few applying criteria from previous review s. Most quality items Study Design . A r and omized controlled trial . Objective . To investigate feed-forward activation or timing of abdominal muscle activation in response to rapid shoulder flexion after 8 weeks with core stability exercises , sling exercises , or general exercises in chronic nonspecific low back pain ( LBP ) patients . Summary of Background Data . Delayed onset in abdominal muscles has been associated with LBP . Low load exercises to volitionally activate the transversus abdominis were introduced to restore trunk muscle activation deficits . More forceful co-contraction exercises have been advocated by others . This study explored whether abdominal muscle onset changed after low-load core stability exercises , high-load sling exercises , or general exercises . Methods . Subjects ( N = 109 ) with chronic nonspecific LBP of at least 3 months ' duration were r and omly assigned to 8 weekly treatments with low-load core stability exercises , high-load stabilizing exercises in slings , or general exercises in groups . Primary outcome was onset recorded bilaterally by m-mode ultrasound imaging in the deep abdominal muscles in response to rapid shoulder flexion . Results . No or small changes were found in onset after treatment . Baseline adjusted between group differences showed a 15 ms ( 95 % confidence interval [ CI ] , 1–28 ; P = 0.03 ) and a 19 ms ( 95 % CI , 5–33 ; P < 0.01 ) improvement with sling relative to core stability and general exercises , respectively , but on 1 side only . There was no association between changes in pain and onset over the intervention period ( R2 ⩽ 0.02 ) . Conclusion . Abdominal muscle onset was largely unaffected by 8 weeks of exercises in chronic LBP patients . There was no association between change in onset and LBP . Large individual variations in activation pattern of the deep abdominal muscles may justify exploration of differential effects in subgroups of LBP OBJECTIVE Our purpose was to measure the agreement , reliability , construct validity , and feasibility of a measurement tool to assess  systematic review s ( AMSTAR ) . STUDY DESIGN AND SETTING We r and omly selected 30 systematic review s from a data base . Each was assessed by two review ers using : ( 1 ) the enhanced quality assessment question naire ( Overview of Quality Assessment Question naire [ OQAQ ] ) ; ( 2 ) Sacks ' instrument ; and ( 3 ) our newly developed measurement tool ( AMSTAR ) . We report on reliability ( interobserver kappas of the 11 AMSTAR items ) , intraclass correlation coefficients ( ICCs ) of the sum scores , construct validity ( ICCs of the sum scores of AMSTAR compared with those of other instruments ) , and completion times . RESULTS The interrater agreement of the individual items of AMSTAR was substantial with a mean kappa of 0.70 ( 95 % confidence interval [ CI ] : 0.57 , 0.83 ) ( range : 0.38 - 1.0 ) . Kappas recorded for the other instruments were 0.63 ( 95 % CI : 0.38 , 0.78 ) for enhanced OQAQ and 0.40 ( 95 % CI : 0.29 , 0.50 ) for the Sacks ' instrument . The ICC of the total score for AMSTAR was 0.84 ( 95 % CI : 0.65 , 0.92 ) compared with 0.91 ( 95 % CI : 0.82 , 0.96 ) for OQAQ and 0.86 ( 95 % CI : 0.71 , 0.94 ) for the Sacks ' instrument . AMSTAR proved easy to apply , each review taking about 15 minutes to complete . CONCLUSIONS AMSTAR has good agreement , reliability , construct validity , and feasibility . These findings need confirmation by a broader range of assessors and a more diverse range of review Objectives Although motor control exercises have been shown to be effective in the management of  low back pain ( LBP ) the mechanism of action is unclear . The current study investigated the relationship between the ability to recruit transversus abdominis and clinical outcomes of participants in a clinical trial . Methods Ultrasonography was used to assess the ability to recruit transversus abdominis in a nested design : a sample of 34 participants with chronic LBP was recruited from participants in a r and omised controlled trial comparing the efficacy of motor control exercise , general exercise and spinal manipulative therapy .  Perceived recovery , function , disability and pain were also assessed . Results Participants with chronic LBP receiving motor control exercise had a greater improvement in recruitment of transversus abdominis ( 7.8 % ) than participants receiving general exercise ( 4.9 % reduction ) or spinal manipulative therapy ( 3.7 % reduction ) . The effect of motor control exercise on pain reduction was greater in participants who had a poor ability to recruit transversus abdominis at baseline . There was a significant , moderate correlation between improved recruitment of transversus abdominis and a reduction in disability ( r = −0.35 ; 95 % CI 0.02 to 0.62 ) . Conclusion These data provide some support for the hypothesised mechanism of action of motor control exercise and suggest that the treatment may be more effective in those with a poor ability to recruit transversus abdominis Many studies have identified changes in trunk muscle recruitment in clinical low back pain ( LBP ) . However , due to the heterogeneity of the LBP population these changes have been variable and it has been impossible to identify a cause-effect relationship . Several studies have identified a consistent change in the feedforward postural response of transversus abdominis ( TrA ) , the deepest abdominal muscle , in association with arm movements in chronic LBP . This study aim ed to determine whether the feedforward recruitment of the trunk muscles in a postural task could be altered by acute experimentally induced LBP .  Electromyographic ( EMG ) recordings of the abdominal and paraspinal muscles were made during arm movements in a control trial , following the injection of isotonic ( non-painful ) and hypertonic ( painful ) saline into the longissimus muscle at L4 , and during a 1-h follow-up . Movements included rapid arm flexion in response to a light and repetitive arm flexion-extension . Temporal and spatial EMG parameters were measured . The onset and amplitude of EMG of most muscles was changed in a variable manner during the period of experimentally induced pain . However , across movement trials and subjects the activation of TrA was consistently reduced in amplitude or delayed . Analyses in the time and frequency domain were used to confirm these findings . The results suggest that acute experimentally induced pain may affect feedforward postural activity of the trunk muscles . Although the response was variable , pain produced differential changes in the motor control of the trunk muscles , with consistent impairment of TrA activity Study Design . A r and omized clinical trial with 1-year and 3-year telephone question naire follow-ups . Objective . To report a specific exercise intervention ’s long-term effects on recurrence rates in acute , first-episode low back pain patients . Summary of Background Data . The pain and disability associated with an initial episode of acute low back pain ( LBP ) is known to resolve spontaneously in the short-term in the majority of cases . However , the recurrence rate is high , and recurrent disabling episodes remain one of the most costly problems in LBP . A deficit in the multifidus muscle has been identified in acute LBP patients , and does not resolve spontaneously on resolution of painful symptoms and resumption of normal activity . Any relation between this deficit and recurrence rate was investigated in the long-term . Methods . Thirty-nine patients with acute , first-episode LBP were medically managed and r and omly allocated to either a control group or specific exercise group . Medical management included advice and use of medications . Intervention consisted of exercises aim ed at rehabilitating the multifidus in cocontraction with the transversus abdominis muscle . One year and three years after treatment , telephone question naires were conducted with patients . Results . Question naire results revealed that patients from the specific exercise group experienced fewer recurrences of LBP than patients from the control group . One year after treatment , specific exercise group recurrence was 30 % , and control group recurrence was 84 % ( P < 0.001 ) . Two to three years after treatment , specific exercise group recurrence was 35 % , and control group recurrence was 75 % ( P < 0.01 ) . Conclusion . Long-term results suggest that specific exercise therapy in addition to medical management and resumption of normal activity may be more effective in reducing low back pain recurrences than medical management and normal activity alone Study Design . Prospect i ve case series . Objective . To examine spinal stiffness in patients with low back pain ( LBP ) receiving spinal manipulative therapy ( SMT )  , evaluate associations between stiffness characteristics and clinical outcome , and explore a multivariate model of SMT mechanisms as related to effects on stiffness , lumbar multifidus ( LM ) recruitment , and status on a  clinical prediction rule  ( CPR ) for SMT outcomes . Summary of Background Data . Mechanisms underlying the clinical effects of SMT are poorly understood . Many explanations have been proposed , but few studies have related potential mechanisms to clinical outcomes or considered multiple mechanisms concurrently . Methods . Patients with LBP were treated with two SMT sessions over 1 week . CPR status was assessed at baseline . Clinical outcome was based on the Oswestry disability index ( ODI ) . Mechanized indentation measures of spinal stiffness and ultrasonic measures of LM recruitment were taken before and after each SMT , and after 1 week . Global and terminal stiffness were calculated . Multivariate regression was used to evaluate the relationship between stiffness variables and percentage ODI improvement . Zero-order correlations among stiffness variables , LM recruitment changes , CPR status , and clinical outcome were examined . A path analysis was used to evaluate a multivariate model of SMT effects . Results . Forty-eight patients ( 54 % women ) had complete stiffness data . Significant immediate decreases in global and terminal stiffness occurred post-SMT regardless of outcome . ODI improvement was related to greater immediate decrease in global stiffness ( P = 0.025 ) , and less initial terminal stiffness ( P = 0.01 ) . Zero-order correlations and path analysis supported a multivariate model suggesting that clinical outcome of SMT is mediated by improvements in LM recruitment and immediate decrease in global stiffness . Initial terminal stiffness and CPR status may relate to outcome though their relationship with LM recruitment . Conclusion . The underlying mechanisms explaining the benefits of SMT appear to be multifactorial . Both spinal stiffness characteristics and LM recruitment changes appear to play a role OBJECTIVE To compare trunk muscle coordination in people with and without low back pain with varying speeds of limb movement . STUDY DESIGN Abdominal and back extensor muscle activity in association with upper limb movement was compared among three speeds of movement and between people with and without low back pain . PARTICIPANTS Fourteen subjects with a history of recurrent low back pain and a group of age- and sex-matched control subjects . MEASURES The onsets of electromyographic activity of the trunk and limb muscles , frequency of trunk muscle responses , and angular velocity of arm movements . RESULTS Early activation of transversus abdominis ( TrA ) and obliquus internus abdominis ( OI ) occurred in the majority of trials , with movement at both the fast and intermediate speeds for the control group . In contrast , subjects with low back pain failed to recruit TrA or OI in advance of limb movement with fast movement , and no activity of the abdominal muscles was recorded in the majority of intermediate speed trials . There was no difference between groups for slow movement . CONCLUSION The results indicate that the mechanism of preparatory spinal control is altered in people with lower back pain for movement at a variety of speeds Background There has been increasing focus on factors predicting the development of chronic musculoskeletal disorders . For patients already experiencing chronic non-specific low back pain it is also relevant to investigate which prognostic factors predict recovery . We present the design of a cohort study that aims to determine the course and prognostic factors for recovery in patients with chronic non-specific low back pain . Methods / Design All participating patients were recruited ( Jan 2003-Dec 2008 ) from the same rehabilitation centre and were evaluated by means of ( postal ) question naires and physical examinations at baseline , during the 2-month therapy program , and at 5 and 12 months after start of therapy . The therapy protocol at the rehabilitation centre used a bio-psychosocial approach to stimulate patients to adopt adequate ( movement ) behaviour aim ed at physical and functional recovery . The program is part of regular care and consists of 16 sessions of 3 hours each , over an 8-week period ( in total 48 hours ) , followed by a 3-month self-management program . The primary outcomes are low back pain intensity , disability , quality of life , patient 's global perceived effect of recovery , and participation in work . Baseline characteristics include information on socio-demographics , low back pain , employment status , and additional clinical items status such as fatigue , duration of activities , and fear of kinesiophobia . Prognostic variables are determined for recovery at short-term ( 5 months ) and long-term ( 12 months ) follow-up after start of therapy . Discussion In a routine clinical setting it is important to provide patients suffering from chronic non-specific low back pain with adequate information about the prognosis of their complaint OBJECTIVE To underst and lumbar multifidus ( LM ) muscle activation as a clinical feature to predict patients with low back pain ( LBP ) who are likely to benefit from stabilization ( STB ) exercises .  DESIGN Prospect i ve , cohort study . SETTING Outpatient physical therapy clinics . PARTICIPANTS Persons with LBP were recruited for this study . Subjects ( N=25 ) were classified as either eligible to receive STB exercises or ineligible on the basis of current clinical prediction rules . INTERVENTIONS Six weeks of STB treatment . MAIN OUTCOME MEASURES Before and after treatment , subjects underwent rehabilitative ultrasound imaging to quantify LM-muscle activation and completed disability and pain question naires . Analyses were performed to examine the ( 1 ) relation between LM-muscle activation and current clinical features used to predict patients with LBP likely to benefit from STB exercises , ( 2 ) LM-muscle activation between the STB-eligible and STB-ineligible groups before and after STB treatment , and ( 3 ) relation between LM-muscle activation before STB treatment and ( a ) disability and ( b ) pain outcomes after treatment for both groups . RESULTS No relation was found between LM-muscle activation and the number of clinical features . Before STB treatment , LM-muscle activation between the STB-eligible and STB-ineligible groups did not differ . After STB treatment , LM-muscle activation differed between the groups ; however , this interaction was because the LM-muscle activation for the STB-eligible group decreased after treatment while that for the STB-ineligible group increased after treatment . Finally , only the STB-eligible group had a significant reduction in disability following treatment ; however , no relation was found between LM-muscle activation before treatment and ( a ) disability or ( b ) pain outcomes after treatment in the STB-eligible group . CONCLUSIONS LM-muscle activation does not appear to be a clinical feature that predicts patients with LBP likely to benefit from STB exercises Study Design . Prospect i ve , cross-sectional observational study . Objectives . The aim of this study was to determine if there was an association between wasting of psoas and multifidus as observed on MRI scans and the presenting symptoms , reported pathology , pain , or disability of a cohort of patients presenting with unilateral low back pain . Summary of Background Data . Current physiotherapy practice is often based on localized spine stabilizing muscle exercises ; most attention has been focused on transversus abdominus and multifidus with relatively little on psoas . Method . Fifty consecutive patients presenting to a back pain triage clinic with unilateral low back pain lasting more than 12 weeks were recruited . The cross-sectional surface area ( CSA ) of the muscles was measured . Duration of symptoms , rating of pain , self-reported function , and the presence of neural compression were recorded . Results . Data analysis compared the CSA between the symptomatic and asymptomatic sides . There was a statistically significant difference in CSA between the sides ( P < 0.001 ) . There was a positive correlation between the percentage decrease in CSA of psoas on the affected side and with the rating of pain ( rho = 0.608 , P < 0.01 ) , reported nerve root compression ( rho = 0.812 , P < 0.01 ) , and the duration of symptoms ( rho = 0.886 , P < 0.01 ) . There was an association between decrease in the CSA of multifidus and duration of symptoms . Conclusions . Atrophy of multifidus has been used as one of the rationale s for spine stabilization exercises . The evidence of coexisting atrophy of psoas and multifidus suggests that a future area for study should be selective exercise training of psoas , which is less commonly used in clinical practice Study Design . Prospect i ve case-control study of multifidus muscle atrophy in 39 patients with unilateral lumbosacral radiculopathy and lumbosacral disc herniation and 20 controls . Objective . To evaluate quantitatively the asymmetry of multifidus muscles in unilateral lumbosacral radiculopathy with disc herniation ( herniated intervertebral disc ; HIVD ) by using magnetic resonance imaging ( MRI ) . Summary of Background Data . Histologic and morphologic changes of multifidus muscles have been reported in lumbosacral disc herniation , but there are few imaging studies on the changes of multifidus muscles in unilateral radiculopathy . Methods . Bilateral multifidus muscles in L3–L4 , L4–L5 , and L5–S1 levels were detected in fast spin-echo T1 axial MRI images . The total cross-sectional area ( CSA ) of multifidus muscles ( TMA ) and the density of pure muscle CSA ( PMA ) were measured by a computerized analysis program , and the ratios of PMA to TMA ( PMA/TMA ) and the PMA ratios of involved to uninvolved sides ( IMA/UMA ) were calculated . The patients were divided into 2 groups according to the electrodiagnosis results : a radiculopathy ( RAD ) group and an HIVD group without definite radiculopathy . Results . Fourteen patients had lumbosacral radiculopathies ( RAD group ) while 25 had no radiculopathy ( HIVD group ) . No significant difference was found between the RAD and HIVD groups in TMA , PMA , and PMA/TMA . In terms of the criteria for the upper limit of IMA/UMA , 78.6 % in the RAD group had an abnormal IMA/UMA ratio in at least 1 level , compared with 24 % in the HIVD group and 10 % in the control group . Thus , more cases with less muscle volume in the involved side were seen in the RAD group than in the HIVD and control groups . Conclusion . Asymmetry of the multifidus muscles as seen in MRI was a useful finding to assess patients who had unilateral lumbosacral radiculopathy with HIVD . This may reflect the denervation of multifidus muscles in lumbosacral radiculopathy Background Clinical prediction rules ( CPRs ) for treatment selection in musculoskeletal conditions have become increasingly popular . Purpose The purpose s of this review are : ( 1 ) to critically appraise studies evaluating CPRs and ( 2 ) to consider the clinical utility and stage of development of each CPR . Data Sources Pertinent data bases were search ed up to April 2009 . Studies aim ing to develop or evaluate a CPR for treatment response in musculoskeletal conditions were included . Two independent review ers assessed eligibility and extracted method ological data , stage of development , and effect size information . Study Selection / Data Extraction and Synthesis Eighteen studies , evaluating 15 separate CPRs , were included . Fourteen CPRs were at the derivation stage , and all CPRs had been evaluated using a single-arm trial design , thus it is not possible to determine whether the CPRs identify prognosis ( regardless of treatment ) or specifically response to treatment . The CPR at the validation stage investigated spinal manipulative therapy ( SMT ) for low back pain and had been evaluated in 2 separate well-conducted r and omized controlled trials . The first trial demonstrated a clinical ly meaningful effect of the SMT CPR ; the additional effect from SMT in patients “ positive-on-the-rule ” was 15 Oswestry disability units at week 1 and 9 units at week 4 . The second trial showed that the CPR did not generalize to a different clinical setting , including a modified treatment . Limitations Due to differences in methods of reporting and journal publication restraints ( eg , word count restrictions ) , some quality assessment items may have been completed in the included studies , but not captured in this review . Conclusions There is , at present , little evidence that CPRs can be used to predict effects of treatment for musculoskeletal conditions . The principal problem is that most studies use design s that can not differentiate between predictors of response to treatment and general predictors of outcome . Only 1 CPR has been evaluated within an RCT design ed to predict response to treatment . Validation of these rules is imperative to allow clinical application Study Design . A subgroup analysis of patient outcomes from a r and omized controlled trial comparing a Back to Fitness program with usual general practitioner care . Objectives . To test whether patients with high scores on measures of fear-avoidance and distress/depression  benefit the most . Summary of Background Data . A fitness program , ongoing since the 1980s , was developed for use in the community and has been shown to be effective in reducing disability . Detailed analyses are needed to identify patient groups who benefit . Recent evidence points to the potentially important role of fear , distress , and depression . Method . Data from 98 patients allocated to normal general practitioner care and 89 patients allocated to a group exercise program  were analyzed after categorizing baseline scores on fear-avoidance beliefs ( high/low ) and distress/depression ( at risk/normal ) . The main outcome measure was the Rol and Disability Question naire . Outcomes were compared between the intervention and control groups at 6 weeks , 6 months , and 12 months . Results . High fear-avoiders fared significantly better in the exercise program than in usual general practitioner care at 6 weeks and at 1 year . Low fear-avoiders did not . Patients who were distressed or depressed were significantly better off at 6 weeks , but the benefits were not maintained long-term . Conclusion . Patients with high levels of fear-avoidance beliefs could significantly benefit from the Back to Fitness program . The benefits of the exercise program for patients with high levels of distress/depression  appear to be short-term only . Average attendance was only 4 to 5 classes , which may not be sufficient for more recalcitrant cases . Further research is indicated Rehabilitative ultrasound imaging ( RUSI ) is considered a valid method to measure muscle activation in key spinal muscles in asymptomatic subjects . Research measuring muscle activation with RUSI in painful subjects is limited . The aim of this study was to determine if changes in muscle activation from experimentally induced pain can be measured by RUSI . Six male subjects performed tasks known to activate the transverse abdominis ( TrA ) and lumbar multifidus ( LM ) while RUSI measurements of muscle thickness were obtained during control and hypertonic saline conditions . The abdominal draw-in maneuver was used to volitionally activate the TrA and a series of upper extremity lifting tasks were used to automatically activate the LM . Pain was induced by injecting 5 % hypertonic saline into the longissimus muscle adjacent to the LM at the L4 level . The percent change in muscle thickness from rest to contraction represented muscle activation . Activation was significantly less ( p<0.01 ) during the painful condition on 4 of the 5 tasks performed for the LM and on the task performed for the TrA. These results indicate that RUSI can be used to measure pain-related changes in deep trunk muscle activation . Future research should include a larger sample size and women OBJECTIVE To investigate the relationship between changes in thickness and EMG activity  in the transversus abdominis muscle of healthy subjects and the reliability of ultrasound measurements using different modes and transducers . DESIGN Convenience sampling . BACKGROUND Chronic low back pain is associated with transversus abdominis dysfunction but EMG studies of this muscle are restricted to invasive techniques . Since the thickness of transversus abdominis changes with activity , such changes measured from ultrasound images might provide insight into this muscle 's function non-invasively . In addition , little is known about the comparability of ultrasound measurements from different modes and transducers , nor the reliability of transversus abdominis measurements . METHODS In 9 healthy subjects ( aged 29 - 52 years , four male )  transversus abdominis was studied at rest and during activity ( 5 - 80 % max ) with simultaneous EMG and ultrasound ( M mode , 5 MHz curvilinear transducer ) measurements . Intra-rater reliability for thickness measurements was studied on 13 subjects using 7.5 MHz linear and 5 MHz curvilinear transducers in B and M modes . RESULTS Muscle thickness changes correlated well with EMG activity ( P < 0.001 , R2 = 0.87 ) and there were no significant differences between subjects ( P > 0.05 ) . Using 7.5 MHz head , the ICC for B mode was 0.989 and for M mode was 0.981 for between days reliability . The ICC for between transducer reliability was 0.817 . CONCLUSIONS Changes in thickness of transversus abdominis can be used to indicate changes in the electrical activity in this muscle . RELEVANCE Ultrasound scanning can be used in the clinical setting to provide objective information about transversus abdominis function STUDY DESIGN Validation study . OBJECTIVES To investigate the association between changes in electromyographic ( EMG ) signal amplitude and sonographic measures of muscle thickness of 4 abdominal muscles , during 2 clinical tests , in adults with and without lumbopelvic pain . BACKGROUND There is a trend in rehabilitation to use ultrasound imaging ( USI ) to determine the extent of abdominal muscle contraction . However , the literature investigating the relationship between abdominal muscle thickness change and level of activation is inconclusive and has not included clinical ly relevant tasks . METHODS Simultaneous recording from fine-wire EMG and USI was performed for 4 abdominal muscles , in 7 adults with lumbopelvic pain ( mean ± SD age , 29.7 ± 12.0 years ) and 7 adults without lumbopelvic pain ( 32.0 ± 10.6 years ) , during an active straight leg raise ( ASLR ) test and an abdominal drawing-in maneuver  ( ADIM ) . Cross-correlation functions and linear regression analyses were used to describe the relationship between the 2 measures . Analyses of variance were used to compare individuals with and without lumbopelvic pain , with an alpha set at .05 . RESULTS Across all muscles , peak cross-correlation values were low ( ASLR , r = 0.28 ± 0.09 ; ADIM , r = 0.35 ± 0.11 ) , and there was large variability in associated time lags ( ASLR , τ = 0.69 ± 2.56 seconds ; ADIM , τ = 0.53 ± 3.75 seconds ) . Regression analyses did not detect a systematic pattern of association between EMG signal amplitude and USI measurements , and analyses of variance revealed no differences between cohorts . CONCLUSION These results suggest a weak relationship between EMG amplitude and abdominal muscle thickness change measured with USI during the ADIM and ASLR , and raise questions about thickness change derived from USI as a measure of muscular activity for the abdominal musculature Introduction Various studies have shown that spine stabilisation exercise therapy elicits improvements in symptoms/disability in patients with chronic non-specific low back pain ( cLBP ) . However , few have corroborated the intended mechanism of action by examining whether clinical improvements ( 1 ) are greater in patients with functional deficits of the targeted muscles and ( 2 ) correlate with post-treatment improvements in abdominal muscle function . Methods Pre and directly after 9 weeks ’ therapy , 32 cLBP patients ( 44.0 ± 12.3 years ) rated their LBP intensity ( 0–10 ) and disability ( 0–24 , Rol and –Morris ; RM ) and completed psychological question naires . At the same timepoints , the voluntary activation of transversus abdominis ( TrA ) , obliquus internus and obliquus externus during “ abdominal-hollowing ” and the anticipatory ( “ feedforward ” ) activation of these muscles during rapid arm movements were measured using M-mode ultrasound with tissue Doppler imaging . Results Pre-therapy to post-therapy , RM decreased from 8.9 ± 4.7 to 6.7 ± 4.3 , and average pain , from 4.7 ± 1.7 to 3.5 ± 2.3 ( each P < 0.01 ) . The ability to voluntarily activate TrA increased by 4.5 % ( P = 0.045 ) whilst the anticipatory activation of the lateral abdominal muscles showed no significant change ( P > 0.05 ) . There was no significant correlation between the change in RM scores after therapy and either baseline values for voluntary ( r = 0.24 , P = 0.20 ) or anticipatory activation ( r = 0.04 , P = 0.84 ) , or their changes after therapy ( voluntary , r = 0.08 , P = 0.66 ; anticipatory , r = 0.16 , P = 0.40 ) . In multiple regression , only a reduction in catastrophising ( P = 0.0003 ) and in fingertip – floor distance ( P = 0.0006 ) made unique contributions to explaining the variance in the reduction in RM scores . Conclusion Neither baseline lateral abdominal muscle function nor its improvement after a programme of stabilisation exercises was a statistical predictor of a good clinical outcome . It is hence difficult to attribute the therapeutic result to any specific effects of the exercises on these trunk muscles . The association between changes in catastrophising and outcome serves to encourage further investigation on larger groups of patients to clarify whether stabilisation exercises have some sort of “ central ” effect , unrelated to abdominal muscle function per se In a retrospective survey , 487 research projects approved by the Central Oxford Research Ethics Committee between 1984 and 1987 , were studied for evidence of publication bias . As of May , 1990 , 285 of the studies had been analysed by the investigators , and 52 % of these had been published . Studies with statistically significant results were more likely to be published than those finding no difference between the study groups ( adjusted odds ratio [ OR ] 2.32 ; 95 % confidence interval [ Cl ] 1.25 - 4.28 ) . Studies with significant results were also more likely to lead to a greater number of publications and presentations and to be published in journals with a high citation impact factor . An increased likelihood of publication was also associated with a high rating by the investigator of the importance of the study results , and with increasing sample size . The tendency towards publication bias was greater with observational and laboratory-based experimental studies ( OR = 3.79 ; 95 % Cl = 1.47 - 9.76 ) than with r and omised clinical trials ( OR = 0.84 ; 95 % Cl = 0.34 - 2.09 ) . We have confirmed the presence of publication bias in a cohort of clinical research studies . These findings suggest that conclusions based only on a review of published data should be interpreted cautiously , especially for observational studies . Improved strategies are needed to identify the results of unpublished as well as published studies OBJECTIVE We aim ed to determine to what extent covariate adjustment could affect power in a r and omized controlled trial ( RCT ) of a heterogeneous population with traumatic brain injury ( TBI ) . STUDY DESIGN AND SETTING We analyzed 14-day mortality in 9,497 participants in the Corticosteroid R and omization After Significant Head Injury ( CRASH ) RCT of corticosteroid vs. placebo . Adjustment was made using logistic regression for baseline covariates of two vali date d risk models derived from external data ( International Mission on Prognosis and Analysis of Clinical Trials in Traumatic Brain Injury [ IMPACT ] ) and from the CRASH data . The relative sample size ( RESS ) measure , defined as the ratio of the sample size required by an adjusted analysis to attain the same power as the unadjusted reference analysis , was used to assess the impact of adjustment . RESULTS Corticosteroid was associated with higher mortality compared with placebo ( odds ratio=1.25 , 95 % confidence interval=1.13 - 1.39 ) . RESS of 0.79 and 0.73 were obtained by adjustment using the IMPACT and CRASH models , respectively , which , for example , implies an increase from 80 % to 88 % and 91 % power , respectively . CONCLUSION Moderate gains in power may be obtained using covariate adjustment from logistic regression in heterogeneous conditions such as TBI . Although analyses of RCTs might consider covariate adjustment to improve power , we caution against this approach in the planning of RCTs Intra-abdominal pressure ( IAP ) increases during many tasks and has been argued to increase stability and stiffness of the spine . Although several studies have shown a relationship between the IAP increase and spinal stability , it has been impossible to determine whether this augmentation of mechanical support for the spine is due to the increase in IAP or the abdominal muscle activity which contributes to it . The present study determined whether spinal stiffness increased when IAP increased without concurrent activity of the abdominal and back extensor muscles . A sustained increase in IAP was evoked by tetanic stimulation of the phrenic nerves either unilaterally or bilaterally at 20 Hz ( for 5 s ) via percutaneous electrodes in three subjects .  Spinal stiffness was measured as the force required to displace an indentor over the L4 or L2 spinous process with the subjects lying prone . Stiffness was measured as the slope of the regression line fitted to the linear region of the force-displacement curve . Tetanic stimulation of the diaphragm increased IAP by 27 - 61 % of a maximal voluntary pressure increase and increased the stiffness of the spine by 8 - 31 % of resting levels . The increase in spinal stiffness was positively correlated with the size of the IAP increase . IAP increased stiffness at L2 and L4 level . The results of this study provide evidence that the stiffness of the lumbar spine is increased when IAP is elevated BACKGROUND AND PURPOSE The purpose of this r and omized controlled trial was to examine the usefulness of the addition of specific stabilization exercises to a general back and abdominal muscle exercise approach for patients with subacute or chronic nonspecific back pain by comparing a specific muscle stabilization-enhanced general exercise approach with a general exercise-only approach . SUBJECTS Fifty-five patients with recurrent , nonspecific back pain ( stabilization-enhanced exercise group : n=29 , general exercise-only group : n=26 ) and no clinical signs suggesting spinal instability were recruited . METHODS Both groups received an 8-week exercise intervention and written advice ( The Back Book ) . Outcome was based on self-reported pain ( Short-Form McGill Pain Question naire ) , disability ( Rol and -Morris Disability Question naire ) , and cognitive status ( Pain Self-Efficacy Question naire , Tampa Scale of Kinesiophobia , Pain Locus of Control Scale ) measured immediately before and after intervention and 3 months after the end of the intervention period . RESULTS Outcome measures for both groups improved . Furthermore , self-reported disability improved more in the general exercise-only group immediately after intervention but not at the 3-month follow-up . There were generally no differences between the 2 exercise approaches for any of the other outcomes . DISCUSSION AND CONCLUSION A general exercise program reduced disability in the short term to a greater extent than a stabilization-enhanced exercise approach in patients with recurrent nonspecific low back pain . Stabilization exercises do not appear to provide additional benefit to patients with subacute or chronic low back pain who have no clinical signs suggesting the presence of spinal instability Background : Little is known about chronic low back pain ( CLBP ) in combination with widespread musculoskeletal pain ( WMP ) . Objective : This study examined factors that may be common to these conditions , with the objective of detecting factors that could improve the course of these diseases . Design : This was a prospect i ve case control study . Patients and Intervention : A group of patients with CLBP and WMP ( CLBP+WMP group , n=97 ) was compared with a group of individuals who were pain-free and without a history of musculoskeletal problems ( control group , n=97 ) and with a group of patients with CLBP but without WMP ( CLBP-only group , n=52 ) . The mean age of the participants was 42.9 years ( SD=8.74 ) ; 76 % were women , and 24 % were men . Measurements : A total of 74 variables were measured , including sociodemographic , physical , and psychosocial variables . After univariate examination for group differences and analyses of variables available for all 3 groups , logistic regression on selected factors was performed . The α level was set at .05 , but was adjusted to avoid r and omly significant results . Results : For a number of variables , significant differences among the 3 groups were observed . For regression model 1 for the CLBP+WMP and control groups , 4 out of 9 variables showed significant likelihood tests : income ( lower in the WMP group ) , depression , anxiety , and fear-avoidance behavior . For regression model 2 , 2 out of 13 variables showed significant likelihood tests : endurance capacity ( more in the CLBP+WMP group ) and balance capability ( worse in the CLBP+WMP group ) . The models predicted at least 91.2 % of all cases to the correct group . The regression analysis regarding the CLBP+WMP and CLBP-only groups predicted 86.7 % of all cases to the correct group . Three out of 10 variables showed significant likelihood tests : high disability , fear-avoidance behavior , and number of treatments . Limitations : Some variables in testing the patients with WMP and the individuals who were pain-free were not used with the patients with CLBP only . Conclusions : Patients with CLBP and WMP should be examined for indicated physical and psychosocial factors . Therapeutic management should consider them in the early stage of the disease . These findings also might apply to patients with fibromyalgia or myofascial pain STUDY DESIGN Prospect i ve case series . OBJECTIVE To examine the relation between improved disability and changes in abdominal and lumbar multifidus ( LM ) thickness using ultrasound imaging following spinal manipulative therapy ( SMT ) in patients with low back pain ( LBP ) . BACKGROUND Although there is a growing body of literature demonstrating physiologic effects following the application of SMT , few studies have attempted to correlate these changes with clinical ly relevant outcomes . METHODS Eighty-one participants with LBP underwent 2 thrust SMT treatments and 3 assessment sessions within 1 week .  Transversus abdominis  ( TrA ) , internal oblique ( IO ) , and LM muscle thickness  was assessed during each session , using ultrasound imaging of the muscles at rest and during submaximal contractions . The Modified Oswestry Disability Index was used to quantify participants ' improvement in LBP-related disability . Stepwise hierarchical multiple linear regression and repeated- measures analysis of variance were performed to examine the multivariate relationship between change in muscle thickness and clinical improvement over time . RESULTS After controlling for the effects of age , sex , and body mass index , change in contracted LM muscle thickness was predictive of improved disability at 1 week ( P = .02 ) . As expected , larger increases in contracted LM muscle thickness at 1 week were associated with larger improvements in LBP-related disability . Contrary to our hypothesis , significant decreases in both contracted TrA and IO muscle thickness were observed immediately following SMT ; but these changes were transient and unrelated to whether participants experienced clinical improvements . CONCLUSION These findings provide evidence that clinical improvement following SMT is associated with increased thickening of the LM muscle during a submaximal task . LEVEL OF EVIDENCE Prognosis , level 4
target: Evidence synthesis showed limited evidence supporting poor baseline transversus abdominis contraction thickness ratio as a treatment effect modifier favoring motor control exercise .
  Limited evidence supported that high baseline transversus abdominis lateral slide was associated with higher pain intensity after various exercise interventions at 1-year follow-up .
  However , there was limited evidence for the absence of relation between the contraction thickness ratio of transversus abdominis or anticipatory onset of lateral abdominal muscles at baseline and the short- or long-term LBP intensity after exercise interventions .
  There was conflicting evidence for a relation between baseline percent thickness change of lumbar multifidus during contraction and the clinical outcomes of patients after various conservative treatments .
background: Although individual reports suggest that baseline morphometry or activity of transversus abdominis or lumbar multifidus predict clinical outcome of low back pain ( LBP ) , a related systematic review is unavailable .
  Therefore , this review summarized evidence regarding the predictive value of these muscular characteristics .