multifidus and paraespinal sist rev

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Multifidus and Paraspinal Muscle

Group Cross-Sectional Areas ofPatients With Low Back Pain andControl Patients: A Systematic ReviewWith a Focus on BlindingMaryse Fortin, Luciana Gazzi Macedo

Background. Several studies have investigated differences in paraspinal musclemorphology between patients with low back pain (LBP) and control patients. How-

ever, inconsistencies in the results of some of these studies may limit generalizations.

Objective. The purpose of this study was to systematically review studies evalu-ating paraspinal muscle morphology in patients with LBP and control patients, witha focus on the effects of blinding.

Data Sources. An electronic search was performed with the use of relevantdatabases. Study quality was evaluated by means of the Newcastle-Ottawa Quality

Assessment Scale.

Study Selection. Case-control studies investigating paraspinal muscle sizebetween patients with LBP and control patients who were healthy were included.Studies that compared paraspinal muscle size between symptomatic and asymptom-

atic sides of patients with unilateral LBP also were included.

Data Extraction. Studies investigating the same outcomeat the same spinallevel and for the same muscle and populationwere pooled. Mean differences with95% confidence interval were calculated for each study.

Data Synthesis. Eleven studies were included. All but 1 pooled result werestatistically significant different between groups, suggesting that paraspinal musclesare smaller in patients with chronic LBP than in control patients and on the symp-

tomatic side of patients with chronic unilateral LBP. In patients with acute unilateralLBP, there was no significant difference between sides. A qualitative examinationdemonstrated a trend toward an increased effect size when outcome assessors were

unblinded.

Limitations. Limitations of this review include the small number of studiesincluded and their small sample size. Misclassification of blinding status may have

occurred when the study did not report blinding status.

Conclusions. Evidence suggests that paraspinal muscles are significantly smallerin patients with chronic LBP than in control patients. Although no definite conclusioncould be taken as to the effects of blinding, future imaging studies should considerthe use blinded outcome assessors.

M. Fortin, BSc, CAT(C), PhD Can-didate, Common Spinal DisordersResearch Group, Faculty of Reha-bilitation Medicine, University of

Alberta, 3-48 Corbett Hall,Edmonton, Alberta, Canada T6G2G4. Address all correspondenceto Ms Fortin at: [email protected].

L.G. Macedo, PhD, Department ofPhysical Therapy, Common SpinalDisorders Research Group, Facultyof Rehabilitation Medicine, Uni-versity of Alberta.

[Fortin M, Macedo LG. Multifidusand paraspinal muscle groupcross-sectional areas of patientswith low back pain and controls:

a systematic review with a focuson blinding. Phys Ther. 2013;93:xxx-xxx.]

2013 American Physical TherapyAssociation

Published Ahead of Print:March 15, 2013

Accepted: March 11, 2013Submitted: November 14, 2012

Research Report

Post a Rapid Response tothis article at:ptjournal.apta.org

July 2013 Volume 93 Number 7 Physical Therapy f 1


2/16

Several low back pain (LBP) stud-ies have emphasized the impor-tant role of paraspinal muscle

morphology on the etiology, progno-sis, and management of patients with

this condition. Theories on the roleof these muscles arose from imagingstudies suggesting that patients withLBP have smaller multifidus musclecross-sectional area (CSA)14 andmore fatty infiltration compared

with asymptomatic control patientswho are healthy.2,5,6 However, thereare inconsistencies among the resultsof these studies, with some suggest-

ing a significant difference in para-spinal muscle morphology betweenpatients with LBP and control

patients, whereas others suggest nodifferences between patients withLBP and control patients.1,3,7 Incon-sistencies also can be found in theresults of studies evaluating paraspi-nal muscle morphology between

the symptomatic and asymptomaticsides of patients with unilateralLBP.810

As with all scientific studies, specificmethodological safeguards must be

followed to minimize bias in studyresults. A specific methodologicalcriterion that has been reported to

be often lacking in the report ofimaging studies looking at patients

with LBP is blinding.11 Blinding ofthe outcome assessors is importantto ensure the internal validity of astudy.12,13 The use of unblinded out-come assessors has been reported,in other research designs, to consis-tently overestimate the treatment

effect as much as 17% to 40%.1315

Similarly, it has been shown thatwhen diagnostic studies are con-ducted without adequate blinding ofassessors, the diagnostic odds ratiocan be overestimated as much as30%.16

Although some studies and system-

atic reviews have reported on theeffect of the use of unblinded asses-sors in diagnostic accuracy tests, we

are unaware of any systematicreviews that evaluated the impact ofthis methodological issue in imagingstudies looking at quantitative mea-sures and, most importantly, on the

morphology of paraspinal muscles.Performing measurements unblinded,that is, knowing patients clinical his-tory or having access to radiologistreports, can potentially influencethe results and conclusions of thestudies. Therefore, in an effort tobridge the aforementioned knowl-edge gaps, the purposes of this sys-tematic review were: (1) to review

the literature regarding the associa-tion between paraspinal muscle mor-phology and LBP and (2) to assess

the difference between blinded andunblinded assessors when perform-ing quantitative paraspinal musclemeasurements with the use of imag-ing modalities.

MethodData Sources and SearchesThis systematic review was con-ducted following the PRISMA state-ment to ensure transparency andcomplete reporting of the results.17

To identify relevant articles, an elec-tronic database search was con-ducted with the use of the earliestrecord to the current day on MED-LINE (1948 to February 2012),

EMBASE (1980 to February 2012),and Scopus (1960 to February 2012).Key words for LBP and paraspinalmuscle atrophy were included in thedatabase search by use of MeSH(Medical Subject Headings of theNational Library of Medicine) terms,

as well as word truncations specificfor each database. Search strategies

and terms used for each databasesearch are presented in the Appen-dix. There were no language limits inour search. Experts in the area ofLBP and paraspinal muscle measure-ment were contacted and asked toreview the list of selected studiesand to identify any missed or unpub-lished study.

One reviewer performed the elec-tronic database searches and 2 inde-pendent reviewers screened titlesand abstracts for eligibility. Full arti-cles were obtained and reviewed by

2 independent reviewers on thebasis of a standardized inclusion cri-teria form. In the case of disagree-ment regarding whether a study metan inclusion criterion, the specificcriterion was reviewed and dis-cussed until a common consensus

was reached. If additional informa-tion was needed to determine theinclusion of a study, the authors

were contacted. We contacted 3authors about the eligibility of 4 dif-ferent studies.1821 All authors

responded to our request, and, onthe basis of the responses, 1 study

was deemed eligible for inclusion inthe review.20 The bibliographies ofall eligible studies were scrutinizedto identify possible studies missed

by the electronic search. Electronicdatabases also were searched toidentify possible relevant systematicreviews that were previously pub-lished. Citation tracking with the useof ISI Web of Science and manual

searches of the reference lists of pre-vious reviews also were performed.

Study SelectionStudies were considered for inclu-sion if they met all of the followingcriteria: (1) case-control studies(patients with LBP versus controlpatients) or studies evaluatingpatients with unilateral LBP pain andcomparing paraspinal muscle sizebetween the symptomatic side and

asymptomatic side (normal con-trol); (2) patients with nonspecificLBP (with or without leg pain) or

with specific LBP (eg, radiculopathy,disk herniation, sciatica, spinal ste-nosis, spondylitis, spondylolysis,spondylolisthesis, osteoarthritis, orfacet joint osteoarthritis); (3) patientsolder than 18 years of age; (4) studies

evaluating patients with acute LBP(6 weeks), patients with subacuteLBP (between 6 and 12 weeks), or

Multifidus and Paraspinal Muscle Cross-Sectional Areas of Patients With LBP and Control Patients

2 f Physical Therapy Volume 93 Number 7 July 2013


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patients with chronic LBP (12weeks) (mixed population studieswere included only if data were avail-able for each patient group separate-ly); (5) use of ultrasound, magnetic

resonance imaging or computedtomography (CT) scan to performparaspinal muscle measurements;(6) inclusion of at least 1 of the fol-lowing outcomes: multifidus or para-spinal muscle group (multifidus anderector spinae combined) CSA orfunctional CSA (FCSA) (fat-free area);(7) assessment at either L4-L5 orL5-S1, or at the level below or

same level in cases of symptomaticand asymptomatic studies looking ata specific pathological spinal level.

Exclusion criteria were: (1) previousspine surgery, (2) cauda equina syn-drome, (3) spine fracture, (4) malig-nant or inflammatory disease, or(5) pregnancy.

Data Extraction and QualityAssessmentMethodological quality of theincluded studies was assessed by 2independent reviewers throughthe use of the Newcastle-Ottawa

Quality Assessment Scale for case-control studies. Any disagreement

was resolved through discussion.

Methodological quality score wasnot considered as an inclusion crite-rion. The Newcastle-Ottawa Quality

Assessment Scale for case-controlstudies allows evaluation of studieson 3 specific criteria: (1) subjectselection, (2) comparability betweencases and control patients, and(3) exposure. A maximum of 10 stars

can be awarded to each study.

Two independent reviewers extractedthe data from the selected studies,

which included sample size andmean (standard deviation) musclesize (CSA or FCSA) for each muscleat the levels of interest through theuse of a standardized form. Authors

were contacted if not enough infor-mation was provided to allow quan-titative data analysis.1,9

Data Synthesis and AnalysisAn effect estimate (mean difference)with 95% confidence interval (95%CI) was calculated for each study.The effect estimate was calculated

to facilitate the interpretation of theresults and allow for a simple quan-tification of the difference betweenthe LBP group and the controlgroup. An effect estimate also wascalculated to determine the differ-ence between the blinded and pre-sumed unblinded studies. A meta-analysis with the use of RevMan 5.1from the Cochrane Library (Copen-

hagen, Denmark: The NordicCochrane Centre, The Cochrane Col-laboration [www.Cochrane.org]) was

performed by pooling the resultsof homogenous studies. Case-controlstudies and studies that used patients

with unilateral LBP, comparing mus-cle morphology of the asymptomatic

with the symptomatic side, were

evaluated separately. Results werepooled when studies used similaroutcomes for the same muscle, at thesame spinal level for a similar patientpopulation. Weighted mean differ-ences were used when the outcome

measures were the same for thepooled studies and standardizedmean differences were used when

the outcome measures were differ-ent. The effect estimate for eachmuscle of interest and selected spi-nal level was evaluated separatelybecause previous reports suggestedthat paraspinal muscle atrophy isgenerally more important at L5-S1than at L4-L5.3,22

When case-control studies reportedthe mean muscle size for the rightand left sides, the mean measure-ment and standard deviations forboth sides were pooled to calculatethe effect estimate. The same calcu-lation was performed if the authorsreported separate mean measure-ments for men and women. In 2 par-

ticular studies, the authors com-pared 2 groups of patients with LBP(eg, unilateral LBP and bilateral LBP,

moderate LBP, and severe LBP) witha group of control patients who

were healthy.2,3 For the purpose ofthis study, the data for all LBP groups

were pooled to calculate the effect

estimate.

Homogeneity of the studies wasdetermined with the use of I2 calcu-lated by use of RevMan 5.1. As sug-gested by the Cochrane Handbook

for Systematic Reviews of Interven-

tions,23 I2 was used to assess statisti-cal heterogeneity. An I2 value 50%indicates considerable heterogene-

ity, and thus studies with an I250%were pooled with the use of arandom-effects model, whereas

homogenous studies (I250%) werepooled with the use of a fixed-effectsmodel.23 Both random and fixed-effects meta-analyses were per-formed with the use of the inverse

variance method.

We had initially planned to run ameta-regression to evaluate theeffects of blinding as a single covari-ate. However, we did not conductthis analysis because the small

number of studies included in thisreview, particularly evaluating thesame outcome (same muscle and spi-

nal level), would lead to a low powerand consequently increased chanceof type II error. Therefore, all evalu-ations of the effects of blinding wereperformed qualitatively.

ResultsStudy SelectionThe electronic search yielded a total

of 145 studies after removal of dupli-cates. After reviewing titles and

abstracts, 28 studies were potentiallyeligible for inclusion. One additionalstudy was deemed potentially eligi-ble after a Web of Science searchof these articles.24 Therefore, a totalof 28 studies were considered forinclusion, but only 11 original stud-ies 14,79,20,2527were found to fulfillthe inclusion criteria (Fig. 1).




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Methodological QualityMethodological quality of theincluded studies is presented in theTable. The mean methodologicalscore of all studies was 6 of a total of10. Seven studies used blinded out-come assessors1,4,8,9,2527 and 4 stud-ies were deemed as unblinded.2,3,7,20

Studies were considered blindedwhen the authors clearly stated thatthe outcome assessor was blinded to

all participants clinical history orradiologist report at the time ofimaging assessment. Studies werepresumed to be unblinded when:(1) the authors did not explicitlystate that the outcome assessor wasblinded to participants clinical his-tories and radiologist reports, (2) the

outcome assessor was not blindedto group allocation, or (3) no infor-mation was mentioned concerning

the blinding status of the outcomeassessor.

Study CharacteristicsSeven of the included studies were

case-control studies, all comparingparaspinal muscle group or multifi-dus muscle size between patients

with chronic nonspecific LBP andcontrol patients.14,7,20,25 Three ofthe case-control studies were con-ducted with the outcome assessorblinded, and 4 were presumed as notblinded. Four studies were con-ducted with the use of patients with

a clinical presentation of unilateralLBP, in which muscle size was com-pared between the symptomatic and

asymptomatic sides.8,9,26,27 One ofthese studies looked at patients withacute symptoms,26 another com-pared a group of patients with acuteand chronic symptoms,27 and theother 2 studies included patients

with chronic pain.8,9 All unilateralLBP studies were blinded, and there-fore comparison of the effect esti-mate between presumed unblindedand blinded studies was not possible.The pathological level (eg, disk her-

niation, degenerative disk disease) ofthe unilateral cases was identifiedthrough imaging. In these cases,

muscle measurements were takenabove, below, or at the same spinallevel of the pathology. Refer to theTable for the study characteristics.

Case-Control StudiesFour case-control studies with a totalof 111 patients with chronic LBP and110 control patients compared the

multifidus muscle CSA at L4.3,4,7,25

Three studies were conducted withthe use of ultrasound3,7,25 and 1 withthe use of CT scan.4 When authorsprovided measurements of the mul-tifidus muscle CSA at the upper andlower L4, the data from the lowerL4 were used.4 The methodologicalappraisal of these studies ranged

from 2 and 6 on a 10-point scale. Thepooled weighted mean difference ofmultifidus muscle CSA (cm2) at L4

Database searches: February 2012

MEDLINE: 69EMBASE: 89

Scopus: 76Hand search: 2Expert communication: 2

Total after removing duplicates: 145

28 potentially eligible afterassessing titles and abstracts

11 original studies

11 original studies

Web of Science search = 1unknown symptoms duration24

Reasons for exclusion

1 no LBP symptoms at time of assessment221 patient with asymmetry >11% between sides28

3 no control group29-31

2 did not measure outcome of interest32,33

5 unknown symptoms duration18,19,21,34,35

1 included patients


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Table.

DescriptionoftheIncludedStudies

a

Study

Comparison

CaseDefinition

SampleSize

Age(y),

X

SD

Symptom

Duration,

X

SD

Imaging

Modality

OutcomeMeasures

In

cludedinThis

Review

Internal

Reliability

Testing

Blinding

Status

Methodological

Quality

(NOS)

Case-controlstudies

Danneelsetal1

(2000)

Case-control

M

echanicalCLBP1y,with

o

rwithoutdiskprotrusion

Patientsinvolvedinsportsor

fitnesstrainingforlowback

m

uscles(inprevious3mo)

w

ereexcluded

Patients:32

Controlpatients:

23

Patien

ts:37.349.78

Controlpatients:

36.9110.26

9.167.41y

CTscan

Paraspinalmuscle

g

roupCSA(muscle

toboneratio)at

lo

werL4

Couldnotpoolthe

m

ultifidusmuscle

d

ataastheywere

p

rovidedasbone-

to-muscleratio

(authorsdidnot

respondtoour

requesttoobtain

rawdata)

Intrarater

ICC.81.92

Blinded

6

Hidesetal3(2008)

Case-control

H

istoryofCLBP3mo

Patientswereclassifiedinto

2

groups:bilateralor

u

nilateralbasedonbody

chartreport

Patients:42

Controlpatients:

40

Patien

ts:46.813.2

(ag

eofthe50

pat

ientsrecruited

and

notthe42

ana

lyzed)

Controlpatients:

28.45.7

62.910.58

mo,range

340y

Ultrasound

Mu

ltifidusmuscle

C

SAatmidL4and

L5

IntraraterCV3.58%

Datafrom

thesame

clinician,calculated

beforethestudy

Not blinded

5

Kamazetal4(2007)

Case-control

W

omenwithahistoryof

C

LBP1y

N

otphysicallyactiveapart

fr

om

dailyhousework

Patients:36

Controlpatients:

34

Patien

ts:43.26.9

Controlpatients:

44.47.7

Notprovided

CTscan

Mu

ltifidusmuscleand

p

araspinalmuscle

g

roupCSAatlower

L4

Interrater

ICC.68.99

Blinded

6

Leeetal7(2006)

Case-control

LBP1y

Allparticipantswerelaborers

Patients:16

Controlpatients:

19

Patien

ts:39.9,

ran

ge3447

Controlpatients:41.7,

ran

ge3547

Notprovided

Ultrasound

Mu

ltifidusmuscle

C

SAatL4andL5

Notprovided

Not blinded

5

Leeetal20

(2008)

Case-control

W

omenwithdegenerative

lu

mbarflatbackdeformity

w

ithmarkedstopping

d

iagnosedthroughclinical

andradiologicalfindings

Allpatientshaddifficulty

w

alkingandclimbingslopes

o

rstairs,inabilitytolift

h

eavyobjects,andneedto

supportthemselvesusing

theirelbowswhenworking

in

thekitchen

Patients:11

Controlpatients:

10

Patien

ts:65.87.4

Controlpatients:

59.83.4

17.79.05y,

range

1030y

MRI

Paraspinalmuscle

g

roupCSA

(muscle-to-disk

ratio)L4-L5

Significanceof

interraterand

intraraterreliability

wasassessedwith

theuseof

multivariateanalysis

Intrarater

6.7348(P.725)

Interrater

.00013(P.758)

Not blinded

7 (Continued)




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Table.

Continued

Study

Comparison

CaseDefinition

SampleSize

Age(y),

X

SD

Symptom

Duration,

X

SD

Imaging

Modality

OutcomeMeasures

In

cludedinThis

Review

Internal

Reliability

Testing

Blinding

Status

Methodological

Quality

(NOS)

Parkkolaetal2

(1993)

Case-control

PatientswithCLBP

A

groupofpatientswith

m

oderateCLBPsuitablefor

activeandmultidimensional

rehabilitation

A

groupofpatientswith

severeCLBPandserious

b

ackproblemssuitablefor

m

oderaterehabilitationonly

Patients:48

Controlpatients:

60

Allag

e3047y

Notprovided

MRI

Paraspinalmuscle

g

roupCSAatL4-L5

Notprovided

Not blinded

6

Wallworketal25

(2009)

Case-control

H

istoryofnonspecificCLBP

3mo

Patients:17

Controlpatients:

17

Patien

ts:41.913.7,

ran

ge:1860

Controlpatients:

33.911.2,

ran

ge:1845

Notprovided

Ultrasound

Mu

ltifidusmuscle

C

SAatL4andL5

Notprovidedforthis

study

Previoustrialshave

shownthatthe

trainedassessorwas

reliable

Blinded

2

Symptomatic/asymptomaticstudies

Battietal26

(2012)

Symptomaticside

comparedwith

asymptomatic

side

Posterolateraldiskherniation

atonly1disklevel(L4L5or

L5S1),withradicular

u

nilateralsymptoms

fo

llowinganerveroot

d

istributioninthelegonthe

sideoftheherniation

In

tervalfrom

symptom

onset

toimaging6wk

43

41,ra

nge2263

28d,range

345d

MRI

Mu

ltifidusmuscle

C

SAoftheinvolved

le

velandthelevel

b

elow

Intrarater

ICC.90.99

Blinded

7

Barkeretal8(2004)

Symptomaticside

comparedwith

asymptomatic

side

Between1865yofage

U

nilateralLBP12wk

Self-reportofunilateralLBP

d

iagnosis

Spinelevelindicatedon

clinicalpresentationwas

id

entifiedonMRI

48

44.3

11.8,

ran

ge1965

15.65.8wk,

range12

26

MRI

Mu

ltifidusmuscle

C

SAofthe

clinicallyindicated

symptomaticlevel

a

ndthelevelbelow

Intrarater

ICC.89

Blinded

6

Kim

etal27

(2011)

Symptomaticside

comparedwith

asymptomatic

side

Single-levellumbardisk

h

erniationatL4L5

Severelegpainconsistent

w

ithradiologicalfinding

N

otresponsiveto

conservativetreatment

Patientswereseparatedinto

2

groups:groupAhad

symptomsduration1mo,

g

roupBhadsymptoms

d

uration3mo

GroupA:39

GroupB:37

GroupA:42.27.9,

ran

ge2558

GroupB:46.69.1,

ran

ge2258

GroupA:

0.60.4mo,

range0.11

mo

GroupB:

5.42.7mo,

range312

mo

MRI

Mu

ltifidusmuscle

C

SAatthesame

le

velasthedisk

h

erniation(L4L5)

Intrarater

ICC.95.99

Interrater

ICC.95.99

Blinded

8 (continued)




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was 1.08 (95% CI1.44, 0.72);thus, the multifidus muscle was sig-nificantly smaller in patients withchronic LBP than in control patients(Fig. 2A). The individual weighted

mean difference of the 2 blindedstudies was 1.09 (95% CI1.54,0.64) compared with1.11 (95%CI2.19, 0.02) for the 2 pre-sumed unblinded studies. Thus, themean difference between blindedand presumed unblinded studies wasnegligible (0.02 difference, 1.84%increase). The 95% CI of the pre-sumed unblinded studies was much

wider than that of the blinded stud-ies. The results of the 2 presumedunblinded studies were contradic-

tory, which could be the reason forthe difference in 95% CI values.Hides et al3 found that the multifidusmuscle was significantly smaller inpatients with chronic LBP than incontrol patients, whereas Lee et al7

reported no significant differencebetween the 2 groups. Other possi-ble reasons for the wide 95% CIinclude difference in sample size andmeasurement error.

Three studies compared the multi-fidus muscle CSA (cm2) at L5 inpatients with chronic LBP, with a

total of 75 patients with chronic LBPand 76 control patients,3,7,25 and allused ultrasound as imaging modality.The pooled weighted mean differ-ence was 1.67 (95% CI3.15,

0.19); thus, the multifidus musclealso was significantly smaller inpatients with chronic LBP than incontrol patients at L5 (Fig. 2B). The

individual pooled mean difference ofthe blinded study was statisticallysignificantly different: 1.75 (95%CI2.52, 0.98), whereas thepooled weighted mean difference ofthe 2 presumed unblinded studies

was not statistically different: 1.61(95% CI4.32, 1.09). Again, the 2presumed unblinded studies included

in this comparison had contradictoryresults. Hides et al3 found a signifi-cant difference between the 2 groups,T

able.

Continued

Study

Comparison

CaseDefinition

SampleSize

Age(y),

X

SD

Symptom

Duration,

X

SD

Imaging

Modality

OutcomeMeasures

In

cludedinThis

Review

Internal

ReliabilityTesting

Blinding

Status

Methodological

Quality

(NOS)

Ploumisetal9

(2011)

Symptomaticside

comparedwith

asymptomatic

side

C

ontinuousunilateralLBP

3mowith1-level

d

egenerativediskdisease

(lossofdiskheightorsignal

in

tensity)ofthelumbar

spinewithoutdiskextrusion

U

nilateralLBPwasself-

reportedaspainthatwas

lo

calizedon1sideofthe

b

ackwithorwithoutsciatica

40

34.2

7.6,

ran

ge2045

15.514.1mo

MRI

Mu

ltifidusmuscle

FCSA,samespinal

le

velandlevel

b

elowthe

id

entified

p

athologicallevel

Intrarater

ICC.92(.86.98)

Interrater

ICC.89(.84.92)

Blinded

8

a

MRImagneticresonanceimaging,NOS

NewCastleOttawascore,CLBPchroniclowbackpain,CTcomputedtomography,LBPlo

wbackpain,CSAcross-sectionalarea,FCSAfunctionalcross-

sectionalarea,ICCintraclasscorrelationc

oefficient,CVcoefficientofvariation.




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A

Study

LBPGroup

Control

Group

Weight

MeanDif

ferenceIV,

Fixed,

95%

CI

MeanDifferenceIV,

Fixed,

95%

CI

Mean

SD

Total

Mean

SD

Total

Kamazetal4(blinded)

4.59

1.13

36

5.65

1.3

3

34

38.7%

1.06(1

.64,0.48)

Wallworketal25

(blinded)

3.47

1.10

17

4.61

1.0

0

17

26.0%

1.14(1

.85,0.43)

Hidesetal3(unblinded)

3.74

2.29

42

5.42

1.8

8

40

15.9%

1.68(2

.59,0.77)

Leeetal7(unblinded)

7.08

1.13

16

7.65

1.3

4

19

19.4%

0.57(1

.39,0.25)

Total(95%

CI)

111

110

100.0%

1.0

8(1

.44,

0.7

2)

Heterogeneity:

23.21,

df3(P.36),I27%

Testforoveralleffect:Z5.89(P.00001)

B

Study

LBPGroup

ControlG

roup

Weight

MeanDiffer

enceIV,

Random,9

5%

CI

MeanDifference

IV,

Random,

95%

CI

Mean

SD

Total

Mean

SD

Total

Wallworketal25

(blinded)

3.81

1.20

17

5.56

1.10

17

34.1%

1.75(2.52,0.98)

Hidesetal3(unblinded)

3.50

2.10

42

6.48

1.72

40

33.6%

2.98(3.81,2.15)

Leeetal7(unblinded)

6.98

1.06

16

7.20

1.85

19

32.3%

0.22(1.20,0.76)

Total(95%

CI)

75

76

100.0%

1.6

7(3.15

,

0.1

9)

Heterogeneity:

21.51,

217.77,

df2(P.0001),I289%


Figure

2.

Meandifferencesand95%

confidenceintervals(95%

CIs)ofblindedandunblindedstudiesevaluatingmultifidus

musclecross-sectionalarea(insquarecentimeters)at(A)

L4and(B)L5betweenpatientswithchroniclowbackpain(LBP)andcon

trolpatients.IVinversevariance.




9/16

whereas Lee et al7 reported no sig-nificant difference.

The paraspinal muscle group CSA(cm2) at L4-L5 (or lower L4) was eval-

uated in 2 studies, with a total of 84patients with chronic LBP and 94control patients.2,4 One study usedCT scan4 and the other used MRI2

as the imaging modality. The pooledweighted mean difference was statis-tically significant: 1.93 (95% CI2.90, 0.95), suggesting that theparaspinal muscle group is smaller inpatients with chronic LBP compared

with control patients (Fig. 3). Asshown in Figure 3, the mean differ-ence for the blinded study was

1.71 (95% CI2.97,0.45) com-pared with2.25 (95% CI3.80,

0.70) for the presumed unblindedstudy. Although both studies showedthat the paraspinal muscle groupCSA was significantly smaller in the

chronic LBP group, the effect esti-mate was larger (0.54 difference,31.6% increase) for the presumedunblinded study. Because we did notperform a meta-regression, it is notpossible to determine whether this

difference is significant and relatedto the blinding status or whetherother methodological issues are at

the origin of this difference.

In an attempt to facilitate compari-sons between individuals, someauthors provided the L4-L5 (or lowerL4) paraspinal muscle group CSAmuscle to bone or disk ratio, mean-ing that the muscle CSA was dividedby the vertebral body or disk CSA of

the same spinal level. Thus, anothercomparison was made for this group,which included 2 studies with atotal of 43 patients with chronic LBPand 33 control patients.1,20 Lee etal20 conducted an MRI study to com-pare paraspinal muscle size betweenpatients with degenerative flat back(degenerative deformity character-

ized by a loss of lumbar lordosis) andnormal control patients, whereasDanneels et al1 compared patients

with chronic mechanical LBP with agroup of control patients. Thepooled weighted mean difference

was statistically significant (0.26[95% CI0.38, 0.14]), whereas

the individual mean difference of theblinded study was 0.26 (95%CI0.48, 0.04) compared with0.26 (95% CI0.40, 0.12) forthe presumed unblinded study(Fig. 4). These results show that bothstudies demonstrated the paraspinalmuscle group CSA was statisticallysignificant smaller in patients withchronic LBP compared with the con-

trol patients and suggest that theeffects of blinding were negligible.

Symptomatic/AsymptomaticComparison Between SidesMost symptomatic and asymptom-atic studies included in this reviewused paired t tests to evaluate thedifference between sides, which

control for the effect of intra-individual variation and take largerconsideration of the within-groupdifference. However, we used themean and standard deviations pro-

vided in the original manuscript to

calculate mean difference and 95%CI estimates presented in this reviewas suggested in the Cochrane Hand-

book for Systematic Review of Inter-

ventions.23 Thus, it is important toconsider that the 95% CI estimatespresented in this review are moreconservative and are not representa-tive of the original study results9,26,27

because they ignore the intra-individual correlation and are basedon different statistical analyses and

assumptions.

Only 2 studies looking at patientswith acute unilateral LBP were eligi-ble for this review, with a total of 82patients.26,27 Both studies were con-ducted with the use of MRI and mea-sured multifidus muscle CSA (cm2) atthe same spinal level as the pathol-

ogy (disk herniation). The pooledmean difference was not signifi-cantly different between sides: 0.25

(95% CI0.31, 0.82) (Fig. 5A). Thisfinding suggests that there is no sig-nificant difference between the mul-tifidus muscle CSA of the symptom-atic side and asymptomatic side in

patients with acute unilateral LBP.

Two blinded MRI studies of patientswith chronic LBP, with a total of 72patients, compared the multifidusmuscle CSA or FCSA (cm2) for thespinal level below the pathology.8,9

Because the studies included in thiscomparison investigated either CSAor FCSA, a standardized mean differ-

ence was obtained. The pooled stan-dardized mean difference demon-strated a statistically significant

different between sides: 0.40 (95%CI0.73, 0.07), although resultsof each study were contradictory(Fig. 5B). Note that the original meanmultifidus muscle CSA presented byBarker et al8 varied between 46.6

64.6 mm2, which is very small andimprobable for multifidus musclemeasurement. An error when trans-forming units could have been thecause of this inaccuracy.

Three blinded MRI studies ofpatients with chronic LBP (N125)compared the multifidus muscle CSA

or FCSA (cm2) between sides at thepathological spinal level.8,9,27 Thestandardized mean difference wasobtained because the outcomes

were different (CSA or FCSA)between studies. The pooled stan-dardized mean difference was0.43(95% CI0.68, 0.18) and statisti-cally significant different between

sides (Fig. 5C). However, the resultsare contradictory because 1 study8

showed a significant differencebetween muscle sides, whereas 2studies did not show a significantdifference.9,27

DiscussionThe aims of this systematic review

were: (1) to review the literatureregarding the differences in paraspi-nal muscle morphology between




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Study

LBPGroup

ControlG

roup

Weight

MeanDiffer

enceIV,

Fixed,95

%

CI

MeanDifference

IV,

Fixed,

95%CI

Mean

SD

Total

Mean

SD

Total

Kamazetal4(blinded)

17.89

2.71

36

19.6

2.68

34

60.0%

1.71(2.97,0.45)

Parkkolaetal2(unblinded)

22.50

4.77

48

24.75

3.0

60

40.0%

2.25(3.80,0.70)

Total(95%

CI)

84

94

100.0%

1.9

3(2.90,

0.9

5)

Heterogeneity:

20.28,

df1(P.60),I20%


Figure

3.



CIs)ofblindedandu

nblindedstudiesevaluatingparaspinalmusclegroupcross-sectionalarea(insq

uarecentimeters)

atL4L5orlowerL4betweenpatientswithchroniclowbackpain(LBP)a

ndcontrolpatients.IVinversevarianc

e.

Study

LBPGroup

ControlGroup

Weight

MeanDiffer

enceIV,

Fixed,95

%

CI

MeanDifference

IV,

Fixed,

95%CI

Mean

SD

Total

Mean

SD

Total

Danneelsetal1(blinded)

2.46

0.40

32

2.72

0.42

23

29.1%

0.26(0.48,0.04)

Leeetal20

(unblinded)

0.94

0.22

11

1.20

0.09

10

70.9%

0.26(0.40,0.12)

Total(95%

CI)

43

33

100.0%

0.2

6(0.38

,

0.1

4)

Heterogeneity:

20.00,

df1(P1.00),I

20%


Figure

4.



CIs)ofblindedandu

nblindedstudiesevaluatingparaspinalmusclegroupcross-sectionalarearatioatL4L5orlower

L4betweenpatientswithchroniclowbackpain(LBP)controlandcontrolpatients.IVinversevariance.




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A

Study

SymptomaticSide

AsymptomaticSid

e

Weight

MeanDifferenceIV

,Fixed,

95%

CI

MeanDifference

IV,

Fixed,

95%C

I

Mean

SD

Total

Mean

SD

Total

Battieetal26

(blinded)

9.90

2.20

43

9.50

2.00

43

40.3%

0.40(0.49,1.2

9)

Kim

etal27

(blinded)

6.80

1.72

39

6.65

1.57

39

59.7%

0.15(0.58,0.8

8)

Total(95%

CI)

82

82

100.0%

0.2

5(0.3

1,0.8

2)

Heterogeneity:

20.18,

df1(P.67),I20%;Testforoveralleffect:Z0.87(P.38)

B

Study

Symp

tomaticSide

AsymptomaticSid

e

Weight

StandardMeanDifferenceIV,

Fixed,

95%

CI

StandardMeanDiffe

renceIV,

Fixed,

95%C

I

Mean

SD

Total

Mean

SD

T

otal

Barkeretal8(blinded)

0.54

0.19

48

0.65

0.20

48

65.8%

0.56(0.97,0

.15)

Ploumisetal9(blinded)

7.20

2.11

24

7.40

2.00

24

34.2%

0.10(0.66,0.4

7)

Total(95%

CI)

72

72

100.0%

0.4

0(0.7

3,

0.0

7)

Heterogeneity:

21.70,


C

Study

Symp

tomaticSide

AsymptomaticSid

e

Weight

StandardMeanDifferenceIV,

Fixed,

95%

CI

StandardMeanDiffe

renceIV,

Fixed,

95%C

I

Mean

SD

Total

Mean

SD

T

otal

Barkeretal8(blinded)

0.49

0.22

48

0.61

0.22

48

37.9%

0.54(0.95,0

.13)

Kim

etal27

(blinded)

6.33

1.23

37

6.75

1.34

37

29.9%

0.32(0.78,0.1

4)

Ploumisetal9(blinded)

6.47

1.76

40

7.16

1.60

40

32.1%

0.41(0.85,0.0

4)

Total(95%

CI)

125

125

100.0%

0.4

3(0.6

8,

0.1

8)

Heterogeneity:

20.50,


Figure

5.


confide

nceintervals(95%

CIs)forsymptomatic/asymptomaticstudiescomparing(A)multifidusmusclecross-sectionalarea

(CSA)(insquare

centimeters)betweensidesinpatie

ntswithacutelowbackpain(LBP)atthepathologicspinallevel,(B)multifidusmuscleCSAorfunctionalCSA(insquarecentimeters)

betweensidesinpatientswithchron

icLBPatlevelbelowlumbarpathology,

and(C)multifidusmuscleCSAorfunctionalCSA(insquarecentimeters)betwee

nsidesinpatients

withchronicLBPatthepathologic

spinallevel.IVinversevariance.




12/16

patients with LBP and controlpatients who were healthy andbetween symptomatic and asymp-tomatic sides and (2) to assess thedifference between blinded and

unblinded assessors when takingquantitative paraspinal muscle mea-surements in patients with LBP. Ourfindings revealed that the multifidusand paraspinal muscle groups aresmaller in patients with chronic LBPcompared with control patients andthat the multifidus muscle is signifi-cantly different between sides forpatients with unilateral chronic LBP

but not patients with acute LBP.When looking at the individual effectestimate of the presumed unblinded

studies, there was a tendency for theeffect estimate to be greater com-pared with blinded studies, but thisdifference did not change the direc-tion of the results. This trend, how-ever, was not observed in all of our

comparisons. Caution should betaken when interpreting the differ-ence in effect estimates between theblinded and presumed unblindedstudies because the small samplesize and small number of studies

included in this review limit the evi-dence to suggest that blinding statuscould potentially lead to systematic

error or differential bias. However,because blinding of the outcomeassessors, for the most part, is easilyachievable in this field, future relatedimaging studies should use blindedassessors to increase their internal

validity.

The results of most studies suggest

that multifidus and paraspinal mus-cle groups are smaller in patientswith chronic LBP than in controlpatients who are healthy because allpooled estimates were statisticallysignificant. In addition, our resultsshowed that patients with chronicLBP appear to have more multifidusmuscle atrophy at L5 than L4

because the pooled effect estimateswere greater for the L5 multifidusmuscle CSA comparison. Overall, the

CSA of the multifidus muscle at L4and L5 was reported as between3.47 and 7.08 cm2 for patients

with chronic LBP3,4,7,25 and between4.61 and 7.65 cm2 for control

patients,3,4,7,25

with a mean differ-ence between groups of 1.08 and1.67 cm2. Whether this difference isclinically significant is unclear, but,because the multifidus muscle actsprimarily as a spinal stabilizer andcontrols the intersegment motion ofthe individual vertebrae,40 any atro-phy or injury to the multifidusmuscle is expected to compromise

spinal function. Similar findings alsowere true for studies comparingmuscle size between the symptom-

atic painful side and asymptomaticside of patients with chronic LBP.There were some conflicting resultsacross studies, but the pooled effectestimates (standardized mean differ-ence) were statistically significant

for both the pathological spinal leveland the level below, demonstratingthat patients with chronic unilateralLBP have smaller muscles on thesymptomatic side compared withthe asymptomatic side. However,

there is some evidence to suggestthat patients with acute (6 weeks)unilateral LBP have no significant

difference in multifidus muscle CSAbetween the symptomatic side andthe asymptomatic side. Among thestudies comparing the paraspinalmuscle group size between patients

with chronic LBP and controlpatients, all 4 studies found thatparaspinal muscle as a group wasstatistically significantly smaller in

patients with chronic LBP.

Disuse, muscle denervation, andreflex inhibition have been proposedas possible mechanisms for muscleatrophy in patients with LBP.28,41

However, whether muscle atrophy,asymmetry, or fatty infiltration eval-uated by imaging modalities results

from LBP and pathology or repre-sents a risk factor is still beingargued.6 Thus, future prospective

studies should focus on identifyingwhether muscle atrophy is a causeor a result of LBP. More studies areneeded to better understand therole of the multifidus and paraspinal

muscle groups in the etiology andmanagement of common spinaldisorders.

When looking at case-control com-parisons of the multifidus muscleCSA at L4 and L5, our attention wasdrawn to the notably smaller effectestimate and nonsignificant resultsobtained from the Lee et al study.7 It

is noteworthy that the results of thatstudy are somewhat questionablebecause the reported multifidus mus-

cle mean CSA was considerablylarger than that in all of the otherstudies included in this comparison.The case definition and mean age ofthe chronic LBP group were similarto those characteristics in the other

3 studies; the major difference wasthat all patients (patients withchronic LBP and control patients)

were active laborers, which isunlikely to be the only reason toexplain the much larger multifidus

muscle mean CSA reported by Lee etal.7 Moreover, the multifidus musclebecomes larger as we move caudally

down the lumbar spine, which wasnot observed in the study by Leeet al.7

The use of different imaging modali-ties could have introduced bias intothe results of this review, which maypartly explain some of the conflict-ing results found in this review. Mag-

netic resonance imaging technologyprovides higher image resolutioncompared with ultrasound and CTscan and allows better detection ofsoft tissues such as fat and mus-cle.42,43 Atrophied muscles havemore irregular boundaries and fattyinfiltration, which greatly increasethe level of difficulty when tracing

the borders of the muscle of inter-est.43 Moreover, ultrasound does notallow the differentiation of muscle




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and fat tissues; thus, accurate distinc-tion of muscle tissues from fat bor-ders is virtually impossible.25,44,45

Furthermore, there is some evidenceto suggest that intrarater and inter-

rater reliability are better whenlumbar paraspinal measurements areobtained with MRI compared withCT scan.43 Differences also existbetween the image acquisition ofultrasound and MRI (or CT scan);ultrasound imaging is generally per-formed in a prone position andrequires short acquisition time asopposed to MRI, which is performed

in a supine position and necessitatesconsiderably longer acquisition time.However, a previously published

study comparing multifidus muscleCSA measurements obtained withMRI and ultrasound45 suggested thatthe 2 modalities can be used inter-changeably. Although the latterstudy included a small sample of only

10 young women who were healthy(2131 years old) and such measureshave yet to be validated in olderindividuals with LBP conditions, wehave decided to perform a mixedanalysis in this study, pooling the

results of the 3 imaging modalities.

To our knowledge, this is the first

meta-analysis reviewing the litera-ture on multifidus and paraspinalmuscle group morphology changesassociated with LBP. Moreover, thisis the first study evaluating blinding

when performing quantitative imag-ing measurement of paraspinal mus-cles. An extensive database search

with the use of a strict standardized

method is one of the primarystrengths of this review. There aresome limitations to this review thatshould be acknowledged. First, onlya small number of studies met theinclusion criteria. Second, most ofthe included studies had small sam-ple sizes, which decreased the studypower and increased the possibility

of making a type II error. Addition-ally, we might have misclassifiedsome blinded studies as unblinded

when authors did not provide infor-mation about blinding of the out-come assessor. Finally, because ofthe small number of studies, we

were not able to perform a meta-

regression to quantitatively evaluatethe effects of blinding on the resultsof the studies.

ConclusionThe results of this systematic review

suggest that multifidus and paraspi-nal muscle groups are significantlysmaller in patients with chronic LBPthan in control patients who arehealthy and on the symptomatic sideof patients with chronic unilateralLBP compared with the asymptom-

atic side. Thus, the role of paraspinalmuscle morphology on the etiology,

prognosis, and treatment of patientswith LBP must be further investi-gated. When examining the esti-mates of the individual studies, thereseems to be a trend toward anincrease in effect size when the out-come assessor is presumed to beunblinded.

Future related imaging studies

should use blinded outcome asses-sors to increase their internal valid-ity. How blinding is achieved shouldbe clearly stated in the methodsection of the studies because thisaspect often is inadequately describedin publications.46A clear descriptionof the assessors experience also

should be provided to help thereader judge the level of skill of theassessor and facilitate future clinicalcomparisons.11

Both authors provided concept/idea/re-search design, writing, data collection andanalysis, and consultation (including reviewof manuscript before submission). Ms Fortinprovided project management. The authorsthank Michele Crites Battie for her review ofthis work and helpful comments.

Ms Fortin received support from the Euro-pean Union Communitys Seventh Frame-work Programme (FP7, 20072013; grantHEALTH F2-2008-201626; project GENO-DISC). Dr Macedo is supported by the

Canadian Institutes of Health Research andAlberta Innovates Health Solutions.

DOI: 10.2522/ptj.20120457

References

1 Danneels LA, Vanderstraeten GG, CambierDC, et al. CT imaging of trunk musclesin chronic low back pain patients andhealthy control subjects. Eur Spine J.2000;9:266272.

2 Parkkola R, Rytokoski U, Kormano M. Mag-netic resonance imaging of the discs andtrunk muscles in patients with chroniclow back pain and healthy control sub-

jects. Spine. 1993;18:830836.

3 Hides J, Gilmore C, Stanton W, et al. Mul-tifidus size and symmetry among chronicLBP and healthy asymptomatic subjects.Man Ther. 2008;13:4349.

4 Kamaz M, Kiresi D, Oguz H, et al. CT mea-surement of trunk muscle areas in patients

with chronic low back pain. Diagn Inter-

vent Radiol. 2007;13:144148.5 Mengiardi B, Schmid MR, Boos N, et al. Fat

content of lumbar paraspinal muscles inpatients with chronic low back pain andin asymptomatic volunteers: quantifica-tion with MR spectroscopy. Radiology.2006;240:786 792.

6 Kjaer P, Bendix T, Sorensen JS, et al. AreMRI-defined fat infiltrations in the multifi-dus muscles associated with low backpain? BMC Med. 2007;5:2.

7 Lee SW, Chan CK, Lam TS, et al. Relation-ship between low back pain and lumbarmultifidus size at different postures. Spine.2006;31:2258 2262.

8 Barker KL, Shamley DR, Jackson D.

Changes in the cross-sectional area of mul-tifidus and psoas in patients with unilateralback pain: the relationship to pain anddisability. Spine. 2004;29:E515E519.

9 Ploumis A, Michailidis N, Christodoulou P,et al. Ipsilateral atrophy of paraspinal andpsoas muscle in unilateral back painpatients with monosegmental degenera-tive disc disease. Br J Radiol. 2011;84:709713.

10 Hyun JK, Lee JY, Lee SJ, et al. Asymmetricatrophy of multifidus muscle in patients

with unilateral lumbosacral radiculopathy.Spine. 2007;32:E598 E602.

11 Costa LOP, Maher CG, Latimer J, et al.Reproducibility of rehabilitative ultra-sound imaging for the measurement of

abdominal muscle activity: a systematicreview. Phys Ther. 2009;89:756 769.

12 Schulz KF, Grimes DA. Blinding in ran-domised trials: hiding who got what. Lan-cet. 2002;359:696 700.

13 Schulz KF, Chalmers L, Hayes RJ, et al.Empirical evidence of bias: dimensions ofmethodological quality associated withestimates of treatment effects in con-trolled trials. JAMA. 1995;273:408412.

14 Poolman RW, Struijs PAA, Krips R, et al.Reporting of outcomes in orthopaedic ran-domized trials: does blinding of outcomeassessors matter? J Bone Joint Surg Am.2007;89:550 558.




14/16

15 Liu CJ, Lavalley M, Latham NK. Dounblinded assessors bias muscle strengthoutcomes in randomized controlled trialsof progressive resistance strength trainingin older adults? Am J Phys Med Rehabil.2011;90:190 196.

16 Lijmer JG, Mol BW, Heisterkamp S, et al.

Empirical evidence of design-related biasin studies of diagnostic tests. JAMA.1999;282:10611066.

17 Moher D, Liberati A, Tetzlaff J, et al. Pre-ferred reporting items for systematicreviews and meta-analyses: the PRISMAstatement. Ann Intern Med. 2009;151:264269.

18 Hides J, Stanton W, Freke M, et al. MRIstudy of the size, symmetry and functionof the trunk muscles among elite cricket-ers with and without low back pain. Br JSports Med. 2008;42:509 513.

19 Hides J, Stanton W, McMahon S, et al.Effect of stabilization training on multifi-dus muscle cross-sectional area among

young elite cricketers with low back pain.J Orthop Sports Phys Ther. 2008;38:101108.

20 Lee JC, Cha JG, Kim Y, et al. Quantitativeanalysis of back muscle degeneration inthe patients with the degenerative lumbarflat back using a digital image analysis:comparison with the normal controls.Spine. 2008;33:318325.

21 McGregor AH, Anderton L, GedroycWMW. The trunk muscles of elite oars-men. Br J Sports Med. 2002;36:214 217.

22 Beneck GJ, Kulig K. Multifidus atrophy islocalized and bilateral in active persons

with chronic unilateral low back pain.Arch Phys Med Rehabil. 2012;93:300306.

23 Higgins JPT, Green S, eds. Cochrane

Handbook for Systematic Reviews ofInterventions Chichester, United King-dom: John Wiley & Sons Ltd; 2012.

24 Iwai K, Nakazato K, Irie K, et al. Physicalcharacteristics of university wrestlers withlow back pain. Jpn J Phys Fitness SportsMed. 2002;51:423 436.

25 Wallwork TL, Stanton WR, Freke M, et al.The effect of chronic low back pain onsize and contraction of the lumbar multi-fidus muscle. Man Ther. 2009;14:496500.

26 Battie MC, Niemelainen R, Gibbons LE,et al. Is level- and side-specific multifidusasymmetry a marker for lumbar discpathology? Spine J. 2012:12:932939.

27 Kim WH, Lee S, Lee DY. Changes in thecross-sectional area of multifidus andpsoas in unilateral sciatica caused by lum-bar disc herniation. J Korea NeurosurgSoc. 2011;50:201204.

28 Hides JA, Richardson CA, Jull GA. Multifi-dus muscle recovery is not automatic after

resolution of acute, first-episode low backpain. Spine. 1996;21:27632769.

29 Gibbons LE, Latikka P, Videman T, et al.The association of trunk muscle cross-sectional area and magnetic resonanceimage parameters with isokinetic and psy-chophysical lifting strength and static backmuscle endurance in men. J Spinal Dis-ord. 1997;10:398403.

30 Kang CH, Shin MJ, Kim SM, et al. MRI ofparaspinal muscles in lumbar degenerativekyphosis patients and control patients

with chronic low back pain. Clin Radiol.2007;62:479486.

31 Kraft CN, Pennekamp PH, Becker U, et al.Magnetic resonance imaging findings ofthe lumbar spine in elite horseback riders:correlations with back pain, body massindex, trunk/leg-length coefficient, andriding discipline. Am J Sports Med.2009;37:22052213.

32 Hides J, Hughes B, Stanton W. Magneticresonance imaging assessment of regionalabdominal muscle function in elite AFLplayers with and without low back pain.Man Ther. 2011;16:279 284.

33 Hultman G, Nordin M, Saraste H, et al.Body composition, endurance, strengthcross-sectional area and density of mmerector spinae in men with and withoutLBP. J Spinal Disord. 1993;6:114123.

34 Kulig K, Scheid AR, Beauregard R, et al.Multifidus morphology in persons sched-uled for single-level lumbar microdiscec-tomy: qualitative and quantitative assess-ment with anatomical correlates. Am JPhys Med Rehabil. 2009;88:355361.

35 Paalanne N, Niinimaki J, Karppinen J, et al.Assessment of association between lowback pain and paraspinal muscle atrophyusing opposed-phase magnetic resonanceimaging: a population-based study among

young adults. Spine. 2011;36:19611968.

36 Hides JA, Stokes MJ, Saide M, et al. Evi-dence of lumbar multifidus muscle wast-ing ipsilateral to symptoms in patients

with acute/subacute low back pain. Spine.1994;19:165172.

37 Sitilertpisan P, Hides J, Stanton W, et al.Multifidus muscle size and symmetryamong elite weightlifters. Phys Ther Sport.2012;13:1115.

38 Jinkins JR. Lumbosacral interspinous liga-ment rupture associated with acute intrin-sic spinal muscle degeneration. Eur

Radiol. 2002;12:23702376.39 Smuck M, Yarjanian J, Fetzer A, et al. Cor-

relation of paraspinal atrophy and dener-vation in back pain and spinal stenosis rel-ative to asymptomatic controls. Presentedat: 25th Annual Meeting of the North

American Spine Society; October 59,2010; Orlando, Florida. Spine J. 2010;10(9suppl 1):47S48S.

40 Solomonow M, Zhou BH, Harris M, et al.The ligamento-muscular stabilizing systemof the spine. Spine. 1998;23:25522562.

41 Hodges P, Holm AK, Hansson T, et al.Rapid atrophy of the lumbar multifidus fol-lows experimental disc or nerve root inju-ry. Spine. 2006;31:2926 2933.

42 Ranson CA, Burnett AF, Kerslake R, et al.

An investigation into the use of MR imag-ing to determine the functional cross sec-tional area of lumbar paraspinal muscles.Eur Spine J. 2006;15:764 773.

43 Hu Z, He J, Zhao F, et al. An assessment ofthe intra- and inter-reliability of the lumbarparaspinal muscle parameters using CTscan and magnetic resonance imaging.Spine. 2011;36:E868 E874.

44 Pressler JF, Heiss DG, Buford JA, et al.Between-day repeatability and symmetryof multifidus cross-sectional area mea-sured using ultrasound imaging. J OrthopSports Phys Ther. 2006;36:1018.

45 Hides JA, Richardson CA, Jull GA. Mag-netic resonance imaging and ultrasonogra-phy of the lumbar multifidus muscle: com-

parison of two different modalities. Spine.1995;20:5458.

46 Hrobjartsson A, Pildal J, Chan A, et al.Reporting on blinding in trial protocolsand corresponding publications was ofteninadequate but rarely contradictory. J ClinEpidemiol. 2009;62:967973.




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Appendix.Search Strategies

MEDLINE1. Low back pain.mp.2. Low backache.mp.3. low back pains.mp.4. back pain, lower.mp.5. sciatica.mp.6. radiculopathy.mp.7. lumbago.mp.8. disc herniation.mp.9. exp Intervertebral Disc displacement/ or exp Intervertebral disc displacement.mp.

10. disk herniation.mp.11. disc degeneration.mp. or exp Intervertebral Disc Degeneration/12. spondylolisthesis.mp.13. spondylolisis.mp. or exp Spondylolysis/ or exp Spondylolisthesis/14. spinal stenosis.mp.15. or/11416. paraspinal muscles.mp.17. paravertebral muscles.mp.18. vertebral muscle.mp.19. erector spinae.mp.20. multifidus.mp.21. trunk muscles.mp.22. or/162123. 15 and 2224. paraspinal muscle asymmetry.mp.25. muscular atrophy.mp. or exp Muscular Atrophy/26. muscle wasting.mp.27. muscle degeneration.mp.

28. muscle size.mp.29. muscle morphology.mp.30. paraspinal muscle atrophy.mp.31. muscle atrophy.mp.32. cross-sectional area.mp.33. functional cross-sectional area.mp.34. or/243335. 23 and 3436. magnetic resonance imaging.mp. or exp Magnetic Resonance Imaging/37. MRI.mp.38. exp Tomography, X-Ray Computed/ or CT scan.mp.39. Ultrasound.mp.40. or/3639

41. 35 and 40(Continued)




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Appendix.Continued

EMBASE1. Low back pain.mp.2. Low backache.mp.

3. low back pains.mp.4. back pain, lower.mp.5. sciatica.mp.6. radiculopathy.mp. or exp radiculopathy/7. lumbago.mp.8. disc herniation.mp. or exp intervertebral disk hernia/9. disk herniation.mp.

10. intervertebral disc displacement.mp.11. exp intervertebral disk degeneration/ or disc degeneration.mp.12. exp spondylolysis/ or exp spondylolisthesis/ or spondylolisis.mp.13. spondylolisthesis.mp.14. spinal stenosis.mp. or exp vertebral canal stenosis/15. or/114

16. exp back muscle/ or paraspinal muscle.mp.17. back muscle.mp.18. paravertebral muscles.mp.19. vertebral muscle.mp.20. trunk muscles.mp.21. erector spinae.mp.22. multifidus.mp.23. or/162224. 15 and 2325. exp muscle atrophy/ or paraspinal muscle asymmetry.mp.26. muscular atrophy.mp. or exp muscle atrophy/27. muscle wasting.mp.28. muscle degeneration.mp.29. muscle size.mp.

30. muscle morphology.mp.31. paraspinal muscle atrophy.mp.32. cross-sectional area.mp.33. functional cross-sectional area.mp.34. or/253335. 24 and 3436. magnetic resonance imaging.mp. or exp nuclear magnetic resonance imaging/37. MRI.mp.38. CT scan.mp. or exp computer assisted tomography/39. Computed Tomography.mp.40. ultrasound.mp. or exp ultrasound/41. or/36 4042. 35 and 41

Scopus1. (TITLE-ABS-KEY(magnetic resonance imaging OR mri OR tomography OR x-ray computed OR ct scan OR

ultrasound)) OR (TITLE-ABS-KEY(multifidus morphology OR multifidus atrophy))2. (TITLE-ABS-KEY(paraspinal muscle asymmetry OR muscle atrophy OR paraspinal muscle atrophy OR muscular

atrophy OR muscle wasting OR muscle degeneration OR muscle size OR muscle morphology OR cross-sectionalarea OR functional cross-sectional area)) OR (TITLE-ABS-KEY(multifidus morphology OR multifidus atrophy))

3. ((TITLE-ABS-KEY(paraspinal muscle asymmetry OR muscle atrophy OR paraspinal muscle atrophy OR muscularatrophy OR muscle wasting OR muscle degeneration OR muscle size OR muscle morphology OR cross-sectionalarea OR functional cross-sectional area)) OR (TITLE-ABS-KEY(multifidus morphology OR multifidus atrophy)))

AND ((TITLE-ABS-KEY(magnetic resonance imaging OR mri OR tomography OR x-ray computed OR ct scan ORultrasound)) OR (TITLE-ABS-KEY(multifidus morphology OR multifidus atrophy)))


multifidus and paraespinal sist rev

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