Part 2-Chronic Pain and ODG from AAOS - American Osteopathic

52 Pages·2013·0.43 MB·English

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Chronic Pain: Fundamental
Scientific Considerations,
Specifically For Legal Claims
RobertJ.Barth,Ph.D.
Chronic Pain: Fundamental Scientific Considerations, Specifically
For Legal Claims
byRobertJ.Barth
ParkridgeHospitalPlazaTwo
2339McCallieAve,Suite202
Chattanooga,TN 37404
423/624-2000
Previouslypublishedversionsofthisdiscussion:
 BarthRJ. ChronicPain:FundamentalScientificConsiderations,Specifically
forLegalClaims. AMAGuides Newsletter,Jan/Feb2013. AmericanMedical
Association.
NOTE: TheAMA’seditorialprocess involvesanunusuallyextensive
review. Theunusualthoroughnessis exemplifiedbytheAMA’s typical
recruitmentofninereviewers(inadditiontotheprimaryeditors). In
contrast,other editorialprocesses(suchastheeditorialworkthatIdo
fortheJournalofBoneandJointSurgery)typicallyinvolveonlythree
reviewers. TheAMA’sextensivereview processfailedtoleadtothe
identificationofanyadditionalscientificfindings ofrelevancetothis
paper–therebyindicatingthatthis paper summarizes therelevant
scientificknowledgebaseinarelativelycomprehensivefashion.
TheAMAversionofthisprojectcanbepurchasedbycallingtheAMA
at(800)621-8335(theoptionforpurchasingdirectlyoffthewebsiteis
nolongeravailable).
 BarthRJ. ChronicPain: HowtoMakeSenseofItWithinOrthpaedicClaims.
In: MelhornJMandCarrageeE. 14thAnnualAmericanAcademyof
OrthopaedicSurgeonsOccupationalOrthopaedicsandWorkers
Compensation:AMultidisciplinaryPerspective.2012. AmericanAcademyof
OrthopaedicSurgeons.
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I.Introduction
I.A.Chronicpainis anormal,non-injury-relatedpartoflife
Chronicpainisnormal.Thenormalnatureofchronicpainwasdemonstratedbya
Galloppollin2011(Brown).Findingsfromthatpollincluded:
 31%ofU.S.adultshavechronicneckorbackpain
 26%havechronickneeorlegpain
 18%havesomeotherchronicpain
 47%oftheadults hadatleastoneofthesechronicpainproblems.
Thenormalnatureofchronicpainisoftenoverlookedwithinlegalclaims,andthepain
is insteadmisinterpretedasanindicationthataninjuryhasoccurred(withthe
correspondingmisinterpretationthataninjuryisthecauseofthepain’s persistent
nature).
I.B.Thetendencyforlegalclaims tomisrepresentpainasapurelyinjury-relatedor
generalmedicalissueisinconsistentwiththepsychologicalnatureofpain.
Apparentlybecauseofthemisdirectedemphasisoninjurywithinlegalclaims,general
medicalclinicians(meaningclinicianswhodonotspecializeinpsychologicalissues)
areregularlyaskedtoevaluatechronicpaincomplaints withinsuchclaims. Referralto
ageneralmedicalclinicianforsuchapresentationis oftenacompoundingofthe
misdirection,inthatthedefinitionofpain(Merskey&Bogduk)actuallynotesthat:
 Painis“alwaysapsychologicalstate”
 Painis“always”“anemotionalexperience”
 “Activityinducedinthenociceptorandnociceptivepathways byanoxious
stimulusisnotpain…”
 “Manypeoplereportpainintheabsenceoftissuedamageoranylikely
pathophysiologicalcause;usuallythishappens forpsychologicalreasons.There
is usuallynowaytodistinguishtheirexperiencefromthatduetotissuedamage
ifwetakethesubjectivereport.”
Similarly,eachofthetwomostrecenteditions oftheAmericanMedicalAssociation’s
GuidestotheEvaluationofPermanentImpairment (Rondinelli;Cocchiarellaand
Andersson)havespecifiedthatpainis definitionallyan“emotionalexperience”.
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TheAmericanMedicalAssociationhasalsopublishedadditionaldefinitional
considerations(Evans),whichhavebeenspecificallybuiltontheIASPdefinitionthat
wasdiscussedabove:
 ThoseAMAmaterials (Evans)specifythat“painisaperceptionandnota
sensation”:
o Sensationis definedas“theprocessorexperienceofperceivingthrough
thesenses”(VandenBos)
o Perceptionis definedas“theprocessorresultofbecomingawareof
objects,relationships,andeventsbymeansofthesenses,whichincludes
suchactivitiesasrecognizing,observing,anddiscriminating.These
activities enableorganisms toorganizeandinterpretthestimulireceived
intomeaningfulknowledge.”(VandenBos)
o Consequently,this distinctionthatis madeintheAMAmaterials
(Evans)regardingthenatureofpainemphasizesthatpainis notan
automaticsensoryphenomenon,butis insteadaprocessofthe
individualrecognizing,observing,discriminating,organizing,and
interpretingthesensation,andisalsotheresultofallofthat
psychologicalactivity. Inotherwords,painisinherentlypsychological.
 TheseAMAmaterials (Evans)summarizethesignificanceoftheabove
distinctioninthefollowingfashion:“Inallcases,therealitythatpainisa
perceptionindicatesthepotentialforprofoundinfluenceofpsychologicaland
emotionalfactors…”
 TheseAMAmaterials (Evans)additionallyemphasizeahierarchicalmodel
whichalsohighlights theprimarilypsychologicalnatureofpain. Theprimarily
psychologicalnatureofpainis indicatedbythestrictlypsychologicalnatureof
twoofthethreecomponentsofthathierarchy[“amotivational–affective
component(e.g.,depression,anxiety),andacognitive-evaluativecomponent
(e.g.,thoughtsconcerningthecauseandsignificanceofthepain)”].Thethird
componentinvolvessensation,butindicatesthatthesensationaspectsofpain
areinextricablylinkedtothepsychological/perceptualaspects[“asensory-
discriminativecomponent(e.g.,location,intensity,quality)”].
 TheseAMAmaterials (Evans)additionallyspecifythatthereisnotaninherent
relationshipbetweenpainandgeneralmedicalphenomena. Relevantpassages
include:
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o “Thereis animportantimplicationofboththeIASPdefinitionandthe
hierarchicalmodelofpain:Asaperception,painmayormaynot
correlatewithanidentifiablesourceofinjury.”
o “…paincandevelopandbeunrelatedtoanyidentifiablephysical
process…”
Consistentwiththesedefinitionalconsiderations,scientificfindingshaveindicatedthat
psychologicalandsocialfactorsarethedrivingforcesbehindmostchronicbenignpain
presentations(especiallywhenthepresentationoccurs withinalegalclaimcontext).
Therelevantscientificknowledgebasehas beendiscussedinavarietyofpublications
fromtheAmericanMedicalAssociation. Forexample,the FifthEditionoftheAMA’s
GuidestotheEvaluationofPermanentImpairment (CocchiarellaandAndersson)
providedasummaryofrelevantscientificknowledgebasewhichemphasizesthat“a
varietyofnonbiologicalfactorsstronglyinfluence”presentationsofpain.The
“nonbiological”factorsthatarespecifiedintheassociatedtextinclude:
 “beliefs,expectations,rewards,attention,andtraining”
 “socialandenvironmentalfactors”
 “spousesolicitousness”
 “jobdissatisfaction,lackofsupportatwork,stress andperceivedinadequacyof
income”
 “financialcompensation,receiptofwork-relatedsicknessbenefits,and
compensation-relatedlitigation”
 “pooreducation,languageproblems,andlowincome”
 “tendenciestobepreoccupiedwithone’s bodyandsymptoms”
 “depressionanddailyhasslesatwork”
Discussions ofpsychologicalandsocialfactorsthathavebeenscientificallyindicated
asbeingthedominantdrivingforcesbehindlegalclaimsinvolvingafocusonpainare
alsoprovidedinotherpublicationsfrom theAmericanMedicalAssociation’sGuides
Library(examplesinclude:BarthNovember/December,2006;Barth
September/October2007;BarthMay/June2009;BarthNovember/December2009;
BarthMarch/April,2011;Barth2013;MelhornandAckerman;Melhorn,Talmage,
Ackerman,&Hyman).
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Amoredetaileddiscussionofsuchscientificfindingsis providedthroughoutthe
remainderofthischapter.
Thesignificanceofthisscientificknowledgebaseis highlightedbyitsrelevanceforat
leastthreeoftheAMAGuides:
 GuidestoEvaluationofDiseaseandInjuryCausation (Melhornand
Ackerman;Melhorn,Talmage,Ackerman,&Hyman):Forexample,these
findings aredirectlyrelevanttothefourthstepofthecausationanalysis
protocol,whichcallsfor“determiningifotherriskfactors provideabetter
explanationfortheclinicalpresentation,thanthatwhichisprovidedbythe
claimedcause”(Barth2012).
 AMAGuides toWorkAbilityandReturntoWork(Talmage2011): These
findings providedirectionfordeterminingwhichscientificallyestablishedrisk
factorsforchronicpainareofrelevancetotheindividualcase,sothatan
individualizedrehabilitation/treatmentplancanbeformulated.
 GuidestotheEvaluationofPermanentImpairment (Rondinellietal.): These
findings providedirectionfordeterminingthefactors thataredrivingtheclaims
ofimpairment,andforapportionmentofimpairmentratings.
II. TheDominantRoleofFinancialCompensation
Awidevarietyofscientificfindingshavestronglyindicatedthateligibilityforcompensationis
thedominantfactorforchronicpainclaims.
II.A. ProspectiveResearch
Prospectiveresearchdesignsprovidethemostcredibleandreliablescientificinformation
(Melhorn&Ackerman).Becauseoftheuniquevalueofprospectiveresearch,thisarticle
beginsthereviewofscientificfindingsbyfocusingonCarragee’sone-of-a-kindprospective
project. Theresultsofthatlowbackpain(LBP)projectwerefirstpresentedatthe2005
AnnualMeetingoftheNorthAmericanSpineSociety(NASS),andthenpublishedin2006,
withdiscussions inbothSpineandTheSpineJournal.
Theresearchers actuallyrecruited200participants whodeniedanyhistoryofsignificant
problemswithlowbackpain. Foreachparticipant,theresearchers:
 Gathereddetailedgeneralmedicaldataatbaseline(e.g.spineimaging,detailed
physicalexaminationwithanintensefocusontheback)
 Gatheredminimal,butsignificant,psychologicaldataatbaseline.Thiswaslimitedto
theModifiedSomaticPerceptionQuestionnaire(whichaddresses somatoform
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phenomena)andtheZungDepressionInventory. Althoughthisisaminimalsetof
data,itis significantbecausescientificfindingshaveindicatedthatthesequestionnaires
havepredictivepowerforthedevelopmentoflowbackpain,andyettheyare
insensitivetotheeffects oflowbackpain(Mannion).Consequently,thereisno
"chickenortheegg"issuewiththesequestionnaires.Therelationshipbetween
abnormalitiesonthesequestionnairesandthedevelopmentofpainislargely
unidirectional:abnormalrespondingonthesequestionnairesis predictiveofthe
developmentofpain,butthedevelopmentofpaindoes notsignificantlychangethe
responsepatternonthesequestionnaires.
 Theresearchers thenfollowedeachparticipantforfiveyears. Overthecourseofthe
project,thestatus ofeachparticipantwascheckedeverysix months.
 Theexperienceofphysicaltraumawasmonitoredoverthecourseoftheproject. The
project’sdefinitionofphysicaltraumaincludedlifting(aswellas falls,roadtraffic
accidents,sports/exerciseinjuries,andan“other”category). Thesephenomenawere
consideredtraumaticiftheywereassociatedwiththedefinitionsof“serious lowback
pain”,“minortrauma”,or“majorinjury”providedbelow.
Inordertofullycomprehendthefindingsthatarereportedbelow,thefollowingdefinitions
mustbeunderstood. Theresearchers defined“serious lowbackpain”as“painintensity
definedbyanumericalratingscale>6/10foratleastoneweek”. Theresearchersdefined
“minortrauma”as “anyperceivedinjurytothelowbackareawithabackpainintensity>2/10
foratleast48hoursbutnotmeetingthemajorinjurydefinition”. The“majorinjury”
definitionwas“lowbackpainepisodes associatedwithhighenergytraumaresultinginserious
visceralinjury,proximallongbone,orpelvicorspinalfractureordislocation”.
Extensivedetailsofthefindingsfromthis projectwerepublishedin SpineandTheSpine
Journal in2006(seetheCarrageereferences inthereferencelist). However,forthepurpose
ofthis discussion,theprimaryauthor’ssimplestsummarystatementregardingthefindings was
partofapresentationattheAnnualMeetingoftheNorthAmericanSpineSociety(as
documentedinTheBackLetter,Volume20,No.11,November2005). Inthatpresentation,
Dr.Carrageeexplained:“Minortraumawas onlyassociatedwithseriouslowbackpainina
compensationsetting.”
Inotherwords,eligibilityforcompensationwasactuallyanecessaryfactorforthe
developmentofserious lowbackpainfollowingminortraumainthis researchsample. None
oftheparticipantswhowerenoteligibleforcompensationdevelopedseriouslowbackpain
followingminortrauma.
Consistentwiththefindingthatserious lowbackpainfollowingminortraumawaslimitedto
participantswhowereeligibleforcompensation,thefindingsrevealedalackofoverall
associationbetweenminortraumaandadverselowbackpainevents.Thiswas thecasein
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termsofalackofdifferenceinseriouslowbackpaineventsbetweenpeoplewhoreported
experiencinganynumberofminortraumaticevents,versuspeoplewhoreportedthattheyhad
notexperiencedanytrauma. Incontradictionof"cumulativetrauma"claims,thefindingsalso
includedalackofsignificantincreaseinseriouslowbackpainreports forpeoplewhoreported
experiencingmorethanfourminortraumaticevents,comparedtothosewhoreported
experiencingnone.
Theresearchers furtherreportedthat,"serious lowbackpainepisodesweremostfrequently
seenarisingspontaneouslyorwithusualdailyactivitiesratherthaninvolvingtraumaofany
sort".
Formotorvehicleaccidents,theriskofseriouslowbackpainwassignificantlygreaterwhen
thesubjectperceivedothers tobeatfaultfortheincident(19%),comparedtowhenthe
participantperceivedtheaccidenttobetheirownfault,ornoone'sfault(2.1%,andnoneof
theseinstancesofseriouslowbackpainwereassociatedwithdisability).Whentheparticipant
didperceivetheaccidenttobehis/herownfaultornoone'sfault,theepisodesofseriouslow
backpainwerelimitedtorelativelyhigh-speedaccidents (30and35mph).Incontrast,forthe
participantswhoreportedseriouslowbackpainfollowingamotorvehicleaccidentthatthey
perceivedtobecausedbysomeoneelse,onlyonewas reportedasoccurringataspeedover30
mph,themajoritywerereportedasoccurringbetween20and30mph,severalwerereported
forspeeds oflessthan20mph,andtwowerereportedforspeedsless than10mph.Inthe
reportofresults thatwaspublishedin Spine,theresearchers noted:
 "serious lowbackpainevents weremorelikelyatlowspeedwhenothers were
perceivedasresponsiblefortheaccident(P=0.001)”.
 "Itisinterestingthattraumaticepisodesassociatedwiththeleastrelativeforces
describedwerehighlycorrelatedwithcompensationclaimsortheperceptionofothers
beingatfaultforanaccident."
Interms ofanatomicalfindings,theresearchers’summarystatements included:
 "Subjectswithadvancedstructuralfindingswerenotmorelikelytobecome
symptomaticwithminortraumaevents thanwithspontaneouslyevolvinglowback
painepisodes."
 "Follow-upmagneticresonanceimagingevaluatingnewseriouslowbackpainillness
rarelyrevealednewclinicallysignificantfindings." Only3%ofthecasesofnewback
painproducednewimagingfindingsthatwereclinicallyrelevant.
Forthesubjects whodevelopeddisabilitylastingmorethanonemonthduringthecourseofthe
study,only14%hadnewfindingsonspineMRI(onesubjecthadnewspondylolisthesis,
progressionofendplatechanges andadvancedstenosis;onehadextrudeddischerniationwith
rootcompression;andonehadanadvanceofdegenerativediscdiseasefromgrade1tograde
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3-4). Theresearcherspointedoutthatthemostimportantofthesefindings (newdisk
extrusion,newspondylolisthesis,andprogressiontoseverestenosis)occurredintheabsence
ofanytrauma.
Inthediscussionofresultsthatwas publishedin Spine,theresearchersexplainedthat,even
thoughsubjects withcompensationclaimsweremorelikelytohaveanewMRIperformed
afterminortrauma,theywereactuallylesslikelytohaveneworprogressivefindings onthe
newMRI. Inthediscussionofresultsthatwaspublishedin TheSpineJournal,theresearchers
furtherexplainedthat:"Nopatientwithacompensationclaimhadaclearnewfindingof
significantpathology." Theresearchersfurtherexpressedconcerninregardtothefindingthat
factorswhichindicatealackofneedforspineimaging(thefilingofamedical-legalclaim,
pre-painabnormalrespondingtopsychologicalquestionnaires,pre-existingchronicpain,a
historyofsmoking)wereallactuallypredictiveofahigherlikelihoodofspineimagingbeing
conducted(researchersreferenceprevious scientificfindingswhichindicatethatsuch
unjustifieduseofimagingispredictiveofalessersenseofwell-beingforthepatients).
Inregardtospecifictypesofanatomicalfindings,theresearchersreported:
 "Seriouslowbackpaineventswerenotsignificantlymorecommoninsubjectswith
discdegenerationorannularfissures,whetherthesubjectshadaminortraumaornot".
 21%ofsubjectswithnodiscdegenerationhadadisabilityeventduringthecourseof
thestudy,comparedto22%withdiscdegeneration.
 "Therewasnoincreaseddisabilityinsubjects withendplatechangescomparedto
thosewithout."
 Moderatetosevereendplatechangeswerenotsignificantlyassociatedwithbackpain.
 Moderatetoseverespinalcanalstenosis was notsignificantlyassociatedwithlowback
pain.
 Severelossofdischeightwasnotsignificantlyassociatedwithbackpain.
Inthediscussionofresultsthatwas publishedin TheSpineJournal,theresearchers
additionallyemphasizedthecommonnatureofseveralspinefindingsforindividualswhoare
freefrompain.Theynotedthatsuchspinefindingsareoftenmistakenlyinterpretedas an
explanationforpaincomplaints,andevenas evidenceofinjury. Theywarnedthatthe
commonnatureofthesefindingsamongpeoplewhodonothaveanypaincausesthepremise
thatthereisanassociationbetweenthesefindingsandpain,othersymptoms,orinjuryto
become"untenable". Theyofferedthefollowingexamples ofspineimagingfindings which
arecommonforpeoplewhoarefreefrompain:
 discprotrusionorextrusion(50%oftheirsampleofpain-freeindividuals)
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 annularfissures (nearly30%oftheirsampleofpain-freeindividuals)
 potentialrootirritation(22%oftheirsampleofpain-freeindividuals)
Inthediscussionofresultsthatwas publishedin Spine,theresearchersprovidedareviewof
previousliteraturewhichsimilarlydocumentedthelackofrelationshipbetweenspineimaging
andbackpain. Inthediscussionofresultsthatwas publishedin TheSpineJournal,the
researchersprovidedamoreextensiveliteraturereview,andcommentedthatallofthe
followinghavebeenhypothesizedascauses oflowbackpain,butthosehypotheses havebeen
thwartedbyscientificfindingsthatalloftheseissuescanbefoundinsubjects withnoback
painoronlyminorproblems:
 acuteannulartearextendingintotheenervatedouterannulus
 anexistingannularfissuremaybecomeinflamedandappearasabrightannularsignal
onMRI
 minorendplatefailurescausingrapidstructuralfailureofthedisc
 discherniationanddistentionoftheannulusorcompressionofneuralelements
Alsointhediscussionofresultsthatwaspublishedin TheSpineJournal,theresearchers
reportedthatthemostcommonimagingfinding(progressiveloss ofdiscsignalintensity)has
beenshown(inthefindings frompreviousscientificinvestigations)tobeprimarilyanaging
phenomenonthatisnotwellcorrelatedwithsymptoms. Similarly,theyreportedthattheir
secondmostcommonfinding(progressivefacetarthrosis)isaslowlyevolvingprocessthatis
unlikelytoberelatedtotraumaoranyotherrecentevent.
Inthediscussionofresultsthatwas publishedin TheSpineJournal,theresearchersspecified
thattheirfindingssupportedbothofthefollowingconclusions:
 Thereis notacausativerelationshipbetweenstructuralchanges inthespineandserious
lowbackpain.
 Thereis notacrediblebasis foran“injurymodel”forlowbackpain.
Aswas reportedabove,minortraumawas notpredictiveofthedevelopmentofseriouslow
backpain.Thebaselinefactorswhichdidpredictthedevelopmentofserious lowbackpain
were(apredictionmodelutilizingthefollowingfourfactorscorrectlypredicted80%ofthe
seriouslowbackpainevents):
 previoushistoryofchronicpaincomplaintsforanotherpartofthebody
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 ahistoryofsmoking
 abnormalrespondingtothepsychologicalquestionnaires atbaseline
 aprevioushistoryoffilingmedical-legalclaims.
Similarly,apredictionmodelutilizingonlyabnormalrespondingonthebaselinepsychological
questionnairesandaprevious historyofmedical-legalclaimscorrectlypredicted93%ofthe
disabilityeventsattributedtobackpainduringthecourseoftheproject.
Inthereportofresults thatwaspublishedin Spine,theresearchers providedareviewof
previousprojectswhichhadsimilarlyfoundthatpre-existingpsychologicalfactorswere
significantpredictorsofthedevelopmentofbackpainandworkincapacity(whilespine
imagingdidnotprovidesignificantpredictors inthisregard). Inthereportofresultsthatwas
publishedinTheSpineJournal,theresearcherssummarizedpreviousscientificfindings which
indicatedthat:"Progressionofsubclinicalcommonbackacheoracutebackpaintoserious
disablinglowbackpainillness appears tobeassociatedwithvariousnonstructuralissues such
asemotionaldistress,poorcopingstrategies,compensationdisputes,andotherchronicpain
problems." Theyalsoreiteratedthatpreviousscientificprojectshaverepeatedlyfoundthat
psychologicalandsocialissueswerebetterpredictorsofsignificantlowbackpainthanwere
generalmedicalfindings.
Thedominantroleoffinancialfactorsinthesefindings isespeciallynoteworthybecauseof
someotherfeatures oftheresearchdesign:
 Theresearchers recruitedparticipantswhowereathighriskforthedevelopmentof
significantbackpain. Factors thatdeterminedthishighriskstatusincludedprevious
complaints ofchronicpainforotherbodyparts,previous medical-legalclaims,and
abnormalrespondingonthesomatoformanddepressionquestionnairesthatwere
discussedabove.
 Theresearchers alsoemphasizedtherecruitmentofparticipants withspinal
degenerativedisease,eventhoughsuchdiseaseis notariskfactorforpain. They
recruitedsuchparticipantsspecificallyforthepurposeofaddressingtheunvalidated
premisewhichtheyreportedhas“gainedcurrencyinthelastcentury”. Thatpremiseis
thatspinaldegenerativediseaseisasignificantriskfactorforthedevelopmentof
significantbackpain.
 Traumawasspecificallyanalyzedforapotentialroleasariskfactorfortheonsetof
seriousbackpain.