SPINE Volume 38, Number 24, pp 2118-2123©2013, Lippincott Williams & WilkinsSpine

HEALTH SERVICES RESEARCH

Twenty-Five Years With the Biopsychosocial Modelof Low Back Pain—Is It Time to Celebrate?

A Report From the Twelfth International Forum for Primary Care Research on Low Back Pain

Tamar Pincus, PhD,* Peter Kent, PhD,t Gert Bronfort, PhD,4:§ Patrick Loisel, PhD,i||Glenn Pransky, MD, MoccH,**tt*4: and Jan Hartvigsen, PhD§§§

Study Design. An integrated review of current knowledge aboutthe biopsychosocial model of back pain for understanding etiology,prognosis, and interventions, as presented at the plenary sessionsof the XII International Forum on LBP Research in Primary Care(Denmark; October 17-19, 2012).Objective. To evaluate the utility of the model in referenceto rising rates of back pain-related disability, by identifying (a)the most promising avenues for future research in biological,psychological, and social approaches, (¿i) promising combinationsof all 3 approaches, and (c) obstacles to effective implementation ofbiopsychosocial-based research and clinical practice.Summary of Background Data. The biopsychosocial model ofback pain has become a dominant model in the conceptualizationof the etiology and prognosis of back pain, and has led to thedevelopment and testing of many interventions. Despite this backpain remains a leading source of disability worldwide.Methods. The review is a synthesis based on the plenary sessionsand discussions at the XII International Forum on LBP Research in

Primary Care. The presentations included evidence-based reviewsof the current state of knowledge in each of the 3 areas (biological,psychological, and social), identification of obstacles to effectiveimplementation and missed opportunities, and identification of themost promising paths for future research.Results. Although there is good evidence for the role of biological,psychological, and social factors in the etiology and prognosis ofback pain, synthesis of the 3 in research and clinical practice hasbeen suboptimal.Conclusion. The utility of the biopsychosocial framework cannotbe fully assessed until we truly adopt and apply it in research andclinical practice.Key words: biopsychosocial model, back pain, pain-relateddisability, return to work, clinical research, clinical practice,international conference.Level of Evidence: N/ASpine 2013;38:2118-2123

From the *Department of Psychology, Clinical, Health, and Social Psychology,Royal Holloway, University of London, England, United Kingdom; tResearchDepartment, Spine Centre of Southern Denmark, Institute of Regional HealthServices Research, Hospital Lillebaelt, University of Southern Denmark,Middelfart, Denmark; íMusculoskeletal Research Program, NorthwesternHealth Sciences University, Minnesota; §Nordic Institute of Chiropractic andClinical Biomechanics, Odense, Denmark; HDalla Lana School of PublicHealth, University of Toronto, Toronto, Ontario, Canada; l|Canadian MemorialChiropractic College, Toronto, Ontario, Canada; **Liberty Mutual ResearchInstitute for Safety, Hopkinton, Massachusetts; ++Department of FamilyMedicine and Community Health, University of Massachusetts MedicalSchool, Worcester, MA; i i Harvard School of Public Health, Boston, MA;and §§lnstitute of Sports Science and Clinical Biomechanics, University ofSouthern Denmark, Odense, Denmark.

Acknowledgment date: May 6, 2013. First revision date: |uly 15, 2013.Acceptance date: August 9, 2013.

The manuscript submitted does not contain information about medicaldevice(s)/drug(s).

No funds were received in support of this work.

Relevant financial activities outside the submitted work: consultancy andgrants/grants pending.Address correspondence and reprint requests to Tamar Pincus, PhD,Department of Psychology Clinical, Health and Social Psychology, RoyalHolloway, University of London, England, United Kingdom; E-mail: t.pincus®rhul.ac.uk

DOI: 10.1097/BRS.Ob013e3182a8c5d6

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The seminal article by Gordon WaddelF on the bio-psychosocial model in back pain published by Spinemarked a fundamental change in the conceptualization

of back pain. The tnodel suggests that back pain should bemore broadly understood than is possible from a biomédi-cal perspective alone, because for many individuals the mainproblem lies not with the common and frequently transientexperience of pain, but rather in their own and society's per-ceptions and reactions to pain. Inappropriate reactions mayinclude unnecessary avoidance of physical activity and socialinteractions, absenteeism from work, and high health care uti-lization.

The 25th year anniversary of the publication by Waddellwas a focus of the Forum for Research in Back Pain in Pri-mary Care XII that was held in Odense, Denmark, October17-19, 2012. The goal of the Forum is to share the latestconcepts, methods, and results of research on low back pain(LBP) diagnosis, evaluation, treatment, and disability preven-tion. The presentations described here addressed the 3 dimen-sions of the biopsychosocial model, how it has been applied,and promising areas for research to further develop this

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Spine HEALTH SERVICES RESEARCH Biopsychosocial Model of Back Pain • Pincus et al

conceptual view of LBP. The evidence reviewed constitutes asynthesis of keynote presentations and discussions. Althoughcitations are provided to illustrate the arguments, and wherepossible, we rely on evidence from systematic reviews, we rec-ognize that possible bias and lack of comprehensiveness maybe inherent in this review.

Back pain remains an alarming worldwide health problemand is now the leading cause of disability, with an estimated632 million affected people.^ When considering both deathand disability, musculoskeletal conditions have the fourthgreatest impact on the health of the world population, andback pain accounts for nearly half of this. Disability due tomusculoskeletal disorders is estimated to have increased by45%, from 1990 to 2010, and, with increasingly obese, sed-entary and aging societies, is expected to increase even morein the years to come.' Against this backdrop, one can hardlysay that the introduction of the biopsychosocial model inresearch and practice has been a public health success. In fact,alongside with the increasing rates of disability, and againstguideline advice, are increases in tests,"* and in the provisionof biological monotherapies that are costly and mostly inef-fective.^ The question therefore is whether it is the model itselfthat has failed to deliver or whether it is the scientific andhealth care communities that have failed to adopt the model.

DISCUSSION

Explaining the Current StatusUnderstanding the underlying principles of a condition is aprerequisite for designing effective interventions, and whilewe are still struggling to identify the precise biological basisfor most back problems, there is good evidence to suggestthat psychological constructs such as pre-existing somatiza-tion, depression, anxiety, fear avoidance beliefs, poor copingstrategies, and poor self-efficacy are significant predictors ofoutcomes such as more severe pain, greater functional disabil-ity, and work loss. Similar constructs play a role in the transi-tion from acute to persistent pain and disability.^* Neverthe-less results from trials testing interventions aimed at changingpsychological factors have been disappointing,' and findingsfrom systematic reviews of psychological interventions forchronic pain groups show that effects are at best modest.'"

Evidence also suggests that social and organizational factorsinfluence the consequences of back pain such as work absentee-ism, but only a few trials have evaluated the effect of social inter-ventions." Furthermore, regardless of whether interventionsare based on biological, psychological, or social approaches,results consistently show only small to moderate effects.'̂

One explanation may be that interventions in trials haverarely integrated all 3 components of the biopsychosocialmodel. In addition, some interventions that have attemptedto integrate psychological methods into general practice andphysiotherapy care have been compromised by delivery atsuboptimal levels of dosage, content, fidelity, and mode ofdelivery.'

Progress has also been compromised by lack of clar-ity about the selection of appropriate outcomes. Thus, theSpine

experience of back pain per se and the consequential disabil-ity and loss of social participation, such as work absence areoften confused in studies. These domains of health status areonly weakly associated, and one should not be considered tobe a proxy for the others." For example, a certain level ofback pain intensity may occur in one patient with significantpain-related disability and work absence, whereas anotherpatient with an equal level of pain may continue to have anactive life without loss of work participation. Thus in a studythat used work participation as the outcome, the first patientwould be classified as having a poor outcome and the seconda good outcome, whereas in a study focusing on pain inten-sity, both would be classified as having a poor outcome. Suchexamples highlight the need for multidomain assessment andinterpretation in clinical studies.'•*''""'

Finally, within clinical practice, there is mostly little rewardor opportunity for primary care practitioners to use a com-prehensive biopsychosocial approach, given current practiceand payment structures. This may explain why practitionersseem reluctant to attempt to influence the social aspects of thepain experience, especially those related to work.'^ Even inthe occupational health context of the United States, wherethere is sufficient payment and other incentives based on out-come evaluations, providers retreat to the "safe" biologicalarena when faced with psychosocial problems.'* Also, train-ing for most of the professions that treat back pain remainsbiomedically focused and grounded in profession-specific tra-dition rather than on contemporary evidence.''

The Biopsychosocial Model: New and PromisingFindings From the 3 Components

BiologicalThe absence of established biomarkers of back pain has led tocalls for increased efforts to understand the biological com-ponents of back pain.̂ "-̂ ^ These include the use of diagnosticimaging to quantify the degree of disc degeneration, verte-bral marrow (Modic) changes, endplate lesions, and verte-bral joint degeneration.-''̂ ** These findings have shown posi-tive associations with the presence and severity of back painsymptoms on a population level, but currently they are nota useful way of diagnostically classifying individual patients,nor of informing treatment choice.-̂ '-̂ '̂

Spinal intersegmental motion assessment technology (e.g.,quantitative video fluoroscopy,^' kinematic magnetic reso-nance imaging,^^ and tissue elastography^' has now reacheda level of sophistication that its application in research islikely to provide a greater understanding of the associa-tion between spinal biomechanical dysfunction and backpain. Using previous technology, it is possible to distinguishpatients with LBP from healthy controls by comprehensivebiomechanical analysis of trunk motion associated with stan-dardized functional tasks.^" However, there is considerablevariability both within and between the populations withand without pain on these tasks, and we have no knowledgeabout the role of spinal functional performance as a treat-ment effect modifier or prognostic factor. Currently, there is

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HEALTH SERVICES RESEARCH Biopsychosocial Model of Back Pain • Pincus et al

no evidence for a causal path between such manifestations,disability, and pain.

Central nervous system sensitization and abnormal cen-tral processing of pain is emerging as an important biologicalexplanation for the persistence of pain.̂ '"^^ There is even evi-dence that persistent back pain may alter brain morphologyby reducing the volume of gray matter in the prefrontal areaand the thalamus,^^ and that such changes may be reversibleonce the pain is effectively treated.^* Such mechanisms mayexplain the small to moderate effects of numerous evidence-based treatments, despite their being assumed to have verydifferent mechanisms of action.'̂ -^^ Early evidence suggeststhat it may be feasible to normalize pain processing throughreal time functional magnetic resonance imaging feedbacktraining.^*

Another potentially important biological mechanism isepigenetics, which through interactions with environmentalfactors, controls the expression of genetic predispositions.Genetic factors have been shown to influence various spinalpain phenotypes strongly,^' and epigenetic modulation hasbeen shown to be involved in the transition from acute tochronic pain,"*" in addition to the degree of spinal disc degener-ation.''^ Thus, the ability to influence epigenetic expression inthe future may lead to improvements in back pain treatment."*^

PsychologicalChallenges being addressed by research into psychologicalaspects of back pain can be divided into 2 broad goals: {a)To better understand which psychological risk factors impacton which outcomes, and {b)To elucidate mechanisms relatedboth to psychological dysfunction and to recovery.

In relation to both goals, an international consensuspaneF^ recognized the need to standardize the predictorsincluded in prospective cohort research investigating thetransition from acute to persistent back pain. Identifying theunique contribution of factors within specific subgroups willrequire extremely large samples. In addition, the consortiumrecognized the potential impact of social arrangement, healthstructures, and local cultural beliefs, which have been largelyignored in most previous research. Pooling of samples frominternational regions is now possible, and provides a promis-ing avenue to address limitations in current knowledge.*'''

In addition, recent emerging evidence about practitionersbeliefs,''-' behaviors,*"^ and perceptions of their role, especiallyin reference to patient's work,'''' present both a potential anda challenge for future research, because it implies that practi-tioners may inadvertently play a role in maintaining patients'disability.

Finally, a promising direction is the inclusion of new psy-chological approaches that aim to increase acceptance of inev-itable pain states and increase engagement with all aspectsof life through changes in psychological flexibility, perceivedvalues, and mindfulness informed therapy.''*-'"

SocialSocial factors including potential obstacles to recovery, in theform of legislation, compensation systems, and social and

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economic conventions and infrastructures are perhaps themost neglected area of research in back pain. Furthermore,when studied as outcomes, social factors have been typicallymeasured as secondary outcomes, and in many cases studieshave been insufficiently powered to draw reliable conclusionsfrom their findings.

Measurement of social factors can be problematic becausethey include factors operating both at an individual and at agroup level. Thus, they include factors relating to the individ-uals' status (such as employment), those relating to the indi-viduals' perception and reaction to their status (such as jobsatisfaction), those relating to group level, including regionalor national level (such as incapacity legislation), and thoserelating to the process at group level (such as the time andease of obtaining incapacity benefit). Although the former fac-tors have been studied, comparisons between systems neces-sitate large samples and careful coding of complex systems toenable clarification of the role they might play in maintainingdisability. Not surprisingly, the impact of compensatory sys-tems on the rising rates of back pain-related disability remainsunclear. Yet, this is one of the most promising areas for futureresearch, and register-based information collectable at thelevel of incapacity and welfare systems provide a comprehen-sive picture of how social structures influence disability at thesocietal level.

There is emerging evidence that social factors contributesubstantially to disability beyond the factors operating at thelevel of individuals."'™'^' For instance, Anema et a P com-pared sustainable return to work rates between 6 differentcountries and found that differences in applied work inter-ventions, job characteristics, and social disability systemswere more important than medical interventions, patient, andinjury-related factors in explaining the large between countrydifferences.'" In addition, the findings indicated that longerdelays before assigning permanent incapacity benefits, andavailability of financial support for partial return to workwere associated with more favorable outcomes. Eliminatingcompensation for pain and suffering after a whiplash injuryin one Canadian province was associated with a decreasedincidence of those injuries as well as improved prognosis forpatients.^^ Research on workers with chronic musculoskel-etal pain showed that personal and work-related factors weremore important than pain as determinants of work abilityand staying at work.^^ Taken together, the evidence suggeststhat the less engagement and investment patients have withdisability compensation systems, and the more they are sup-ported in work resumption, the better their outcomes.

The positive impact of engaging the workplace in prevent-ing work disability and supporting return to work in LBP is aconsistent finding.''''" Key components include early and sup-portive communication from the workplace, arrangements toensure a safe return to work within the physical capabilitiesof the worker, and ongoing support from supervisors andcoworkers. Some of these interventions are most effective ifprimarily focused in the workplace, and thus have the benefitof avoiding an overly medical /disease orientation in manage-ment of a condition that does not benefit greatly from medical

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interventions."'" In those with more chronic work disability,multifaceted interventions involving workers, employers, andhealth care providers, along with a return to work coordi-nator, may be required to achieve positive results.̂ **'̂ ' Manyapproaches found to be effective are not easily evaluated ina randomized controlled trial, and thus the evidence is some-times interpreted as weak, despite consistency of findingsacross studies, countries, and conditions.*" The high cost ofwork disability for workers, employers, and society has ledto conclusions that diffusion of these principles into generalpractice is a priority.*"'

In addition, recent qualitative studies have indicated thatemployer perceptions about when an employee should returnto work after a period of sick leave because of back pain mayresult in longer periods off work than necessary," suggest-ing that there is scope to intervene also at the employer level.Of importance, that study identified problems associatedwith processes within workplaces, health care, vocationalrehabilitation, and workers compensation, which operate toextend absence from work in patients. Lack of communica-tion between the different systems is at the core of increaseddisabihty, an observation reflected in the publication byWaddell" for all stakeholders to get onside if disability is tobe meaningfully reduced.

CONCLUSION

A Synthesis of New DirectionsThe Forum concluded with a discussion on the opportunitiesfor future research and applications of the biopsychosocialmodel. One new and promising direction is stratified care forback pain, where patients are screened for known biopsy-chosocial risk factors using reliable and valid tools, and thenreferred to interventions designed to target their specific prob-lem and risk profile.*'' Tbe challenge is to develop appropri-ately validated instruments that stratify patients into streamsof care that optimize their chance of a good outcome. Suchresearch is underway but needs further development, test-ing, and wider validation, especially with respect to measur-ing social determinants of work disability outcomes.***"** Thisapproach may also eventually allow us to target the particularneeds of subgroups in the population, such as older people,for whom back pain can lead to social isolation and reductionin physical activity or younger people, for whom preventinglong-term work-related disability may change their life trajec-tory." Lifespan research is also needed to clarify the chang-ing impact of psychological factors at different points in aperson's life course, including childhood and adolescence.* '̂***Forum participants stressed the importance of distinguishingbetween psychological and social domains in botb researchand clinical practice.

Another approach is infiuencing beliefs and behaviors atthe population level where mass media campaigns may beuseful if delivered efficiently.*' Wbether at the population orindividual person level, meaningful reduction in the burden ofback pain will require integrating strategies, for example: seek-ing input and active engagement from stakeholders such asSpine

employers to the design of interventions; increasing incentivesfor appropriate clinician responses to social factors; and shift-ing public perceptions of the role of active self-management.

Lastly, clarity about which predictors of outcome areprognostic factors and which are potential treatment effectmodifiers^" may help guide best practice treatment and theprevention of disability. Some factors exert an influence onoutcome regardless of treatment, whereas some only influenceresponse to specific treatments. Applying such information toidentifiable subgroups of patients and at the individual patientlevel will require focused research and methodology develop-ment but may be well worth the effort. Interventions for somehigh-risk groups may be complex and cosdy, but expensivecare that is appropriately targeted may still prove to be cost-effective.

In taking stock of the current state of knowledge, it seemsevident that vast gaps remain in our understanding about theetiology, prognosis, and effective interventions in back pain,despite the biopsychosocial model. In our view, the biopsycho-social model has not failed to explain back pain—what hasfailed is the mosdy restrictive way it has been understood andapplied. Forum discussants concluded that the utility of thebiopsychosocial framework cannot be fully assessed until wetruly adopt and integrate it into research and clinical practice.

Key Points

• It ¡s 25 years since Spine published tbe seminalarticle on the biopsychosocial model in back painby Gordon Waddell,

Ü Back pain remains an alarming worldwidehealth problem and is now the leading cause ofdisability,

U This may be a consequence of tbe mostlyrestrictive way tbe biopsycbosocial model in back ̂pain bas been understood and applied ratbertban 'a failure of tbe model itself,

• The utility of tbe biopsychosocial frameworkcannot be fully assessed until we truly adopt andapply it in research and clinical practice..

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