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International Journal of Osteopathic Medicine 8 (2005) 79e80

www.elsevier.com/locate/ijosm

Editorial

Osteopathy in the cranial field e moving towards evidence forcausality and effectiveness

There are few topics within the osteopathic professionthat are as contentious as the debate about osteopathyin the cranial field (OCF). Reading the ‘Letters to theEditor’ of the various association newsletters suggeststhat as a profession we are firmly divided on the issue ofOCF as a mainstream part of osteopathy.

Readers of the manual medicine or complementaryand alternative medicine literature will have observedthat research of OCF has been dominated by in-vestigation of palpatory reliability. These studies havefor the most part, focused on intra- and inter-examinerreliabilities of cranial rhythm frequency, and a narrativereview of these studies has been published.1 With regardto inter-examiner reliability, the results of all recentinvestigations of reasonable quality consistently dem-onstrate that there are very low levels of concordancebetween different examiners when palpating the samesubject, either separately or simultaneously. Predictably,intra-examiner reliability fairs slightly better, although itstill falls well short of levels considered acceptable inhealthcare. On the basis of such poor reliability, therehave been calls to exclude OCF from training programsin osteopathy.1 However, it is important to consider thatthe research conducted to date has focused on thereliability of palpation for cranial rhythm frequency,and not other important characteristics that are usedto direct treatment. Although such studies have ofteninvestigated characteristics that are of lesser directclinical relevance, they do provide evidence to suggestthat there are significant flaws in the basic concepts ofthe most commonly accepted model of OCF. Forexample, the ‘core-link’ hypothesis as taught in manyundergraduate courses, and outlined in basic referencetexts,2,3 lacks concept validity as demonstrated bystudies employing simultaneous palpation at the headand sacrum.4,5

Studies investigating frequency alone do not directlyaddress questions about the reliable detection ofdysfunction on the basis that assessment of cranialrhythm frequency is only one of several characteristics

oi:10.1016/j.ijosm.2005.08.002

used to identify dysfunction in an OCF model. Futurestudies of reliability in the cranial field should bebroadened beyond frequency, and include other quali-tative characteristics that are regarded by proponents asbeing of greater clinical relevance. Such characteristicsshould be developed through dialogue and collaborationwith clinical experts and leading educators within theOCF discipline.

Although reliability studies of reasonable qualityhave been published, there has been a scarcity ofcomment in the indexed literature in response by thoseinvolved in the education and training of OCF. In fact,as critics have highlighted, the traditional theories ofOCF are still being promulgated in current textbooksand educational curricula despite contemporary evi-dence that would suggest that a thorough revision ofmany OCF concepts is warranted.6 As a profession,have we become so enamored with our justifiably proudheritage that we have stopped developing and modifyingour concepts and theories? It seems that while the paceof development in medicine and healthcare continues toincrease, there is little development and testing of newtheories and hypotheses within osteopathy. Osteopathyin the cranial field is not the only area of osteopathythat requires revision in the light of contemporary scien-tific knowledge. Educators and proponents should beengaged in active revision of osteopathic theory ratherthan acting as defenders and protectors of knowledgethat is presumed to be beyond critique or question.

A classification adapted from a 1999 systematicreview of craniosacral therapy7 provides a useful guidefor researchers to focus their work. The OCF literaturemay be broadly considered in three categories:

(1) Reliability and validity for the assessment of dys-function according to models used within OCF.

(2) Evidence that links dysfunction as defined in OCF topoor health outcomes.

(3) Evidence on the effectiveness of OCF managementin altering health outcomes.

80 Editorial / International Journal of Osteopathic Medicine 8 (2005) 79e80

Category (1) has received the majority of attention inrecent years, and the next logical evolution of work in thisarea should begin to explore explanations for the poorresults observed to date. The strongest of OCF criticsmay suggest that poor reliability is to be expected fora phenomenon that is illusory. An objective analysis basedsolely on the published datamust at least acknowledge thispossibility. Yet for many practitioners there is simply toomuch anecdotal experience of palpable cranial phenomenato explain poor reliability as a manifestation of a sophis-ticated form of expectation bias: that is, we observewhatever it is that we are expecting to observe.8

Like other areas of research in osteopathy, we havebeen slow to turn our attention to research questions thatanswer the deceptively simple, but critically importantquestion of ‘Is the treatment effective?’ Clinical outcomestudies are the type of research urgently required tojustify our place within government and insurancesubsidised reimbursement schemes.

Category (2) of the framework includes basic scienceresearch that investigates the anatomy and physiologyrelating to OCF. Category (2) also includes consider-ation of an as yet undemonstrated association betweenhealth status and somatic dysfunction.9 While basicscience studies investigating the mechanisms underlyingOCF are of interest, they are of secondary importance tothe question of effectiveness (Category (3)). In otherwords, ‘how does it work?’ is less important than ‘does itwork?’. For example, a detailed investigation of cranialsuture movement could consume resources for manyyears but may then turn out to be superfluous in lightof subsequent investigations into clinical effectiveness.With limited resources available, a pragmatic approachthat focuses on the association between cranial dysfunc-tion and health status is justifiable, as this has beena long held assumption and is central to the applicationof OCF to healthcare. Hill’s criteria for examiningcausal relationships provide a robust framework forresearch design in this area.10 If a causal relationshipbetween health status and cranial dysfunction isestablished, the priority would then become investigat-ing how effective various clinical techniques are fora range of common complaints. When both causalityand effectiveness have been demonstrated it would thenbe logical to pursue the detailed investigation of theunderlying mechanisms of effect. Methodological de-signs used to demonstrate causality and effectiveness arewell established within epidemiology. This two-prongedapproach would serve the purpose of providing both theclinical effectiveness evidence required by third partypayers, and also provided the solid foundation ofcausality on which to embark on the basic science toexplore mechanisms if required.

Osteopathy in the cranial field seems to attract morewidespread and vigorous critical attention than all othercomponents of osteopathic practice combined. Suchcritical attention when ignored and left unanswered canonly be detrimental to the advancement of osteopathy inmodern healthcare. A failure to engage in scholarlydebate serves the profession poorly, and we would allbenefit from high quality systematic investigation intocausality and effectiveness of OCF. Effectiveness studiesfor other forms of osteopathic treatment are starting toemerge,11,12 and there is no reason why OCF should beexcluded from such investigation.

References

1. Hartman SE, Norton JM. Interexaminer reliability and cranial

osteopathy. Sci Rev Altern Med 2002;6:23–34.

2. Magoun HI. Osteopathy in the cranial field. Kirksville: Journal

Printing Company; 1976.

3. King HH, Lay EM. Osteopathy in the cranial field. In: Ward RC,

editor. Foundations for osteopathic medicine. 2nd ed. Philadelphia:

Lippincott Williams & Wilkins; 2002. p. 985–1001.

4. Moran RW, Gibbons P. Intraexaminer and interexaminer re-

liability for palpation of the cranial rhythmic impulse at the head

and sacrum. J Manipulative Physiol Ther 2001;24:183–90.

5. Rogers JS, Witt PL, Gross MT, Hacke JD, Genova PA. Simul-

taneous palpation of the craniosacral rate at the head and feet:

intrarater and interrater reliability and rate comparisons. Phys

Ther 1998;78:1175–85.

6. Hartman SE, Norton JM. A review of King HH and Lay EM,

‘‘Osteopathy in the cranial field,’’ in Foundations for Osteopathic

Medicine. 2nd ed. Sci Rev Altern Med 2004/2005;8:24–8.

7. Green C, Martin CW, Bassett K, Kazanjian A. A systematic review

and critical appraisal of the scientific evidence on craniosacral

therapy. Vancouver: BC Office of Health Technology Assessment;

1999.

8. O’Malley JN. How real is the subluxation? J Manipulative Physiol

Ther 1997;21:482–7.

9. Lucas N, Moran RW. What is the significance of somatic dysfunc-

tion in a multicausal model of aetiology? Int J Osteopath Med

2005;8:39–40.

10. Hill AB. Principles of medical statistics. New York: Oxford Univer-

sity Press; 1971.

11. Fryer G, Alvizatos J, Lamaro J. The effect of osteopathic treatment

on people with chronic and sub-chronic neck pain: a pilot study. Int

J Osteopath Med 2005;8:41–8.

12. Licciardone JC, Stoll ST, Fulda KG, Russo DP, Siu J, Winn W,

et al. Osteopathic manipulative treatment for chronic low back

pain: a randomized controlled trial. Spine 2003;28:1355–62.

Robert MoranSchool of Health and Community Studies,

Unitec New Zealand,Private Bag 92025, Auckland, New Zealand

E-mail address: rmoran@unitec.ac.nz