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Dynamic Chiropractic Canada – November 1, 2008, Vol. 01, Issue 02
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The C.H.I.R.O. (Chiropractic Hospital-Based Interventions Research Outcomes) Study

By Paul Bishop, DC, MD, PhD

The large majority of all published studies that have evaluated the efficacy of non-operative treatments for patients with spinal pain have been "superiority" clinical trials, in which the outcomes from differing treatments are compared.

This has certainly been the case with the clinical trials that have evaluated chiropractic spinal manipulative therapy.1-5 This type of clinical research strategy advocates the use of one form of treatment over another, rather than promoting a continuum of care model and removing barriers that patients must currently overcome to access the treatments they should receive. While the results of these studies have proven helpful to clinicians and patients, using this type of research methodology as a basis for improving patient care is not in synchrony with patient preference, the typical patterns of practice of primary care physicians, or current standards of evidence-based care.6

For the past several years, clinical practice guidelines for the treatment of acute mechanical lower back pain have been derived from independent systematic reviews carried out on an international scale.7-14 Their recommendations have been shown to be highly consistent and based on sound scientific evidence rather than consensus.15 Despite wide dissemination of this significant body of work, the implementation of these guidelines has been alarmingly limited.16-18 Multiple studies have demonstrated a poor correlation between what primary health care providers think is effective treatment and what has actually been shown to be effective treatment.19,20

While perhaps not causal, it is at least paradoxical that the best-evidence-based treatments are not commonly prescribed, while the incidence and prevalence of acute and spinal pain and its associated disability continue to escalate to epidemic proportions. Not surprisingly, patients are now making their own choices about treatment, with the most recent large-scale spine research studies reporting that the treatment patients now receive is often determined by patient preference, rather than by physician recommendation.21-23 What is now needed, and is starting to appear, is a "second generation" of clinical research study design that evaluates evidence-based, non-operative therapies used in a synergistic fashion and in a manner that is supported by acceptable levels of scientific evidence.24

The Chiropractic Hospital-Based Interventions Research Outcomes (C.H.I.R.O.) Study is a series of gold-standard, research-methodology clinical trials designed to evaluate the chiropractic assessment and treatment of patients with acute or chronic cervical, thoracic or lumbosacral spine pain stratified by underlying spine pathology. These studies are being carried out in a hospital-based, tertiary-care Orthopaedic and Neurosurgical Spine Program at Canada's National Spine Institute (ICORD), in the Faculty of Medicine at the University of British Columbia in Vancouver. All participating chiropractors have full hospital privileges and work in a continuum of care team model that involves related medical and surgical disciplines (orthopaedic surgery, neurosurgery, physical medicine, neurology, anaesthesiology and spine pathology).

The initial C.H.I.R.O. study was an outcome assessment of the medical and chiropractic management of patients with acute mechanical lower back pain. The study's design was a randomized clinical trial comparing family physician-directed treatment ("usual care") with "study care," which included a component of lumbar spinal manipulative therapy administered by chiropractors. The results showed that study care resulted in significantly better functional improvements and quality of life outcomes than usual care. The C.H.I.R.O. study results have been recently presented at the Canadian Spine Society Meeting, the International Society for the Study of the Lumbar Spine, and the North American Spine Society, with the latter presentation resulting in a request to submit the manuscript for publication in the "Special Paper" edition of Spine.25-27

The second C.H.I.R.O. study also used randomized, control-trial methodology to evaluate CSMT administered in combination with other evidence-based treatments in patients with acute mechanical lower back pain and underlying spinal stenosis, intervertebral disc degeneration, facet arthropathy or no identifiable spine pathology. The results will be presented at the upcoming North American Spine Society meeting.

Additional C.H.I.R.O. studies are ongoing and still others are planned. When completed, this body of work will help define the future role of chiropractors in the spinal pain patient assessment and treatment clinical team. It will also help the chiropractic profession move away from an old paradigm that has been largely adversarial to one that is inclusive, truly evidence-based and of increased benefit to patients.


This author gratefully acknowledges the receipt of a research grant from WorkSafe BC (formerly the Workers' Compensation Board) and funding from the Ontario Chiropractic Association.


  1. French SD, Grant WD, Green S, Walker B. Chiropractic interventions for low back pain. (Protocol). Cochrane Database of Systematic Reviews 2005;3:CD005427. DOI:10.1002.
  2. Assendelft WJJ, Morton SC, Yu EI, et al. Spinal manipulative therapy for low-back pain. Cochrane Database of Systematic Reviews 2004;3:CD00447. DOI:10.1002/14651858.
  3. Hurwitz EL, Morgenstern H. The effects of comorbidity and other factors on medical versus chiropractic care for back problems. Spine 1997;22(19):2254-63.
  4. Meade TW, Dyer S, Browne W, et al. Low back pain of mechanical origin: randomised comparison of chiropractic and hospital outpatient treatment. BMJ 1990 Jun 2;300(6737):1431-7.
  5. Bronfort G, Haas M, Evans RL, Bouter LM. Efficacy of spinal manipulation and mobilization for low back pain and neck pain: a systematic review and best evidence synthesis. Spine J 2004;4(3):335-56.
  6. Assendelft WJ, Koes BW, van der Heijden GJ, Bouter LM. The effectiveness of chiropractic for treatment of low back pain: an update and attempt at statistical pooling. J Manipulative Physiol Ther 1996;19(8):499-507.
  7. Bishop P. Real advances in low back pain treatment: moving toward evidence-based care. BC Med J Sept 2004;46(7):349-53.
  8. Bigos SJB, Boyer OR, Braen GR, et al. Clinical Practice Guideline Number 4: Acute Low Back Problems in Adults. 1994, Agency for Health Care Policy and Research, Public Service, US Department of Health and Human Services: Rockville, Md. pp. 65-0642.
  9. Spitzer WO, Walter O. Scientific approach to the assessment and management of activity-related spinal disorders. A monograph for clinicians. Report of the Quebec Task Force on Spinal Disorders. Spine 1987;12(suppl)(7):S1-59.
  10. Kendall NA, Linton SJ, Main CJ. Guide to Assessing Psychosocial Yellow Flags in Acute Low Back Pain: Risk Factors for Long-Term Disability and Work Loss. 1997, Accident Rehabilitation and Compensation Insurance Corporation of New Zealand and the National Health Committee.: Wellington (NZ).
  11. Abenhaim L, Rossignol M, Valat JP, et al. The role of activity in the therapeutic management of back pain. Report of the International Paris Task Force on Back Pain. Spine 2000;25(4 Suppl):1S-33S.
  12. Bogduk N. Draft Evidence Based Clinical Guidelines for the Management of Acute Low Back Pain. 2000, National Health and Medical Research Council: Australia.
  13. Manniche C, ed. Low back pain: frequency, management and prevention from HTA perspective. 1999, Danish Institute for Health Technology Assessment.
  14. Borkan J, Reis S, Werner S, et al. Guidelines for Treating Low Back Pain in Primary Care. 1996, The Israeli Low Back Pain Guideline Group.
  15. Koes BW, van Tulder MW, Ostelo KA, et al. Clinical guidelines for the management of low back pain in primary care: an international comparison. Spine 2001;26(22):2504-13; discussion 2513-4.
  16. Bishop PB, Wing, PC. Compliance with clinical practice guidelines in family physicians managing worker's compensation board patients with acute lower back pain. Spine J 2003;3(6):442-50.
  17. Gonzalez-Urzelai V, Palacio-Elua L, Lopez-de-Munain J. Routine primary care management of acute lower back pain: adherence to guidelines. Eur Spine J 2003;12:589-594.
  18. Bishop PB, Wing PC. Knowledge transfer in family physicians managing patients with acute lower back pain: a prospective randomized controlled trial. Spine J 2006;6(3):282-288.
  19. Burton AK, Waddell G. Clinical guidelines in the management of low back  pain. Baillieres Clin Rheumatol 1998;12(1):17-35.
  20. Hart LG, Deyo RA, Cherkin DC. Physician office visits for low back pain. Frequency, clinical evaluation, and treatment patterns from a U.S. national survey. Spine 1995;20(1):11-9.
  21. Weinstein JN, Tosteson TD, Lurie JD, et al. Surgical vs nonoperative treatment for lumbar disk hernation. The Spine Patient Outcomes Research Trial (SPORT): a randomized trial. JAMA 2006;296:2451-9.
  22. Thomas KC, Fisher CF, Boyd M, Bishop P, Wing P, Dvorak MF. Outcome evaluation of surgical and nonsurgical management of lumbar disc protrusion causing radiculopathy. Spine 2007 Jun 1;32(13):1414-22.
  23. Fisher CF, Bishop PB. SPORT and the Canadian experience. Spine J 2007;(7):263-265.
  24. UK BEAM Trial Team. United Kingdom back pain exercise and manipulation randomized trial; effectiveness of physical treatments for back pain in primary care. BMJ 2002. Trial summary available at beam/ukbam.htm.
  25. Bishop P, Quon J, Olson D, Nixdorf D, Yee B, Fisher C, Dvorak M. A randomized controlled trial on the effectiveness of clinical practice guidelines in the medical and chiropractic management of patients with acute mechanical lower back pain. Can J Surg Jun 2007;50(Suppl):S6-7.
  26. Bishop P, Quon J,  Olson D, Nixdorf D, Yee B, Dvorak M, Fisher C. The C.H.I.R.O. Study. Clinical practice guidelines for medical and chiropractic care of acute lower back pain: a randomized controlled trial. Spine J 2007;(7)5S:11.
  27. Bishop P, Quon J, Olson D, Nixdorf D, Yee B. The C.H.I.R.O. (Chiropractic Hospital-Based Interventions Research Outcomes) Study. Part 1 - a randomized controlled trial on the effectiveness of clinical practice guidelines in the medical and surgical management of patients with acute mechanical lower back pain. Proc ISSLS 2007:8.

Dr. Paul Bishop is a clinical associate professor of orthopaedics in the Combined Neurosurgical and Orthopaedic Spine Program in the Faculty of Medicine at the University of British Columbia. He holds an academic appointment of the same rank in ICORD, Canada’s National Spine Institute, and is both director of the outpatient clinic and head of non-operative care in the Division of Spine, Department of Orthopaedics at the Vancouver General Hospital and Health Sciences Centre. Dr. Bishop is the deputy editor of The Spine Journal, a member of the editorial board of JMPT, and an external reviewer for three other scientific journals.

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