Letters

Chiropractic for low back pain

Experts in both UK and US believe that chiropractic works

Efficacy of spinal manipulation for low back pain has not been reliably shown

Chiropractic is one of safest forms of treatment available

Evidence for manipulation is stronger than that for most orthodox medical treatments

Editorial included topics unrelated to its title

Authors' reply

Experts in both UK and US believe that chiropractic works

EDITORErnst and Assendelft's editorial on chiropractic for low back pain seems to have been written more in a spirit of professional aversion than in one of critical doubt.¹ This impression is conditioned by previous commentaries by these authors in the popular press and the biomedical literature.

The question is, why? There is substantial scientific evidence that the manipulation that chiropractors (and indeed osteopaths and some physiotherapists) do for back pain is both effective and safe. This evidence has been reviewed by multidisciplinary panels of experts in both the United Kingdom and the United States, which has resulted in the production of two national clinical practice guidelines for acute back pain that totally disagree with these authors. The only randomised controlled trial of overall chiropractic management for back pain, ^{2 3} in contrast to manipulation alone, is not mentioned in this editorial. Yet this trial (included erroneously by one of these authors in 1991 in a review of manipulation trials) was ranked as high quality, was positive in its evidence for chiropractic management, and yet was subsequently condemned as seriously flawed by Ernst in a separate paper. This editorial is equally contradictory.

No one would dispute the need to research further the evidence for the effectiveness, cost effectiveness, and safety of manipulation and associated treatment approaches. The Medical Research Council is currently supporting a large randomised trial by a multidisciplinary research team led by the department of health sciences and clinical evaluation at the University of York. Many other studies are in progress. Nevertheless, the United Kingdom's current national clinical practice guideline and evidence review states: "Within the first 6 weeks of acute or recurrent low back pain, manipulation provides better short-term improvement in pain and activity levels and higher patient satisfaction than the treatments to which it has been compared" and "the risks of manipulation for low back pain are very low, provided patients are selected and assessed properly and it is carried out by a trained therapist or practitioner."⁴

The Chiropractors and the Osteopaths Acts and the chiropractors' and the osteopaths' general councils will provide these assurances for the public, but there is no certainty in science. Those who demand certain proof of things are already prejudiced against them.

Alan Breen, Research director.  .
Anglo-European College of Chiropractic, Bournemouth BH5 2DF alan.breen{at}aecc-chiropractic.ac.uk

1. Ernst E, Assendelft WJJ. Chiropractic for low back pain. BMJ 1998; 317: 160[Free Full Text]. (18 July.)
2. Meade TW, Dyer S, Browne W, Townsend J, Frank AO. Low back pain of mechanical origin: randomised comparison of chiropractic and hospital outpatient treatment. BMJ 1990; 300: 1431-1437.
3. Meade TW, Dyer S, Browne W, Frank AO. Randomised comparison of chiropractic and hospital outpatient management for low back pain: results from extended follow-up. BMJ 1995; 311: 349-351[Abstract/Free Full Text].
4. Waddell G, Feder G, McIntosh A, Lewis M, Hutchinson A. Clinical guidelines for the management of acute low back pain: clinical guidelines and evidence review. London: Royal College of General Practitioners , 1996.

Efficacy of spinal manipulation for low back pain has not been reliably shown

EDITORIn their editorial¹ Ernst and Assendelft refer to a review by Shekelle et al, which concludes that "spinal manipulation is of short-term benefit in some patients, particularly those with uncomplicated, acute low-back pain."² Ernst and Assendelft point out that this work did not contain a single trial of chiropractic. The references in the review by Shekelle et al do in fact include chiropractic trials.² The second reference listed is the trial by Meade et al.³

The second paragraph of the editorial refers to a review by Assendelft et al of eight randomised controlled trials of chiropractic treatment. This review concludes that the eight trials provide no convincing evidence for the effectiveness of chiropractic treatment for acute or chronic low back pain.⁴ Therefore, readers are left with the impression that chiropractic treatment is less effective than manipulation in general. Had the authors included a seventh reference to their own worka review of spinal manipulation for low back pain⁵ published in the same year as the review of the chiropractic trialsit would have changed readers' impression altogether. This document reviews 36 randomised clinical trials comparing manipulation with other treatments and concludes that "the efficacy of spinal manipulation for patients with acute or chronic low back pain has not been demonstrated with sound randomised clinical trials."⁵

These inaccuracies show that one can never be too critical when reading published material.

Eva Leerberg, Doctor of chiropractic. 
Kirkcaldy Chiropractic Clinic, Kirkcaldy, Fife KY1 1HB

1. Ernst E, Assendelft WJJ. Chiropractic for low back pain. BMJ 1998; 317: 160. (18 July.)
2. Shekelle PG, Adams AH, Chassin MR, Hurwitz EL, Brook RH. Spinal manipulation for low-back pain. Ann Intern Med 1992; 117: 590-598.
3. Meade TW, Dyer S, Browne W, Townsend J, Frank AO. Low back pain of mechanical origin: randomised comparison of chiropractic and hospital outpatient treatment. BMJ 1990; 300: 1431-1437.
4. Assendelft WJJ, Koes BW, van der Heijden GJMG, 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: 499-507[Medline].
5. Koes BW, Assendelft WJJ, van der Heijden GJMG, Bouter LM. Spinal manipulation for low back pain. Spine 1996; 21: 2860-2873[Medline].

Chiropractic is one of safest forms of treatment available

EDITORIf you would like information on chiropractic's track record for treating low back pain¹ perhaps you should ask the 20 million patients who will visit doctors of chiropractic this year alone. Patients' satisfaction with chiropractic care has consistently rated higher than traditional medical care for low back pain. A recent study found that "compared to those who sought care from medical doctors, those who sought care from chiropractors were more likely to feel that treatment was helpful, more likely to be satisfied with their care, and less likely to seek care from another provider for that same episode of pain."²

Shekelle et al showed that chiropractic treatment is appropriate for low back pain in a considerable number of cases. They found that 46% of a sample of patients with low back pain received appropriate care from doctors of chiropractican appropriateness rating similar to that of common medical procedures.³

Chiropractic is one of the safest forms of treatment available today. According to a study by Hurwitz et al, a serious adverse reaction from cervical manipulation occurs once in 1 million manipulations.⁴ Complication rates for manipulation of the lumbar region of the spine are even lower. When compared with the number of illnesses and deaths that will occur this year from the appropriate use of prescription and over the counter drugs, the number of serious complications from chiropractic treatment is extremely low. A study by Lazarou et al found that more than 2 million Americans become seriously ill every year from reactions to correctly prescribed drugs and 106 000 die from those side effects.⁵

My profession, like every other healthcare profession, is by no means beyond reproach. I agree that more and better chiropractic research is required. More and better medical research is required as well. I hope that the chiropractic and medical professions will continue to work together in this regard. Our patients will be the ultimate beneficiaries.

Michael D Pedigo, President. 
American Chiropractic Association, 1701 Clarendon Boulevard, Arlington, VA 22209, USA

^a FFeather{at}amerchiro.org

1. Ernst E, Assendelft WJJ. Chiropractic for low back pain. BMJ 1998; 317: 160. (18 July.)
2. Carey TS, Evans AT, Hadler NM, Lieberman G, Kalsbeek WD, Jackman AM, et al. Acute severe low back pain. A population-based study of prevalence and care-seeking. Spine 1996; 21: 339-344[Medline].
3. Shekelle PG, Coulter I, Hurwitz EL, Genovese B, Adams AH, Mior SA, et al. Congruence between decisions to initiate chiropractic spinal manipulation for low back pain and appropriateness criteria in North America. Ann Intern Med 1998; 129: 9-17[Abstract/Free Full Text].
4. Hurwitz EL, Aker PD, Adams AH, Meeker WC, Shekelle PG. Manipulation and mobilization of the cervical spine. A systematic review of the literature. Spine 1996; 21: 1746-1759[Medline].
5. Lazarou JL, Pomeranz BH, Corey PN. Incidence of adverse drug reactions in hospitalized patients. A meta-analysis of prospective studies. JAMA 1998; 279: 1200-1205[Abstract/Free Full Text].

Evidence for manipulation is stronger than that for most orthodox medical treatments

EDITORAs one of the coauthors of the Clinical Standards Advisory Group's report on back pain¹ and the Royal College of General Practitioners' guidelines on acute low back pain,² I am disappointed by Ernst and Assendelft's editorial on chiropractic.³ The authors present a critical view of chiropractic under the guise of scientific objectivity, but I had hoped that we had got beyond that stage of interprofessional confrontation.

Burton and I recently reviewed international guidelines for low back pain, and none of them specifically recommend chiropractic.⁴ What they do all say, and what all recent reviews conclude to varying degrees, is that considerable evidence now exists that manipulation is an effective treatment for low back pain. Indeed, there is stronger evidence for manipulation than for most orthodox medical treatments. The guidelines also advise that manipulation should be performed by a trained professional but that there is no clear evidence whether it is better performed by a chiropractor, an osteopath, a physiotherapist, or a doctor with special training.

Ernst and Assendelft's review of the risks of manipulation is particularly biased. Although the subject of this editorial is low back pain, they concentrate on the admittedly higher risks of cervical manipulation. Even then, orthodox medicine has a long way to go to reduce the rate of serious complications of most of our investigations and treatments to the order of 1:0.2-1 million. The adverse reactions to which the authors refer are temporary aggravations of symptoms or minor subjective reactions; in a personal series, that rate is comparable to figures for every other orthodox treatment for back pain. What matters is the balance of effectiveness versus risk, and that is strongly in favour of manipulation. The politics and costs of any NHS provision of a service are a completely separate and more relevant debate.

None of us have a good answer for low back painorthodox medicine, professors, and methodologists least of all. Chiropractic is not the magic answer for back pain, and it should and can stand up to fair criticism, but orthodox medicine could potentially also learn a lot from chiropractic.⁵ The needs of patients with back pain should override our professional dignities, and the real need is for us all to work together. That cooperation is not likely to be helped by this kind of editorial.

Gordon Waddell, Orthopaedic surgeon. 
Glasgow Nuffield Hospital, Glasgow G12 0PJ

1. Clinical Standards Advisory Group. Report on back pain. London: HMSO , 1994.
2. Royal College of General Practitioners. Clinical guidelines for the management of acute low back pain. London: RCGP , 1996.
3. Ernst E, Assendelft WJJ. Chiropractic for low back pain. BMJ 1998; 317: 160. (18 July.)
4. Burton AK, Waddell G. Clinical guidelines in the management of low back pain. In: Nordin M, ed. New approaches to the low back pain patient. London: Baillière Tindall, 1998:17-35. (Baillière's clinical rheumatology.)
5. Waddell G. The back pain revolution. Edinburgh: Churchill Livingstone , 1998.

Editorial included topics unrelated to its title

EDITORErnst and Assendelft's editorial is titled "Chiropractic for low back pain" but refers to cervical manipulations, potential overuse of radiographs by chiropractors, and a negative attitude of some chiropractors to immunisation.¹ Therefore, one must assume that a buckshot approach aimed fairly and squarely at chiropractic has been taken, as topics unrelated to the title of the editorial have clearly been included. The apparent attempt to define chiropractic intervention in the editorial's opening paragraph is incorrect, stating that, for example, chiropractic is used in the "hope of correcting vertebral disc displacements" and in the hope of correcting "spinal misalignment." Properly qualified chiropractors do not hope to correct "vertebral disc displacements" by manipulating the spine, as is implied. It would be stupid to contemplate manipulating the spine for disc displacement, by which the authors presumably mean extruded disc material. Spinal misalignment can be corrected by using an appropriate shoe raise when an inequality in leg length and pelvic obliquity are the cause of the postural scoliosis (or spinal misalignment).²

Ernst and Assendelft have selectively cited the literature. For example, they cite two papers published in the Journal of Manipulative and Physiological Therapeutics (references 4 and 13) written by Assendelft et al (1996) and Assendelft and Bouter (1993). Why was the important paper by Terrett, in which he clearly cites misuse of the literature by medical authors in discussing spinal manipulative therapy injury,³ selectively excluded when the editorial raises the issue of "cervical manipulations are burdened with severe adverse reactions such as vertebrobasilar accidents and paralyses due to fractures"? The only reference to this topic is by Assendelft et al (reference 5).

Ernst and Assendelft apparently saw it as appropriate that Ernst's paper on chiropractors' use of x ray films should be included (reference 8), as well as Ernst's paper apparently referring to the "negative attitude of some chiropractors towards immunisation" (reference 9).

Normally, scientific documents at least reflect the topic under discussion in the title, and in my opinion the editorial's title is misleading. Furthermore, from a scientific point of view it would be more appropriate to use references other than a preponderance of one's own to make a particular point and not to omit any pertinent reference, such as to Terrett's paper.

Lynton G F Giles, Director. 
Spinal Pain Unit, Townsville General Hospital, Townsville, Queensland 4810, Australia Lynton.Giles{at}jcu.edu.au

1. Ernst E, Assendelft WJJ. Chiropractic for low back pain. BMJ 1998; 317: 160. (18 July.)
2. Giles LGF, Taylor JR. Low back pain associated with leg length inequality. Spine 1981; 6: 510-521[Medline].
3. Terrett AGJ. Misuse of the literature by medical authors in discussing spinal manipulative therapy injury. J Manipulative Physiol Ther 1995; 18: 203-210[Medline].
4. Koes BW, Assendelft WJJ, van der Heijden GJMG, Bouter LM, Knipschild PG. Spinal manipulation and mobilisation for back and neck pain: a blinded review. BMJ 1991; 303: 1298-1303.
5. Ottenbacher K, De Fabio RP. Efficacy of spinal manipulation/mobilisation therapy; a meta-analysis. Spine 1985; 10: 833-837[Medline].

Authors' reply

EDITORThe main focus of our editorial was on chiropractic and not spinal manipulation in general. For each favourable study cited in favour of chiropractic in these letters, at least one recent less favourable one can be found.

Breen addresses some apparent inconsistencies in our previous work. In one of our reviews¹ Meade et al's study did indeed rank as one of the methodologically best,² although the methods score was 48%. In this review Meade et al's trial was reported as positive because we followed the authors' conclusion. In a later review we made an independent judgment, on the basis of our interpretation of the clinical relevance of the results.³ We considered the 2% difference on the Oswestry scale to be unconvincing. As Breen knows, our critique of Meade et al's study⁴ was one of the starting points of the Medical Research Council's current trial that he describes, so the critique was probably less flawed than he implies.

Contrary to what Leerberg writes, we insist that there was no chiropractic study among the nine trials that Shekelle et al cited as favourable evidence for the effectiveness of spinal manipulation for low back pain.⁵ Leerberg implies that we introduced inaccuracies by selectively citing reviews, but this is not the case. We cited Shekelle et al's review because it was the basis of several guidelines. We did not imply that chiropractic is less effective than manipulation in general. Leerberg states that we only selectively cited the literature on complications, but the cited reference by Terrett⁶ is addressed in our review on complications.⁷ We fail to understand what this reference would have contributed to our editorial.

Pedigro suggests that we should ask the many satisfied users of chiropractic. Indeed, in various studies patient satisfaction with chiropractic is relatively high. Although this is encouraging, we demand additional proof of effectiveness in terms of validly assessed increased functionality, decreased pain, or less absenteeism. Waddell states that "there is now considerable evidence that manipulation is an effective treatment." In the editorial we restricted ourselves to the effectiveness of chiropractic. Even for manipulation in general, however, our standpoint remains conservative. There are not yet enough methodologically sound randomised clinical trials that show strong, consistent, positive, and cost effective outcomes. The two most recent randomised controlled trials of chiropractic provide further support for our reserved attitude. Cherkin et al showed that for acute, uncomplicated back pain, both chiropractic and McKenzie physiotherapy lead to roughly the same results, which were not superior to those in controls who merely received an educational booklet, which previously had been shown to be ineffective.⁸ The design of Skargren et al's trial⁹ resembled that of Meade et al.² Half of the patients had acute back pain. The authors concluded that the effectiveness and total costs of physiotherapy or chiropractic, to reach the same results immediately after treatment and six months later, were similar.

We agree with Waddell that the risk-effectiveness balance is crucial, but insufficient data exist to allow us to evaluate this balance yet. Good prospective or case-control studies on complications are lacking.⁷ Therefore, comparisons of complication rates with those for other, better evaluated treatments such as non-steroidal anti-inflammatory drugs are problematic.¹⁰

We also find positive messages in the letters. Breen acknowledges the need for further research, and both he and Waddell emphasise that a distinction should no longer be made between the various professions delivering spinal manipulation. Giles states that use of radiography and attitudes towards immunisation are irrelevant in relation to low back pain. This, however, is not the case; physicians want to be sure how a referred patient is approached. The challenge for national chiropractic associations is to develop clear standards of care addressing these issues and to change the behaviour of those practitioners who consistently overuse radiographs and interfere with immunisation programmes.

E Ernst, Professor. 
Department of Complementary Medicine, School of Postgraduate Medicine and Health Sciences, University of Exeter, Exeter EX2 4NT E.Ernst{at}exeter.ac.uk

W J J Assendelft, Senior researcher. 
Institute for Research in Extramural Medicine, Faculty of Medicine, Vrije Universiteit, 1081 BT Amsterdam, Netherlands

1. Koes BW, Assendelft WJJ, van der Heijden GJMG, Bouter LM, Knipschild PG. Spinal manipulation and mobilisation for back and neck pain: a blinded review. BMJ 1991; 303: 1298-1303.
2. Meade TW, Dyer S, Browne W, Townsend J, Frank AO. Low back pain of mechanical origin: randomised comparison of chiropractic and hospital outpatient treatment. BMJ 1990; 300: 1431-1437.
3. Assendelft WJJ, Koes BW, van der Heijden GJMG, Bouter LM. The effectiveness of chiropractic for treatment of low back painan update and attempt at statistical pooling. J Manipulative Physiol Ther 1996; 19: 499-507.
4. Assendelft WJJ, Bouter LM, Kessels AGH. Effectiveness of chiropractic and physiotherapy in the treatment of low back pain: a critical discussion of the British randomized clinical trial. J Manipulative Physiol Ther 1991; 14: 281-286[Medline].
5. Shekelle PG, Adams AH, Chassin MR, Hurwitz EL, Brook RH. Spinal manipulation for low-back pain. Ann Intern Med 1992; 117: 590-598.
6. Terrett AGJ. Misuse of the literature by medical authors in discussing spinal manipulative therapy injury. J Manipulative Physiol Ther 1995; 18: 203-210.
7. Assendelft WJJ, Bouter LM, Knipschild PG. Complications of spinal manipulation: a comprehensive review of the literature. J Fam Pract 1996; 42: 475-480[Medline].
8. Cherkin DC, Deyo RA, Battie M, Street J, Barlow W. A comparison of physical therapy, chiropractic manipulation, and provision of an educational booklet for the treatment of patients with low back pain. N Engl J Med 1998; 339: 1021-1029[Abstract/Free Full Text].
9. Skargren EI, Öberg BE, Carlsson PG, Gade M. Cost and effectiveness analysis of chiropractic and physiotherapy treatment for low back pain. Spine 1997; 22: 2167-2177[Medline].
10. Assendelft WJJ, Bouter LM. Spinal manipulation: reply. J Fam Pract 1996; 43: 334-335.