Chiropractic – A Brief Overview, Part II

Last week I reviewed the history of chiropractic and discussed issues relating to its underlying claims and treatments for non-musculoskeletal indications. Today I will focus on chiropractic for back pain and similar indications.

Manipulative Therapy

There is evidence to support the very narrow indication of spinal manipulation for the symptomatic management of acute uncomplicated lower back strain. The good news for chiropractors is that this is a very common condition and does not respond well to conventional management – actually all treatments: medical management, physical therapy, manipulation, and even just patient education, appear to be equally and quite modestly effective.

There is a body of clinical studies that are relevant to the question of manipulation for lower back strain. A review of this research was published in 1989 by the RAND corporation, an independent research group that put together a panel of both physicians and chiropractors to review the available research on manipulative therapy. They concluded that evidence from 22 studies supported the use of manipulative therapy for acute uncomplicated lower back pain (again – no real pinched nerves). It is important to understand, however, that they were referring to manipulative therapy, not chiropractic. In fact only 4 of the 22 studies mentioned included chiropractors. In the other studies the manipulative therapy was performed by physicians and physical therapists.

The RAND study went on to enumerate a long list of situations in which spinal manipulation should not be performed, including evidence of nerve root compression. Other contraindications include a greater than 6 month duration, X-ray or clinical evidence of malignancy, failure to respond to manipulation or a history of not responding to manipulation, among others. They also concluded that there was insufficient evidence to justify the use of manipulation for most forms of chronic lower back pain. The study in no way supported chiropractic subluxation theory or the scope of chiropractic practice. Nor did it make any comparison between manipulation and other forms of treatment for low back pain.

Because of the popular confusion of chiropractic with manipulative therapy, and the use of manipulation for symptomatic treatment vs the pseudoscientific treatment of subluxations and innate intelligence – some chiropractors were able to exploit this and other positive studies of manipulation to advertise that “chiropractic works” as a way of promoting chiropractic treatments that have nothing to do with manipulation for lower back pain. The number of misrepresentations prompted Paul G. Shekelle, MD, MPH of the RAND corp. who designed the study to write:

“Through RAND’s process of monitoring the popular media, we have become aware of numerous instances where our results have been seriously misrepresented by chiropractors writing for their local paper or writing letters to the editor.”

There have been further studies since the 1989 review. The Meade study, which was published in the British Medical Journal in 1990, concluded that:

“For patients with low back pain in whom manipulation is not contraindicated, chiropractic almost certainly confers worthwhile long-term benefit in comparison with hospital outpatient management.”

There are some serious limitations of this study, however. The two treatment groups were not comparable, because the chiropractic group received 44% more treatment (costing 50% more) over twice as long a period of time and in a private setting. The outpatient physical therapy group was part of the National Health Service, and were noted to have limited resources and could not treat their patients in the same fashion that a private practitioner could.

Second, patients entered into the study were put through a medical screening process including X-rays that were interpreted by hospital radiologists. Between 25 and 50% of patients entering the study were eliminated because they were felt to have contraindications to manipulation. This fact alone makes it impossible to accurately apply the results of this study to the way chiropractic is practiced in the real world, where there is rarely independent radiological review or other medical screening. Of course, practices vary greatly, and some chiropractors do collaborate with physicians for medical screening.

A large 1998 study compared chiropractic to physical therapy to a third group that only received an informational booklet. The study concluded:

For patients with low back pain, the McKenzie method of physical therapy and chiropractic manipulation had similar effects and costs, and patients receiving these treatments had only marginally better outcomes than those receiving the minimal intervention of an educational booklet. Whether the limited benefits of these treatments are worth the additional costs is open to question.

The safety of manipulative therapy has not been adequately established. This 2001 review concludes:

The most valid studies suggest that about half of all patients will experience adverse events after chiropractic SM. These events are usually mild and transient. No reliable data exist about the incidence of serious adverse events. These data indicate that mild and transient adverse events seem to be frequent. Serious adverse events are probably rare but their incidence can only be estimated at present. Further prospective investigations are needed to define their incidence more closely.

A 2004 review of spinal manipulation and mobilizing for acute and chronic back and neck pain concluded:

Our data synthesis suggests that recommendations can be made with some confidence regarding the use of SMT and/or MOB as a viable option for the treatment of both low back pain and NP (neck pain). There have been few high-quality trials distinguishing between acute and chronic patients, and most are limited to shorter-term follow-up. Future trials should examine well-defined subgroups of patients, further address the value of SMT and MOB for acute patients, establish optimal number of treatment visits and consider the cost-effectiveness of care.

The research which has been done into the effectiveness of manipulative therapy can best be summarized as suggesting a role for spinal manipulation in the symptomatic treatment of uncomplicated low back pain, provided adequate medical screening is performed. This includes manipulation by some chiropractors, or by physical therapists, physiatrists and others. Manipulation is no more effective, and is often more expensive than, other forms of treatment – such as best medical management or simple physical therapy with good home back care.

Other Uses of Chiropractic

Many chiropractors also use spinal manipulation for other indications, without evidence to support their safety and effectiveness. For example, neck manipulation for headache is not uncommon, despite a lack of adequate evidence for efficacy. The study most often cited by chiropractors to support manipulation for migraine compared neck manipulation to 25mg of Elavil for 8 weeks vs combined therapy and found no difference in outcome. They conclude from this that neck manipulation works as well as medical management.

However, 25mg of Elavil is too low a dose for most patients to response, and the duration of treatment before a response is typically seen is 6-8 weeks. Often a significant response is only seen after several months, and after increasing the dose to between 50-100mg per day. In other words, they used an inadequate control – a treatment that would not be expected to work. Therefore, the more reasonable conclusion to reach from this study is that chiropractic manipulation does not work for migraine. Also, the lack of any additive effect is consistent with pure placebo response.

A recent Cochrane review from 2004 of physical treatments for headaches, including manipulation, concluded:

The clinical effectiveness and cost-effectiveness of non-invasive physical treatments require further research using scientifically rigorous methods.

“Requires further research” means that there is no currently proven benefit.

With neck manipulation there is also a concern for serious risk. Although the statistical risk is low, there are reported cases of stroke and even death following neck manipulation, resulting from arterial dissection – a tear in an artery in the neck. There is insufficient evidence to conclude firmly what the risk is, but given the soft evidence for a benefit for neck manipulation even a small chance of a serious side effect like stroke is likely not justified.

Many chiropractors also offer “maintenance therapy” – regular visits for manipulation to prevent disease or symptoms. There is no evidence and no biological plausibility to justify maintenance chiropractic manipulation.

This critical summary by Edzard Ernst, in my opinion, is appropriate.

The core concepts of chiropractic, subluxation and spinal manipulation, are not based on sound science. Back and neck pain are the domains of chiropractic but many chiropractors treat conditions other than musculoskeletal problems. With the possible exception of back pain, chiropractic spinal manipulation has not been shown to be effective for any medical condition. Manipulation is associated with frequent mild adverse effects and with serious complications of unknown incidence. Its cost-effectiveness has not been demonstrated beyond reasonable doubt. The concepts of chiropractic are not based on solid science and its therapeutic value has not been demonstrated beyond reasonable doubt.


The chiropractic profession has its roots firmly planted in pure pseudoscience, but despite this there happens to be a plausible role for spinal manipulation for the limited indication of uncomplicated lower back strain. Further research is needed to explore subgroups, cost effectiveness, safety, and whether or not there is any legitimate role for neck manipulation.

Due, it seems, to the personality and personal beliefs of B.J. Palmer, the chiropractic profession has had an ongoing hostile relationship with mainstream scientific medicine. This is unfortunate. Also, the profession has expanded its philosophy and practice to the point that there are now many separate professions all practicing under the banner of chiropractic, leading to much public confusion and poor to nonexistent maintenance of a standard of care within chiropractic.

The chiropractic profession is in need of serious reform. They are unlikely to accept the recommendations of an outsider like myself, but I am going to give them anyway.

First, the profession needs to clean house. Much like the Flexner report did a century ago for medicine – closing most medical school because they were substandard, the chiropractic profession needs to go through a similar purging.

– This means rejecting completely subluxation theory, including the notion of innate intelligence and the existence of mysterious chiropractic subluxations.

– Along with subluxation theory, chiropractors should condemn the use of manipulative therapy to treat medical conditions and diseases, including asthma, ear infections, ulcers, migraines, and other conditions.

– The chiropractic profession should endorse the principles of science-based medicine and dedicate themselves to high standards of science and transparency. This includes subjecting their treatments to more clinical research, changing their practice based upon the evidence, exploring the risks as well as the benefits of their own treatments, and internally policing their practitioners in order to maintain an adequate standard of care across their profession.

– Chiropractors should seek to align themselves with other science-based professions. This includes endorsing science-based public health measures, like immunization. They should not foster hostility toward science-based practitioners, and they should refer patients to other specialists when appropriate.

– Chiropractors should not seek to expand their scope of practice beyond their training and ability. They should not present themselves as primary care providers, nor lobby for regulations to allow them to do so.

– Chiropractors can thrive as a health-care profession as experts in back care and physical medicine. This would provide them with a sufficiently broad scope of practice to be viable, in an area where there is a great need for expertise and symptomatic management. In fact, many science-based chiropractors do just fine within this scope, and provide a best-practice model for their profession.

– The chiropractic profession should purge from their training and practice modalities other than spinal manipulation that are pseudoscientific – including iridology, applied kinesiology, homeopathy, and nutritional pseudoscience. Of course, the medical profession now needs to do this too, as pseudoscience has infiltrated mainstream medicine, but that is a separate article. Also, the percentage of chiropractors using such methods is far greater than within mainstream medicine, and is therefore much more of a problem.

– Chiropractic colleges should change their curriculum so that they are more uniform and more in line with modern scientific concepts and practice.

I harbor no illusions that anything like what I have described above will happen anytime soon, if ever. I hold out a little hope, as there is a small minority of chiropractors who also endorse what I have outlined and are trying to reform their profession from within. I wish them well, and I eagerly await the day that I can feel comfortable with the average chiropractor as an allied science-based health professional.

Until then, in my opinion, public criticism of pseudoscientific claims and practices within chiropractic is the only ethical response.

Posted in: Chiropractic

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