We have discussed the risks of (chiropractic) spinal manipulation more often than I care to remember. The reason for this is simple: it is an important subject; making sure that as many consumers know about it will save lives, I am sure. Therefore, any new paper on the subject is likely to be reported on this blog.
Objective of this review was to identify characteristics of 1) patients, 2) practitioners, 3) treatment process and 4) adverse events (AE) occurring after cervical spinal manipulation (CSM) or cervical mobilization. Systematic searches were performed in 6 electronic databases. Of the initial 1043 studies, 144 studies were included.
They reported 227 cases. 117 cases described male patients with a mean age of 45 (SD 12) and a mean age of 39 (SD 11) for females. Most patients were treated by chiropractors (66%) followed by non-clinicians (5%), osteopaths (5%), physiotherapists (3%) and other medical professions. Manipulation was reported in 95% of the cases (mobilisations only in 1.7%), and neck pain was the most frequent indication.
Cervical arterial dissection (CAD) was reported in 57% of the cases and 46% had immediate onset symptoms; in 2% onset of symptoms took for more than two weeks. Other complications were disc rupture, spinal cord swelling and thrombus. The most frequently reported symptoms included disturbance of voluntary control of movement, pain, paresis and visual disturbances.
In most of the reports, patient characteristics were described poorly. No clear patient profile, related to the risk of AE after CSM, could be extracted. However, women seem more at risk for CAD.
The authors concluded that there seems to be under-reporting of cases. Further research should focus on a more uniform and complete registration of AE using standardized terminology.
I do not want to repeat what I have stated in previous posts on this subject. So,let me just ask this simple question: IF THERE WERE A DRUG MARKTED FOR NECK PAIN BUT NOT SUPPORTED BY GOOD EVIDENCE FOR EFFICACY, DO YOU THINK IT WOULD BE ON THE MARKET AFTER 227 CASES OF SEVERE ADVERSE EFFECTS HAD BEEN DESCRIBED?
I think the answer is NO!
If we then consider the huge degree of under-reporting in this area which might bring the true figure up by one or even two dimensions, we must ask: WHY IS CERVICAL MANIPULATION STILL USED?
‘The use of a harmless alternative therapy is not necessarily wrong. Even if the treatment itself is just a placebo, it can help many patients. Some patients feel better with it, and it would be arrogant, high-handed and less than compassionate to reject such therapies simply because they are not supported by sufficient scientific evidence’.
How often have I heard this notion in one or another form?
I hear such words almost every day.
Arguments along these lines are difficult to counter. Any attempt to do so is likely to make us look blinkered, high-handed and less than compassionate.
Yet we all – well almost all – know that the notion is wrong. Not only that, it can be dangerous.
I will try to explain this with a concrete example of a patient employing a harmless alternative remedy with great success… until… well, you’ll see.
The patient is a married women with two kids. She is well known to her doctor because she has suffered from a range of symptoms for years, and the doctor – despite extensive tests – could never find anything really wrong with her. He knows about his patient’s significant psychological problems and has, on occasion, been tempted to prescribe tranquilizers or anti-depressants. Before he does so, however, he tells her to try Rescue Remedies@ (homeopathically diluted placebos from the range of Bach Flower Remedies). The patient is generally ‘alternatively inclined’, seems delighted with this suggestion and only too keen to give it a try.
After a couple of weeks, she reports that the Rescue Remedies (RR) are helping her. She says she can cope much better with stressful situations and has less severe and less frequent headaches or other symptoms. As she embarks on a long period of taking RR more or less regularly, she becomes convinced that the RR are highly effective and uses them whenever needed with apparent success. This goes on for months, and everyone is happy: the patient feels she has finally found a ‘medication that works’, and the doctor (who knows only too well that RR are placebos) is pleased that his patient is suffering less without needing real medication.
Then, a few months later, the patient notices that the RR are becoming less and less effective. Not only that, she also thinks that her headaches have changed and are becoming more intense. As she has been conditioned to believe that the RR are highly effective, she continues to take them. Her doctor too agrees and encourages her to carry on as before. But the pain gets worse and worse. When she develops other symptoms, her doctor initially tries to trivialise them, until they cannot be trivialised any longer. He eventually sends her to a specialist.
The patient has to wait a couple of weeks until an appointment can be arranged. The specialist orders a few tests which take a further two weeks. Finally, he diagnoses a malignant, possibly fast growing brain tumour. The patient has a poor prognosis but nevertheless agrees to an operation. Thereafter, she is paralysed on one side, needs 24-hour care, and dies 4 weeks post-operatively.
The surgeon is certain that, had he seen the patient several months earlier, the prognosis would have been incomparably better and her life could have been saved.
I suspect that most seasoned physicians have encountered stories which are not dissimilar. Fortunately they often do not end as tragically as this one. We tend to put them aside, and the next time the situation arises where a patient reports benefit from a bogus treatment we think: ‘Even if the treatment itself is just a placebo, it might help. Some patients feel better with it, and it would be arrogant, high-handed and less than compassionate to reject this ‘feel-good factor’.
I hope my story might persuade you that this notion is not necessarily correct.
If you are unable to make your patient feel better without resorting to quackery, my advice is to become a pathologist!!!
Acupuncture is often recommended as a treatment for shoulder pain, but its effectiveness is far from proven. A new study has just been published; but does it change this uncertainty?
A total of 227 patients with subacromial pain syndrome were recruited to this RCT. The patients were allocated to three groups who received either A) group exercise, B) group exercise plus acupuncture or C) group exercise plus electro-acupuncture. The primary outcome measure was the Oxford Shoulder Score. Follow-up was post treatment, and at 6 and 12 months. Data were analysed on intention-to-treat principles with imputation of missing values.
Treatment groups were similar at baseline. All treatment groups demonstrated improvements over time. Between-group estimates were, however, small and non-significant.
The authors concluded that neither acupuncture nor electro-acupuncture were found to be more beneficial than exercise alone in the treatment of subacromial pain syndrome.
Well, that was to be expected!… I hear the rationalists amongst us exclaim.
Actually, I am not so sure.
One could easily have expected that the acupuncture groups (B and C) show a significant advantage over group A.
Because acupuncture is a ‘theatrical placebo’, a ritual that impresses patients and thus impacts on results, particularly on subjective outcomes like pain. If the results had shown a benefit for acupuncture + exercise (groups B and C) versus exercise alone (group A), what would we have made of it? Acupuncture fans would surely have claimed that it is evidence confirming acupuncture’s effectiveness. Sceptics, on the other hand, would have rightly insisted that it demonstrates nothing of the sort – it merely confirms that placebo effects can affect clinical outcomes such as pain.
As it turned out, however, this trial results happened to indicate that these placebo-effects can be so small that they fail to reach the level of statistical significance.
I think there is one noteworthy message here: RCTs with such a design (no adequate control for placebo effects) can easily generate false-positive results (in this case, this did not happen, but it was nevertheless a possible outcome). Such studies are popular but utterly useless: they don’t advance our knowledge one single iota. If that is so, we should not waste our resources on them because, in the final analysis, this is not ethical. In other words, we must stop funding research that has little or no chance of advancing our knowledge.
The ACUPUNCTURE NOW FOUNDATION (ANF) has featured on this blog before. Today I want to re-introduce them because I just came across one of their articles which I found remarkable. In it, they define what many of us have often wondered about: the most important myth about acupuncture.
Is it acupuncture’s current popularity, its long history, its mode of action, its efficacy, its safety?
No, here is the answer directly from the ANF:
The most important myth that needs to be put to rest is the idea promoted by a small group of vocal critics that acupuncture is nothing more than a placebo. Many cite the fact that studies showing acupuncture to be highly effective were of low quality and that several higher quality studies show that, while acupuncture was clinically effective, it usually does not outperform “sham” acupuncture. But those studies are dominated by the first quality issue cited above; studies with higher methodological rigor where the “real” acupuncture was so poorly done as to not be a legitimate comparison. Yet despite the tendency toward poor quality acupuncture in studies with higher methodological standards, a benchmark study was done that showed “real” acupuncture clearly outperforming “sham” acupuncture in four different chronic pain conditions.3 When you add this study together with the fact veterinary acupuncture is used successfully in many different animals, the idea of acupuncture only being placebo must now be considered finally disproven. This is further supported by studies which show that the underlying physiological pathways activated by acupuncture sometimes overlap, but can be clearly differentiated from, those activated by placebo responses.
Yes, I was too.
The myth, according to the ANF, essentially is that sceptics do not understand the scientific evidence. And these blinkered sceptics even go as far as ignoring the findings from what the ANF consider to be a ‘benchmark study’! Ghosh, that’s nasty of them!!!
But, no – the benchmark study (actually, it was not a ‘study’ but a meta-analysis of studies) has been discussed fully on this blog (and in many other places too). Here is what I wrote in 2012 when it was first published:
An international team of acupuncture trialists published a meta-analysed of individual patient data to determine the analgesic effect of acupuncture compared to sham or non-acupuncture control for the following 4 chronic pain conditions: back and neck pain, osteoarthritis, headache, and shoulder pain. Data from 29 RCTs, with an impressive total of 17 922 patients, were included.
The results of this new evaluation suggest that acupuncture is superior to both sham and no-acupuncture controls for each of these conditions. Patients receiving acupuncture had less pain, with scores that were 0.23 (95% CI, 0.13-0.33), 0.16 (95% CI, 0.07-0.25), and 0.15 (95% CI, 0.07-0.24) SDs lower than those of sham controls for back and neck pain, osteoarthritis, and chronic headache, respectively; the effect sizes in comparison to no-acupuncture controls were 0.55 (95% CI, 0.51-0.58), 0.57 (95% CI, 0.50-0.64), and 0.42 (95% CI, 0.37-0.46) SDs.
Based on these findings, the authors reached the conclusion that “acupuncture is effective for the treatment of chronic pain and is therefore a reasonable referral option. Significant differences between true and sham acupuncture indicate that acupuncture is more than a placebo. However, these differences are relatively modest, suggesting that factors in addition to the specific effects of needling are important contributors to the therapeutic effects of acupuncture”.
… even the enthusiastic authors of this article admit that, when compared to sham, the effect size of real acupuncture is too small to be clinically relevant. Therefore one might argue that this meta-analysis confirms what critics have suggested all along: acupuncture is not a useful treatment for clinical routine.
Unsurprisingly, the authors of the meta-analysis do their very best to play down this aspect. They reason that, for clinical routine, the comparison between acupuncture and non-acupuncture controls is more relevant than the one between acupuncture and sham. But this comparison, of course, includes placebo- and other non-specific effects masquerading as effects of acupuncture – and with this little trick (which, by the way is very popular in alternative medicine), we can, of course, show that even sugar pills are effective.
I do not doubt that context effects are important in patient care; yet I do doubt that we need a placebo treatment for generating such benefit in our patients. If we administer treatments which are effective beyond placebo with kindness, time, compassion and empathy, our patients will benefit from both specific and non-specific effects. In other words, purely generating non-specific effects with acupuncture is far from optimal and certainly not in the interest of our patients. In my view, it cannot be regarded as not good medicine, and the authors’ conclusion referring to a “reasonable referral option” is more than a little surprising in my view.
Acupuncture-fans might argue that, at the very minimum, the new meta-analysis does demonstrate acupuncture to be statistically significantly better than a placebo. Yet I am not convinced that this notion holds water: the small residual effect-size in the comparison of acupuncture with sham might not be the result of a specific effect of acupuncture; it could be (and most likely is) due to residual bias in the analysed studies.
The meta-analysis is strongly driven by the large German trials which, for good reasons, were heavily and frequently criticised when first published. One of the most important potential drawbacks was that many participating patients were almost certainly de-blinded through the significant media coverage of the study while it was being conducted. Moreover, in none of these trials was the therapist blinded (the often-voiced notion that therapist-blinding is impossible is demonstrably false). Thus it is likely that patient-unblinding and the absence of therapist-blinding importantly influenced the clinical outcome of these trials thus generating false positive findings. As the German studies constitute by far the largest volume of patients in the meta-analysis, any of their flaws would strongly impact on the overall result of the meta-analysis.
So, has this new meta-analysis finally solved the decades-old question about the effectiveness of acupuncture? It might not have solved it, but we have certainly moved closer to a solution, particularly if we employ our faculties of critical thinking. In my view, this meta-analysis is the most compelling evidence yet to demonstrate the ineffectiveness of acupuncture for chronic pain.
END OF QUOTE
The ANF-text then goes from bad to worse. First they cite the evidence from veterinary acupuncture as further proof of the efficacy of their therapy. Well, the only systematic review in this are is, I think, by my team; and it concluded that there is no compelling evidence to recommend or reject acupuncture for any condition in domestic animals. Some encouraging data do exist that warrant further investigation in independent rigorous trials.
Lastly, the ANF mentions acupuncture’s mode of action which they seem to understand clearly and fully. Congratulations ANF! In this case, you are much better than the many experts in basic science or neurology who almost unanimously view these ‘explanations’ of how acupuncture might work as highly adventurous hypotheses or speculations.
So, what IS the most important myth about acupuncture? I am not sure and – unlike the ANF – I do not feel that I can speak for the rest of the world, but one of the biggest myths FOR ME is how acupuncture fans constantly manage to mislead the public.
Meniscus-injuries are common and there is no consensus as to how best treat them. Physiotherapists tend to advocate exercise, while surgeons tend to advise surgery.
Of course, exercise is not a typical alternative therapy but, as many alternative practitioners might disagree with this statement because they regularly recommend it to their patients, it makes sense to cover it on this blog. So, is exercise better than surgery for meniscus-problems?
The aim of this recent Norwegian study aimed to shed some light on this question. Specifically wanted to determine whether exercise therapy is superior to arthroscopic partial meniscectomy for knee function in patients with degenerative meniscal tears.
A total of 140 adults with degenerative medial meniscal tear verified by magnetic resonance imaging were randomised to either receiving 12 week supervised exercise therapy alone, or arthroscopic partial meniscectomy alone. Intention to treat analysis of between group difference in change in knee injury and osteoarthritis outcome score (KOOS4), defined a priori as the mean score for four of five KOOS subscale scores (pain, other symptoms, function in sport and recreation, and knee related quality of life) from baseline to two-year follow-up and change in thigh muscle strength from baseline to three months.
The results showed no clinically relevant difference between the two groups in change in KOOS4 at two years (0.9 points, 95% confidence interval −4.3 to 6.1; P=0.72). At three months, muscle strength had improved in the exercise group (P≤0.004). No serious adverse events occurred in either group during the two-year follow-up. 19% of the participants allocated to exercise therapy crossed over to surgery during the two-year follow-up, with no additional benefit.
The authors concluded that the observed difference in treatment effect was minute after two years of follow-up, and the trial’s inferential uncertainty was sufficiently small to exclude clinically relevant differences. Exercise therapy showed positive effects over surgery in improving thigh muscle strength, at least in the short-term. Our results should encourage clinicians and middle-aged patients with degenerative meniscal tear and no definitive radiographic evidence of osteoarthritis to consider supervised exercise therapy as a treatment option.
As I stated above, I mention this trial because exercise might be considered by some as an alternative therapy. The main reason for including it is, however, that it is in many ways an exemplary good study from which researchers in alternative medicine could learn.
Like so many alternative therapies, exercise is a treatment for which placebo-controlled studies are difficult, if not impossible. But that does not mean that rigorous tests of its value are impossible. The present study shows the way how it can be done.
Meaningful clinical research is no rocket science; it merely needs well-trained scientists who are willing to test the (rather than promote) their hypotheses. Sadly such individuals are as rare as gold dust in the realm of alternative medicine.
This website tells us that ‘Stopain Migraine’ is the first topical product to effectively relieve migraine pain. It is a safe alternative to other migraine relief products that begins to work as soon as it’s applied. And the press release informs us that Troy Healthcare extended its Stopain line with a Stopain Migraine offering – a topical pain relieving gel that is massaged onto the back of the neck and behind each ear.
“Many of the women we shopped with told us they like that Stopain Migraine lacks systemic side effects and can be used in conjunction with other products – whether that’s natural remedies like peppermint essential oil, Epsom salts and ginger tea, or even prescription drugs or other over-the-counter products,” stated Anthony Cicini, VP Troy Healthcare.
Stopain Migraine begins to work as soon as it’s applied, can be reapplied after 30 minutes, and can be used up to four times daily, the company noted. It’s unique in that it can be used alone, or in addition to other ingestible migraine products to relieve migraine pain.
The homeopathic blend of ingredients follow the guidelines of The Homeopathic Pharmacopoeia of the United State and is recommended by both by primary care physicians and OBGYNs, the company stated.
In addition to providing effective relief quickly, Stopain Migraine offers peace of mind for migraine sufferers, knowing the product is free from aspirin, acetaminophen and caffeine, has no known drug interactions and contains no dyes or preservatives.
Consumers can now find Stopain Migraine nationwide for the suggested retail price of $11.99
END OF PRESS RELEASE
Any evidence, you’d probably ask. A quick Medline search located this abstract:
To determine whether topical menthol 6% gel will relieve a migraine attack.
MATERIALS AND METHODS:
A single-center, open-label pilot trial of 25 patients with at least 1 year of diagnosed episodic migraine and <15 headache days per month. Patients treated one migraine attack with STOPAIN topical menthol 6% gel to skull base within 2 h of headache onset. Headache pain severity was assessed prior to and after gel application.
Thirty-two patients enrolled and 25 completed the study. Prior to treatment, 7 patients had mild pain, 13 moderate pain, and 5 severe pain. Two hours following gel application, 7 (28%) patients had no pain, 7 (28%) mild pain, 6 (25%) moderate pain, and 5 (20%) severe pain. The majority of patients had similar pain intensity (8; 32%) or improvement (13; 52%). At 24-h, only two non-rescued patients still had mild headache. Of the 25 completers, 2 patients took rescue medication prior to the 2-h period, and an additional 10 patients rescued between 2 and 24 h.
Study results showed a significant improvement in headache intensity by 2 h after gel application. This pilot study shows STOPAIN gel may be effective in treating an acute migraine attack.
A pilot study! I thought pilots were for testing feasibility, not effectiveness!
No control group! The observed effect is therefore not attributable to ‘Stopain’ at all!
But there is more! Iranian researchers published this RCT:
To investigate the efficacy and safety of the cutaneous application of menthol 10% solution for the abortive treatment of migraine.
Peppermint and its active ingredient menthol have long been used for the treatment of various pain conditions including headache.
This is a randomised, triple-blind, placebo-controlled, crossed-over study conducted in the neurology Clinic of Nemazee Hospital, affiliated with Shiraz University of Medical Sciences, Shiraz, southern Iran, from March 2007 to March 2008. The patients were recruited via local newspaper advertisements. Eligible patients were categorised into two groups and a 10% ethanol solution of menthol (as drug) and 0.5% ethanol solution of menthol (as placebo) were applied to the forehead and temporal area in a crossover design. Pain free, pain relief, sustained pain free and sustained pain relief end-points were measured by questionnaires using a visual analogue scale.
The intent-to-treat population consisted of 35 patients (80% women, 20% men, mean age: 29.6 +/- 6.2) with 118 migraine attacks. In the intent-to-treat population, the menthol solution was statistically superior to the placebo on 2-h pain free (p = 0.001), 2-h pain relief (p = 0.000), sustained pain free and sustained pain relief end-points (p = 0.008). The menthol solution was also more efficacious in the alleviation of nausea and/or vomiting and phonophobia and/or photophobia (p = 0.02). In the per-protocol population, there was significantly higher number of patients who experienced at least one pain free/pain relief after the application of menthol rather than the placebo (p = 0.002). No significant difference was seen between the adverse effects of the drug and the placebo groups (p = 0.13).
Menthol solution can be an efficacious, safe and tolerable therapeutic option for the abortive treatment of migraine.
Yes, you are quite right; this must be a different product. It contains just menthol and at a higher concentration than ‘Stopain’.
So what does ‘Stopain’ actually contain? I must say that 6% menthol does not sound very homeopathic to me! The website of Troy Healthcare tells us that it has a total of 4 ingredients:
|Mentholum 1X HPUS – 50.00%|
|Belladonna 3X HPUS – 1.33%|
|Iris Versicolor 6X HPUS – 1.33%|
|Sanguinaria Canadensis 6X HPUS – 1.33%|
And what do the three homeopathically diluted ingredients do?
Is the term ‘homeopathic’ used here merely to attract a certain type of customer?
And why do they claim that ‘Stopain’ is effective when there is no evidence?
Or perhaps there is evidence and they haven’t published it?
And why do they claim that ‘Stopain’ is the first topical product?
Wasn’t a German topical menthol product marketed years ago?
Search me! I am not sure I know all the answers.
I hope someone from Troy Healthcare reads this and cares to explain.
The risks of consulting a chiropractor have regularly been the subject of this blog (see for instance here, here and here). My critics believe that I am alarmist and have a bee in my bonnet. I think they are mistaken and believe it is important to warn the public of the serious complications that are being reported with depressing regularity, particularly in connection with neck manipulations.
It has been reported that the American model Katie May died earlier this year “as the result of visiting a chiropractor for an adjustment, which ultimately left her with a fatal tear to an artery in her neck” This is the conclusion drawn by the L.A. County Coroner.
According to Wikipedia, Katie tweeted on January 29, 2016, that she had “pinched a nerve in [her] neck on a photoshoot” and “got adjusted” at a chiropractor. She tweeted on January 31, 2016 that she was “going back to the chiropractor tomorrow.” On the evening of February 1, 2016, May “had begun feeling numbness in a hand and dizzy” and “called her parents to tell them she thought she was going to pass out.” At her family’s urging, May went to Cedars Sinai Hospital; she was found to be suffering a “massive stroke.” According to her father, she “was not conscious when we got to finally see her the next day. We never got to talk to her again.” Life support was withdrawn on February 4, 2016.
Katie’s death certificate states that she died when a blunt force injury tore her left vertebral artery, and cut off blood flow to her brain. It also says the injury was sustained during a “neck manipulation by chiropractor.” Her death is listed as accidental.
Katie’s family is said to be aware of the coroner’s findings. They would not comment on whether they or her estate would pursue legal action.
The coroner’s verdict ends the uncertainty about Katie’s tragic death which was well and wisely expressed elsewhere:
“…The bottom line is that we don’t know for sure. We can’t know for sure. If you leave out the chiropractic manipulations of her neck, her clinical history—at least as far as I can ascertain it from existing news reports—is classic for a dissection due to neck trauma. She was, after all, a young person who suffered a seemingly relatively minor neck injury that, unbeknownst to her, could have caused a carotid artery dissection, leading to a stroke four or five days later… Thus, it seems to be jumping to conclusions for May’s friend Christina Passanisi to say that May “really didn’t need to have her neck adjusted, and it killed her.” … Her two chiropractic manipulations might well have either worsened an existing intimal tear or caused a new one that led to her demise. Or they might have had nothing to do with her stroke, her fate having been sealed days before when she fell during that photoshoot. There is just no way of knowing for sure. It is certainly not wrong to suspect that chiropractic neck manipulation might have contributed to Katie May’s demise, but it is incorrect to state with any degree of certainty that her manipulation did kill her.”
My conclusions are as before and I think they need to be put as bluntly as possible: avoid chiropractors – the possible risks outweigh the documented benefits – and if you simply cannot resist consulting one: DON’T LET HIM/HER TOUCH YOUR NECK!
The placebo response might be important in clinical practice, but it is certainly difficult to study and the findings of such investigations can be confusing. This seems to be exemplified by two new trials.
The first study examined the possibility of using theatrical performance tools, including stage directions and scripting, to reproducibly manipulate the style and content of a simulated doctor-patient encounter and influence the placebo response (defined as improvement of clinical outcome in individuals receiving inactive treatment) in experimental pain.
A total of 122 healthy volunteers were exposed to experimental pain using the cold pressor test and assessed for pain threshold and tolerance before and after receiving a placebo cream from a “doctor” impersonated by a trained actor. The actor alternated between two distinct scripts and stage directions. One script emulated a standard doctor-patient encounter (scenario A), while the other emphasized elements present in ritual healing such as attentiveness and strong suggestion (scenario B).
The placebo response size was calculated as the % difference in pain threshold and tolerance after exposure relative to baseline. Subjects demonstrating a ≥30% increase in pain threshold or tolerance relative to baseline were defined as responders. Each encounter was videotaped in its entirety.
Inspection of the videotapes confirmed the reproducibility and consistency of the distinct scenarios enacted by the “doctor”-performer. Furthermore, scenario B resulted in a significant increase in pain threshold relative to scenario A. This increase derived from the placebo responder subgroup; as shown by two-way analysis of variance (performance style, F = 4.30; p = 0.040; η(2) = 0.035; style × responder status interaction term, F = 5.21; p = 0.024) followed by post hoc analysis showing a ∼60% increase in pain threshold in responders exposed to scenario B (p = 0.020).
Performance style and response size in placebo responders and non-responders. Bars represent mean ± SE of % change in CPT threshold of 60 subjects in scenario A: 53 non-responders vs. 7 responders and 62 subjects in scenario B: 51 non-responders and 11 responders. Two-way ANOVA by performance style and responsiveness revealed significant effects of doctor’s performance (F = 4.30; p = 0.040; η2 = 0.035) and responsiveness (F = 134.71; p < 0.001) as well as a significant interaction term (F = 5.21; p = 0.024). ∗p = 0.020, Fisher’s least significant difference post hoc test.
The authors concluded that these results support the hypothesis that structured manipulation of physician’s verbal and non-verbal performance, designed to build rapport and increase faith in treatment, is feasible and may have a significant beneficial effect on the size of the response to placebo analgesia. They also demonstrate that subjects, who are not susceptible to placebo, are also not susceptible to performance style.
In the second study, the authors investigated if an implicit priming procedure, where participants were unaware of the intended priming influence, affected placebo analgesia.
In a double-blind experiment, healthy participants (n = 36) were randomized to different implicit priming types; one aimed at increasing positive expectations and one neutral control condition. First, pain calibration (thermal) and a credibility demonstration of the placebo analgesic device were performed. In a second step, an independent experimenter administered the priming task; Scrambled Sentence Test. Then, pain sensitivity was assessed while telling participants that the analgesic device was either turned on (placebo) or turned off (baseline). Pain responses were recorded on a 0-100 Numeric Response Scale.
Overall, there was a significant placebo effect (p < 0.001), however, the priming conditions (positive/neutral) did not lead to differences in placebo outcome. Prior experience of pain relief (during initial pain testing) correlated significantly with placebo analgesia (p < 0.001) and explained 34% of placebo variance. Trait neuroticism correlated positively with placebo analgesia (p < 0.05) and explained 21% of placebo variance.
The authors concluded that priming is one of many ways to influence behaviour, and non-conscious activation of positive expectations could theoretically affect placebo analgesia. Yet, we found no SST priming effect on placebo analgesia. Instead, our data point to the significance of prior experience of pain relief, trait neuroticism and social interaction with the treating clinician.
The two studies are similar but generate somewhat contradictory results. In the discussion section, the authors of the first paper stress that “replication of our findings in clinical populations; employing professional physicians of both sexes, are necessary in order to establish their generality and possible application in medical training, with the aim of improving patient outcome across diseases and treatment modalities.” This is certainly true. They continue by stating that “future studies using performance tools in clinical trial settings could demonstrate the potential of borrowing performance principles and techniques from traditional healing and applying them to physician–patient encounters in Western medicine, following certain necessary modifications. Performance tools could thus eventually be incorporated into the systematic training of physicians and medical students, possibly to complement programs in Narrative Medicine and Relational Medicine.”
These ideas are not dissimilar to what we have been discussing on this blog repeatedly. For instance, I have previously tried to explain that “the science and the art of medicine are essential elements of good medicine. In other words, if one is missing, medicine is by definition not optimal. In vast areas of alternative medicine, the science-element is woefully neglected or even totally absent. It follows, that these areas cannot be good medicine. In some areas of conventional medicine, the art-element is weak or neglected. It follows that, in these areas, medicine is not good either.”
The fact that the two studies above show contradictory findings is not easy to interpret. Possibly, this shows how fragile the placebo response can be. It can be influenced by a multitude of factors related to an experiment or the clinical setting. If that is so, and placebo effects are truly unreliable, it would be yet another argument for not relying on them in clinical routine. In my view, clinicians should try to maximize them where they can. Yet placebo effects are not normally a justification for employing placebo therapies in clinical practice. In other words, the fact that a bogus treatment can generate a placebo response is not a good reason for using it on patients who need help.
Good clinicians have probably always been good ‘performers’. Alternative practitioners tend to be excellent ‘performers’, and I am sure their success is mainly due to this ability. I see little reason why conventional practitioners should not (re-)learn the skills that once upon a time were called ‘good bed-side manners’. Maximizing the placebo effect in this way might maximize the benefit patients experience – and for that we do not require the placebo-therapies of alternative medicine.
A new study tested the efficacy of chiropractic spinal manipulative therapy (CSMT) for migraine. It was designed as a three-armed, single-blinded, placebo -controlled RCT of 17 months duration including 104 migraineurs with at least one migraine attack per month. Active treatment consisted of CSMT (group 1) and the placebo was a sham push manoeuvre of the lateral edge of the scapula and/or the gluteal region (group 2). The control group continued their usual pharmacological management (group 3).
The RCT began with a one-month run-in followed by three months intervention. The outcome measures were quantified at the end of the intervention and at 3, 6 and 12 months of follow-up. The primary end-point was the number of migraine days per month. Secondary end-points were migraine duration, migraine intensity and headache index, and medicine consumption.
The results show that migraine days were significantly reduced within all three groups from baseline to post-treatment (P < 0.001). The effect continued in the CSMT and placebo groups at all follow-up time points (groups 1 and 2), whereas the control group (group 3) returned to baseline. The reduction in migraine days was not significantly different between the groups. Migraine duration and headache index were reduced significantly more in the CSMT than in group 3 towards the end of follow-up. Adverse events were few, mild and transient. Blinding was strongly sustained throughout the RCT.
The authors concluded that it is possible to conduct a manual-therapy RCT with concealed placebo. The effect of CSMT observed in our study is probably due to a placebo response.
Chiropractors often cite clinical trials which suggest that CSMT might be effective. The effects sizes are rarely impressive, and it is tempting to suspect that the outcomes are mostly due to bias. Chiropractors, of course, deny such an explanation. Yet, to me, it seems fairly obvious: trials of CSMT are not blind, and therefore the expectation of the patient is likely to have major influence on the outcome.
Because of this phenomenon (and several others, of course), sceptics are usually unconvinced of the value of chiropractic. Chiropractors often respond by claiming that blind studies of physical intervention such as CSMT are not possible. This, however, is clearly not true; there have been several trials that employed sham treatments which adequately mimic CSMT. As these frequently fail to show what chiropractors had hoped, the methodology is intensely disliked by chiropractors.
The above study is yet another trial that adequately controls for patients’ expectation, and it shows that the apparent efficacy of CSMT disappears when this source of bias is properly accounted for. To me, such findings make a lot of sense, and I suspect that most, if not all the ‘positive’ studies of CSMT would turn out to be false positive, once such residual bias is eliminated.
Chiropractic for animals?
Yes, it can!!!
Animal Chiropractic “is a field of animal health care that focuses on the preservation and health of the neuro-musculo-skeletal system. Why? Nerves control everything that happens in your animals. Anything adversely affecting the nervous system will have detrimental effects that will resonate throughout the entire body. The command centers of the nervous system are the brain and spinal cord which are protected by the spine. The spine is a complex framework of bones (vertebra), ligaments, muscles and nerves. If the movement and biomechanics of the vertebra become dysfunctional, they can interfere with the performance of the nerves that are branching off of the spinal cord and going to the all of the muscles and organs. As this occurs, your animal can lose normal mobility; resulting in stiffness, tension, pain and even organ dysfunction. Additionally, when normal movement is affected, and left unattended, it will ultimately impact your animal’s entire wellbeing and quality of life…”
As you see, much the same nonsense as for human chiropractic is now also advertised for animals, particularly horses. Chiropractic for horses and other animals has become a thriving business; today there are even colleges that specialise in ‘educating’ animal chiropractors, and the ‘AMERICAN VETERINARY CHIROPRACTIC ASSOCIATION promotes “animal chiropractic to professionals and the public, and [acts] as the certifying agency for doctors who have undergone post-graduate animal chiropractic training. Members working together within their disciplines to expand and promote the knowledge and acceptance of animal chiropractic to their professions, the public and governments; locally, nationally and internationally.”
Recently I came across a remarkable website which promoted chiropractic specifically for horses. Here are a few paragraphs from the promotional text:
In recent years, the demand among horse owners for alternative equine therapies has spurred many veterinarians to explore therapies like acupuncture and chiropractic. Equine chiropractic techniques provide relief by restoring movement to the spinal column and promoting healthy neurologic functioning. In turn, the entire musculoskeletal system benefits, and the overall health of the animal increases.
Perhaps the greatest clinical application of chiropractic techniques is for animals with a vague sort of lameness that is not localized to any specific area, and for horses that experience a sudden decline in performance for seemingly no reason. These issues often relate back to musculoskeletal disorders that can be diagnosed through chiropractic techniques.
Some horse owners use chiropractic as a preventative measure. Subclinical conditions, meaning those that do not yet show symptoms, can often be detected by an equine chiropractor, as can abnormal biomechanics that could cause lameness down the road. Conditions that originate in the spine often result in a changed gait that can affect how force is applied to joints in the lower limbs. Over time, this shifted force can cause lameness, but chiropractic attention may help identify and deal with problems before they become a real issue…
Several situations can benefit from meeting with an equine chiropractor. The most significant sign that a horse could benefit from chiropractic treatment is pain. If the animal’s behavior suddenly changes or its posture seems abnormal, the horse may be experiencing pain. Similarly, reduced performance, refusing to jump, and tossing the head under saddle can indicate pain.
Owners should familiarize themselves with the many signs that a horse is experiencing pain. Some other indicators include chronic weight loss, sensitivity when being groomed, and difficulty turning. A chiropractor is a great option for identifying the issues leading to these behaviors and correcting them as quickly as possible — before the problems compound.
While pain is a great reason to seek equine chiropractic therapy, individuals may also want to consider the option if the horse is not responding to more conventional therapies. Chiropractors can also aid in recovery after significant trauma or lameness. However, horse owners should recognize that chiropractic therapy does not reverse degenerative changes already present, so working with a practitioner early in a disease’s progression can slow its advancement. Chiropractic may also help manage chronic conditions and prevent them from worsening…
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And where is the evidence for all this? I did a quick search and found virtually nothing to write home about. A review which I did locate made it clear why: “…only anecdotal evidence exists in horses…”
And that statement does, of course, prompt me to quickly remind everyone: THE PLURAL OF ANECDOTE IS ANECDOTES, NOT EVIDENCE!