During my almost 30 years of research into so-called alternative medicine (SCAM), I have published many papers which must have been severe disappointments to those who advocate SCAM or earn their living through it. Many SCAM proponents thus reacted with open hostility. Others tried to find flaws in those articles which they found most upsetting with a view of discrediting my work. The 2012 article entitled ‘A Replication of the Study ‘Adverse Effects of Spinal Manipulation: A Systematic Review‘ by the Australian chiropractor, Peter Tuchin, seems to be an example of the latter phenomenon (used recently by Jens Behnke in an attempt to defame me).
Here is the abstract of the Tuchin paper:
Objective: To assess the significance of adverse events after spinal manipulation therapy (SMT) by replicating and critically reviewing a paper commonly cited when reviewing adverse events of SMT as reported by Ernst (J Roy Soc Med 100:330-338, 2007).
Method: Replication of a 2007 Ernst paper to compare the details recorded in this paper to the original source material. Specific items that were assessed included the time lapse between treatment and the adverse event, and the recording of other significant risk factors such as diabetes, hyperhomocysteinemia, use of oral contraceptive pill, any history of hypertension, atherosclerosis and migraine.
Results: The review of the 32 papers discussed by Ernst found numerous errors or inconsistencies from the original case reports and case series. These errors included alteration of the age or sex of the patient, and omission or misrepresentation of the long term response of the patient to the adverse event. Other errors included incorrectly assigning spinal manipulation therapy (SMT) as chiropractic treatment when it had been reported in the original paper as delivered by a non-chiropractic provider (e.g. Physician).The original case reports often omitted to record the time lapse between treatment and the adverse event, and other significant clinical or risk factors. The country of origin of the original paper was also overlooked, which is significant as chiropractic is not legislated in many countries. In 21 of the cases reported by Ernst to be chiropractic treatment, 11 were from countries where chiropractic is not legislated.
Conclusion: The number of errors or omissions in the 2007 Ernst paper, reduce the validity of the study and the reported conclusions. The omissions of potential risk factors and the timeline between the adverse event and SMT could be significant confounding factors. Greater care is also needed to distinguish between chiropractors and other health practitioners when reviewing the application of SMT and related adverse effects.
The author of this ‘replication study’ claims to have identified several errors in my 2007 review of adverse effects of spinal manipulation. Here is the abstract of my article:
Objective: To identify adverse effects of spinal manipulation.
Design: Systematic review of papers published since 2001.
Setting: Six electronic databases.
Main outcome measures: Reports of adverse effects published between January 2001 and June 2006. There were no restrictions according to language of publication or research design of the reports.
Results: The searches identified 32 case reports, four case series, two prospective series, three case-control studies and three surveys. In case reports or case series, more than 200 patients were suspected to have been seriously harmed. The most common serious adverse effects were due to vertebral artery dissections. The two prospective reports suggested that relatively mild adverse effects occur in 30% to 61% of all patients. The case-control studies suggested a causal relationship between spinal manipulation and the adverse effect. The survey data indicated that even serious adverse effects are rarely reported in the medical literature.
Conclusions: Spinal manipulation, particularly when performed on the upper spine, is frequently associated with mild to moderate adverse effects. It can also result in serious complications such as vertebral artery dissection followed by stroke. Currently, the incidence of such events is not known. In the interest of patient safety we should reconsider our policy towards the routine use of spinal manipulation.
In my view, there are several things that are strange here:
- Tuchin published his paper 5 years after mine.
- He did not publish it in the same journal as my original, but in an obscure chiro journal that hardly any non-chiropractor would ever read.
- Tuchin never contacted me and never alerted me to his publication.
- The journal that Tuchin chose was not Medline-listed in 2012; consequently, I never got to know about the Tuchin article in a timely fashion. (Therefore, I did never respond to it.)
- A ‘replication study’ is a study that repeats the methodology of a previous study.
- Tuchin’s paper is therefore NOT a replication study. Firstly, mine was a review and not a study. Secondly, and crucially, Tuchin never repeated my methodology but used an entirely different one.
But arguably, these points are trivial. They should not distract from the fact that I might have made mistakes. So, let’s look at the substance of Tuchin’s claim, namely that I made errors or omissions in my review.
As to ‘omissions’, one could argue that a review such as mine will always have to omit some details in order to generate a concise summary. The only way to not omit any details is to re-publish all the primary papers in one large volume. Yet, this can hardly be the purpose of a systematic review.
As to the ‘errors’, it seems that the ages and sex of three patients were wrong (I have not checked this against the primary publications but, for the moment, I believe Tuchin). This is, of course, lamentable and – even though I have no idea whether the errors happened at the data extraction phase, during the typing, the revising, or the publishing of the paper – it is entirely my responsibility. I also seem to have mistaken a non-chiropractor for a chiropractor. This too is regrettable but, as the review was about spinal manipulation and not about chiropractic, the error is perhaps not so grave.
Be that as it may, these errors are unquestionably not good, and I can only apologise for them. If Tuchin had dealt with them in the usual way – by publishing in a timely fashion a ‘letter to the editor’ of the JRSM – I could have easily corrected them for everyone to see.
But I think there is a more important point to be made here:
Tuchin concludes his paper stating that it is unwise to make conclusions regarding causality from any case study or multiple case studies. The number of errors or omissions in the 2007 Ernst paper significantly limit any reported conclusions. I believe that both sentences are unjustified. The safety of any intervention in routine use has to be examined on the basis of published case studies. This is particularly true for chiropractic where no post-marketing surveillance similar to that for drugs exists.
The conclusions based on such evidence can, of course, never be firm, but they provide valuable signals that can prompt more rigorous investigations in the interest of patient safety. In view of such considerations, my own conclusions in my 2007 paper were, I think, correct and are NOT invalidated by my relatively trivial mistakes: spinal manipulation, particularly when performed on the upper spine, has repeatedly been associated with serious adverse events. Currently the incidence of such events is unknown. Adherence to informed consent, which currently seems less than rigorous, should therefore be mandatory to all therapists using this treatment. Considering that spinal manipulation is used mostly for self-limiting conditions and that its effectiveness is not well established, we should adopt a cautious attitude towards using it in routine health care.
And my conclusions in the abstract have now, I believe, become established wisdom. They are thus even less in jeopardy through my calamitous lapsus or Tuchin’s ‘replication study’: Spinal manipulation, particularly when performed on the upper spine, is frequently associated with mild to moderate adverse effects. It can also result in serious complications such as vertebral artery dissection followed by stroke. Currently, the incidence of such events is not known. In the interest of patient safety we should reconsider our policy towards the routine use of spinal manipulation.