Spinal manipulation is a form of treatment that is used occasionally by some doctors, physiotherapists and osteopaths – but, for chiropractors, it is the hallmark intervention. The birth of this branch of healthcare can be dated to 18 September 1895. On this day DD Palmer, a magnetic healer and the founder of chiropractic, manipulated the neck of a deaf man whose hearing was subsequently restored. His second patient was a man with heart problems whose symptoms also improved with spinal manipulation. This history is important: the early chiropractic literature provides ample evidence for the fact that chiropractic was not originally meant as a treatment for musculoskeletal problems, but as a cure for any human condition Citation[1].
To understand this seemingly bizarre claim a little better, one should glance at the concepts that underlie chiropractic. Palmer was convinced that he had discovered a law of nature. In his view, all human illness and disease were caused by the blockage of the ‘innate intelligence’ through vertebral malalignments or subluxations. Therefore, all conditions could and should be treated with adjustments of these abnormalities, in other words, spinal manipulation. This would restore the flow of the innate intelligence and, in turn, would cure whatever condition the patient was suffering from Citation[1].
It seems obvious to any critical evaluator that these concepts are little more than fantasy: there is no evidence for any innate intelligence, and there is no reason to assume that adjusting malalignments of vertebra (if they at all exist) are the cause of disease or illness. Today, the chiropractic profession is divided into the ‘straights’ who still believe every word of Palmer’s gospel, and the ‘mixers’ who have freed themselves, at least partly, from his theories. The straights treat most diseases with spinal manipulation, while the mixers managed to gradually redefine themselves as back specialists.
The fact that the original concepts of chiropractic spinal manipulation were bizarre and misguided does, however, not necessarily mean that the treatment is useless. It is perfectly possible that a therapy works through other mechanisms than originally assumed. To answer the question of whether spinal manipulation is effective, we need to look at the results of controlled clinical trials. Currently, there are well over 100 such studies. Unsurprisingly, their results are not uniform. In order to create the most reliable overall picture possible, we must thus resist the temptation of selecting those trials which, for whatever reason, we might like. The best way forward is to critically evaluate the totality of the reliable evidence – in other words, it is best to rely on well-conducted systematic reviews of high-quality clinical trials.
A recent overview of the most up to date and authoritative systematic reviews found such articles relating to a range of indications: back pain, neck pain, headache, dysmenorrhoea, asthma, infantile colic and cervicogenic dizziness Citation[2]. This seems to confirm that spinal manipulation is purely meant as a treatment for musculoskeletal problems. The Cochrane review of the back pain trials suggested that spinal manipulation is as good (or bad) as conventional treatments in easing pain or improving function. For all other conditions, the systematic reviews were even less encouraging: there was no definite evidence that spinal manipulation was effective on any of them Citation[2].
Treatment decisions cannot not be based on effectiveness data alone. Another important factor obviously is safety. It is in this respect that spinal manipulation disappoints most. Several large-scale surveys have shown that approximately half of all patients suffer mild-to-moderate symptoms, such as pain, after receiving spinal manipulation Citation[3]. As these problems are usually gone within 24 h, one could perhaps agree with the view of most chiropractors that these adverse effects are negligible and form part of the process of recovery. One is, however, far less inclined to take serious complications lightly. Approximately 700 cases of serious adverse effects have been associated with spinal manipulation Citation[4]. They frequently relate to upper spinal manipulation, which can entail manipulative movements beyond the physiological range of motion. This can conceivably lead to injuries, most frequently to dissections of the vertebral arteries. Such cases often present as strokes, which can sometimes be fatal Citation[4].
Many chiropractors deny that a causal relationship exists between spinal manipulation and such complications Citation[1]. Others argue that these incidents are extreme rarities and provide figures of one in three million patients Citation[1]. Our own research shows that under-reporting of serious complications can be as high as 100% Citation[5]. Therefore, estimates are simply not possible and the 700 documented cases Citation[4] are likely to be the tip of a much bigger iceberg.
Weighing the risks of spinal manipulation against its benefits is therefore an exercise that involves a considerable amount of uncertainty. Whenever uncertainty exists, it seems wise to err on the side of caution. Applying the cautionary principle to spinal manipulation generates discouraging evidence. For most indications, there is no evidence of benefit Citation[2]; therefore, any risk–benefit assessment cannot result in a positive verdict. For back pain, the situation is slightly more complex. Here, we do have evidence that spinal manipulation is as effective (or as ineffective) as conventional options, including physiotherapeutic exercise Citation[2]. But, on the risk side of the balance, we have mild-to-moderate adverse effects in approximately 50% of all patients Citation[3] and serious complications of unknown frequency Citation[4]. Compare this with exercise, which has no known serious risks, and you will probably find it difficult to recommend spinal manipulation even for back pain.
In conclusion, spinal manipulation is based on questionable pathological concepts and therefore lacks biological plausibility Citation[1]. Its risks may be considerable Citation[4] and its benefits have not been convincingly demonstrated in rigorous trials Citation[2]. What follows is sobering: the benefits of spinal manipulation do not seem worth the potential risks.
Financial & competing interests disclosure
The author has no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.
No writing assistance was utilized in the production of this manuscript.
References
- Ernst E. Chiropractic – a critical evaluation. J. Pain Symptom Mange. (2007) (Epub ahead of print).
- Ernst E, Canter PH. A systematic review of systematic reviews of spinal manipulation. J. R. Soc. Med.99, 192–196 (2006).
- Ernst E. Prospective investigations into the safety of spinal manipulation. J. Pain Symptom Mange.21, 238–242 (2001).
- Ernst E. Adverse effects of spinal manipulation: a systematic review. J. R. Soc. Med.100, 330–338 (2007).
- Stevinson C, Honan W, Cooke B, Ernst E. Neurological complications of cervical spine manipulation. J. R. Soc. Med.94, 107–110 (2001).