“Consider a woman consulting a chiropractor for neck pain, which is a common reason for people to seek chiropractic care, and chiropractors claim that it can be effectively treated with spinal manipulation. The relevant facts regarding such a case are as follows:
• Treatment would be elective, i.e. the patient could, without serious risks, postpone her treatment decision.
• Other treatments exist, some of which, like exercise, are virtually risk-free [5].
• The risk of not having any treatment at all is minimal.
• Chiropractic treatment of neck pain has not been demonstrated to be effective or more effective than competing therapies [6].
Manipulation of the upper spine is associated with material and significant risks. About half of all patients will experience transient discomfort or pain, and in a (probably small but essentially unknown) number of cases, it may cause arterial dissection with potentially serious sequelae [7]. ‘A significantly more thorough standard of disclosure is needed where the treatment is elective and … the law may require disclosure of all known risks …’ [8]. Thus chiropractors must advise patients with neck pain that the risk–benefit balance of upper spinal manipulation is not demonstrably in favour of this approach and that other, less risky and effective treatments (e.g. exercise) exist [9]. Many patients would be alarmed by these facts and decline treatment. As most chiropractors are self-employed, full informed consent is overtly against their own financial interest. Consequently chiropractors might rarely provide such information (to date no data are available). Yet the mere fact that the patient might become upset by hearing the information, or might refuse treatment, is not sufficient to act as a justification for non-disclosure of information [3]. ‘Therapeutic privilege’ could be the solution and, in fact, seems to be current clinical practice. It means that chiropractors limit disclosure of risks in the belief that this is in the patient’s best interest. However, therapeutic privilege only applies where ‘treatment is so necessary to maintain the life or health of the patient and the consequences of failing to carry it out are so clearly disadvantageous’ [8].”

Edzard Ernst, letter to Rheumatology, (2004)