Placebo injections are more effective than placebo pills, and neither is as potent as sham surgery.

ECONOMIST: Alternative medicine: Think yourself better | The

In the year after the procedure, 57 percent of those who had the actual surgery reported the complete elimination of migraine headaches, compared with just 4 percent in the sham surgery group.

CNN: Facial surgery may offer migraine cure

Medtronic argues that a sham surgery trial for kyphoplasty is not needed because the Lancet trials followed patients for a full year, and that a placebo effect would be unlikely to persist for this long.

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The study will assess if "sham feeding" can stop nausea after surgery which can be caused by a patient being starved before a general anaesthetic.

BBC: Robert Jones and Agnes Hunt Orthopaedic Hospital

In addition, 84 percent of those who had the surgery reported at least a 50 percent reduction in migraine pain compared with just 58 percent in the sham group.

CNN: Facial surgery may offer migraine cure