This cool study in the JNNP reminds us that pain is determined by the brain’s answer to the question ‘how dangerous is this?’ Pain relief is determined by the brain’s answer to the question ‘How dangerous is this NOW?’ These researchers randomly allocated back surgery patients to either be shown the parts of their disc that had been removed or to not be shown them. The surgeon was blinded, the assessors were blinded. The results clearly show that if you are shown the bits they have taken out you have less pain, disability and weakness than if you were not shown the bits. OK OK, they had 25% drop out which raises the possibility that the effect would not hold up in the full sample. But let’s say it does – why might it work? This is what the authors said:
How does giving patients their excised disc material in a pot improve outcome after LMD? There are several possibilities: firstly, the pot may provide a powerful visual confirmation to the patient that the operation was technically successful.
Secondly, we found that patients often keep the pot for several months, which may augment the disc fragments’ beneficial effect. One patient reported that referring to the excised disc prevented recurrence of symptoms.
Thirdly, since many patients show the pot to friends and family, we speculate that the positive comments made by these people amplify the benefit produced by merely seeing the disc material.
It is all, as far as i can see, providing the patient’s brain with important evidence with which to answer the question ‘how dangerous is this, now that the dangerous bits are here in a glass pot, not inside my back putting me at risk of spinal cord injury’. It seems pretty powerful. Of course it is.
If you are really interested in this sort of thing, check out Dan Moerman’s book: Meaning, Medicine and the Placebo Effect
if you are either clever or poor or both, you could get out of buying the book and read this paper instead:
Daniel E. Moerman and Wayne B. Jonas, (2002) Deconstructing the Placebo Effect and Finding the Meaning Response. Annals of internal medicine 136, 6, 471-6
 Tait MJ, J Levy, M Nowell, C Pocock, V Petrik, B A Bell, M C Papadopoulos (2009) Improved outcome after lumbar microdiscectomy in patients shown their excised disc fragments: a prospective, double blind, randomised, controlled trial. Journal of Neurology, Neurosurgery, and Psychiatry 80, 1044-6