The most recent casualty of the sham surgery trial, adding to the list of operations that looked good and had good results until put to the leased biased test, is a procedure called renal denervation (cutting the nerves to the kidney). Years of good results showing that this procedure lowered blood pressure are now met with a blinded sham-controlled trial that showed no significant benefit over placebo.
The article is reported here in the New England Journal of Medicine and a nice editorial can be found here (paywall, sorry). You can read overviews and interviews in Medscape,
Renal denervation is a procedure that involves damaging nerves to the kidney. It is usually done in patients with high blood pressure who do not respond to medications. It is approved for use in many countries and thousands have been (and probably still are) performed worldwide.
Previous reports (without blinded control groups) showed that the blood pressure falls after using this device, dramatically. It should be noted that the blood pressure (on average) also fell quite a bit (14 mm Hg) in those receiving renal denervation in this sham study. My point, however, is that the blood pressure also fell in the sham group (12 mm Hg), either from natural history, other treatments or behaviours, regression to the mean or what is loosely referred to as the placebo effect. The fact that both groups improved by a similar degree (there was no significant difference) means that the surgery had no specific effect (of its own) and this, above all else, is why you need properly controlled, blinded, placebo studies. This is how we find out what really works, not what we think works. This is how we assign causation, instead of assuming it from association.
The bottom line
Once again we have a highly touted treatment, in this case one that was initially thought to be a “cure” for high blood pressure, having a true level of effectiveness much lower than we believed, and not coincidentally, a lot lower than we wanted to believe.