Yet there is very little evidence that spine fusion surgery for back pain is effective. It is very expensive (the implants alone are often tens of thousands of dollars per case), often leads to complications, often requires further surgery, is associated with increased mortality, and often does not even result in the spine being fused. The rate of spine fusion surgery is increasing and has been increasing for many years. The rate in the US has gone way past the rate of one spine fusion per 1000 population per year. It has overtaken hip replacement surgery and continues to rise. The rates of surgery vary widely across the US, where back fusion is associated with a high degree of practice variation. Several reasonably decent randomised clinical trials have been published comparing surgery to non-operative treatment for back pain. There have been no sham surgery trials, but the evidence from these [other] trials indicate that this surgery might achieve its results through the placebo effect. Two of the studies put spine fusion surgery up against non-operative treatment alternatives: cognitive behavioural therapy in one study, and intensive physical rehabilitation in another. These studies found no significant differences in the outcomes between the operative and non-operative groups (except that the complication rate in the surgical group was higher). As usual, both groups showed improvement. The point is that roughly the same proportion of patients in each group improved, by roughly the same amount. A third study concluded that the surgical group did better. Interestingly, the surgical group didn't do any better than in the other studies; the difference was that the non-operative group didn't get better at all. This is because the non-operative treatment was not dressed up as something that might work (that is, it wasn't a good placebo).

Interestingly, in the rare cases that physical therapies have been compared to sham treatments, there is no consistent difference in the results between real and sham exercise. One could reasonably conclude that if you do something (anything) that looks like it might work for back pain, is structured and has plausibility, about two thirds of the patients will get better, as for many of the placebo treatments already discussed. With spine injections many patients improve afterwards, but when compared to placebo injections in properly blinded studies, the results are no better. Surgery for back pain has the exact effect I would expect it to have if it was a placebo. If it was a placebo, it would also explain why it doesn't matter what surgical approach you use, whether or not you put any implants in, and whether or not the spine fuses. I once attended a course by an internationally renowned spine surgeon (yes, I used to be a spine surgeon, and I used to do spine fusions) who explained that nearly all treatments for back pain result in improvements in about two thirds of the patients. I asked him why he did spine fusions for back pain, if it was no more effective than the alternatives. He said, 'Because it works in about two thirds of the patients'. The other thing about spine fusion surgery is that even the case series aren't that great. Re-operation rates of 20 per cent or more after only a few years are common, persistent pain is common, and ongoing need for treatment such as physical therapy and opioids is common. The failure of spine surgery is so common that it has been given a name: failed back syndrome (FBS).

One study showed that the most common cause of death after spine fusion surgery is opioid overdose. Spine surgery is not just a sugar pill; it is a much more elaborate placebo than that, and it is much more dangerous. The onus is on doctors to prove that spine fusion surgery for back pain is better than placebo before subjecting so many people to the risks of such major surgery. Also, with a back-of-the-envelope calculation multiplying 500,000 spine fusions a year in the US (including neck fusions) at an average cost of $100,000 each, I am certainly not convinced that it is worth $50 billion a year. Somebody is winning here and it isn't the patients. This is an edited extract from Surgery, The Ultimate Placebo: A surgeon cuts through the evidence by Ian Harris (NewSouth) published on 1 March 2016. rrp $24.99