With evidence mounting that many minor operations owe their success to the placebo effect, is it time to call a halt to some routine procedures?

What’s the difference between a homeopath and a surgeon? It’s a question that sounds like a joke, and it won’t have many surgeons laughing. Homeopathy is the scientifically implausible idea that diluted substances can somehow treat disease: it has never been shown to work and any effect is, at very best, a placebo effect. It’s a world away from the glinting scalpels and cut-and-dried logic of surgery. See a problem, cut it out, sew it back up. Right?

Well, it is until you start looking for evidence of effectiveness for some operations, and then you’re left thinking that the line between the two is not as clear as you first thought.

“Nobody is suggesting that a liver transplant, cancer surgery or a cataract operation is ineffective or down to placebo,” says Andy Carr, a professor of surgery at the University of Oxford. “But for more routine surgeries, where outcomes are subjective things, such as pain or stiffness, there’s good evidence that many are little more than placebo. Given that these operations cause risk to patients and cost to hospitals, that is good evidence that we should stop doing them.”

Evidence-based medicine works a little like a fairground ride in that there’s a you-must-be-this-high-to-ride sign at its gate. To be accepted, an intervention must be shown to work better than a placebo in a randomised trial in which participants don’t know whether they are getting the active treatment or the placebo. With drugs, that placebo is a sugar pill, but with a surgical intervention it’s what’s called a sham surgery: a faked procedure that omits the step thought to be therapeutically beneficial but includes incision and anaesthetic if necessary. When put through the wringer of this type of testing, many surgical interventions come up short.

You can no longer say, as a doctor, that homeopathy is rubbish because you’re doing the same thing

Carr and his colleagues reviewed 53 trials of less invasive surgical interventions (ones that didn’t include cutting open entire cavities or lots of dissection) and found that, for half of surgeries tested, there was little sign that they were any better than placebo. Under the harsh light of the evidential operating table, it’s tough to justify their continued use.

Here are some of the surgical interventions that have been tested worldwide and have failed to convince: arthroscopy for arthritic knee; spinal cement injections for vertebral fractures; some gastric balloon procedures for obesity; meniscectomy (the surgical removal of all or part of a torn meniscus in the knee); sphincterotomy to reduce pain after gall stone removal; and laser surgery for angina.

“Once you accept that some or all of the effect of the surgery you are doing is down to placebo, but you carry on doing it anyway, you have removed the only barrier between mainstream medicine and alternative medicine,” says Ian Harris, a professor of surgery at the University of New South Wales in Sydney.

“You can no longer say, as a doctor, that homeopathy is rubbish because you’re doing the same thing.”

How, in the hyper-regulated and much scrutinised world of medicine, have we been doing surgeries that are ineffective and might put patients at unnecessary risk? Part of it is down to the culture and tradition of surgery. “Surgery evolved around the middle ages, in wars, and was all about saving lives,” says Carr. “We’d operate if there was a bullet wound or if a bomb went off, or if we needed to amputate a leg.”

Put simply, there is not much time for boffins when someone is dying on your operating table. This led to a culture in surgery, stretching from training to regulation, of learning from others and improvising as you go, says Carr. “It was fine for life-saving operations, but as you start doing surgery for softer, subjective indications such as knee pain and back pain, you introduce the possibility that an element of what you’re delivering is the placebo effect. Pain is hugely modifiable and affected by things like mood, context, expectation and belief.”

It’s tempting to think of the placebo effect as magic but it’s not. In much the same way that information from a drug can cross from your blood to your brain and cause it to effect change, information can also enter your brain through your eyes, ears, mouth and nose and cause it to effect a similar change.

“We know that placebos can make your brain release more neurotransmitters such as endorphins or cannabinoids or dopamine,” says Ted Kaptchuk, a placebo researcher and professor of medicine at Harvard Medical School. “We know that the doctor-patient relationship is an important factor in how patients feel about their treatment, and we know that patients respond to the rituals of medicine.”

The rituals of surgery are strong – the nil-by-mouth command, the surgical gown, the anaesthetic and smell of surgical spirit, the incision, the sound of the drill, the reassuring words as you flinch, the overnight stay, the (probably terrible) breakfast, the pain, the leftover scar. All these factors can cement in your mind the belief that something happened that was done to help you.

Facebook Twitter Pinterest ‘If the end result is still a happy patient: what’s the problem if the operation is a placebo?’ Photograph: Ridofranz/Getty Images/iStockphoto

Placebo aside, there’s probably a more likely reason that people feel better after these surgeries: the fact that things tend to get better on their own, or to give it its fancy medical name, regression to the mean.

“People with arthritis of the knee or recurrent sore knees will have good times and bad times,” says Harris. “If you see them at a time when their symptoms are particularly bad, then any time after that their symptoms won’t be as bad. It fluctuates, but people incorrectly associate the surgery as something that caused their pain to get better.”

It’s not just patients who fall for this association, says Harris, doctors do too. “Surgery is taught like an apprenticeship – you rotate around hospitals, watch senior surgeons and learn what they do. You don’t necessarily learn the scientific method, you don’t necessarily learn about the biases you may form about the effectiveness of a particular operation, and you end up forming the same biases that other doctors and the general public fall for by assuming causation where you see association.”

For that reason, he says, much of the change in surgery might have to be generational. “Younger practitioners coming in understand the concepts and realise that they need sufficient evidence to justify what they do. But to tell a surgeon who has been doing knee arthroscopies for 30 years, and who has seen patients getting better, that they have just been wasting their time is very difficult.”

It will be especially difficult to convince surgeons who are known and respected for their skill in specific operations – more so when those operations are the source of their often comfortable livelihood.

The path forward is clear, says Carr. “We need to do the proper, definitive trials of surgical interventions where uncertainty about effectiveness exists. I don’t think people should be subjected to operations, particularly routine ones that are done in their tens or hundreds of thousands a year, if there is insufficient evidence for knowing whether they work.

“We need a whole community, which involves patients, doctors, regulators, the industry, the politicians, the press, all to come to a realisation that the most important thing is that we do good clinical studies and do trials that provide clear, robust evidence.”

It is important that patients understand the need to do placebo-controlled studies so that they are more willing to take part in the studies needed to weed out the operations that don’t work, even if it means they received sham surgery.

Risk to patients aside, it just means that we are wasting a hell of a lot of money

With the costs and professional upheaval involved in such testing, it might be tempting to turn a blind eye: if the end result is still a happy patient, what’s the problem if the operation is a placebo? Kaptchuk, for instance, has shown that openly giving placebo pills to patients with chronic lower back pain or irritable bowel syndrome can help them manage their discomfort better. “A placebo pill is one thing,” he says, “but the risks involved in surgery are huge – I do not think people should undergo surgery to get a placebo effect.”

Carr agrees: “I’d be very concerned if surgery was being used as a sham because every now and then somebody will have a pulmonary embolism or a life-threatening infection, which would completely negate any benefit.”

It’s acceptable for a magician to conjure a string of colourful napkins from his pocket, but if he has to knock you out and drill a hole in your kneecap to do so, even David Blaine would agree that that’s probably a step too far.

Once a surgical operation has been tested and shown to be ineffective, money could instead be used on finding treatments that actually work.

“You name it, public transport, education, literally anything is a better use of public money than ineffective surgery,” says Harris, who suggests that there might also be a need to address the expectations around the surgeon-patient relationship.

“If a patient comes to you and says they’ve got trouble with their knee, then it should be reasonable to tell them that you understand that it’s making life difficult for them but that over time the pain will subside,” he says. “We should be able to reassure them that it’s nothing serious, and that without any treatment, and without any added cost to them, their pain will settle down.”

“More and more, it’s looking like a lot of surgeries have no benefit,” he continues, “and as long as we keep doing them anyway – risk to patients aside – it just means that we are wasting a hell of a lot of money, and that doesn’t even touch the surgeries that we haven’t studied yet.”

If evidence is the line that separates robust science from squishy pseudoscience, and if that evidence is missing in many cases of surgery, what is the difference between a homeopath and a surgeon? You’d hope that it is the way they react if they find out their treatments don’t work.