Usually, when we think of a placebo it's a harmless sugar pill, taken in place of an experimental drug. This is common practice, so that medical researchers can compare the results between two groups of volunteers and thus determine if the new treatment is effective. Less common are placebo or sham surgeries. These involve sedation, scalpels and stitches, but just not the actual intervention. Even though they are relatively rare, they are sometimes used to determine in studies how effective a "real" surgery is.
For example, a 2013 study out of Finland looked at the results of 146 patients, some of whom had arthroscopic partial meniscectomy (a common knee surgery), and some of whom just had an incision with no actual repair. Researchers concluded that outcomes were no better for the people who received the full procedure, compared with those who underwent the placebo.
A 2014 study from the University of Oxford in England found that there was essentially no difference between patients who underwent real surgery for shoulder impingement, compared with those who "only" had a hole drilled in. For what it's worth, everyone who signed up for the study knew that they might get a sham surgery, a real surgery or no surgery at all.
The study on shoulder impingement surgery was repeated in 2018 in Finland with similar results — both groups had equally little shoulder pain two years after the procedure, whether they had received the real or the sham surgery. "With nearly 21,000 decompression surgeries done in the U.K. every year, and ten times that many in the United States, the impact of this study is huge," said adjunct professor Simo Taimela, the research director of the Finnish Centre for Evidence-Based Orthopedics (FICEBO) at the University of Helsinki in a press release.
Teppo Järvinen, M.D., Ph.D., chief surgeon at Helsinki University Hospital and a professor and academic head at the University of Helsinki was one of the researchers in the 2018 study. He says the patients in the placebo group underwent the same procedure as those in the other group except for the critical part, "which is the removal of bone from the acromion (a hook-shaped extension of the scapular bone) to allegedly decompress the passage of the rotator cuff tendons)," he says by email. This was a randomized trial and patients were informed in advance that they could be in either group and if their symptoms didn't improve in six months, they could "cross over" and get the actual surgery if they had been in the placebo surgery group, according to the study.
Järvinen considers performing placebo surgery vital to the success of the study. "Given the large contextual ('placebo') effect of surgery on patients (and also caregivers), both the patients (evaluating the outcome of surgery) and the caregivers and researchers (evaluating the success of surgery from their own perspective and possible influencing patients with their own views) have to be blind to the treatment given to be able to objectively assess the outcome/success of the treatment given."
As surgery can be painful, expensive and difficult to recover from, it's easy to see why many people consider placebo surgery to be unethical.
"Those kinds of operations are ethically unacceptable," says Dr. Lewis Flint, editor-in-chief of the American College of Surgeons journal, Selected Readings in General Surgery. He notes that this is his personal opinion and not necessarily reflective of any policies with the American College of Surgeons. "When we do medical research we operate under the first 'do no harm' rule and that is what the ethical basis of avoiding placebo surgery is," he adds.
The problem that Flint and many other medical researchers have with placebo surgeries is that operations expose patients to risk of complications, however small. In their opinion, this risk is not worth it for comparison's sake.
Risk Level in Placebo Surgery
In a 2014 review published in the BMJ, the researchers did an analysis of 53 trials involving placebo surgeries. "In 39 out of 53 (74%) trials there was improvement in the placebo arm and in 27 (51%) trials the effect of placebo did not differ from that of surgery. In 26 (49%) trials, surgery was superior to placebo but the magnitude of the effect of the surgical intervention over that of the placebo was generally small," the study authors wrote. In other words, in about half the trials, people who got the placebo surgeries did as well as those who got real thing and in the other half, those who had the real surgery did only slightly better.
The authors did note that overall the patients in the placebo groups had less serious complications than those who got the actual surgeries because the main surgical elements in the procedures were omitted. They found "harms" definitively related to the surgical placebo in just two trials and both were stopped early because of safety concerns.
Flint points out that the procedures described in the 2014 study were mostly the type done with mild sedation rather than general anesthesia. "These procedures are associated with very low complication rates so it is not surprising that the risk for patients undergoing the 'placebo' procedure is low. There were, however, a small number of serious complications and the question remains, should a patient be exposed to risk, however low, from a procedure that was not needed?"
Finland's Järvinen strongly disagrees with people who find placebo surgery unethical: "Which do you find more unethical: To continue an enormously popular/common surgical practice (keep subjecting people to a surgical procedure over and over again) that is based on poor/non-existing evidence or to study the efficacy and safety of the procedure once and for all, by subjecting a very restricted number of participants to placebo surgery, which has (a) never been shown to be more harmful than the surgical procedure under investigation, and (b) has been shown to be non-inferior (at least as good) as the surgical procedure under investigation in more than 50 percent of the studies that have used placebo surgery?"
Other Types of "Shams"
Less controversial than sham surgeries are sham procedures, which don't involve any cutting or actual risk to the patient.
"There are certain placebo procedures done as part of medical research that you can create a situation where a patient believes that they're receiving a procedure when they're actually not that may be ethically acceptable," Flint explains. For example, he references a research study that compared the effects of acupuncture on lower back pain. One group received the acupuncture, and the placebo group merely had toothpicks put down on the patient's skin. "So they got a sensation, but actually were not having a needle in their skin," he says. (Blunt-tipped retractable needles have also been used, and results have shown that results are just as good for the patients who were in the placebo group).
Placebo surgeries may produce positive results for the same reasons that placebo drugs do: The belief that you're taking something that will make you well is powerful to the mind. The elaborate rituals around surgery may even increase the placebo effect over a non-invasive procedure, like a sugar pill. And it appears that placebo drugs may activate the same biochemical pathways that are affected by actual interventions.