Monday, 19 March 2018

Experience versus evidence, regarding Ian Harris








Professor Ian Harris, author of the book, "Surgery, the ultimate placebo", is a traumatologist who directs a research unit focused on the results of surgical practice in Sydney. Harris says in the book's introduction: "Lack of evidence allows surgeons to practice techniques for the simple reason that they have always been done, because they learned them from their mentors, because they are convinced that it works or simply because it does everybody. It's easier to have no problems if you behave like most colleagues, my argument, says the author, is that trusting tradition and perceptions often leads, in terms of clinical effectiveness, to unconvincing results."

The placebo effect

It’s only scarcely a century ago when surgeons practiced bloodletting to treat people who had diseases or manifestations as diverse as pneumonia, cancer, diabetes or jaundice. Bloodletting met all the requirements of a good placebo: it was an invasive, painful and a drastic technique based on pseudoscientific reasoning. Harris says that many of those who laugh at the lack of consistency and the real risk that the practice of bloodletting brought to humanity from the Mesopotamian civilizations until well into the 20th century, when you show them that there is evidence that what they do, doesn’t respond well to methodologically sound evaluations, they defend themselves with the arguments that it  has always been done in that way, assuming, from personal observations, cause-effect relationships that are not proven.

The placebo effect is the extra benefit generated by the perception of improvement, with a tendency to relate this sensation to the treatment received, especially if it has been invasive, painful, drastic and based on pseudoscientific arguments, disregarding the eventuality that perhaps that process would also have gone well without any intervention. Human nature makes us see what we want to see. When we believe in a treatment, we tend to attribute all the positive effects to it, whereas if they appear as negative, we associate them with other causes.

Ethics of surgical clinical trials (sham surgery)

When a surgical clinical trial is proposed, there is a certain ethical prevention arising from the concern for the people who are in the control group, since they will receive a sham surgery, that is, the skin will be opened and they will be sewn without having had any surgical procedure. Harris, however, defends studies with false surgery, since, he says, it’s less ethical to submit lots of people to treatments that have not been sufficiently evaluated, than not to get a few consents for a clinical trial, where the individual risk of the volunteers can bring many benefits to the community. Another aspect in favour of the rigorous evaluation is that in a systematic review of 53 clinical trials with placebo it was discovered that in half of the analyzed interventions, the operation was not better than the false surgery and that in those cases when it was, the difference was not significant.

It’s a fact that many patients improve after a real operation, but there’s also the fact that many patients also improve after a false intervention. Arthroscopies and vertebroplasties would be two of the examples cited by the author as techniques in which the false operated patients improved in the same way as those who actually had the real thing done. For this reason it’s worrisome that, according to a study by Ian Harris's research unit, of the 9,000 surgical procedures performed in orthopaedic and traumatology services of three public university hospitals in the Sydney area, only half are backed by consistent scientific evidence.

Experience versus evidence

The search for success via invasive precision techniques is one of the main motivations of many doctors when they choose a surgical specialty. This is clear, says the author, when we observe that surgeons tend to measure the results in objective terms: straightening of a bone after a fracture, the amount of tumour removed, etcetera; while patients tend to assess more subjective issues such as pain or functionality, and too often the two approaches are dissociated. The question, however, is that there is no greater satisfaction for a surgeon than to see how things improve after having worked hard within a body. In these circumstances, the association of cause and effect is much stronger than the coldness of some evidence based on work done by others with who knows what intentions.

Evidence documents of common procedures

Apart from the author's reflections on the scientific shortcomings of today’s surgery, the reader, if interested, will find small files on the degrees of evidence of many common interventions such as: vertebral fusions, shoulder surgery, hysterectomies, caesarean sections, appendicitis, laparoscopies peritoneal adhesions, angioplasties, venous filters for emboli, renal ptosis, tendon ruptures, fracture surgery, cancer surgery, etc. 

By way of closing, I’ll feature a famous phrase within the surgical environment as highlighted by Ian Harris in the book. "Any surgeon can operate, a good surgeon knows when he or she has to operate, but only the best know when they should not operate."


Jordi Varela
Editor

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