Use of placebo controls in the evaluation of surgery: systematic review
Two pages on PainSci cite Wartolowska 2014: 1. Knee Replacement Surgery Doubts 2. Make exercise as sexy as the scalpel
PainSci commentary on Wartolowska 2014: ?This page is one of thousands in the PainScience.com bibliography. It is not a general article: it is focused on a single scientific paper, and it may provide only just enough context for the summary to make sense. Links to other papers and more general information are provided wherever possible.
In 53 placebo-controlled trials of surgeries, a shame produced results just as good as the surgery in 27 (51%). “Placebo controlled trial is a powerful, feasible way of showing the efficacy of surgical procedures.” More properly controlled studies of surgery are badly needed.
original abstract †Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.
OBJECTIVE: To investigate whether placebo controls should be used in the evaluation of surgical interventions.
DESIGN: Systematic review.
DATA SOURCES: We searched Medline, Embase, and the Cochrane Controlled Trials Register from their inception to November 2013.
STUDY SELECTION: Randomised clinical trials comparing any surgical intervention with placebo. Surgery was defined as any procedure that both changes the anatomy and requires a skin incision or use of endoscopic techniques.
DATA EXTRACTION: Three reviewers (KW, BJFD, IR) independently identified the relevant trials and extracted data on study details, outcomes, and harms from included studies.
RESULTS: 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. Serious adverse events were reported in the placebo arm in 18 trials (34%) and in the surgical arm in 22 trials (41.5%); in four trials authors did not specify in which arm the events occurred. However, in many studies adverse events were unrelated to the intervention or associated with the severity of the condition. The existing placebo controlled trials investigated only less invasive procedures that did not involve laparotomy, thoracotomy, craniotomy, or extensive tissue dissection.
CONCLUSIONS: Placebo controlled trial is a powerful, feasible way of showing the efficacy of surgical procedures. The risks of adverse effects associated with the placebo are small. In half of the studies, the results provide evidence against continued use of the investigated surgical procedures. Without well designed placebo controlled trials of surgery, ineffective treatment may continue unchallenged.
related content
- “Sham Surgery in Orthopedics: A Systematic Review of the Literature,” Louw et al, Pain Med, 2016.
- “To what extent are surgery and invasive procedures effective beyond a placebo response? A systematic review with meta-analysis of randomised, sham controlled trials,” Jonas et al, BMJ Open, 2015.
- Surgery: The ultimate placebo (book), by Ian Harris (book review).
This page is part of the PainScience BIBLIOGRAPHY, which contains plain language summaries of thousands of scientific papers & others sources. It’s like a highly specialized blog. A few highlights:
- Common interventional procedures for chronic non-cancer spine pain: a systematic review and network meta-analysis of randomised trials. Wang 2025 BMJ.
- Gabapentinoids and Risk of Hip Fracture. Leung 2024 JAMA Netw Open.
- Classical Conditioning Fails to Elicit Allodynia in an Experimental Study with Healthy Humans. Madden 2017 Pain Med.
- Topical glyceryl trinitrate (GTN) and eccentric exercises in the treatment of mid-portion achilles tendinopathy (the NEAT trial): a randomised double-blind placebo-controlled trial. Kirwan 2024 Br J Sports Med.
- Placebo analgesia in physical and psychological interventions: Systematic review and meta-analysis of three-armed trials. Hohenschurz-Schmidt 2024 Eur J Pain.