The Characteristics and Ethics of Sham Surgeries: A Systematic Review of Randomized Controlled Trials

We sought to perform a large-scale systematic review across all sham-controlled studies currently present in the literature to better characterize the ethical considerations of these studies.

Innovative surgical procedures are often introduced into the clinical setting without the robust clinical trials required for medicinal treatments. Sham surgeries serve as placebos by performing all steps of a surgical intervention aside from those deemed therapeutically necessary. Yet, sham trials are underutilized because of ethical controversy.

Ovid MEDLINE was queried through April 2022 with combinations of the Medical Subject (MeSH) headings and keywords including, but not limited to, "surgery," "endoscopy," "randomized controlled trial," and "sham procedure." Primary outcomes were surgical indications and characteristics, outcome measurements, and whether the investigational treatment was offered to the sham cohort.

One hundred seventy-two articles fit our inclusion criteria, with gastrointestinal pathologies being the most common surgical indication. Participants, personnel, and outcome assessment were all blinded in 8.7% of trials (n=15). Study populations included adult subjects (age ≥18) in 170 studies (98.8%), and two involved children. The most common level of dissection and type of anesthesia were deep (n=66, 38.4%) and general (n=49, 28.5%), respectively. An open surgical approach was utilized in 20.9% of studies (n=36). Primary outcomes were objective in 75 studies (43.6%) and subjective in 97 (56.4%), 62 of which used validated outcome measures (36.0%). Four trials explicitly did not offer the surgery to the sham arm (2.3%), whereas 106 had no mention of whether the intervention was offered (61.6%).

Our systematic review of 172 randomized, sham-controlled trials highlights the ethical considerations that must be considered in these studies, namely the importance of transparent study design and objective outcome reporting, the difficulty of informed consent, and the inherent risks associated with surgical interventions.