Why some Patients Benefit from Participating in a Sham Surgery Trial

We analyze the ethics of sham surgical trials from a utilitarian perspective and explore whether patients can benefit from participating in these trials.

Sham-controlled randomized trials are an essential tool to evaluate the risks and benefits of some surgical procedures. However, sham trials are controversial because they expose patients to the harms of a sham procedure without the possibility of benefit. We argue that ethical analyses of sham trials have focused only on the harms of sham surgery and neglected to account for the harms of the procedure being studied.

We develop a theoretical model to estimate the harms and benefits experienced by patients who enter a sham surgery trial, taking into account the harms and benefits of the sham and intervention.

When the procedure in question is found to be ineffective, sham trials typically result in a net benefit to participants because some participants are only exposed to the harms of the sham procedure, which are much lower than the harms of the full procedure. When the procedure is found to be beneficial, the primary harm to patients who underwent the sham is not due to the sham itself but because they suffer a delay in receiving an effective intervention.

Patients often benefit from participating in sham surgery trials because the harms of the sham procedure are lower than the harms of the full procedure, which may turn out to be ineffective. Our results call for re-thinking the ethics of sham surgery trials.