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[Methodological problems of controlled clinical trials in surgical subspecialties].

Surgical subspecialties are handicapped in classical drug development considering professional and ethical solutions to questions in relation to introduction of new methods. The experts of invasive procedures are challenged significantly to comply with evidence based medicine and answer questions of the national health fund and/or health insurance companies, which are responsible for resource allocation. Sham operation is one of the ways to carry out controlled clinical trials. It had been pursued less frequently in the past, but we can see it as an important tool of invasive clinical trials nowadays. The contemplation about the applicability of sham operation contributes to understand other important issues in the development of invasive procedures.