Interventions in randomised controlled trials in surgery: issues to consider during trial design.

Until recently, insufficient attention has been paid to the fact that surgical interventions are complex. This complexity has several implications, including the way in which surgical interventions are described and delivered in trials. In order for surgeons to adopt trial findings, interventions need to be described in sufficient detail to enable accurate replication; however, it may be permissible to allow some aspects to be delivered according to local practice. Accumulating work in this area has identified the need for general guidance on the design of surgical interventions in trial protocols and reports. Key issues to consider when designing surgical interventions include the identification of each surgical intervention and their components, who will deliver the interventions, and where and how the interventions will be standardised and monitored during the trial. The trial design (pragmatic and explanatory), comparator and stage of innovation may also influence the extent of detail required. Thoughtful consideration of surgical interventions in this way may help with the interpretation of trial results and the adoption of successful interventions into clinical practice.