Methods for evaluating innovative surgery: a nested ideal phase 2 study within an external randomised pilot (the ROMIO trial).

Pragmatic surgical RCTs are needed but it is unclear how to design studies with evolving innovative interventions. The aim of this paper was to describe how a pilot RCT comparing two standard techniques incorporated an additional randomised group with a nested IDEAL (Idea, Development, Evaluation, Assessment and Long-term evaluation of innovative surgery) Phase 2b evaluation of an evolving technique to inform main trial design.