Design of surgical randomized controlled trials involving multiple interventions

Area of Science:

• Surgical Research Methodology
• Clinical Trial Design

Background:

• Evaluating multiple surgical interventions requires careful selection of trial design.
• Parallel and factorial trial designs are common methods, but their optimal use is debated.

Purpose of the Study:

• To compare the strengths and weaknesses of parallel and factorial trial designs.
• To inform the choice of design for studies involving multiple surgical interventions.

Main Methods:

• Illustrative comparison using trials of interventions for day-case laparoscopic cholecystectomy.
• Analysis of design characteristics, statistical implications, and practical considerations.

Main Results:

• Parallel designs are simple but require numerous trials for multiple interventions and do not detect interactions.
• Factorial designs reduce sample size, allow interaction exploration, but risk statistical errors and are unsuitable for mutually exclusive interventions.

Conclusions:

• Both parallel and factorial designs have trade-offs for multiple surgical interventions.
• Modified factorial designs may mitigate shortcomings but need larger sample sizes.
• The optimal choice depends on balancing error costs and the risk of missing intervention interactions.