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Research Methods & Reporting

IDEAL framework for surgical innovation 3: randomised controlled trials in the assessment stage and evaluations in the long term study stage

BMJ 2013; 346 doi: (Published 18 June 2013) Cite this as: BMJ 2013;346:f2820
  1. Jonathan A Cook, methodologist1,
  2. Peter McCulloch, clinical reader in surgery2,
  3. Jane M Blazeby, professor of surgery3,
  4. David J Beard, professor of musculoskeletal sciences45,
  5. Danica Marinac-Dabic, director6,
  6. Art Sedrakyan, associate professor of public health and cardiac surgery7
  7. On behalf of the IDEAL group
  1. 1Health Services Research Unit, University of Aberdeen, Aberdeen AB25 2ZD, UK
  2. 2Nuffield Department of Surgical Science, University of Oxford, Oxford, UK
  3. 3Centre for Surgical Research, School of Social and Community Medicine, University of Bristol, UK
  4. 4Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, UK
  5. 5National Institute for Health Research Oxford Musculoskeletal Biomedical Research Unit, Oxford, UK
  6. 6Division of Epidemiology, Office of Surveillance and Biometrics, Center for Devices and Radiological Health, Food and Drug Administration, MD, USA
  7. 7Weill Cornell Medical College of Cornell University and New York Presbyterian Hospital, New York, NY, USA
  1. Correspondence to: J A Cook j.a.cook{at}
  • Accepted 15 March 2013

The complexity of surgical procedures often poses challenges for conducting a rigorous and comprehensive evaluation. This paper considers the final two IDEAL stages of surgical innovation. Surgical randomised controlled trials are often challenging to undertake and require careful consideration of the intervention definition, who should deliver it, and the impact of surgeon and patient preferences. In the long term study stage, better monitoring of surgical procedures is needed, along with improved surveillance of devices.


The IDEAL framework describes the stages through which interventional therapy innovation normally passes: idea, development, exploration, assessment, and long term follow-up (also known as stages 1, 2a, 2b, 3, and 4, respectively). This paper focuses on the stages of assessment (specifically in relation to randomised trials) and long term follow-up. By the assessment stage, a new intervention will have shown early promise and be used increasingly by the surgical community; however, the intervention’s relative benefit compared with alternative approaches will be uncertain. At the long term follow-up stage, a surgical intervention will need further assessment owing to technical refinements or to related devices or procedures being brought onto the market.

Surgical procedures are conducted with an almost infinite set of subtle variations: surgeon training, team expertise, personal practice, centre policy and infrastructure, anatomical features of the patient, and the use of a variety of medical devices. Beyond the procedure, other factors are implicitly part of the intervention: the type of anaesthesia used,1 preoperative and postoperative management (including drug treatments such as aspirin),2 physiotherapy,3 and psychological interventions (including verbal guidance).4 These linked and interdependent components produce a complex intervention.5 At the assessment and long term stages, this complexity is most apparent and challenging for conducting a rigorous and comprehensive evaluation of a surgical intervention.

Another challenge is to measure outcomes comprehensively; surgical …

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