An oft quoted retort to purists seeking an evidence base for everything is whether a randomised controlled trial has ever been performed regarding the benefits of using a parachute, or not, when jumping from an aircraft. That trial, of course, will never happen (despite some larking around from the BMJ). On a similar, more pertinent, note we will also never conduct an RCT to see whether removing an extradural haematoma in a comatose patient works. The operation evidently saves lives.
Confirming the efficacy of surgical simulation is more complex. No one has yet done an RCT of being operated on by new-start surgeons - who have never had any simulation training - versus those surgeons who have. It is increasingly unlikely that such a trial would receive ethical approval, given an evidence ladder that grows more and more compelling.
Each rung is a logical continuation of the next:
Rehearsal with a box simulator improves quantifiable performance metrics over time:
Johnston TJ, Tang B, Alijani A, Tait I, Steele RJ, Ker J, et al. Laparoscopic Surgical Skills are Significantly Improved by the Use of a Portable Laparoscopic Simulator: Results of a Randomized Controlled Trial. World J Surg. 2013 May;37(5):957–64.
Improved skills in a simulator result in improved skills in theatre:
Dawe SR, Pena GN, Windsor JA, Broeders JA, Cregan PC, Hewett PJ, Maddern GJ. Systematic review of skills transfer after surgical simulation-based training. Br J Surg. 2014 Aug;101(9):1063-76. doi: 10.1002/bjs.9482.
Procedures performed by surgeons with superior objectively measured minimally invasive technical skills have better patient-centred post-op outcomes:
Birkmeyer JD, Finks JF, O’Reilly A, Oerline M, Carlin AM, Nunn AR, et al. Surgical skill and complication rates after bariatric surgery. N Engl J Med. 2013 Oct 9;369(15):1434–42.
In summary, rehearsing on a box simulator improves measurable metrics. Such improvements translate to improved intra-operative skills. Those with better skills have better outcomes. It is intuitively clear, but this evidence ladder helps to spell it out.
Consultant Neurosurgeon and Honorary Senior Lecturer, Edinburgh