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Original research
Validation studies of virtual reality simulation performance metrics for mechanical thrombectomy in ischemic stroke
  1. Robert Crossley1,
  2. Thomas Liebig2,
  3. Markus Holtmannspoetter3,
  4. Johan Lindkvist4,
  5. Pat Henn5,
  6. Lars Lonn6,
  7. Anthony Gerald Gallagher7
  1. 1 Neuroradiology, North Bristol NHS Trust, Southmead Hospital, Bristol, UK
  2. 2 Institute of Neuroradiology, Ludwig Maximilians University of Munich, Munich, Germany
  3. 3 Department of Neuroradiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
  4. 4 Mentice AB, Gothenburg, Sweden
  5. 5 School of Medicine, University College Cork, Cork, Ireland
  6. 6 Department of Cardiovascular Radiology, National Hospital, Copenhagen University, Copenhagen, Denmark
  7. 7 Faculty of Life and Health Sciences, Ulster University, Londonderry, UK
  1. Correspondence to Professor Anthony Gerald Gallagher, Faculty of Life and Health Sciences, Ulster University, Londonderry BT48 7JL, UK; anthonyg.gallagher{at}


Introduction Mechanical thrombectomy (MT) has transformed the treatment of ischemic stroke. However, patient access to MT may be limited due to a shortage of doctors specifically trained to perform MT. The studies reported here were done to (1) develop, operationally define, and seek consensus from procedure experts on the metrics which best characterize a reference procedure for the performance of an MT for ischemic stroke and (2) evaluate their construct validity when implemented in a virtual reality (VR) simulation.

Methods In study 1, the metrics for a reference approach to an MT procedure for ischemic stroke of 10 phases, 46 steps, and 56 errors and critical errors, were presented to an international Delphi panel of 21 consultant level interventional neuroradiologists (INRs). In study 2, the metrics were used to assess 8 expert and 10 novice INRs performing a VR simulated routine MT procedure.

Results In study 1, the Delphi panel reached consensus on the appropriateness of the procedure metrics for a reference approach to MT in ischemic stroke. Group differences in median scores in study 2 demonstrated that experienced INRs performed the case 19% faster (P=0.029), completed 40% more procedure phases (P=0.009), 20% more steps (P=0.012), and made 42% fewer errors (P=0.016) than the novice group.

Conclusions The international Delphi panel agreed metrics implemented in a VR simulation of MT distinguished between the computer scored procedure performance of INR experts and novices. The studies reported here support the demonstration of face, content, and construct validity of the MT metrics.

  • stroke
  • thrombectomy

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  • Contributors All of the authors contributed to the writing of the article. RC, TL, and MH are very experienced mechanical thrombectomy interventional neuroradiologists. LL and PH are very experienced clinicians and medical education specialists. JL is a senior computer engineer. AGG developed and helped validate proficiency based progression simulation training. TL, MH, RC, LL, JL, and AGG have characterised a reference approach to mechanical thrombectomy. JL developed and formatted the VR simulation from the CT angiography of the stroke patient reported in this paper. AGG and PH produced the first draft of this paper. All authors contributed to editing the paper post editorial review. Study 1, study design and data collection: RC, TL, MH, JL, LL, and AGG. Study 2, study design and data collection: RC, TL, MH, JL, PH, and AGG. Data analysis: RC, TL, MH, JL, and AGG. Paper writing: RC, TL, MH, JL, PH, and AGG. Results interpretation, paper critical revisions, and agreed on final draft: RC, TL, MH, JL, PH, LL, and AGG.

  • Funding The research and researchers on this paper were supported by a grant from the Swedish government agency for innovation (Vinnova) to Mentice AB (Gothenburg, Sweden) to characterize, develop, and then validate the metrics for a reference approach to performance of mechanical thrombectomy.

  • Competing interests MH has received honoraria from Microvention, Medtronic Neurovascular, Mentice AB, and Stryker Neurovascular for consulting and proctoring. RC has received honorarium for speaking (Stryker Neurovascular, UK) and educational sponsorship to attend meetings/conferences from Microvention, Stryker, Medtronic, Penumbra, and Johnson & Johnson. JL works as an engineer at Mentice and developed the VR model of the real patient data. LL has served as a clinical advisor and then Medical Director of Mentice.

  • Patient consent Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.