reoperative surgical marking remains a challenging domain in surgical education. 1 Opportunities to perform deliberate practice with the aim of mastering the design of a specific local flap in plastic surgery, 2-4 while simultaneously receiving objective, specific, and practical feedback, remain extremely limited in clinical settings. 5 The transition toward competency-based education has culminated in a surge in popularity of simulation-based training platforms, [6][7][8] with local flap design remaining notably amenable to simulation-based training. 9 Given that no objective assessment tools exist to evaluate local flap designs, we sought to develop such a tool based on statistical shape analysis. 10 We used a bilobed nasal flap design as a proof of concept, [11][12][13] with a focus on the capacity of the proposed model to provide real-time feedback to learners that remains objective, specific, and practical for design improvement.
METHODS
Model DevelopmentObjective assessment of surgical designs is fundamentally a shape analysis exercise, comparing one shape's similarity to a reference standard. This allows for the use of a well-established mathematical principle from the field of statistical shape analysis termed Procrustes analysis, 14 previously implemented for objective assessment of facial symmetry in plastic surgery. 15 The essential components of such an analysis comprise, initially, mathematical Euclidean similarity transformations of a given design, including translation, rotation, and scale, in order to maximize the fit of one shape to a reference standard and attain the minimally achievable dissimilarity possible. Subsequently, the degree of this minimally