“Precision planning for tissue expansion: A three-dimensional scanning-based predictive model to guide surgical timing”

Tissue expansion remains an essential reconstructive technique, yet the timing of expander removal is still largely determined by subjective clinical judgment. We developed a three-dimensional (3D) scanning-based quantitative workflow to objectively monitor expansion progress and provide a practical reference for surgical timing. In this study, serial 3D scans obtained throughout the expansion course were used to evaluate the relationship between the cumulative injected volume and incremental expansion area relative to baseline in a development cohort of 30 patients with congenital melanocytic nevi. Preliminary validation was performed in a temporally separate, independent cohort of 12 additional patients enrolled after model finalization; this cohort was not involved in model development and was not a held-out subset of the original dataset. The volume-area relationship followed a hyperbolic saturation-type pattern, with more rapid surface-area gain during the early phase of expansion and gradual approach to a plateau later in the course. Actual and predicted values showed good agreement in the validation cohort. Thus, this approach may help surgeons more objectively assess expansion progress, determine whether additional inflation is likely to yield clinically meaningful surface-area gain, and guide expander removal and second-stage reconstruction. It is intended to complement, rather than replace, surgical judgment.