Composite tissue allotransplantation: a proposed classification system based on relative complexity

Numerous achievements have been made encompassing a wide array of composite tissue allograft (CTA) subtypes. We sought to develop a simple, reproducible CTA classification system for the purpose of comparing clinical investigation. Each CTA subtype differs in relative complexity and can therefore be theoretically classified based on its unique combination of multiple factors. Eight complexity factors (CFs) are hypothesized: anatomic detail, psychological obstacles, rejection risk, required rehabilitation, relative antigenicity, functionality/cosmesis, skin ratio, and salvageability. A distribution of total complexity scores, ranging from 8 to 24, is classified into 3 ordered categories representing varying degrees of complexity. In conclusion, we have created a new classification system so that ongoing research and future data may be compared in a type-specific fashion.