The Circulasome: A Unifying Theory of Flap Vascularity.

Despite the critical roles of nondominant perforators, choke vessels, and direct and indirect linking vessels in flap vascularity, current models of flap perfusion focus on a primary large caliber perforators. The delay phenomenon, microvascularization, neovascularization, and vascular evolution, which depend on smaller caliber vessels, remain unaccounted for. We propose that the "circulasome" consists of the sum of the entire vascular components of a given region, such that the region is supplied by a primary supplying vessel. The circulasome represents one of the indices of flap supply and is proportional to the angiogenic potential of the region and the vascular substrate capable of promoting growth of vascular networks. By accounting for both the primary flap supplying vessel and secondary vascular structures, the circulasome provides a unifying explanation for neovascularization, delay phenomenon, angiosome and perforasome theories, and vascular evolution in flaps.