Analysis of Major and Minor Pedicles in Flap Perfusion by Computational Fluid Dynamics.

Background: Type 2 muscle flaps are characterized by major and minor pedicles, such that the minor pedicle is unreliable, and the major pedicle is a requirement for the success of the flap. The role of the minor pedicle, beyond the decreased caliber and decreased vascular territory in comparison to the major pedicle, is poorly understood. We sought to model the fluid dynamics of a model flap containing a major and minor pedicle to understand differences between the pedicles and the implications on perfusion.

Methods: We first generated a computer-assisted design model of a type 2 flap with a major and minor pedicle. We then performed computational fluid dynamics to analyze velocities and flow within the pedicles and flap.

Results: In our investigation, we found that the flow velocity within the major pedicle was higher than the minor pedicle, indicative of decreased resistance to flow. Concomitantly, we found decreased pressures within the major pedicle, reflecting decreasing resistance to flow. Interestingly, we found increased kinematic viscosity in flap areas supplied by the minor pedicle, suggesting decreased flow rates and increased resistance.

Conclusions: We identified that the major pedicle has increased flow velocity, decreased resistance, and decreased kinematic viscosity, suggesting its dominance in maintaining flap perfusion. Our study also identifies computational fluid dynamics as a powerful tool in studying flap perfusion dynamics.