Blood Perfusion of Random Skin Flaps in Humans-In Vivo Assessment by Laser Speckle Contrast Imaging.

Background: The viability of random skin flaps (RSFs) depends on an adequate perfusion pressure to avoid necrosis. Laser speckle contrast imaging is a new method to monitor skin flap microcirculation.

Objective: The authors aimed to use laser speckle contrast imaging in evaluating the correlation between the perfusion pressure and the length-to-width ratio (LTWR) of RSFs.

Materials And Methods: Sixty patients submitted to flaps were included: 20 advancement, 20 rotation, and 20 transposition flaps. Laser speckle contrast imaging measurements of perfusion were obtained-after the flaps were planned, dissected, and sutured-from the base to the tip of the flaps, allowing the creation of plot charts and calculation of linear regression equations.

Results: Perfusion consistently and significantly decreased with the dissection of all flaps. A significant correlation between LTWR and perfusion was observed in undermined and sutured stages; a mathematical model was then delineated, explaining objectively the drop of perfusion along LTWR, with statistical significance, in all flaps.

Conclusion: Laser speckle contrast imaging allows accurate, rapid, reproducible, and noncontact measurements of skin blood perfusion over RSF, ultimately leading to an optimization of skin flap planning. This study proves that variation of perfusion pressure along the flap is dependent on the LTWR in a linear decreasing function.