Abstract
Background The anterolateral thigh free flap is an option for repairing soft tissue defects
of the distal lower extremity. This flap uses the descending branch of the lateral
circumflex femoral (LCF) artery as the flap vessel. The recipient vessel in these
flaps is often the anterior tibial (AT), posterior tibial (PT), or peroneal (P) arteries.
Computational fluid dynamic (CFD) evaluation of anastomoses between these vessels
can optimize outcomes.
Methods Thirty-eight CFD models were created to model end-to-side (ETS) and end-to-end (ETE)
anastomoses for lower extremity reconstruction. Seven out of thirty-eight models represented
ETS anastomoses between the LCF and AT arteries with varying anastomotic angles. Nine
out of thirty-eight models represented 45-degree ETS anastomoses between varying diameters
of the LCF and AT, PT, and P arteries. Nine out of thirty-eight models represented
stenosis on the flap vessel and recipient vessel, pre- and post-bifurcation. Nine
out of thirty-eight models represented ETE anastomoses, rather than ETS, with varying
vessel diameters. Four out of thirty-eight models represented ETE anastomoses with
varying regions and levels of stenosis.
Results Stasis of blood flow in ETS models increased as anastomotic angle increased in a
logarithmic relationship (R
2 = 0.918). Flow was optimized overall as flap and recipient vessel diameters approached
one another. In ETS models, flap vessel and postbifurcation recipient vessel stenosis
were found to substantially increase stasis.
Conclusion Selection of flap and recipient vessels with similar diameters can optimize outcomes
in microvascular anastomoses. In the context of lower extremity reconstruction with
the ALT flap, the PT artery can be recommended as a first-line recipient vessel due
to its similar vessel caliber to the LCF and relative ease of surgical access compared
with the P artery. Avoidance of areas of stenosis is recommended to ensure laminar
flow and reduce the operative difficulty associated with performing anastomoses on
nonpliable arteries. Striving for increased acuity of anastomotic angles is recommended
to optimize the flow in ETS microvascular anastomoses.
Keywords
lower extremity reconstruction - anterolateral thigh free flap - microvascular anastomoses
- computational fluid dynamics - end-to-side - end-to-end
