Postoperative Hemodynamic Observations in a Two-Venous Microvascular Anastomotic Free Flap Technique in Head and Neck Oncoreconstruction

The success rate of free tissue transfer (FTT) is reported to exceed 95%. Hemodynamic changes in postoperative blood flow and velocity can contribute to the development of thrombosis, which can lead to flap failure. The purpose of this study was to investigate the postoperative hemodynamics in a 2-vein anastomotic FTT. A duplex ultrasound scan of the pedicle vessels was performed postoperatively on days 2 and 7 in 52 patients who underwent FTT. The primary predictor variable was a 2-vein anastomotic FTT. The primary outcome variable was the assessment of a variety of hemodynamic parameters. Relevant covariates were organized into logical categories (demographic and medical comorbidity) to consider their potential influence on hemodynamics. Descriptive (univariate) and bivariate analyses were conducted with a significance level of <0.05. Peak systolic velocity (PSV) remained stable over the study period. End diastolic (EDV) velocity increased, and resistance index (RI) decreased from day 2 to day 7. Older patients and hypertensive patients demonstrated higher early resistance index values, although these changes did not translate into adverse clinical outcomes. It is difficult for any study to achieve sufficient statistical power to demonstrate that a technique reduces flap failure, given how uncommon the event is. However, as a proxy, duplex measurement of flap flow and resistance supports our contention that a 2-vein anastomotic technique is at least as effective as a single-vein anastomotic technique. Future duplex research could compare single versus double anastomotic technique in a randomized controlled trial.