Color Doppler Assessment of Pedicle Velocity in Free Flap Surgery: Trends and Clinical Implications

Free flap (FF) surgery is central to reconstructive microsurgery, relying heavily on vascular patency for flap survival. While clinical monitoring is standard, the dynamic changes in blood flow velocity following microvascular anastomosis (MVA) remain inadequately studied. This research investigates pedicle velocity trends using Doppler ultrasonography to better understand flap physiology and predict outcomes. A prospective observational study was conducted at All India Institute of Medical Sciences Rishikesh between April 2023 and September 2024, including 35 patients undergoing FF reconstruction. Pedicle blood velocities were measured using high-frequency Doppler ultrasonography at four intervals: before pedicle division (V0), 20 minutes post-anastomosis (V1), and postoperative days 7 (V2) and 28 (V3). Mean velocities were analyzed using repeated-measures ANOVA (analysis of variance) with Bonferroni correction. Both arterial and venous velocities showed a statistically significant change over time (p < 0.001). No significant velocity change was observed immediately post-anastomosis (V0 vs. V1), both arterial and venous velocities increased significantly by POD 7 and stabilized by POD 28. The flap success rate was 97%, with venous thrombosis being the primary cause of failure. The case of venous thrombosis showed abnormal early velocity elevation. Doppler ultrasonography also facilitated preoperative planning and postoperative complication management. Pedicle blood velocity increases progressively following MVA, likely reflecting vascular remodeling and improved perfusion. Early aberrations in velocity trends may serve as warning signs of thrombotic events. Doppler ultrasound emerges as a valuable, noninvasive tool for dynamic flap assessment and warrants broader application in microsurgical practice. Further large-scale studies incorporating waveform analysis may strengthen its role in predictive diagnostics.