"Longitudinal Ultrasonographic Evaluation of Hemodynamic Changes at End-to-Side Anastomoses to Major Arteries in Limb Free Flap Surgery".

[BACKGROUND] End-to-side anastomosis (ETS) to major arteries is a valuable technique for limb free flap reconstruction that preserves distal perfusion; however, its effects on distal circulation remain unclear. Few studies have evaluated longitudinal hemodynamic changes at the anastomotic site. This study aimed to identify and characterize postoperative hemodynamic abnormalities using ultrasonography in limb free flap reconstruction with ETS.

[METHODS] This prospective observational case series included patients who underwent limb reconstruction with ETS between October 2018 and May 2024. Ultrasonography was performed during the early (<3 months) and delayed (≥6 months) postoperative phases. Hemodynamic findings at the anastomotic site were descriptively assessed, and their associations with patient characteristics were explored.

[RESULTS] Fifty-nine free flaps in 51 patients were included. All flaps survived with preserved distal perfusion and no soft tissue complications. Indications were trauma in 35 flaps and infection in 24. Reconstructions involved the upper limb in 26 flaps and the lower limb in 33. Delayed-phase abnormal hemodynamic findings were identified in six flaps, all in lower limb reconstructions: three showed flow acceleration due to anastomotic stenosis, one distal flow loss, and two flow interruption at non-anastomotic sites. Advanced age and higher anesthetic risk scores were more frequent in cases with abnormal findings. Five of six cases showed abnormalities in the early postoperative phase.

[CONCLUSIONS] Subclinical hemodynamic abnormalities may occur after ETS-based limb free flap reconstruction despite favorable clinical outcomes. Early postoperative ultrasonography may help identify patients who may warrant closer vascular surveillance.