Improving intraoperative perfusion reliability in anterolateral thigh free flap reconstruction for diabetic foot ulcers

Abstract

Anterolateral thigh free-flap reconstruction remains an important limb-salvage option for patients with diabetic foot ulcers, particularly when complex soft-tissue defects, infection, or exposed deep structures preclude simpler reconstructive approaches. However, intraoperative perfusion insufficiency continues to limit flap reliability and may compromise wound healing, flap survival, and long-term limb salvage. In this setting, flap perfusion should not be regarded as a purely technical consequence of microsurgical anastomosis but rather as the product of a systemic-regional-microcirculatory continuum shaped by distal vascular capacity, diabetes-related microvascular dysfunction, and modifiable host factors. This review summarizes current advances in intraoperative perfusion assessment for anterolateral thigh flap reconstruction in diabetic foot ulcer, with particular emphasis on indocyanine green fluorescence angiography (ICG-FA). We highlight the limitations of relying on static fluorescence intensity alone and argue that quantitative fluorescence-time curve metrics, including wash-in slope, time to maximum intensity, and area under the curve, may provide more robust and reproducible information for intraoperative decision-making. Because diabetes-associated medial arterial calcification and microvascular impairment can confound perfusion interpretation, ICG-FA should be integrated with complementary measures such as toe pressure/toe-brachial index, skin perfusion pressure, and transcutaneous oxygen tension rather than used as a stand-alone tool. We further discuss the importance of preoperative and perioperative optimization of modifiable systemic factors, including glycemic control, anemia, oxygenation and ventilation, and nutritional reserve, all of which influence tissue oxygen delivery and flap viability. Finally, we propose a quantitative, multimodal clinical framework that links preoperative vascular assessment, standardized intraoperative perfusion imaging, and structured postoperative monitoring to clinically meaningful outcomes. Future priorities include harmonization of ICG-FA acquisition and reporting protocols, prospective multicenter validation, and development of registry-based prediction models to improve reproducibility, risk stratification, and implementation of evidence-based limb-salvage strategies in diabetic foot reconstruction.

Keywords: Anterolateral thigh flap; Diabetic foot ulcer; Indocyanine green angiography; Limb salvage; Nutritional status; Perfusion assessment; Systemic optimization; Tissue oxygenation

Core Tip: Intraoperative perfusion remains a key failure point in anterolateral thigh free-flap reconstruction for diabetic foot ulcers. Perfusion is not determined by microsurgical technique alone but reflects a systemic-regional-microcirculatory continuum, often confounded by diabetes-related macrovascular calcification and microvascular dysfunction. We emphasize standardizing indocyanine green fluorescence angiography and shifting from single intensity snapshots to time-intensity kinetics, interpreted alongside toe pressure/toe-brachial index, skin perfusion pressure, and transcutaneous oxygen tension. An actionable perioperative optimization bundle (glycemia, anemia, oxygen delivery, nutrition, monitoring) may improve flap reliability and limb salvage.