Flap Monitoring and Postoperative ICU Care after Microsurgical Head and Neck Reconstruction

Free tissue transfer has become the gold standard for reconstructing complex head and neck defects, achieving success rates exceeding 95% in experienced centers. Despite these advances, vascular compromise remains the leading cause of flap failure, most commonly occurring within the first 24 to 72 hours postoperatively. Early detection of arterial or venous thrombosis is therefore critical to maximize flap salvage and optimize patient outcomes. Conventional clinical monitoring, including assessing flap color, temperature, capillary refill, tissue turgor, and bleeding on pinprick, remains the cornerstone of postoperative surveillance due to its simplicity, noninvasiveness, and universal applicability. However, its accuracy depends heavily on clinical experience and is limited in cases such as buried or intraoral flaps where direct observation is restricted. To improve diagnostic sensitivity and objectivity, various adjunctive technologies have been introduced, including handheld and implantable Doppler ultrasonography, laser Doppler flowmetry, thermography, and near-infrared (indocyanine green) angiography. These modalities can provide quantitative or continuous perfusion data, facilitating earlier recognition of vascular compromise. Nonetheless, each technique carries limitations related to cost, invasiveness, and susceptibility to artifacts, and no single method has proven superior to clinical evaluation alone. Effective monitoring requires structured protocols, multidisciplinary coordination, and prompt surgical re-exploration when perfusion deficits are suspected. Integration of multimodal strategies tailored to flap type and patients offer the best balance between sensitivity and practicality. This paper aims to standardize monitoring algorithms, evaluate cost-effectiveness, and explore novel technologies such as artificial intelligence-assisted systems to further enhance early detection, improve flap salvage rates, and optimize reconstructive outcomes.