Abstract
BACKGROUND: Microvascular free tissue transfer is a key technique in reconstructive surgery, enabling functional and aesthetic restoration of complex defects. While initial flap survival relies on the vascular pedicle, some flaps may become independent through a process known as autonomization, where new vascular connections form between the flap and recipient site. Understanding the timeline, mechanisms, and clinical relevance of this process is essential for safe surgical planning and postoperative interventions. METHODS: A narrative review was conducted to synthesize current literature on microvascular flap autonomization. Databases including PubMed and Google Scholar were searched up to June 2025, focusing on studies examining flap selection, neovascularization, perfusion monitoring, and predictors of flap vascular independence. Articles were screened based on relevance, methodological quality, and clinical applicability. RESULTS: Flap autonomization showed heterogeneous timelines in literature. Skin and muscle flaps generally tolerated earlier pedicle compromise than jejunal or osteocutaneous flaps, while tissue composition, vascular contact area, recipient bed quality, and comorbidities strongly influenced revascularization. Favorable conditions-such as thin fasciocutaneous or muscle flaps on well-perfused beds-were associated with earlier integration, whereas irradiated tissue and systemic vascular disease delayed independence. Monitoring tools (ICG angiography, laser Doppler, NIRS) aided perfusion assessment but could not confirm full autonomization. Complications were linked to delayed or incomplete neovascularization, particularly during secondary procedures. Adjunctive strategies, including ischemic conditioning and flap "training," showed potential to promote vascular remodeling, but clinical evidence remains limited. CONCLUSION: Flap autonomization is a critical but poorly understood process that varies by flap type and patient context. Despite early neovascular activity, the lack of reliable markers necessitates conservative postoperative protocols. Emerging technologies and bioengineered strategies hold promise but require further validation. Standardized criteria to assess vascular independence could significantly improve outcomes in microvascular reconstructive surgery.