頭頸部マイクロサージャリー再建における「血管枯渇頸」への対応：長庚概念、アプローチ、および系統的レビュー

Microsurgical free tissue transfer has become the standard for complex head and neck reconstruction. One of the most feared scenarios is the so-called "vessel-depleted neck" (VDN), in which prior surgery, irradiation, or multiple reconstructions are thought to preclude suitable recipient vessels. However, definitions of VDN remain inconsistent, and many patients are not truly "depleted." A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) 2020 guidelines. PubMed and Web of Science were searched (1980-2025) using terms related to "vessel-depleted neck," "recipient vessels," and "head and neck reconstruction." Eligible studies included case series, cohorts, and case reports describing reconstructive strategies following prior neck dissection, irradiation, or multiple reconstructions. Fifty-six reports met the inclusion criteria. In addition, we contextualized these findings with the Chang Gung Memorial Hospital (CGMH) experience of >10,000 microvascular reconstructions. The review identified a spectrum of recipient vessel options and technical innovations. Common second-tier choices included the transverse cervical vessels, superficial temporal system, and contralateral cervical vessels. Less common strategies involved cephalic vein transposition, internal mammary vessels, thoracoacromial, or subclavian system. Techniques to overcome pedicle length constraints included vein grafts, Corlett loops, vascular bridge flaps (VBFs), and in situ pedicle lengthening. Local and regional flaps, such as the pectoralis major (PM) and supraclavicular flaps, provided salvage options when free flaps were not feasible. At CGMH, even after multiple reconstructions, ipsilateral vessels (transverse cervical, superior thyroid, facial artery) remained usable in most patients, with contralateral or vein graft use required in fewer than 20%. The concept of a "VDN" is often overstated and may serve as a psychological barrier to optimal reconstruction. Most patients retain viable recipient vessels, and free flaps remain achievable with careful planning and surgical expertise. We advocate reframing these cases as "vessel challenged necks," emphasizing technical demands rather than depletion, to improve decision-making and outcomes.