The use of indocyanine green and spectroscopy in microvascular free tissue transfer

Microvascular free tissue transfer and locoregional flap reconstruction in the head and neck are mainstays given the often-extensive defects encountered after cancer extirpation. While success rates are reported above 93 percent, the ability to assess tissue viability and perfusion is paramount to reducing postoperative complications given the environment in which this tissue is often transplanted. The proximity of the upper aerodigestive structures,the large vessels, and in some cases dural coverage and separation of the sinonasal structures from the brain present a unique reconstructive challenge, and even partial failure can lead to catastrophic consequences including salivary fistula, carotid blow-out, chronic draining wounds, inability to eat, aspiration, cerebrospinal fluid leak, intracranial infection or hemorrhage, hardware exposure, and death. Once elevated, flap tissue is wholly dependent on its pedicle until surrounding tissue can begin to vascularize – often takingweeks to months. Thus, timely assessment of adequate vascularity is vital to success. Historically, imaging technology for vascularity has been limited to standard angiography requiring ionizing radiation and cannulation of the vessels, but modern technology allows for less invasive and in some cases, non-invasive, reliable options.