Utility of Indocyanine Green Angiography for Preventing Pre-expanded Extended Lower Trapezius Myocutaneous Flap Necrosis: How to Make the Correct Decision for Hypoperfused Areas

Abstract

Background: Designing a skin flap that perfectly covers the anatomical and dynamic territories is challenging. Tissues capturing territories beyond may be insufficiently perfused, and these hypoperfused areas can lead to partial flap necrosis. Indocyanine green angiography (ICGA) is an effective tool for identifying hypoperfused areas. This retrospective study proposes a standardized strategy for managing the hypoperfused area identified by ICGA in pre-expanded extended lower trapezius myocutaneous (e-LTMC) flaps. Methods: Patients who underwent pre-expanded e-LTMC flap surgery with perfusion assessment using ICGA between June 2016 and January 2022 were identified. A standardized protocol was applied, and patients were divided into four groups according to different management options for hypoperfused areas detected by ICGA. Preoperative and operative variables of interest and postoperative outcomes, including flap necrosis and flap survival length, were collected and analyzed. Results: Sixty-nine flaps were included in the study. No total flap necrosis was observed. Partial necrosis occurred in 10 flaps. Significant differences were observed in the incidence of full-thickness necrosis between the management groups. The incidence of flap necrosis in cases where management relied on ICGA findings was significantly lower than that of cases where management did not rely on ICGA findings. There were no differences in the relative survival length of the flap between cases with and without intervention for the hypoperfused areas. Conclusion: The proposed standard strategy effectively reduced the necrosis rate of the pre-expanded e-LTMC flap, thus it is sensible to act on the ICGA findings. Prophylactic resection of the hypoperfused area should be recommended. Where resection may lead to poor reconstructive outcomes, flap trimming or a second flap should be the preferred option.

The Forgotten Flap: The Pedicled Trapezius Flap's Utility in Pediatric Head and Neck Reconstruction—A Systematic Review

“…One way to mitigate the risk of postoperative partial flap necrosis in these cases is to perform intraoperative indocyanine green angiography to accurately locate hypo-perfused areas of the flap. 53 Although the rate of partial flap necrosis was 4.5% in our review of pediatric cases, assessing the depth or thickness of necrosis is necessary when flap necrosis does occur. To evaluate the extent of flap necrosis, the flap should be debrided until healthy viable tissue is encountered, as signified by pinpoint bleeding.…”

Utility of Indocyanine Green Fluorescence Imaging in Wound Assessment

“…Even partial flap necrosis can lead to a chronic fistula, especially in coverage of orofacial defects; therefore assessing the reliably perfused area of flaps is crucial to prevent this complication. ICG angiography is utilized not only in free flap reconstruction but also in locoregional flap reconstruction during flap design and inset to improve flap survival [32][33][34]. In addition, it is further used to assess flap vascularity prior to flap division in distant flaps such as the cross-leg flap and paramedian forehead flap [35,36].…”