ICGA-Guided Decision-Making Is Associated with Lower Flap Necrosis Rates in Pre-Expanded Extended Lower Trapezius Myocutaneous Flaps.

Background: Evidence regarding the association between indocyanine green angiography (ICGA) use and flap necrosis remains inconsistent. This inconsistency may partly reflect differences in how studies define comparison groups, particularly whether classification is based on ICGA use or on whether ICGA findings informed the final intraoperative decision. We therefore compared flap necrosis primarily according to the basis for the final decision and secondarily according to ICGA use. Methods: This single-center retrospective comparative cohort study included 108 pre-expanded extended lower trapezius myocutaneous (e-LTMC) flaps in 101 patients between 2012 and 2022. Flaps were classified into the clinical-assessment group (Group A, n = 49) and the ICGA-guided group (Group B, n = 59) according to the basis for the final decision. Outcomes were overall and severe flap necrosis. Firth penalized logistic regression was the primary inferential method. Results: Overall necrosis occurred in 4/59 flaps (6.8%) in Group B and 14/49 (28.6%) in Group A (adjusted odds ratio [OR] 0.223, 95% confidence interval [CI] 0.063-0.661, p = 0.006). Severe flap necrosis occurred in 1/59 flaps (1.7%) and 11/49 (22.4%), respectively (adjusted OR 0.097, 95% CI 0.010-0.436, p = 0.001). Comparisons based on ICGA use alone showed no clear difference in either outcome (p = 0.422 and p = 0.750). Excluding the 11 retained hypoperfused flaps attenuated the difference in overall necrosis (p = 0.056), whereas the difference in severe necrosis remained significant (p = 0.033). Conclusions: In pre-expanded e-LTMC flap reconstruction, a management pathway in which ICGA findings informed or confirmed the final intraoperative decision was associated with lower observed rates and lower adjusted odds of overall and severe flap necrosis. The observed association reflects the management pathway, including perfusion status and the feasibility of modification, rather than ICGA alone. ICGA is therefore best incorporated into intraoperative decision-making alongside clinical assessment.