Neovascularization Perfusion of Melolabial Flaps Using Intraoperative Indocyanine Green Angiography

Abstract

Importance: Assessment of melolabial flap perfusion using indocyanine green (ICG) angiography for nasal reconstruction has not been previously described. Objective: To assess melolabial flap relative perfusion using ICG angiography in nasal reconstruction and highlight its clinical relevance. Design, Setting, and Participants: In this retrospective case series at a tertiary referral center, 10 patients undergoing melolabial flap reconstruction of nasal defects between January 2015 to April 2018 with flap perfusion were assessed by ICG angiography. Exposures: Indocyanine green angiography was performed to assess melolabial flap perfusion at second stage surgery after temporary clamping of the pedicle and after pedicle division and flap inset. Main Outcomes and Measures: Flap perfusion in relation to a reference point on the cheek was calculated after both pedicle clamping and division by 2 methods: (1) ingress (arterial inflow) and egress (venous outflow) flap-to-cheek ratio; (2) flap-to-cheek perfusion (fluorescence) ratio at 3 time points (midpoint of ICG flap inflow, maximum [peak] fluorescence, and midpoint of ICG outflow), and their calculated mean. Correlations of perfusion with time between stages, and patient factors were performed; perfusion parameters after temporary pedicle clamping and after division and flap inset were compared. Results: Ten patients (mean [SD] age, 66 [7.5] years) were enrolled with a mean (SD) interval of 23 (4) days between first and second surgery. No correlation existed between perfusion parameters and time interval between first and second stage, or any other patient factors. Of the different perfusion parameters, a statistically significant difference was observed when comparing temporary clamping and postdivision mean (SD) flap-to-cheek perfusion ratio (0.89 [0.22] and 0.80 [0.19]; 95% CI, 4.1-12.6; P =.001), as well as mean (SD) peak perfusion ratio (0.81 [0.2] and 0.77 [0.2]; 95% CI, 0.005-0.080; P =.02) only. No partial or complete flap necrosis was reported after pedicle division. Conclusions and Relevance: Indocyanine green angiography is an effective method to determine neovascularization perfusion of melolabial flaps, with a mean perfusion of 89% after pedicle clamping. Future applications of this technology include use in patients at high risk for flap necrosis, or those who may benefit from early flap division to ensure adequate perfusion and minimize the time interval between staged procedures. Level of Evidence: NA.