Utility of Indocyanine Green Angiography to Identify Clinical Factors Associated With Perfusion of Paramedian Forehead Flaps During Nasal Reconstruction Surgery

Abstract

Identifying factors affecting forehead flap neovascularization during nasal reconstruction surgical procedures using quantitative dynamics of fluorescence from indocyanine green angiography may be associated with reduced vascular complications.OBJECTIVES To identify quantifiable forehead flap perfusion measures using indocyanine green angiography during nasal reconstruction procedures and to evaluate clinical factors associated with neovascularization. DESIGN, SETTING, AND PARTICIPANTS Retrospective cohort study of 71 patients at a tertiary referral center of Stanford University, Stanford, California, between January 1, 2010, and March 31, 2018, undergoing forehead flap nasal reconstruction surgery with flap perfusion assessed by indocyanine green angiography.EXPOSURES Indocyanine green angiography was performed intraoperatively to record forehead flap neovascularization during the second stage of nasal reconstruction surgery after temporary clamping of the pedicle. MAIN OUTCOMES AND MEASURESWith use of quantifiable data of fluorescence dynamics, flap perfusion in association with a reference point in the cheek after pedicle clamping was assessed by 2 methods: (1) ingress (arterial inflow) and egress (venous outflow) flap-to-cheek ratio and (2) flap-to-cheek perfusion (fluorescence) ratio at 3 time points (midpoint of indocyanine green flap inflow, maximum fluorescence [peak], and midpoint of indocyanine green flap outflow) and their calculated mean. Association of the perfusion measures with patient and procedural factors was performed using linear regression models. RESULTSOf the 71 patients included in the study, 43 (61%) were men; the mean (SD) age was 71.1 (11.0) years. The mean (SD) flap-to-cheek inflow ratio was 0.48 (0.40), peak fluorescence ratio was 0.59 (0.34), and outflow ratio was 0.88 (0.42). The calculated mean (SD) flap-to-cheek perfusion ratio of these measures was 0.65 (0.35). The mean (SD) flap-to-cheek ingress ratio was 0.54 (0.36) and egress ratio was 0.65 (0.98). With use of a multivariable regression model, the time between stages was positively associated with flap-to-cheek ingress ratio (β, 0.015; 95% CI, 0.001 to 0.030), and cartilage grafting was negatively associated with flap-to-cheek outflow ratio (β, -0.240; 95% CI, -0.472 to -0.008). CONCLUSIONS AND RELEVANCEThe findings suggest that indocyanine green angiography is an effective method to quantify relative neovascularization perfusion of forehead flaps. Future applications may include the use of this technology to aid in early flap division and ensure adequate perfusion among high-risk patients.LEVEL OF EVIDENCE NA.

The Use of Indocyanine Green Angiography for Cosmetic and Reconstructive Assessment in the Head and Neck

“…Multiple near-infrared video camera systems have been used for ICG angiography in the head and neck region. The most popular are the SPY Elite system (NOVADAQ Technologies Inc.), 1,21 the IC View System (Pulsion Medical Systems), the PDE-Neo system (Hamamatsu Photonics), 22,23 IR800 (Carl Zeiss AG), and Flow800 (OPMI Pentero, Carl Zeiss AG). 24 Some systems used filtered endoscope-integrated systems such as red/near-infrared excitation (filtered Xenon Short Arc lamp, Karl Storz) coupled to an infrared-sensitive threechip CCD camera (Karl Storz).…”

“…These tools may be helpful in qualitative or quantitative assessments. 1,25 Qualitative tools evaluate the generated fluorescence to evaluate the success of the inset of pedicled flaps or the anastomosis patency in free flaps. This provides a dynamic map of the dermal circulation that serves as a topographic analysis of the effective perfusion to the flap tissue, as shown in ►Fig.…”

“…Quantitative tools have shown interesting objective results over the last decades. 1,10,24 These include either a time-dependent or time-independent assessment. In the time-dependent setting, a measure of the maximum intensity of the flap fluorescence at a certain time point (usually at peak fluorescence) is compared with a reference fluorescence value.…”

“…4 Popular methods include handheld (pencil) Doppler, near-infrared spectroscopy, laser Doppler flowmetry, 5 optical diffusion imaging spectroscopy, 6 color Doppler (duplex) ultrasound, 7 dynamic infrared thermography, 8 fluorescein angiography, 9 and laser-assisted indocyanine green (ICG) angiography. 1,10 These modern intraoperative tools provide essential information regarding adequate flap perfusion after completion of flap inset in locoregional flaps or anastomoses in free flaps, and can, therefore, reduce the amount of flap failure and operative revision in the future. In particular, fluorescence angiography has shown to be a useful tool for detecting obstruction within an anastomoses, or stenosis in the feeding vessels of a flap and, therefore, has a potential impact on improving survival.…”

What Is the Optimal Timing for Dividing a Forehead Flap?

“…Surgeons considering a shift to a paradigm of an earlier flap division may benefit from quantifying flap neovascularization. In a 2019 retrospective review of 71 patients, Abdelwahab et al reported that the indocyanine green angiography (SPY Elite System; LifeCell [Branchburg NJ], Novadaq Technologies [Mississauga, ON, Canada) can effectively qualify and quantify perfusion. The system's infrared‐sensitive camera can measure the perfusion of the intravascular fluorescent dye, and ensure adequate perfusion of forehead flaps among high‐risk patients.…”