April 2020 HSC Section 4 - Plastic and Reconstructive Problems

Original Investigation Research

Indocyanine Green Angiography and Factors Associated With Perfusion of Paramedian Forehead Flaps

independent (the ratio of ingress [arterial inflow] to the flap compared with the cheek and the ratio of egress [venous out- flow] from the flap compared with the cheek). Further inves- tigation is needed to assess which perfusion method is opti- mal. Given the lowrate of vascular complications in this cohort, it was difficult to assess the association of perfusion mea- sureswith the rate of complications. Assessment ofmore high- risk patients or patients with shorter time between stages of reconstructionmay help elucidate the optimal perfusionmea- sures because thesepatients are at greater risk for vascular com- promise. Another area of interest is determining whether pri- mary neovascularization originates from the periphery (ie, coaptation of the subdermal plexus), via the deep side of the flap (ie, subcutaneously), or both equally. Further applications of this technology include assessing a larger number of patients to capturemore complications, as well as those at greater risk for vascular complications. This technology can also be used to assess the perfusion of flaps at decreased time intervals between staged reconstruction to safely perform an accelerated pedicle division and help im- prove patients’ quality of life. Strengths and Limitations A strength of this study includes the large sample size and a standardized technique for perfusion assessment. The study provided a comparative quantitative assessment of forehead flap perfusion and assessment of the association of potential patient and defect factors with neovascularization. Limitations include the variation of comparative quanti- tative data obtained from patients because of variable micro- circulation and hemodynamics. Thus, a ratio between the flap and patient’s own nonsurgically touched tissue was used to provide more accurate comparison between patients. In ad- dition, this study used data from a single institution based on thework of a single surgeon andwith a retrospective study de- sign. Conclusions The findings suggest that indocyanine green angiography is an effective method to qualify and quantify neovascularization perfusion of forehead flaps. Among factors studied, time be- tween stages and cartilage graft use were significantly asso- ciated with perfusion measures. Future applications may in- clude use of this technology to aid in early flap division and ensure adequate perfusion of forehead flaps among high-risk patients.

association between perfusion measures and defect thick- ness were found in our study, 1 of the 2 patients who experi- enced aminor complication (small area of dehiscence) had re- construction of a full-thickness defect. In nasal reconstruction procedures, ICG angiographywas first introduced as a qualitative assessment in a few case reports 23-25 and as comparative quantitative assessment in a case series by Woodard and Most. 6 The modality was also as- sessed tominimize the time between the stages of reconstruc- tion to 2weeks 5 and evaluate the cost-effectiveness of ICG an- giography in nasal reconstruction. 8 Another technology used to provide comparative quantitative data of forehead flap per- fusion is color duplex–Doppler ultrasonography tomeasure the flap resistance index. 7 With use of this method, a statistically significant decrease in the earlyhigh resistance index (first day: 0.871 in the proximal flap and 0.869 in the distal flap) after a 2-week interval (0.597 in the proximal flap and 0.582 in the distal flap) was observed, and it was concluded that the resis- tance index decreased gradually, leading to detectable ve- nous outflowby the end of the first postoperativeweek. 7 This finding was supported by our results, because the flap-to- cheek ingress ratio (arterial inflow) was significantly associ- ated with increased time between stages. In plastic and reconstructive surgery, ICG angiography has beenused to assess groin flaps, vertical rectus abdominis flaps, sural island flaps, and reversed forearm flap. 11 It has also been used to detect arterial and venous anastomotic patency, 26 to measure depth of burns to predict scar contracture, 27 and ex- tensively in breast reconstruction. 28-32 In addition, ICG angi- ography has beenused after nasal osteotomy procedures 13 and renal, 33 liver, and pancreatic transplant. 34 The method used for perfusion assessment was variable among these studies, with some authors reporting flap fluorescence with ICG angi- ography as qualitative proof of vascularity 24,34 and other au- thors providing quantitative data interpreted by the SPY-Q software. 6,13,28 One quantitativemethodusedwas to report the ratio of ICG fluorescence dynamics to the flap in contrast with nonsurgically touched tissue, 5,6,13 and another method re- ported the rate of arterial (ingress) and venous (egress) blood flow of flaps. 28 Despite the variation of methods, in all the previously referenced studies, ICG angiographywas shown to provide a reliable perfusion assessment. In this study, we reported 2 distinct methods using the SPY-Q software to assess flap perfusion using a point on the cheek as a reference. One method was time dependent (com- paring fluorescence between these 2 areas at the midpoint of flap inflow, peak fluorescence, flap outflow, and the calcu- lated mean of these values), and one method was time

Conflict of Interest Disclosures: None reported.

ARTICLE INFORMATION Accepted for Publication: November 3, 2018. Published Online: January 31, 2019. doi: 10.1001/jamafacial.2018.1829 Author Contributions: Dr Spataro had full access to all of the data in the study and takes responsibility for the integrity of the data and the

Acquisition, analysis, or interpretation of data: Abdelwahab, Most, Spataro. Drafting of the manuscript: Abdelwahab, Kandathil, Spataro. Critical revision of the manuscript for important intellectual content: Kandathil, Most, Spataro. Statistical analysis: Spataro. Administrative, technical, or material support: All authors. Supervision: Most, Spataro.

REFERENCES 1 . Burget GC. Aesthetic restoration of the nose. Clin Plast Surg . 1985;12(3):463-480 . 2 . Hessam S, Georgas D, Sand M, Bechara FG. Penetrating defect of the ala nasi: combined reconstruction with a myocutaneous hinge- and paramedian forehead flap. J Dtsch Dermatol Ges . 2014;12(2):169-171 .

accuracy of the data analysis. Concept and design: All authors.

(Reprinted) JAMA Facial Plastic Surgery May/June 2019 Volume 21, Number 3

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