The Clinical And Experimental Studies On The Use Of Indocyanine Green Angiography In Perforator Localization And Flap Perfusion Assessment

Objective:?In this study,we aimed to review our preliminary experience using indocyanine green angiography(ICGA)for perforator localization and flap design to facilitate the clinical application of the pre-expanded pedicled brachial artery perforator(BAP)flap.?This study aimed to compare the accuracy of the hand-held Doppler(HHD)and ICGA in their uses in perforator localization in various donor sites and tried to explore and compare the correlations between these two modalities with flap thickness and body mass index(BMI)respectively.?This study aimed to compare the accuracy of FLIR ONE thermal imaging(FLIR ONE),near-infrared spectroscopy(NIRS)and ICGA for intraoperatively predicting clinical flap necrosis in a rat perforator flap modelMethods:?All patients underwent soft-tissue reconstructions using a pre-expanded BAP flap in two or three stages.ICGA was used to localize perforators during both expander insertion and flap elevation.The pedicle was divided at the third stage three weeks following flap elevation for head and neck cases.?HHD and ICGA were used preoperatively for perforator localization respectively and flap design was performed or adjusted according to the obtained perforator information.During the surgery,the perforators were explored and they were confirmed whether the locations of the actual vessels corresponded with those predicted by HHD and/or ICGA.Measurements of HHD and ICGA for perforator localization were correlated to flap thickness and BMI respectively.?A 10×3-cm epigastric perforator flap was elevated in 14 adult male rats(weighing 250±50 g).Flap perfusion was assessed immediately after flap elevation using FLIR ONE,NIRS,and ICGA.Measurements were correlated to the clinical endpoint and gold standard of flap necrosis on postoperative day 7.Results:?Sixteen patients underwent reconstructions of the head and neck(n=13)or shoulder/trunk(n=3)using 14 perforator-plus and 2 propeller BAP flaps.In total,50 perforators were identified using ICGA,all of which were appreciable during both expander placement and flap elevation.Thirty-five perforators were directly visualized during flap elevation,and an additional 15 perforators were not explored but incorporated into the flap.All flaps survived without necrosis,and the donor sites healed uneventfully without complications.?Thirty flaps were transferred in 30 patients involving 15 different donor sites.Thirty-six perforators in total were detected by HHD preoperatively and 25 of them(69.4%)were confirmed intraoperatively,which were inferior to those of ICGA that 48 perforators were localized preoperatively and 42(87.5%)were found during surgery.The perforators detected using ICG A were chosen as flap pedicles in 21 cases(70%)while that of HHD was 13(43%).Twenty percent(6/30)of patients had intraoperative adjustments implemented because of ICGA data.The sensitivity,specificity,accuracy and positive predictive value for ICGA(79.2%,53.8%,74.2%,87.5%,respectively)were higher than those of HHD(55.6%,15.4%,46.6%,69.4%,respectively).No relationships occurred between the accuracies of perforator localizations and BMI for both HHD and ICGA(both p>0.05)in this study.There exhibited an almost linear deterioration in accuracy of ICGA the thicker the flap thickness(p<0.05),which was not significantly correlated to the HHD examination(p>0.05).?All three technologies detected significant differences in perfusion along flap length(all p<0.001),and were associated with significant differences in the odds of developing flap necrosis(all p<0.001).The area under the receiver operating characteristic curves were 0.948 for ICGA as an absolute value,0.873 for relative changes with thermal imaging(FLIR ONE),and 0.792 for tissue oxygenation.The sensitivity,specificity,and accuracy for ICGA measured as an absolute value were the highest at 97.8%,87.5%,and 92%,respectivelyConclusions:?The medial arm provides thin and pliable skin for the resurfacing of regional defects with relatively minimal donor site morbidity.With the assistance of ICGA,perforators off the brachial artery can be reliably identified,facilitating the pre-expansion and elevation of pedicled BAP flaps for use in head and neck and trunk reconstruction.?ICGA had a higher accuracy in perforator localization than HHD and exhibited an excellent performance in thin donor sites where the perforator detections were more easily influenced by the underlying source arteries.In addition,ICGA showed a better quality than HHD as a reliable and versatile tool which could be applied in multiple key points during the surgery,improving the safety of the surgeries consequently.There existed different results in the correlations between the accuracies of the two modalities with flap thickness or BMI in this study compared with the previous literatures.Additional research can further delineate and detail their interrelationships.?ICGA most accurately predicted flap necrosis in this study;however,tissue oximetry and thermal imaging(FLIR ONE)were also capable of predicting necrosis and represented potentially cheaper or more readily available alternative for objective perfusion assessment.Additional research can further delineate their roles and cost-efficacy in clinical practice.