[Clinical application effects of indocyanine green angiography combined with color Doppler ultrasound in perforator localization of anterolateral thigh perforator flaps].

Objective: To investigate the clinical application effects of indocyanine green angiography (ICGA) combined with color Doppler ultrasound (CDU) in perforator localization of anterolateral thigh perforator flaps. Methods: This study was a retrospective observational study. From January to August 2024, the Department of Hand Surgery admitted 21 patients and the Department of Wound Repair Surgery of Suzhou Ruihua Orthopedic Hospital admitted 35 patients that met the inclusion criteria. These patients underwent surgical repair of the extremity skin and soft tissue defects using anterolateral thigh perforator flaps designed under the assistance of CDU and ICGA. Among them, there were 44 males and 12 females, aged 16 to 71 years. After debridement, the wound area ranged from 7.0 cm×5.5 cm to 40.0 cm×10.0 cm. Before surgery, CDU and ICGA were used to locate the perforators of anterolateral thigh perforator flap. The area of harvested flap ranged from 8.0 cm×6.0 cm to 40.5 cm×11.0 cm. The wounds in flap donor sites were closed directly or covered with the full-thickness skin graft from the contralateral thigh. The number of perforators located by preoperative CDU or ICGA, and the number, origin, type, and caliber of perforators in intraoperative exploration, and flap thickness were recorded. The consistency between preoperative CDU or ICGA localization results and intraoperative exploration findings was assessed. The error distances between preoperative CDU or ICGA localization and intraoperative exploration of perforator, respectively, were measured. Using intraoperative exploration of perforator as the gold standard, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of preoperative CDU and ICGA for perforator localization were calculated. The independent influencing factor for the consistency between CDU or ICGA localization results and intraoperative exploration findings of 56 patients who had anterolateral thigh perforator flap designed under the assistance of CDU and ICGA were screened. Results: A total of 131 perforators were located by CDU and 130 perforators were located by ICGA preoperatively. Intraoperatively, 132 perforators were explored, including 64 perforators from the oblique branch, 49 perforators from the descending branch, 9 perforators from the transverse branch, and 10 perforators from the anterior branch. Among them, 46 perforators were septocutaneous perforators and 86 perforators were musculocutaneous perforators, with a mean caliber of (0.72±0.21) mm. The flap thickness was (1.5±0.6) cm. There was no statistically significant difference in the consistency between preoperative CDU localization results and intraoperative exploration findings and ICGA localization results and intraoperative exploration findings (P>0.05). There was no statistically significant difference in the error distance between preoperative CDU localization and intraoperative exploration of perforator and preoperative ICGA localization and intraoperative exploration of perforator (P>0.05). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of ICGA and CDU in locating perforators were 92.42%, 92.00%, 93.85%, 90.20%, and 92.24%, 84.09%, 80.00%, 84.73%, 79.21%, and 82.33%, respectively. Flap thickness was an influencing factor for the consistency between preoperative ICGA localization results and intraoperative exploration findings of 56 patients who had anterolateral thigh perforator flap designed under the assistance of CDU and ICGA (with odds ratio of 0.20, 95% confidence interval of 0.06-0.66, P<0.05). Perforator type was an influencing factor for the consistency between preoperative CDU localization results and intraoperative exploration findings of 56 patients who had anterolateral thigh perforator flap designed under the assistance of CDU and ICGA (with odds ratio of 3.07, 95% confidence interval of 1.11-8.46, P<0.05). After adjusting for sex, age, body mass index, perforator type, and perforator caliber, flap thickness was an independent influencing factor for the consistency between preoperative ICGA localization results and intraoperative exploration findings of 56 patients who had anterolateral thigh perforator flap designed under the assistance of CDU and ICGA (with odds ratio of 0.15, 95% confidence interval of 0.03-0.73, P<0.05). After adjusting for sex, age, body mass index, flap thickness, and perforator caliber, perforator type was an independent influencing factor for the consistency between preoperative CDU localization results and intraoperative exploration findings of 56 patients who had anterolateral thigh perforator flap designed under the assistance of CDU and ICGA (with odds ratio of 4.25, 95% confidence interval of 1.39-12.98, P<0.05). Conclusions: The combined application of ICGA and CDU for perforator localization in anterolateral thigh perforator flaps in clinic can complete each other to improve the accuracy of localization. Flap thickness significantly affects the accuracy of ICGA localization, while perforator type significantly affects the accuracy of CDU localization.