Augmented reality in preoperative anterolateral thigh flap perforators positioning: A pilot diagnostic study

Background: The anterolateral thigh (ALT) flap is the primary choice for healthy and vascularized soft-tissue coverage for appendicular and axial soft tissue reconstruction, especially in the head and neck regions. Nonetheless, there is substantial anatomic variation in ALT perforators that affect flap integrity, survival rates, and donor-site morbidity. Regardless of the ALT flap type, accurate location of perforators can greatly improve surgical success rates and reduce the risk of secondary surgeries. Therefore, we investigated a novel approach for locating perforators. Method: We utilized augmented reality (AR) technology in combination with a self-designed device, Finder, to locate the perforators of the anterolateral thigh (ALT) flap, and compared its accuracy to that of traditional ultrasound localization. Result: In this study, 24 patients underwent ALT flap reconstruction, with all flaps surviving except one case of partial necrosis. Comparing the two positioning methods, Ultrasonic color Doppler (UCD) showed a sensitivity of 81.1 % [95 % confidence interval (CI) 64.3 %-91.4 %] and an AUC of 0.70 (95 % CI 0.55-0.86). AR-Finder demonstrated a higher sensitivity of 97.5 % (95 % CI 85.3 %-99.9 %, p = 0.031) and an AUC of 0.90 (95 % CI 0.80-1.01, p = 0.035). The average distance difference from the actual perforator to virtually determined location was 3.54 +/- 2.80 mm (95 % CI 2.58-4.50) for AR-Finder and 9.57 +/- 5.84 mm (95 % CI 7.75-11.58) for UCD (p < 0.001). Conclusion: In this pilot study, AR-Finder demonstrated superior accuracy compared to the UCD method for locating perforators in ALT flaps, providing a new and reliable tool for the design and elevation of ALT flaps.