Diagnostic Efficacy of Color Doppler Ultrasonography in Preoperative Assessment of Anterolateral Thigh Flap Cutaneous Perforators

Sir:FigureThe anterolateral thigh flap has become a workhorse flap in the reconstruction of assorted defects. Because of its variable vascular anatomy, preoperative assessment of perforators has been performed using several devices. Among them, color Doppler ultrasonography may apply the Doppler effect with the superposition of flow information as colors on a gray scale in a real-time image. This type of ultrasonography could identify and display the different velocities and directions of blood flow in vessels and map the extent of flow in a certain region. In free flap reconstruction, color Doppler ultrasonography not only offers information about the internal vessel diameter and course but also demonstrates the perivascular anatomy of the flap.1–4 To determine the diagnostic performance of the color Doppler ultrasonography in identifying the cutaneous perforators in the anterolateral flap, we conducted a systematic review for trials comparing the color Doppler ultrasonography findings with intraoperative findings as reference standards. We searched the PubMed database from January of 2000 to May of 2012. We used the following keywords: anterolateral thigh flap and color Doppler ultrasonography. Two reviewers independently extracted data in two steps: titles and abstracts, and then the full-text articles. This search was supplemented by a review of reference lists of potentially eligible studies. We excluded the duplicated reports of the same patient population and studies with incomplete or no presentation of intraoperative findings. Perforators found in both the color Doppler ultrasonography study and intraoperatively were defined as true positive. Perforators found using color Doppler ultrasonography but not identified intraoperatively were defined as false positive. Additional perforators found intraoperatively were regarded as false negative. Four studies were included for a total of 54 anterolateral thigh flaps evaluated (Table 1).1–4 As the data from color Doppler ultrasonography were compared with the intraoperative findings, the pooled sensitivity was 95.7 percent (95 percent confidence interval, 90.9 to 98.0 percent) and the pooled positive predictive value was 94.3 percent (95 percent confidence interval, 89.2 to 97.1 percent).Table 1: Results of Color Doppler Ultrasonography StudiesIn our previous systematic review, the handheld Doppler demonstrated a pooled sensitivity of 89.7 percent (95 percent confidence interval, 85.0 to 93.0 percent) and a pooled positive predictive value of 88.1 percent (95 percent confidence interval, 83.8 to 92.2 percent)5 in identifying the cutaneous perforators in the anterolateral thigh flap. Although color Doppler ultrasonography proposed more precise information about the number and locations of cutaneous perforators than the handheld Doppler did, it was limited by its cost, ponderous apparatus, time-consuming scanning, and requirements of both scanning skill and a detailed knowledge of the flap anatomy and operative procedures. The authors conclude that reconstructive surgeons should choose the diagnostic modality according to their knowledge of the anatomy of the flap, their familiarity with the diagnostic modalities, and clinical cost performance. Hsu-Tang Cheng, M.D. Department of Plastic Surgery, China Medical University Hospital, School of Medicine, China Medical University, Taichung, Taiwan Fu-Yu Lin, M.D. Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan Sophia Chia-Ning Chang, M.D., Ph.D. Department of Plastic Surgery, China Medical University Hospital, School of Medicine, China Medical University, Taichung, Taiwan DISCLOSURE The authors have no financial interest to declare in relation to the content of this article.