Evaluation of Diagnostic Accuracy Using Preoperative Handheld Doppler in Identifying the Cutaneous Perforators in the Anterolateral Thigh Flap

Abstract

Sir:FigureThe anterolateral thigh flap has become a workhorse flap in the reconstruction of various defects. Because of its variable vascular geometry, preoperative assessment of perforators has been performed with several devices.1 The handheld Doppler probe is noninvasive and also the least expensive and the easiest to use of the devices available. Mapping of the cutaneous perforators with a handheld Doppler probe before flap design has been advocated extensively. However, handheld Doppler examination is reported to be relatively unreliable in determining the exact site of the underlying perforators.2,3 A systematic review was performed for trials comparing handheld Doppler imaging with perioperative findings as a reference standard. We searched the PubMed database from January of 2000 to December of 2010. We used the following keywords: “anterolateral thigh flap” and “handheld Doppler.” 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 studies from which a 2 × 2 table could not be formed. We extracted available data on true-positives, false-negatives, false-positives, and true-negatives for detecting the location of anterolateral thigh perforators with the handheld Doppler probe to construct 2 × 2 contingency tables.4 There were three eligible studies containing 224 test results (Table 1). When the data from handheld Doppler imaging were compared with the perioperative findings, the sensitivity was 89.7 percent (95 percent confidence interval, 85.0 to 93.0 percent) and the specificity was 18.2 percent (95 percent confidence interval, 8.6 to 34.4 percent). Handheld Doppler imaging has a positive predictive value of 88.1 percent (95 percent confidence interval, 83.8 to 92.2 percent) and a negative predictive value of 20.7 percent (95 percent confidence interval, 6.2 to 35.8 percent).Table 1: Results of Handheld Doppler StudiesThe positive likelihood ratio is 1.097 (95 percent confidence interval, 0.928 to 1.296) and the negative likelihood ratio is 0.565 (95 percent confidence interval, 0.249 to 1.283). The diagnostic odds ratio with handheld Doppler between the presence of anterolateral thigh perforator versus absence was 1.942 (95 percent confidence interval, 0.726 to 5.196). The accuracy of handheld Doppler is 80.5 percent (95 percent confidence interval, 75.7 to 85.4) (Table 2).Table 2: Pooled Results of Test Indicators of Handheld Doppler Studies*The authors conclude that handheld Doppler is a simple, easy, but not always accurate method for the localization of anterolateral thigh perforators. Mapping and design of the anterolateral thigh flap should not rely completely on handheld Doppler findings. 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.