The hand held Doppler device for the detection of perforators in reconstructive surgery: what you hear is not always what you get.
BACKGROUND Propeller flaps represent an elegant and reliable method for soft-tissue reconstruction of the extremities and trunk, obviating the need for free tissue transfer. Preoperative localisation of perforators adjacent to the defect is important regarding the pivot point and length of the flap. Most commonly unidirectional Doppler sonography is used. The reliability of this method regarding propellerflaps has not thoroughly been evaluated. The aim of this study is to assess the positive predictive value of this method for planning propeller flaps. PATIENTS AND METHOD In a total of 68 patients, soft-tissue reconstruction using propeller flaps was planned with unidirectional Doppler sonography. Defects were located on the lower extremity in 48 cases, the buttock area in 15 cases and the trunk in 5 cases. RESULTS In 12 cases no adequate perforators were located intraoperatively despite a positive Doppler signal. In the lower extremity Doppler produced a false-positive result in 21% of the cases, whereas in the buttock region only 13% false positives result were found. The positive predictive value overall was 82%. When no perforator was located, flap coverage was achieved using the reverse sural artery flap in 6 cases, the free peroneal artery perforator flap in 3 cases, local advancement flaps in 2 cases and skin grafting in 1 case. DISCUSSION The reliability of unidirectional Doppler sonography is inadequate for localisation and selection of the dominant perforator when planning propeller flaps. A high rate of false-positive results needs to be anticipated especially distally in the extremities. In 18% of cases an alternative surgical plan was required to achieve soft tissue coverage. We recommend using colour duplex sonography for a more reliable preoperative localisation of perforators.