The hand held Doppler device for the detection of perforators in reconstructive surgery: What you hear is not always what you get

Background: Perforator-based flaps have become indispensable in the treatment of burn scars. Pre-operative perforator mapping is often performed by use of the hand held Doppler device, partly due to its convenience and the low costs. We expected to find sufficient evidence in literature to support the use of the device, however available literature showed a distinct lack of clinimetric studies that adequately tested the reliability. Methods: To assess reliability, perforator locations were mapped independently by two clinicians using an 8 MHz Doppler device. In healthy volunteers the elbow region or the peri-umbilical region were randomly chosen to be the measurement areas of predefined squares (7 cm x 7 cm). Subsequently, the perforators within the area were mapped with Duplex to establish the validity by means of the positive predictive value. Results: 20 volunteers were included. The hand held Doppler technique showed moderate reliability with a mean Dice coefficient of 0.56. Also, poor validity was found expressed by a mean positive predictive value of 55%. Conclusions: Surprisingly, this study has shown that performance of the hand held Doppler device was moderate. The Doppler should not be used alone for the detection of perforators.