How Accurate Is Preoperative Hand-Held Doppler Examination in Detecting Cutaneous Perforators of the Anterolateral Thigh Flap?

Preoperative localization of the cutaneous perforators is an important step in designing and harvesting the anterolateral thigh flap. Most surgeons rely on the hand-held Doppler because of its convenience and simplicity. However, its accuracy has not been extensively reported.

A single surgeon's experience of 100 anterolateral thigh free flaps was reviewed. Initial experience showed that there were usually 1 to 3 cutaneous perforators in consistent locations; they were grouped as perforators A, B, and C from proximal to distal. Perforator B corresponded to the midpoint between the anterior superior iliac spine (ASIS) and the supralateral corner of the patella (SLP). Perforators A and C were located approximately 5 cm proximal or distal, respectively, to perforator B. Preoperatively, Doppler signals around these three locations were marked and their distances from the ASIS were measured.

This was first done in the clinic using the Huntleigh Mini Dopplex D-900 and repeated just before making the incision, using the Koven mini Doppler ES-100X with sterile probes. After the cutaneous perforators were identified intraoperatively, their exact locations as they entered the fascia were recorded and compared to those detected with the hand-held Doppler devices.

Among the 100 flaps, perforators A, B, and C were present in 51, 89, and 62 cases, respectively. The false positive rate was 34%, 13%, and 26% with the Huntleigh, and 0%, 8%, and 8% with the Koven for perforators A, B, and C. The false negative rates were 3%, 0%, and 0% with the Huntleigh, and 32%, 4%, and 40% with the Koven. Sensitivity was 93%, 100%, and 100% with the Huntleigh, and 39%, 95%, and 44% with the Koven for perforators A, B, and C. The detected Doppler signals were within 1 cm of the actual perforators in 43%, 74%, and 71% of cases with the Huntleigh, and 80%, 70%, and 87% with the Koven for perforators A, B, and C.

Preoperative hand-held Doppler examination is not always accurate and should be used with caution in flap design. This author routinely explores the perforators with a negative Doppler signal and finalizes the flap design only after the perforators have been dissected out.