Perfusion zones of the DIEP flap revisited: a clinical study.

BACKGROUND: The Hartrampf perfusion zones of the lower abdominal flap are generally accepted. They were empirically based on the clinical impression of the perfusion in the first 16 unipedicled transverse rectus abdominis musculocutaneous flaps and have been uncritically adopted for the free transverse rectus abdominis musculocutaneous and the free deep inferior epigastric perforator (DIEP) flap. Scientific data proving the validity of these perfusion zones do not exist. The objective of this study was to evaluate and quantitatively assess the perfusion zones of the DIEP flap.
METHODS: In a clinical, prospective study of 15 patients undergoing DIEP flap breast reconstruction, tissue perfusion was intraoperatively assessed using the method of laser-induced fluorescence of indocyanine green.
RESULTS: Perfusion of zones I, II, and III was seen 25, 41, and 32 seconds, respectively, after injection, and the perfusion index constituted 76, 25, and 47 percent (median) of normal tissue. Perfusion of zone IV was completely absent in five patients (33 percent); in the remaining patients, it was dramatically decreased (5 percent) and occurred with a delay of 67 seconds.
CONCLUSIONS: On the basis of the results of this study, the Hartrampf concept of a centrally perfused skin ellipse with declining perfusion of its peripheral ends is wrong and should be revised. Instead, one should think of the lower abdominal flap as two halves separated by the midline. The ipsilateral half has an axial pattern of perfusion; the contralateral half shows a random-pattern, individually variable blood supply. Therefore, the classic Hartrampf zones should be rearranged, switching zones II and III.