Perforasomes of the DIEP flap: Vascular anatomy of the lateral versus medial row perforators and clinical implications

Background: Regarding the perfusion of a deep inferior epigastric perforator (DIEP) flap, the classic Hartrampf zones II and III were demonstrated by Holm et al. to be reversed using fluorescent perfusion techniques, implying that blood flow from the pedicle travels to the ipsilateral side before crossing the midline. The authors' hypothesis is that the zones of perfusion and the vascular anatomy differ greatly between lateral row and medial row perforators. Methods: Three-dimensional and four-dimensional computed tomographic angiography was utilized to reappraise the zones of vascularity. Thirty-six DIEP flaps were simulated for this study (14 lateral row perforators versus 22 medial row perforators). Individual perforators were injected with contrast and each flap was subjected to dynamic computed tomography scanning. Images were viewed using TeraRecon software, allowing analysis of branching patterns and perfusion flow. Results: The mean vascular territory for a medial perforator DIEP flap injected with contrast was 296 cm², compared with 196 cm² for a lateral perforator DIEP flap. Zone II perfusion was greater in a medial perforator compared with a lateral perforator. Zone III had greater perfusion in a lateral perforator compared with a medial perforator. The authors found that medial perforators conform to the Hartrampf zones of perfusion and lateral perforators follow the Holm theory of perfusion (zones II and III should be reversed for lateral perforator DIEP flaps). Injection of a lateral row-based perforator flap gave a vascular territory that rarely crossed the midline. Conclusion: Medial and lateral row perforators offer distinct and stereotypical zones of perfusion that have a significant effect on flap design and harvesting.