Perforating blood vessel selection in deep inferior epigastric artery perforator flaps

Introduction: The DIEP flap is a popular choice for breast reconstruction, though selection of which perforating blood vessel(s) to supply the flap is still largely based on surgeon preference, with little evidence to support numbers or location of perforators. In addition, many surgeons routinely discard zone IV of the flap, limiting the size of transferrable tissue. The aim of this research was to investigate the effect of number and location of perforators within a DIEP flap, on the total pedicle flow and perfusion of zone IV fat and skin. Methods: This research comprised of two studies; an animal model and a patient study: 1) 20 cranially-based abdominal epigastric perforator flaps were raised in Wistar rats on two perforators. The perforators were sequentially clamped and released in a randomised order and total pedicle flow (measured using microvascular flow-probes) and skin perfusion (measured using laser Doppler Flowmetry) was recorded on the following perforator combinations: • P1 (superior perforator) • P2 (inferior perforator) • P1+2 (both perforators) In addition, half of the animal flaps were randomised to receive a single (15 minute) period of pedicle-clamped ischaemic preconditioning after raising, with all measurements repeated to observe any effect. 2) 13 DIEP flaps were raised in post-mastectomy patients requiring breast reconstruction on two perforators. These were clamped and released as before to assess perfusion of fat and skin in zone IV using SPY Indocyanine-green-fluorescence-angiography scans on the same perforator combinations as in our animal study, listed above. Results: All data were analysed using non-parametric analyses and revealed that in our animal model, total pedicle flow was significantly (p<0.001) greater on a single perforator compared to two but no significant differences were identified in the flap skin perfusion. In our clinical study a single superior perforator supplied zone IV significantly (p=0.039) better than both peroforators, though this was not observed with the single inferior perforator. No significant differences were seen in zone IV skin perfusion. A single period of ischaemic preconditioning significantly (p