Experimental study of survival of pedicled perforator flap with flow-through and flow-end blood supply.

Flap viability after transfer depends on blood flow from the arterial blood supply below the fascia. This study evaluated survival of a pedicle flap with a perforator lateral branch and flow-through blood supply, compared with that of a flap with a flow-end blood supply and perforator terminal branch. Forty Sprague-Dawley rats, 20 in each group, were assigned to transfer of a superficial epigastric artery pedicle island flap with a flow-through or flow-end configuration of blood supply. Laser Doppler imaging was used to evaluate flap perfusion 2 h, 3 days and 5 days after surgery. The rats were killed on day 5, and lead oxide-gelatine-enhanced flap angiography and histology with haematoxylin and eosin staining was performed. Dorsal midline tissue was excised for quantification of vascular endothelial growth factor by western blot assay. On day 5 after surgery, the flow-through group exhibited a significantly greater mean(s.d.) flap survival area (97·8(3·5) versus 80·8(10·2) per cent; P = 0·003), microvascular density (303(19) versus 207(41) per mm(2) ; P < 0·001) and perfusion (8·64(0·14) versus 5·95(0·14) perfusion units; P < 0·001) than the flow-end group. The flow-through group exhibited more angiosomes connected by dilated vascular anastomoses between the skin and subcutaneous fasciae. The flow-through blood supply improved pedicle perforator flap survival. Surgical relevance Perforator flap failure is mainly the result of impaired blood supply, as a flow-end blood configuration is nourished only by the perforator terminal branch of the artery. This work showed that the flow-through blood supply nourished by the perforator lateral branch improved flap survival, with dilatation of collateral vascular anastomoses and increased neoangiogenesis. The use of a flow-through configuration improves perforator flap survival and could therefore minimize morbidity resulting from flap necrosis.