Immediate and delayed use of arteriovenous fistulae in microsurgical flap procedures: a clinical series and review of published cases.

In microsurgical flap procedures, creation of an arteriovenous fistula (AVF) is a technique of vein grafting where the vein graft is connected to recipient vessels as a flow-through loop prior to harvest and inset of the flap. Controversy exists whether this technique can be used as a 2-stage procedure with the loop and flap transfer accomplished in sequential operations or if the loop and flap transfer should be performed in a single operation. We performed 12 consecutive 1-stage AVF-flap procedures, with 1 flap failure. We combined this series with previously published reports to compare outcomes of 1-stage and 2-stage procedures. We found no significant difference in flap outcomes or complication rates between the 2 strategies. We conclude from our experience and this analysis that single-stage AVF-flap procedures are the optimum application of this technique.

The effect of vascular endothelial growth factor on the healing of ischaemic skin wounds.

The effect of exogenous vascular endothelium growth factor (VEGF) on wound healing in an ischaemic skin flap model was evaluated in this study. Seventy-two Sprague-Dawley rats were used. Normal incisional wound and H-shaped double flaps were used as the wound models. The study was divided into two parts. In Part I, VEGF protein levels were determined from the incisional and H-shaped ischaemic wounds at 12 and 24 h, postoperatively. In Part II, tensile strength and immunohistochemical stains were examined to determine the level of microvessel density (MVD) at 1 and 2 weeks, postoperatively in simple incisional wounds, ischaemic wounds, and ischaemic wounds following 1 ml (1 microg/ml) exogenous VEGF injections into the subcutaneous tissue. The results showed a significantly higher level of VEGF protein in the ischaemic wounds than the incisional wounds. Tensile strength was statistically higher in the incisional wound group and in the ischaemic flap wounds with VEGF treatment compared to the ischaemic flaps with no treatment at 1 week, postoperatively (p>0.05). MVD data indicated that ischaemic wound repair with VEGF treatment had significantly higher MVD than the normal incisional wounds and ischaemic wounds without treatment. We conclude that exogenous application of VEGF can increase early angiogenesis and tensile strength in the ischaemic wound.