On occasion when planning reconstruction it is clear from the outset that the intended free flap lacks the pedicle length to reach adequate, healthy receptor vessels. This deficiency may not be apparent until the pro-cedure is underway.
Whether no alternative reconstruction is possible or whether past the point of no return, this shortfall, due to an inher-ently or unexpectedly short flap pedicle or due to fibrosis of receptor vessels resulting from trauma or irradiation, can be overcome by use of vein grafts. Sections of superficial vein from the limbs -basilic or cephalic in the arm, short or long saphenous in the leg -can be harvested and inserted between receptor and flap vessels as a vascular conduit to restore a circulation.
Care is required to select a vessel of suitable calibre to provide a reasonable match for the vessels to which the graft is to be anastomosed. Harvest of the vein graft should be atraumatic, with careful bipolar coagulation or ligation of side branches. The length and axial orientation need to be accurate when it is inserted into the defect. Most importantly the direction must be adjusted to take account of the valves in the vein graft.
Consequently, the graft must be reversed before insertion into the arterial side of the circulation, and be orientated nor-mally for bridging the venous deficit. Con-siderable dilatation of vein grafts bridging arterial defects is the norm. This creates a tendency to turbulent flow and, because there are four rather than two anastomoses, the vascular com-plication rate due to thrombosis tends to be high-er than usual.
The technique of microvascular suture is unaltered and each anastomosis can be end-to-end or end-to-side as local circumstances dictate.