Sixty-five clinical cases of free tissue transfer using long arteriovenous fistulas or vein grafts.

Traumatic limb injuries requiring free tissue transfer for coverage, often lack healthy recipient vessels adjacent to the defect. In these patients, vein grafts are required to bridge the gap of either the artery, vein or both. For the latter situation, a temporary arteriovenous fistula (AVF) can be created and allowed to mature and then divided and used as recipient artery and veins for the free flap. These cases are challenging and several variables including vein graft length, vein graft diameter, and arterial inflow affect the patency of the vessels and the final outcome of the reconstruction. Sixty-five defects were reconstructed with free tissue transfers using vein grafts of significant length (>20 cm for the arterial gap). The ipsilateral or contralateral great saphenous veins were used for vessel lengthening in all cases. Inflow arteries were either major arteries (superficial femoral, popliteal or brachial), or lesser arteries (sural, anterior or posterior tibial, thoracodorsal, or superior gluteal). The patients were divided into those that underwent AVF followed by free tissue transfer in two stages (n = 6), AVF followed by free tissue transfer in one stage (n = 28) and patients that underwent vein grafting for the arterial defect only with (n = 6) or without (n = 25) a simultaneous bypass graft for lower limb revascularization. In the two-stage AVF group, the rate of occlusion of the graft after AVF creation was 50% (3/6); re-exploration rate was 33.3% (2/6); free flap failure rate was 33.3% (2/6); and limb salvage rate was 83.3% (5/6). In the one-stage AVF group: re-exploration rate was 28.6% (8/28); free flap success rate was 89.3% (25/28); and limb salvage rate was 92.9% (26/28). In the long vein graft group for arterial defects only: re-exploration rate was 25.8% (8/31); free flap success rate was 96.8% (30/31); and limb salvage rate was 87.1% (27/31). In patients where the graft was anastomosed to a major artery the re-exploration rate and free flap failure rate were 22.4% (11/49) and 8.2% (4/49). In patients where the graft was anastomosed to a lesser artery, the re-exploration rate and free flap failure rate were 43.4% (7/16) and 12.5% (2/16). The limb salvage rate was comparable in both groups (89.8%, 44/49, versus 87.5%, 14/16). In all groups, patients undergoing re-exploration were noted to have a an arterial gap of 31.78 cm as compared with the patients that did not require re-exploration which had an arterial gap of 26.26 cm. Vein grafting for bridging vascular defects is a safe procedure when proper indications and techniques are followed. Although a longer graft length seemed to be associated with a higher re-exploration rate, there was no statistical significance. One-stage AVFs can be used with good results, however, two-stage AVFs are associated with a high graft occlusion rate, wound failure rate and limb amputation rate. In all cases, a large caliber graft such as the great saphenous vein provided a large (relatively low resistance) conduit for bridging the defect.