Microsurgical free tissue transfer is currently associated with very high success rates and few complications. While interposition vein grafting is clearly an important adjunct to the microsurgeon's armamentarium, it has been associated with higher free flap/replantation failures and complication rates. With appropriate flap planning and surgical techniques, the need for interposition vein grafting should be quite infrequent and hopefully avoided if at all possible. Nevertheless, when necessary, the vein graft remains the gold standard, with virtually all alternative interposition grafts demonstrating lower patency rates. One of the more promising areas of research is the concept of genetic manipulation of the endothelial cell via molecular biological techniques. It is likely that in the near future this may become a clinical reality, not only improving the patency of microsurgical anastomoses and interposition vein grafts, but quite possibly altering the target organ functionally as well.© 1998 Wiley-Liss, Inc.
MICROSURGERY 18:263-266 1998Technical advances in microsurgical expertise, techniques, and suture materials have resulted in free flap success rates of greater than 99% in some clinical series. As microvascular surgery becomes more routine, there is an occasional need, despite preoperative planning, to bridge microvascular defects. Microvascular grafting is clearly an invaluable tool in digital replantation and free tissue transfer to essentially increase the length of the pedicle from the defect to the recipient vessels. The gold standard has long been and continues to be the autogenous vein graft. There is still some controversy regarding the patency rates of free flaps with and without vein grafts. While controlled rat model experiments have demonstrated comparable patency rates for microvascular procedures with and without vein grafts, 1 retrospective clinical reviews often demonstrate lower patency rates in flaps requiring venous interposition grafts.2 The added dissection, surgical time, and possible additional surgical scars of harvesting venous micrografts have led investigators to search for viable alternatives. In order to be considered a viable alternative to the autogenous vein graft, any substitute micrograft should equal the patency rate of vein grafts given the absolute consequences of a failed interpositional graft and subsequent free flap loss.Various synthetic and biologic alternatives to vein grafts have been tried experimentally but, in general, they are complicated by lower patency rates when used as interposition grafts in small diameter low flow vessels. The search for alternate micrografts can be divided into three basic categories: biologic grafts, synthetic or polymer prostheses, and a combination of the two.
CRYOPRESERVED VENOUS AND ARTERIAL ALLOGRAFTSRenewed interest in the use of cryopreserved allografts in peripheral vascular surgery has led to several studies exploring the use of these allografts in microsurgery. In general, clinical use of cryopreserved venous and arterial ...