Experimental use of prosthetic grafts in microvascular surgery

Interpositional microvascular grafts are very often required in reconstructive surgery for bridging microvascular defects, particularly in association with replantation of amputated segments and free tissue transplantation. The present experimental study was undertaken to evaluate patency and healing of small-diameter polytetrafluoroethylene (PTFE) prostheses and to compare them with those of microvenous grafts. 10-mm long microarterial PTFE grafts of 1 mm internal diameter were implanted into the femoral artery of the rabbit to restore vascular continuity. Patency was assessed by Doppler ultrasound up to four weeks postoperatively. After harvesting, all grafts were evaluated macroscopically and examined by light and transmission electron microscopy. According to our results, five of 20 re-explored PTFE grafts (25%) remained patent at four weeks, while all microvenous grafts were judged to be patent at the same time. The difference between patency rates was found to be statistically significant (p < 0.0001). Recent literature on the experimental use of microvascular prostheses is reviewed and various factors affecting graft patency are discussed.