TIMING OF PEDICLE THROMBOSIS AND FLAP LOSS AFTER FREE-TISSUE TRANSFER

A series of 990 consecutive free flaps was reviewed to determine how o ften pedicle thrombosis occurred, when it occurred, and if the timing of thrombosis detection had any relationship to the probability of fla p salvage. The overall thrombosis rate was 5.1 percent, and the flap l oss rate was 3.2 percent. The majority (80 percent) of thrombi occurre d within the first 2 postoperative days. Only 5 thrombi (10 percent) w ere known to have occurred after the third postoperative day. No flaps that developed thrombosis after the third postoperative day were salv aged successfully. Had flap monitoring been discontinued after the fir st 3 postoperative days, our results in this series would have been un changed. Thrombosis of the vein (54 percent) was more common than arte rial thrombosis (20 percent) or thrombosis of both artery and vein (12 percent). Almost all purely arterial thrombi (90 percent) occurred be fore the end of the first postoperative day, whereas 41 percent of all ve nous thrombi occurred later. We conclude that arterial monitoring is most critical immediately after surgery. Beginning on the second po stoperative day, venous monitoring becomes progressively more importan t to flap success. The cost-effectiveness of postoperative monitoring of free flaps is greatest during the first 2 days, after which it decr eases significantly.