Postoperative monitoring of free vascularized bone grafts in reconstruction of bone defects

Vascularized bone transfer is increasingly recognized as a very useful and versatile technique for reconstructing large bone defects. It is especially indicated in patients with challenging conditions, such as nonunions, postoncologic resections, severe trauma, and congenital defects. With increasing experience of reconstructive surgeons, improved microsurgical techniques, and more enhanced flaps, the failure rate of free flaps has been reduced in the last decades. Especially, the early-postoperative period is decisive in the outcome of surgery. Several techniques have been described for monitoring the postoperative viability of microsurgical free vascularized graft, and their sensitivity and reliability continues to be the object of animal experiments and clinical trials. The qualities of an optimal monitoring device should be objective, continuous, noninvasive, safe, reproducible, easily managed, and interpretable for the nursing staff, inexpensive, and a clear indicator of changes in arterial and venous circulation. Presently, no one neither fulfills all of the criteria completely nor is uniformly accepted. In this article, relative advantages and disadvantages of these various postoperative monitoring techniques are discussed.