Free Flap Monitoring Using Near-Infrared Spectroscopy: A Systemic Review

Although free flaps have become a reliable technique, vascular occlusion remains a significant risk. Flap survival is closely linked to the time interval between the onset and surgical repair of a microvascular problem. The newly emerged near-infrared spectroscopy (NIRS) shows the characteristics of being noninvasive, continuous, easy to use, objective, and immediately reflective, possibly making it an ideal candidate for postoperative flap monitoring.

A systemic review was conducted to determine the clinical value of NIRS in the early detection of vascular crisis associated with a free flap. A literature search was conducted using PubMed (MEDLINE), the Cochrane Library, and Web of Science from database inception through October 2013. Studies were selected strictly according to the inclusion/exclusion criteria by 2 independent reviews.

Eight studies were finally included in this review. A total of 710 free flap procedures were performed in 629 patients using NIRS for monitoring. At the same time, 433 free flaps performed in 430 patients without the use of NIRS were included as the control group. No significant differences in the rates of vascular crisis (P = 0.917) and re-exploration (P = 0.187). However, there were significant differences in the salvage rates (P < 0.001) and flap failure rates (P = 0.003). For the free flaps monitored by NIRS that were not associated with vascular crisis, no alarms were raised by NIRS, giving 100% sensitivity and specificity.

Near-infrared spectroscopy seems to be a highly suitable candidate for postoperative flap monitoring. Larger-scale, randomized, multicentric clinical trials are needed in the future.