Free flaps are regularly used in plastic and reconstructive surgery but have a significant failure rate due to vessel thrombosis in the re-established arterial or venous circulation.

For a successful replantation, it is important to monitor the replanted flap vascularity for the early detection and revision of vascular compromise. Current methods based on the visual sign of ischemic flap is subjective, unreliable and hard to detect.


Case Report


A 59-year-old man suffered from oral cancer, tumor was removed after surgery. Replantation was performed. Postoperatively, the flap microcirculation was monitored using our imaging device immediately after the operation with interval of 5 minute and 40 minutes.

Tissue perfusion of the new flap were measured by illuminating the tissue with a 785-nm-wavelength divergent laser beam. A CMOS camera captures the change in blood flow in new flap postoperatively.

With each measurement, the perfusion data from 150 consecutive images were averaged, resulting in a total measurement time of 10 s for each image.

In each image, 2 rectangular regions of interest (ROIs) were selected in image: the replanted flap (ROI2) and healthy skin of face (ROI3). For each image, the average perfusion in each ROI was calculated.

Test were done at 0-minute, 5 minute & 40 minutes, and the perfusion measured in controlled environment during the observation period.

As we can see the new flap (ROI 2) tissue colour is changed within 5 minute showing good tissue perfusion. In 40 minute new flap is survived in new tissue environment.

The perfusion in the replanted flap and the average perfusion of the healthy tissue immediately after the operation was 5.49 and 6.25 perfusion units, respectively. The postoperative change in the skin perfusion measured & presented below.

In the present case, although the skin perfusion of the replanted flap was lower than that of the healthy skin, no appreciable decrease in the perfusion of the new flap was seen during the postoperative period of observation.


Our device monitor microcirculation and tissue perfusion. It provides quantified information of microcirculation of flaps, which helps the doctor to monitor the healing progress of flaps and in early detection of progressing flap ischemia, hastening the required intervention and maximizing the chances of recovering the flap.