Abstract
Flap failure due to impaired blood flow occurs at a certain rate in tissue grafting using free flaps. Early detection of flap failure leads to successful protection of the free flap. The purpose of this study is to develop a flexible optical-sensor-array device that can be attached on the patient's body to detect the flap failure. The prototype device is made up of a silicone (PDMS) substrate and sensors consisted of a green LED and a phototransistor embedded on the substrate with a gap for preventing interference. Animal models of ischemia and congestion were used to evaluate the performance of the device. The device monitored blood flow signals in the flaps of each model and its reference counterpart (controlled flaps) and subsequently detected the flap failure. The results demonstrated that blood flow signals were stably obtained from the controlled flaps, while the signals from ischemia flaps disappeared immediately after the artery ligation. After the vein ligation, a gradual decrease in blood flow signals with time was observed from congestive flaps, and 40 minutes later, the blood flow signals disappeared. Consequently, the device successfully detected the flap failure.
