This is a video which discusses the Vioptix tOX system of near infrared spectroscopy for the monitoring of free tissue transfer. Having information as to the health of the microvascular anastomosis is critical to improved patient outcome and free tissue survival. With better monitoring, supplementing clinical evaluation, surgeons are able to assess the health of the free tissue better and potentially improve patient outcome. The example in this video is of a free breast reconstruction where the tOX system was used to remotely monitor the free flap. The surgeon can follow the flap real time and more importantly follow trend lines to help predict flap complications.