What is the baseline of Total Oxygenation Index (TOI) in transplanted tissue after Free Tissue Transfer (FTT) surgery

Head and neck cancer is the seventh most common cancer worldwide, with over 660,000 new cases and 325,000 deaths each year. After removing a tumor, a common reconstructive method called Free Tissue Transfer (FTT) is used. This involves transplanting skin, muscle, or bone, along with its blood supply, from one part of the body to the surgical site. 

A proper blood supply to the transplanted tissue is crucial. If blood flow is inadequate, complications or tissue death can occur, which may require further surgery or even lead to death. Early detection of changes in blood flow and oxygen levels is key to preventing these issues.

Currently, FTT monitoring relies on hourly visual checks by trained medical staff, which are subjective and not continuous. To address this, our team has developed an optical non-invasive sensor using near-infrared spectroscopy (NIRS). This technology uses light to measure blood flow and oxygen levels in the tissue. It provides a metric called Tissue Oxygenation Index (TOI), which reflects the health of the transplanted tissue. 

Initial testing on four patients showed the sensor could monitor tissue oxygenation continuously for 72 hours after surgery. Amir’s project aims to enhance this technology by creating a wireless, non-invasive sensor. It will transmit data to a monitor and remote systems, allowing doctors to track patient status and receive alerts if TOI changes. 

The next steps include clinical trials with 60 FTT patients to establish TOI baselines and improve the sensor’s hardware and software. The device recently received approval from Health Canada and Clinical Trial governments body. This innovation aims to reduce FTT failures, improve patient outcomes, and lower healthcare costs.