Advanced Surgical Tissue Flap Monitoring for Early Intervention
- An implantable, rapid alert system streamlines tissue flap monitoring, enabling quick action to save surgical flaps and avert additional surgeries.
A new implantable tissue monitoring technology could be a gamechanger for complex head and neck reconstructive surgery, as well as other surgeries. Developed by Vancouver Coastal Health Research Institute (VCHRI) researchers Drs. Babak Shadgan and Donald Anderson, the microvascular free tissue transfer Near-Infrared Spectroscopy (FTT-NIRS) sensor system could reduce the number of revision surgeries needed for invasive skin flap transplants.
“Our technology is a custom, miniaturised version of an advanced Near-Infrared Spectroscopy (NIRS),” Shadgan explains. “It can monitor real-time tissue hemodynamics — circulation within tissues in the form of tissue pulsations — and the level of tissue oxygenation, alerting care teams should these systems become compromised.”
Dr. Babak Shadgan is an assistant professor in the Department of Orthopaedics at the University of British Columbia (UBC), an associate faculty member at the UBC School of Biomedical Engineering, a principal investigator at ICORD and the director of the Implantable Biosensing Laboratory.
“Vascular surgeries could greatly benefit from a sensor like this,” adds Anderson, who has performed microvascular free graft surgery for 41 years.
“This technology could be a gamechanger for a variety of surgical procedures.”
Shadgan and Anderson’s research is looking specifically at the application of the FTT-NIRS sensor and emitter probes in free flap head and neck surgery involving skin tissue sourced from another part of the patient’s body. Complex surgical procedures like this can be required for patients with head or neck cancer or other conditions that require the removal of skin, muscle and potentially bone from the head or neck.
Donor flap tissue taken from the patient must contain arterial and venous connection points to hook up to the arteries and veins at the implant site. Compromised or lost transplanted tissue blood flow often stems from a blocked artery or vein in the graft, such as from a blood clot. Flap emergencies from vascular compromises like this are rare, occurring around four per cent of the time, but have a significant impact on patients and health care providers.
“The critical determinant of flap survival often lies in the immediate postoperative period,” Shadgan explains. “During this vulnerable window, vascular compromise, if not promptly detected, can lead to irreversible flap loss within a few hours, necessitating reoperation and exposing patients to serious complications.”
Attached by wires to a nearby computer, the FTT-NIRS system monitors tissue vital signs for up to 72 hours post-surgery, covering a period in which the risk of graft failure is highest.
Once placed over or implanted within the surgical site, the waterproof FTT-NIRS probes emit near-infrared light — up to two centimetres into tissues — using small, optical sensors that monitor flap hemodynamics and oxygenation. The degree of near-infrared light absorbed by oxygenated and deoxygenated hemoglobin — an iron-rich protein found in red blood cells — supplies the FTT-NIRS algorithm with the necessary data to determine whether tissue oxygenation is too low or tissue circulation is compromised.
Objective, accurate and real-time monitoring of high-risk tissues
Without FTT-NIRS, visual tissue monitoring is conducted at regular intervals by hospital staff. If tissue compromise is suspected, specialised clinicians are called on to determine whether urgent surgical intervention is needed.
“We can get a call in the middle of the night because the tissue flap has lost blood flow,” Anderson shares. “When that happens, immediate action is necessary to save the flap. If the tissues die, a revision surgery is essential, but many factors can impede it, including operating room or donor tissue availability.”
Original source here.