A Self-Calibrated Tissue Viability Sensor for Free Flap Monitoring

Benny Lo,Melissa Berthelot,Guang-Zhong Yang

doi:10.1109/jbhi.2017.2773998

Benny Lo, Melissa Berthelot + Show 1 more

Open Access

https://doi.org/10.1109/jbhi.2017.2773998

Copy DOI

Abstract

In fasciocutaneous free flap surgery, close postoperative monitoring is crucial for detecting flap failure, as around 10% of cases require additional surgery due to compromised anastomosis. Different biochemical and biophysical techniques have been developed for continuous flap monitoring, however, they all have shortcoming in terms of reliability, elevated cost, potential risks to the patient, and inability to adapt to the patient's phenotype. A wearable wireless device based on near infrared spectroscopy has been developed for continuous blood flow and perfusion monitoring by quantifying tissue oxygen saturation (). This miniaturized and low-cost device is designed for postoperative monitoring of flap viability. With self-calibration, the device can adapt itself to the characteristics of the patients' skin such as tone and thickness. An extensive study was conducted with 32 volunteers. The experimental results show that the device can obtain reliable measurements across different phenotypes (age, sex, skin tone, and thickness). To assess its ability to detect flap failure, the sensor was tested in a pilot animal study. Free groin flaps were performed on 16 Sprague Dawley rats. Results demonstrate the accuracy of the sensor in assessing flap viability and identifying the origin of failure (venous or arterial thrombosis).

Highlights

F ASCIOCUTANEOUS free flap surgery is a common operation for reconstructive surgery following cancer or trauma
For under 30 years old females and males groups, the closer the skin tones are, the higher the correlation is between paired participants of the same group - i.e., same phenotype but different skin tone
The methods usually rely on the experience of the clinical team and their routine assessments of the flap via observation and palpations which can be difficult in the case of patients with dark skin tone or thick skin

Summary

Introduction

F ASCIOCUTANEOUS free flap surgery is a common operation for reconstructive surgery following cancer or trauma. The operation consists of the removal of a tissue flap with all skin layers, fascia, blood vessels and fat from the donor site. The flap is anatomosed onto the receiver site. The survival of the flap is usually ensured by one artery (providing oxygenated blood coming from the heart and lungs) and one vein (retrieving the deoxygenated blood). The challenge of this operation lies upon the proper microvascular anastomosis of the blood vessels to secure flap survival by ensuring oxygen and nutrients are supplied through the anatomosed vessels.

Results

Discussion

Conclusion