Optical monitoring of transplanted free flaps using an implantable near-infrared spectroscopy sensor

Abstract

Background: Free tissue transfer (FTT) is a surgical procedure that involves taking tissue from one area of the body and transplanting it to a surgical wound. Near-infrared spectroscopy (NIRS) has the potential to provide continuous and noninvasive monitoring of FTT hemodynamics. A novel NIRS system with a miniaturized implantable sensor was developed for FTT monitoring in head and neck surgery. The objectives of this study were to obtain post-operative NIRS measurements on a cohort of patients undergoing FTT surgery for head and neck cancer and to evaluate the patient's and clinician's experience with the novel NIRS monitoring method. Methods:The NIRS sensor was fixed over the FTT for 72 hours post-operatively to provide tissue oxygenation parameters, including oxygenated (O2Hb), deoxygenated (HHb), and tissue saturation index (TSI). After 72 hours, the patient and clinicians completed a questionnaire to evaluate their experience with the NIRS system. All patients undergoing FTT surgery had a successful operation with no complications to the FTT. Results:The NIRS data showed visible pulsatile O2Hb signals, indicating the proper microvascular function of the FTT. Furthermore, TSI calculations provided an absolute measure of the oxygenation status of the FTT. The questionnaire indicated that the NIRS sensor did not cause additional discomfort or inconvenience to the patients or clinicians. Conclusions:Our results suggest that the novel NIRS sensor can monitor the FTT continuously and non-invasively for 72 hours with minimal interference to patient care. Incorporating a novel NIRS biosensor into FTT monitoring can improve post-operative care and decrease FTT failure rates.