A Wireless Near-Infrared Spectroscopy Device for Flap Monitoring: Proof of Concept in a Porcine Musculocutaneous Flap Model

Changsheng Wu, Alina Y. Rwei, Jong Yoon Lee, Wei Ouyang, Lauren Jacobson, Haixu Shen, Haiwen Luan, Yameng Xu, Jun Bin Park, Sung Soo Kwak, Xiaoyue Ni, Wubin Bai, Daniel Franklin, Shuo Li, Yiming Liu, Xinchen Ni, Amanda M. Westman, Matthew R. Macewan, John A. Rogers, Mitchell A. Pet*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Background Current near-infrared spectroscopy (NIRS)-based systems for continuous flap monitoring are highly sensitive for detecting malperfusion. However, the clinical utility and user experience are limited by the wired connection between the sensor and bedside console. This wire leads to instability of the flap-sensor interface and may cause false alarms. Methods We present a novel wearable wireless NIRS sensor for continuous fasciocutaneous free flap monitoring. This waterproof silicone-encapsulated Bluetooth-enabled device contains two light-emitting diodes and two photodetectors in addition to a battery sufficient for 5 days of uninterrupted function. This novel device was compared with a ViOptix T.Ox monitor in a porcine rectus abdominus myocutaneous flap model of arterial and venous occlusions. Results Devices were tested in four flaps using three animals. Both devices produced very similar tissue oxygen saturation (StO 2) tracings throughout the vascular clamping events, with obvious and parallel changes occurring on arterial clamping, arterial release, venous clamping, and venous release. Small interdevice variations in absolute StO 2value readings and magnitude of change were observed. The normalized cross-correlation at zero lag describing correspondence between the novel NIRS and T.Ox devices was >0.99 in each trial. Conclusion The wireless NIRS flap monitor is capable of detecting StO 2changes resultant from arterial vascular occlusive events. In this porcine flap model, the functionality of this novel sensor closely mirrored that of the T.Ox wired platform. This device is waterproof, highly adhesive, skin conforming, and has sufficient battery life to function for 5 days. Clinical testing is necessary to determine if this wireless functionality translates into fewer false-positive alarms and a better user experience.

Original languageEnglish (US)
Pages (from-to)96-105
Number of pages10
JournalJournal of reconstructive microsurgery
Issue number2
StatePublished - Feb 1 2022


  • flap monitoring
  • near-infrared spectroscopy
  • tissue perfusion monitoring

ASJC Scopus subject areas

  • Surgery


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