Remote monitoring of head and neck free flaps using near infrared spectroscopic tissue oximetry

Purpose: Near infrared spectroscopy (NIRS) measures tissue oximetry and perfusion of free tissue transfer with the advantage of remote wireless monitoring for free tissue transfer. It has been widely used in breast and extremity reconstruction but has had limited adoption in the head and neck. Materials and methods: A retrospective review of head and neck microvascular reconstruction by three different surgical services over 15 months at one tertiary care hospital was performed. Demographics, flap type, monitoring technique, complications, and flap outcomes were recorded. Monitoring techniques were (1) implantable/handheld Doppler or (2) NIRS. Flap monitoring outcomes were evaluated using multivariate analysis. Results: 119 flaps were performed by four surgeons with a success rate of 92% (109/119). Flaps were monitored with Doppler (40%) or NIRS (60%). There was no difference in flap success based on monitoring technique. An ROC analysis identified that the optimal cutoff in immediate StO₂ for classifying flap success at discharge was 68%. Conclusions: NIRS was successfully implemented in a high-volume head and neck reconstructive practice. NIRS remote monitoring allowed for flap surveillance without requiring in-hospital presence and was able to identify both arterial and venous compromise.