Near-infrared spectroscopy for continuous noninvasive monitoring of free flap in head and neck reconstruction: systematic review of the literature and personal experience

Background: Buried free flaps represent a reconstructive challenge concerning monitoring of vitality, which is fundamental for an early detection of flap failure and prompt surgical salvage. Many flap monitoring techniques have been developed over time, and there is still no consensus concerning the best monitoring technique for buried reconstructions. Methods: We performed a systematic review of the literature on NIRS monitoring for head and neck free flaps. Moreover, we presented a case of orbital reconstruction through a buried free myo-fascial anterolateral tight flap (ALTF) in which postoperative monitoring was performed by means of NIRS. Results: Four studies were included with a total of 200 monitored head and neck free flap reconstructions. Flap survival was reported in 96.5% of studies (n = 193/200) with a 3.5% of total flap failure rate (n = 7/200). We monitored the buried myo-fascial ALTF for 7 post-operative days measuring a regional oxygen saturation (rSO(2)) ranging from 55% to 72% (mean = 66%). Conclusions:This device appeared to be an efficient choice for monitoring buried flaps, thanks to its ability to measure tissue perfusion deep under the skin, to the continuous availability of recorded data on the monitor, and to its low impact on the patient. Further prospective studies are advised in order to standardize this monitoring technique and define warning values.