Hyperspectral imaging for monitoring of free flaps of the oral cavity: A feasibility study.

[OBJECTIVES] Hyperspectral imaging (HSI) provides spectral information about hemoglobin, water and oxygen supply and has thus great potential in perfusion monitoring. The aim of the present study was to investigate the feasibility of HSI in the postoperative monitoring of intraoral free flaps.

[METHODS] The 14 patients receiving reconstructive head and neck surgery with a radial forearm free flap were included. HSI was performed intraoperatively (t0), on Day 1 (t1), 2 (t2), 3-6 (t3), 7-9 (t4), 10-11 (t5) and 12-15 (t6) postoperatively. Flap tissue perfusion was assessed on defined regions of interest by calculating the perfusion indices Tissue Hemoglobin Index (THI), hemoglobin oxygenation (StO ), Near Infrared Perfusion Index (NIR Perfusion Index) and Tissue Water Index (TWI).

[RESULTS] Image quality varied depending on location of the flap and time of measurement. StO was >50 intraoperatively and >40 on t1 for all patients. A significant difference was found solely for TWI between t0 and t2 and t0 and t4. No flap loss occurred.

[CONCLUSIONS] The use of HSI in the monitoring of intraoral flaps is feasible and might become a valuable addition to the current clinical examination of free flaps.