Image-Guided Perforator Flap Design Using Invisible Near-Infrared Light and Validation with X-Ray Angiography
In this study, 22 pigs were injected with a bolus of indocyanine green (ICG) through a central venous line and observed with a near infrared (NIR) camera to identify dominant perforator flaps from the deep superior epigastric artery (DSEA). After the flap was identified and cut, it was given another ICG injection to confirm perfusion. In 8 of 22 of the pigs NIR ICG was confirmed with x-ray angiography. Researchers made a direct correlation between the results of the NIR ICG and x-ray angiography. This 2009 animal study “validated the clinical relevance of ICG fluorescence to tissue perfusion… the use of NIR wavelengths for fluorescence emission minimizes tissue autofluorescence and photo scatter, resulting in relatively high sensitivity” (Matsui et al 4).
Matsui, A., Lee, B. T., & Frangioni, J. V. (2009). Image-guided perforator flap design using invisible near-infrared light and validation with x-ray angiography. Annals of Plastic Surgery, 63(3), 327-330. Retrieved from www.ncbi.nlm.nih.gov/pmc/articles/PMC2756078
Laser-induced fluorescence of indocyanine green: plastic surgical applications
This article explores the usefulness of ICG fluorescence in the evaluation of pedicle flaps, monitoring of free tissue transfer and replants, as well as the objective determination of burn depth. The authors found that in addition to normal assessment methods (clinical observation), ICG fluorescence provides invaluable information to the plastic surgeon for the developing an efficient surgery plan. For determining burn depth, the authors wrote that ICG made it possible to objectively differentiate burn wounds that require excision and grafting and those that do not. For pedicle flaps, the authors found that a 1999 paper published in the Annals of Plastic Surgery suggested that the information taken from ICG imaging leads to accurate predictions about flap survival.
Holm, C., Mayr, M., Tegeler, J., Becker, A., Pfieffer, U., & Muhlbauer, W. (2003). Laser-induced fluorescence of indocyanine green: plastic surgical applications. European Journal of Plastic Surgery, 26, 19-35. doi: 10.1007/s00238-003-0466-0
Prediction of flap necrosis with laser induced indocyanine green fluorescence in a rat model.
In this study, German researchers from Rechts der Isar Hospital in Munich used a rat model and ICG fluorescence to determine what level of perfusion gave good indication of future flap necrosis. In areas that would become necrotic they found that the perfusion rate was less than 25% than that of the surrounding area.
Giunta, R. E., Holzbach, T., Taskov, C., Holm, P. S., Brill, T., Busch, R., Gansbacher, B., & Biemer, E. (2005). Prediction of flap necrosis with laser induced indocyanine green fluorescence in a rat model. Department of Plastic and Reconstructive Surgery, Munchen, Germany.
Detection of Skin Perforators by Indocyanin Green Fluorescence Nearly Infrared Angiography
This article studies the effectiveness of Green Fluorescence near-infrared angiography in identifying perforator vessels for use in island flap procedures. The Hamamatsu PDE camera was used for the angiographies. The authors found that the PDE was effective in helping to identify perforator vessels up to a depth of 2 cm below skin surface. Vessels were identified prior to raising the flaps. Compared with the Conventional angiography, magnetic resonance angiography,computed tomographic angiography, ultrasonic Doppler flowmetry, laser Doppler imaging, and recovery-enhanced thermography, the PDE was found to identify perforators more precisely and at a higher resolution with less background noise.
Azuma, Ryuichi; Morimoto, Yuji; Masumoto, Kazuma; Nambu, Masaki; Takikawa, Megumi; Yanagibayashi, Satoshi; Yamamoto, Naoto; Kikuchi, Makoto; and Kiyosawa, Tomoharu. “Detection of Skin Perforators by Indocyanin Green Fluorescence Nearly Infrared Angiography” Plastic and Reconstructive Journal. Volume 122, Number 4. October 2008. Pages 1062-1067.