Fluorescent Augmentation Of The Wisconsin "Blue-Blood" Chicken Thigh Model Enhances The Assessment Of Anastomotic Patency In Supermicrosurgical Training
Nicholas J. Albano, MD1, Weifeng Zeng, MD1, Aaron M. Dingle, PhD1, Christie Lin, PhD2, Adam Uselmann, PhD2, Kevin Eliceiri, PhD3, Samuel Poore, MD, PhD1.
1University of Wisconsin - Madison, Division of Plastic Surgery, Madison, WI, USA, 2OnLume Inc., Madison, WI, USA, 3University of Wisconsin - Madison, Medical Physics, Madison, WI, USA.
PURPOSE: Microsurgery has become a critical component of reconstructive plastic surgery. As these techniques have become more commonplace, we as a field have pushed the application of this practice to include supermicrosurgery, which is the dissection and anastomosis of vessels less than 0.8mm in diameter. Supermicrosurgery has transformed soft tissue reconstruction and lymphedema treatment. Like microsurgery, the skills required for supermicrosurgery are hard earned and difficult to master. Many excellent models for microsurgical training exist, though few have been described for supermicrosurgery. The University of Wisconsin "blue-blood" chicken thigh model has proven to be an excellent source of easily accessed and visualized small vessels (down to 0.25mm), but assessing patency of anastomoses and leaks at this level has proven difficult. We sought to augment this training model with fluorescent imaging to enhance the ability of educators to assess patency of supermicrosurgical anastomoses, therefore improving real-time feedback to trainees.
METHODS: Using the University of Wisconsin "blue-blood" chicken thigh model, seven vessels ranging from 0.35mm-0.45mm were dissected, transected and anastomosed using six, simple, interrupted, 11-0 nylon sutures. The model was then infused with a mixture of "blue blood" (colored saline) and indocyanine green (ICG). Simultaneous white light and fluorescence videos were captured during infusion using a novel wide-field P2 imaging platform (OnLume Inc., Madison, WI), which captures high-resolution, near-infrared fluorescence in real-time under bright, ambient light (representative of an operating room). At the time of video capture, a consensus amongst two surgeons and an imaging specialist was reached regarding the patency of each vessel to create a grading key. All videos (n=14, 7 white light and 7 fluorescent) were separated and randomized into a media presentation. All media were then shown to fellowship trained microsurgeons at the University of Wisconsin, who were asked to grade each anastomosis as either "patent", "not patent" or "unsure". Surgeon accuracy, uncertainty and inter-rater variance were measured for each imaging modality and compared using an unpaired t-test.
RESULTS: A total of seven microsurgeons participated (4 plastic surgery, 3 ENT). When assessing supermicrosurgical anastomoses, use of fluorescence significantly increased surgeon accuracy to 91% compared to 47% with white light alone (p = 0.015). Also, use of fluorescent augmentation decreased surgeon uncertainty to 4% compared to 41% with white light alone. Fluorescence improved inter-rater variability with a standard deviation of 0.29 compared to a standard deviation of 0.6 with white light alone (p = 0.17).
CONCLUSIONS: Augmentation of the University of Wisconsin "blue-blood" chicken thigh model with ICG fluorescence improves accuracy and decreases uncertainty when assessing supermicrosurgical anastomoses in a training setting. Improved real-time feedback will allow for an enhanced educational experience and higher quality training sessions.
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