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Fluorescence-Guided Thoracoscopic Surgery Using Indocyanine Green (ICG) in Canine Cadavers: A Descriptive Evaluation of Video-Assisted (VATS) and Robot-Assisted (RATS) Approaches
by
, , and
Francisco M. Sánchez-Margallo
1,*
,
Lucía Salazar-Carrasco
2
,
Manuel J. Pérez-Salazar
2 and
Juan A. Sánchez-Margallo
2
1
Scientific Direction, Jesús Usón Minimally Invasive Surgery Center, 10171 Cáceres, Spain
2
Bioengineering and Health Technologies Unit, Jesús Usón Minimally Invasive Surgery Center, 10171 Cáceres, Spain
*
Author to whom correspondence should be addressed.
Animals 2025, 15(24), 3519; https://doi.org/10.3390/ani15243519
Submission received: 15 September 2025
/
Revised: 14 November 2025
/
Accepted: 2 December 2025
/
Published: 5 December 2025
(This article belongs to the Section Companion Animals)
Simple Summary
Chylothorax in dogs often requires surgery to ligate the thoracic duct, but anatomical variation and poor visualization can lead to incomplete ligation and recurrence. We tested two minimally invasive approaches: video-assisted thoracoscopy (VATS) and robot-assisted thoracoscopy with the Versius™ platform (RATS) to visualize the duct using near-infrared (NIR) fluorescence after indocyanine green (ICG) injection in four canine cadavers. Both methods identified the duct in all specimens. VATS produced brighter overall fluorescence, whereas RATS delivered higher duct-to-background contrast and greater precision due to three-dimensional imaging and wristed instruments. These findings support the use of fluorescence-guided minimally invasive surgery as a practical approach to enhance thoracic duct mapping. In vivo studies are necessary to confirm whether the robot-assisted approach provides superior outcomes and reduced recurrence rates.
Abstract
Precise intraoperative identification of the canine thoracic duct remains challenging due to anatomical variability and limited visualization. This exploratory cadaveric feasibility study aimed to describe the technical applicability of fluorescence-guided thoracic duct mapping using video-assisted thoracoscopy (VATS) and robot-assisted thoracoscopy (Versius™ system). Four adult Beagle cadavers underwent bilateral thoracoscopic exploration after intranodal injection of indocyanine green (ICG, Verdye®, 0.05 mg/kg; 0.5 mL). Near-infrared (NIR) fluorescence imaging enabled real-time visualization of the thoracic duct and its branches. Fluorescence quality was quantitatively characterized using signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and contrast resolution (CR) calculated from standardized image frames. Both approaches achieved successful duct identification in all cadavers. VATS provided brighter overall fluorescence, whereas the robotic-assisted approach offered stable imaging, enhanced instrument dexterity, and improved duct-to-background discrimination. These findings confirm the feasibility of fluorescence-guided thoracic duct identification using both minimally invasive modalities in canine cadavers. The standardized assessment of optical parameters proposed here may support future in vivo studies to optimize imaging protocols and evaluate the clinical impact of fluorescence-guided thoracic duct surgery in dogs.
