A Novel Fluorescence-Based Leak Test Method for Rectal Anastomoses Using Aerosolized Indocyanine Green

BACKGROUND: The intraoperative air leak test is commonly performed during rectal surgery to evaluate anastomotic integrity. However, its drawbacks include occasional difficulties in visualizing the exact point of the leak while maintaining the pelvis under saline, the need for repeat testing to identify the leak point, and a lack of continuous visualization of the leak point. OBJECTIVE: To evaluate the feasibility and clinical applicability of using aerosolized indocyanine green, a fluorescent tracer, for detecting rectal anastomotic leakage. DESIGN: Animal preclinical study. SETTING: Animal laboratory at Kagawa University. PATIENTS: Six healthy adult female beagles were included. INTERVENTIONS: An anastomotic leakage model with a single air leak point was created in each dog. Indocyanine green was aerosolized using a nebulizer kit with a stream of carbon dioxide flowing at 1.5 to 2.0 L/min. The aerosol was administered into the rectum transanally, and laparoscopic observations were performed. MAIN OUTCOME MEASURES: Air leak points were observed using a near-infrared fluorescence laparoscope, after which the presence of corresponding indocyanine green fluorescence was verified. RESULTS: Aerosolized indocyanine green was visualized laparoscopically at all anastomosis sites but not elsewhere. The median time from the administration of the aerosol to its visualization was 4.5 seconds. Pathological examinations were performed 4 weeks postsurgery in all dogs, and no histological abnormalities related to aerosolized indocyanine green administration were observed at the anastomosis sites. LIMITATIONS: The leak points were surgically created and did not occur naturally. CONCLUSIONS: Visualization of air leaks at the sites of rectal anastomosis was laparoscopically achievable by administering aerosolized indocyanine green transanally into the rectum in our canine model. This novel fluorescent leak test could be a valid alternative to established methods. (C) The ASCRS 2023