BACKGROUND Colonic perfusion status can be assessed easily by indocyanine green (ICG) angiography to predict ischemia related anastomotic complications during laparoscopic colorectal surgery. Recently, various parameter-based perfusion analysis have been studied for quantitative evaluation, but the analysis results differ depending on the use of quantitative parameters due to differences in vascular anatomical structure. Therefore, it can help improve the accuracy and consistency by artificial intelligence (AI) based real-time analysis microperfusion (AIRAM). AIM To evaluate the feasibility of AIRAM to predict the risk of anastomotic complication in the patient with laparoscopic colorectal cancer surgery. METHODS The ICG curve was extracted from the region of interest (ROI) set in the ICG fluorescence video of the laparoscopic colorectal surgery. Pre-processing was performed to reduce AI performance degradation caused by external environment such as background, light source reflection, and camera shaking using MATLAB 2019 on an I7-8700k Intel central processing unit (CPU) PC. AI learning and evaluation were performed by dividing into a training patient group ( n = 50) and a test patient group ( n = 15). Training ICG curve data sets were classified and machine learned into 25 ICG curve patterns using a self-organizing map (SOM) network. The predictive reliability of anastomotic complications in a trained SOM network is verified using test set. RESULTS AI-based risk and the conventional quantitative parameters including T 1/2 max , time ratio (TR), and rising slope (RS) were consistent when colonic perfusion was favorable as steep increasing ICG curve pattern. When the ICG graph pattern showed stepped rise, the accuracy of conventional quantitative parameters decreased, but the AI-based classification maintained accuracy consistently. The receiver operating characteristic curves for conventional parameters and AI-based classification were comparable for predicting the anastomotic complication risks. Statistical performance verifications were improved in the AI-based analysis. AI analysis was evaluated as the most accurate parameter to predict the risk of anastomotic complications. The F1 score of the AI-based method increased by 31% for T 1/2 max , 8% for TR, and 8% for RS. The processing time of AIRAM was measured as 48.03 s, which was suitable for real-time processing. CONCLUSION In conclusion, AI-based real-time microcirculation analysis had more accurate and consistent performance than the conventional parameter-based method.

Background Indocyanine green (ICG) is a multifunctional dye used in tumor localization, tissue perfusion, and lymph node (LN) mapping during fluorescence-guided laparoscopic colorectal surgery. Purpose This study aimed to establish the optimal protocol for preoperative endoscopic submucosal ICG injection to perform fluorescence lymph node mapping (FLNM), along with undisturbed fluorescent tumor localization and ICG angiography during a single surgery. Methods Colorectal cancer patients (n = 192) were enrolled from May 2017 to December 2019. Colonoscopic submucosal ICG injection was performed 12 to 18 h before surgery. ICG injection protocols were modified based on the total injected ICG (mg) and tattooing site number. The concentrations of ICG were gradually decreased from the standard dose (2.5 mg/ml) to the minimum dose (0.2 mg/ml). Successful FLNM (FLNM-s) was defined as distinct fluorescent LNs observed under NIR camera. The patient’s age, sex, body mass index (BMI), stage, cancer location, obstruction, and laboratory findings were compared between the FLNM-s and failed FLNM (FLNM-f) groups to identify clinical and pathological factors that affect FLNM. Results In the ICG dose section of 0.5 to 1 mg, the success rate was highest within all functions including FLNM, fluorescent tumor localization, and ICG angiography. FLNM-s was related to ICG dose (0.5–1 mg), multiple submucosal injections, location of cancer, camera light source, and lower BMI. In the multivariate analysis, camera light source, non-obesity, and multiple injections were independent factors for FLNM-s). The mean total number of harvested LNs was significantly higher in the FLNM-s group than that in the FLNM-f group (p < 0.001). The number of metastatic lymph nodes was comparable between the two groups (p = 0.859). Conclusions Preoperative, endoscopic submucosal ICG injection with dose range 0.5 to 1 mg would be optimal protocol for multifunctional ICG applications during fluorescence-guided laparoscopic colorectal surgery.

Purpose This preliminary in-vitro study was designed to evaluate the risk factors of compression injury from use of a circular stapler for end-to-end anastomosis. Methods Transparent collagen plates were prepared in dry and wet conditions. Physical properties of collagen plates and porcine colon tissue were examined using a rheometer. Adjustable and fixed-type circular staplers were applied on the collagen plates and the gap distance and compressive pressure were measured during anvil approximation. Tissue injury was evaluated using a compression injury scale. Compression properties were accessed to optimal or overcompression based on gap distance. Results Unacceptable injuries were rarely observed on the dry collagens, regardless of compression device. In the adjustable compression, the compressibility ratio was similar between dry and wet collagen. Overcompression and unacceptable injury increased on the wet collagens. In the fixed compression, the compressibility ratio increased significantly and unacceptable injuries were observed in more than 50% of wet collagens. Peak pressure was significantly higher in the fixed-compression types than those of adjustable type. On bivariate correlation analysis, fixed-compression type and wet collagens were respectively associated with overcompression. On multivariate analysis, edematous collagen condition was the most important risk factor and proximal anvil side, fixed compression type, and overcompression were also independent risk factors for unacceptable compression injury. Conclusion In the edematous tissue condition, unintentional overcompression could be increased and result in tissue injury on the compression line of the circular stapler.

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