Enhancing colorectal anastomotic safety with indocyanine green fluorescence angiography: An update

Indocyanine green in left side colorectal surgery segmental resection to decrease anastomotic leak: A parallel retrospective cohort study of 115 patients

BACKGROUND

We investigated the impact of Indocyanine Green (ICG) angiography on reducing anastomotic leakage (AL) after elective left segmental colon resection, including transverse resection. While ICG is widely used in colorectal surgery to assess vascularization, its true effect on AL, particularly in left segmental resections, remains unclear.

STUDY DESIGN

This retrospective, monocentric cohort study included patients undergoing left and transverse colon resection from January 2017 to July 2023. Patients were divided into ICG and no-ICG groups. The primary outcome was AL, with secondary outcomes including postoperative morbidity and length of stay.

RESULTS

Of the 115 patients enrolled, 53 received ICG and 63 did not. AL occurred in 6 patients in the no-ICG group, but none in the ICG group. No significant correlation was found between ICG use and other confounding factors. Postoperative length of stay was also shorter in the ICG group.

CONCLUSIONS

The use of ICG was associated with a reduction in AL, with no cases in the ICG group. These findings suggest a potential benefit of ICG, warranting confirmation in future large-scale studies.

CLINICAL TRIAL REGISTRATION

clinicaltrial.gov (NCT05981937).

Quantification of bowel ischaemia using real-time multispectral Single Snapshot Imaging of Optical Properties (SSOP)

BACKGROUND

Single snapshot imaging of optical properties (SSOP) is a relatively new non-invasive, real-time, contrast-free optical imaging technology, which allows for the real-time quantitative assessment of physiological properties, including tissue oxygenation (StO2). This study evaluates the accuracy of multispectral SSOP in quantifying bowel ischaemia in a preclinical experimental model.

METHODS

In six pigs, an ischaemic bowel segment was created by dividing the arcade branches. Five regions of interest (ROIs) were identified on the bowel loop, as follows: ROI 1: central ischaemic; ROI 2: left marginal; ROI 3: left vascularised; ROI 4: right marginal; and ROI 5: right vascularised. The Trident imaging system, specifically developed for real-time tissue oxygenation imaging using SSOP, was used to image before (T0) and after ischaemia induction. Capillary and systemic lactates were measured at each time point (T0, T15, T30, T45, T60), as well as StO2 values acquired by means of SSOP (SSOP-StO2).

RESULTS

The mean value of SSOP-StO2 in ROI 1 was 30.08 ± 6.963 and was significantly lower when compared to marginal ROIs (ROI 2 + ROI 4: 45.67 ± 10.02 p =  < 0.0001), and to vascularised ROIs (ROI 3 + ROI 5: 48.08 ± 7.083 p =  < 0.0001). SSOP-StO2 was significantly correlated with normalised lactates r = - 0.5892 p < 0.0001 and with histology r =- 0.6251 p = 0.0002.

CONCLUSION

Multispectral SSOP allows for a contrast-free accurate assessment of small bowel perfusion identifying physiological tissue oxygenation as confirmed with perfusion biomarkers.

Deconstructing mastery in colorectal fluorescence angiography interpretation

INTRODUCTION

Indocyanine green fluorescence angiography (ICGFA) is commonly used in colorectal anastomotic practice with limited pre-training. Recent work has shown that there is considerable inconsistency in signal interpretation between surgeons with minimal or no experience versus those consciously invested in mastery of the technique. Here, we deconstruct the fluorescence signal patterns of expert-annotated surgical ICGFA videos to understand better their correlation and combine this with structured interviews to ascertain whether such interpretative capability is conscious or unconscious.

METHODS

For fluorescence signal analysis, expert-annotated ICGFA videos (n = 24) were quantitatively interrogated using a boutique intensity tracker (IBM Research) to generate signal time plots. Such fluorescence intensity data were examined for inter-observer correlation (Intraclass Correlation Coefficients, ICC) at specific curve milestones: the maximum fluorescence signal (Fmax), the times to both achieve this maximum (Tmax), as well as half this maximum (T1/2max) and the ratio between these (T1/2/Tmax). Formal tele-interview with contributing experts (n = 6) was conducted with the narrative transcripts being thematically mapped, plotted, and qualitatively analyzed.

RESULTS

Correlation by mathematical measures was excellent (ICC0.9-1.0) for Fmax, Tmax, and T1/2max (0.95, 0.938, and 0.925, respectively) and moderate (0.5-0.75) for T1/2/Tmax (0.729). While all experts narrated a deliberate viewing strategy, their specific dynamic signal appreciation differed in the manner of description.

CONCLUSION

Expert ICGFA users demonstrate high correlation in mathematical measures of their signal interpretation although do so tacitly. Computational quantification of expert behavior can help develop the necessary lexicon and training sets as well as computer vision methodology to better exploit ICGFA technology.

Effect of Indocyanine Green Fluorescence Angiography on Anastomotic Leakage in Patients Undergoing Colorectal Surgery: A Meta-Analysis of Randomized Controlled Trials and Propensity-Score-Matched Studies

Background

Meta-analyses have demonstrated that indocyanine green (ICG) can effectively prevent anastomotic leakage (AL) after colorectal surgery. However, recent evidence from large randomized controlled trial (RCT) has suggested that ICG fluorescence angiography does not reduce the incidence of AL in colorectal surgery. This study was conducted to evaluate the value of ICG for the prevention of AL following colorectal surgery.

Methods

Up to September 16, 2021, PubMed, Embase, China National Knowledge Infrastructure, Web of Science, Scopus, Cochrane Library, and VIP databases were searched for RCTs and propensity-score matched (PSM) studies evaluating the use of ICG for prevention of AL after colorectal surgery. Mean differences (MDs) or odds ratios (ORs) and 95% confidence intervals (CI) were calculated.

Results

Twenty studies (5 RCTs and 15 PSM studies) with a total of 5,125 patients were included. ICG did not reduce the reoperation rate (OR, 0.71; 95% CI, 0.38, 1.30), conversion rates (OR, 1.34; 95% CI, 0.65, 2.78), or mortality (OR, 0.50; 95% CI, 0.13, 1.85), but ICG did reduce the incidence of AL (OR, 0.46; 95% CI, 0.36, 0.59) and symptomatic AL (OR, 0.48; 95% CI, 0.33, 0.71), and reduced the length of hospital stay (MD,-1.21; 95% CI,-2.06,-0.35) and intraoperative blood loss (MD,-9.13; 95% CI,-17.52,-0.74). In addition, ICG use did not increase the incidence of total postoperative complications (OR, 0.93; 95% CI, 0.64, 1.35), postoperative ileus (OR, 1.26; 95% CI, 0.53, 2.97), wound infection (OR, 0.76; 95% CI, 0.44, 1.32), urinary tract infection (OR, 0.87; 95% CI, 0.30, 2.59), pulmonary infection (OR, 0.23; 95% CI, 0.04, 1.45), urinary retention (OR, 1.08; 95% CI, 0.23, 5.04), anastomotic bleeding (OR, 1.53; 95% CI, 0.27, 8.60), anastomotic stricture (OR, 0.74; 95% CI, 0.24, 2.29), or operative time (MD,-9.64; 95% CI,-20.28, 1.01).

Conclusions

ICG can effectively reduce the incidence of AL, without prolonging the operation time or increasing postoperative complications in colorectal surgery.

Systematic Review Registration

www.crd.york.ac.uk/prospero/#recordDetails, identifier: CRD42021279064.