Indocyanine green fluorescence angiography could reduce the risk of anastomotic leakage in rectal cancer surgery: a systematic review and meta-analysis of randomized controlled trials

Laparoscopic approach for rectal cancer surgery: triumph of reason or necessity of evolution?

The role of laparoscopy in rectal cancer surgery has evolved considerably since the early 2000s. Initial randomized trials, such as COLOR II and COREAN, indicated that laparoscopic approaches offered similar pathological outcomes with better postoperative recovery than open surgery. In contrast, trials like ACOSOG Z6051 and ALaCaRT suggested noninferiority could not be established. Variability in trial outcomes, focusing on either disease-free survival or pathological measures, initially hindered consensus. Long-term analyses have shown no significant difference in disease-free survival between laparoscopic and open approaches. Meta-analyses have reinforced the benefits of laparoscopic surgery, with reduced mortality and similar oncologic effectiveness to open surgery. However, new techniques like transanal TME (TaTME) and robotic approaches have introduced alternatives, though each presents unique challenges, from recurrence rates in TaTME to costs in robotics. While laparoscopy remains the preferred method due to accessibility and outcomes, robotic surgery is expected to gain traction in high-volume centers.

Indocyanine Green Fluorescence Imaging in Prevention of Colorectal Anastomotic Leakage: A Randomized Clinical Trial

Importance

Performing a bowel anastomosis is a critical step in colorectal resection. Assessing the risk of anastomotic leakage remains challenging, even for experienced surgeons.

Objective

To evaluate the use of indocyanine green (ICG) fluorescence imaging in assessing perfusion at the anastomotic site before and after anastomosis and determine whether it helps reduce anastomotic leakages.

Design, Setting, and Participants

ICG-COLORAL is a prospective, randomized, multicenter study conducted from September 1, 2018, to December 31, 2023. Participants were recruited during preoperative outpatient clinic visits by clinicians not involved in the study, as well as by researchers. Participants were elective patients scheduled for laparoscopic resections, excluding low anterior resections, with planned primary anastomosis in 5 Finnish public hospitals experienced in laparoscopic colorectal surgery.

Intervention

The intervention group received 5 mg of ICG intravenously before and after anastomosis formation. The fluorescence signal was assessed with a near-infrared-capable camera. The control group did not receive ICG fluorescence imaging.

Main Outcome and Measure

The primary outcome measure was the anastomotic leak rate as detected by computed tomography.

Results

Among 1136 patients in the intention-to-treat population, 526 (46.3%) were female and 610 (53.7%) male; they had a mean (SD) age of 70 (11) years, body mass index of 28 (5), and age-adjusted Charlson Comorbidity Index of 5 (3). Overall, the anastomotic leak rate was 5.8% (33/567) in the ICG fluorescence imaging group vs 7.9% (45/569) in the control group (odds ratio [OR], 0.73; 95% CI, 0.48-1.13; P = .16). For right-sided operations, the anastomotic leak rate with ICG fluorescence imaging was 5.9% (16/273) vs 6.7% (20/298) in the control group (OR, 0.87; 95% CI, 0.46-1.65). For left-sided operations, the anastomotic leak rate was 5.2% (14/267) with ICG fluorescence imaging vs 9.5% (23/243) without (OR, 0.55; 95% CI, 0.29-1.05). No patients reported adverse events related to ICG.

Conclusions and Relevance

This study found that routine use of ICG fluorescence imaging does not significantly reduce the overall anastomotic leak rate in laparoscopic colorectal surgery if low anterior resections are excluded but may be beneficial in left-sided operations.

Trial Registration

ClinicalTrials.gov Identifier: NCT03602677.

AUGUR-AIM: Clinical validation of an artificial intelligence indocyanine green fluorescence angiography expert representer

AIM

Recent randomized controlled trials and meta-analyses have demonstrated a reduction in the anastomotic leak rate when indocyanine green fluorescence angiography (ICGFA) is used versus when it is not in colorectal resections. We have previously demonstrated that an artificial intelligence (AI) model, AUGUR-AI, can digitally represent in real time where experienced ICGFA users would place their surgical stapler based on their interpretation of the fluorescence imagery. The aim of this study, called AUGUR-AIM, is to validate this method across multiple clinical sites with regard to generalizability, usability and accuracy while generating new algorithms for testing and determining the optimal mode of deployment for the software device.

METHOD

This is a prospective, observational, multicentre European study involving patients undergoing resectional colorectal surgery with ICGFA as part of their standard clinical care enrolled over a 1-year period. Video recordings of the ICGFA imagery will be computationally analysed both in real time and post hoc by AUGUR-AI, with the operating surgeon blinded to the results, testing developed algorithms iteratively versus the actual surgeon's ICGFA interpretation. AI-based interpretation of the fluorescence signal will be compared with the actual transection site selected by the operating surgeon and usability optimized.

CONCLUSION

AUGUR-AIM will validate the use of AUGUR-AI to interpret ICGFA imagery in real time to the level of an expert ICGFA user, building on our previous work to include a larger, more diverse patient and surgeon population. This could allow future progression to develop the AI model into a usable clinical tool that could provide decision support, including to new/infrequent ICGFA users, and documentary support of the decision made by experienced users.

Quantification of indocyanine green fluorescence angiography in colorectal surgery: a systematic review of the literature

BACKGROUND

Indocyanine green fluorescence angiography (ICGFA) during colorectal surgery associates with reduced post-operative anastomotic complication rates. Because its interpretation is subjective, quantification has been proposed to address inter-user variability. This study reviews the published literature regarding ICGFA quantification during colorectal surgery with a focus on impactful clinical deployment.

METHODS

A systematic review was performed of English language publications regarding clinical studies of ICGFA quantification in colorectal surgery in PubMed, Scopus, Web of Science and Cochrane Library on 29th August 2024, updated to 18th November 2024, following PRISMA guidelines. Newcastle Ottawa scale (NOS) was used to assess quality.

RESULTS

A total of 1428 studies were screened with 22 studies (1469 patients) selected. There was significant heterogeneity of ICGFA methodology, quantification methods and parameter selection and only three studies were NOS "high" quality. Extracorporeal application was most common. Four studies (154 patients) conducted real-time ICGFA analyses (others were post hoc) and four utilised artificial intelligence methods. Eleven studies only included patients undergoing left-sided resection (six focusing specifically on rectal resections). Only one study employed the quantification method to guide intra-operative decision-making regarding colonic transection. Twenty-six different perfusion parameters were assessed, with time from injection to visible fluorescence and maximum intensity the most commonly (but not only) correlated parameters regarding anastomotic complication (n = 18). Other grounding correlates were tissue oxygenation (n = 3, two with hyperspectral imagery), metabolites (n = 2) and surgeon interpretation (n = 5).

CONCLUSION

Quantification of the ICGFA signal for colorectal surgery is feasible but has so far seen limited academic advancement beyond feasibility.

Risk factors for anastomotic leakage and its impact on survival outcomes in radical multivisceral surgery for advanced ovarian cancer: an AGO-OVAR.OP3/LION exploratory analysis

BACKGROUND

Anastomotic leakage is a significant complication following bowel resection in cytoreductive surgery for ovarian cancer. Previous studies have highlighted the detrimental effects of anastomotic leakage on patients' postoperative course. However, there is still a lack of precise identification of the high-risk population and established strategies for preventing its occurrence.

MATERIALS AND METHODS

Patients who underwent bowel resection within the surgical phase III trial AGO-OVAR.OP3/LION investigating the impact of systematic pelvic and paraaortic lymphadenectomy in cytoreductive surgery for primary ovarian cancer were included in this analysis. All patients in the AGO-OVAR.OP3/LION trial had undergone complete cytoreduction with no macroscopic residual disease. We analyzed the occurrence of anastomotic leakage regarding surgical procedure (non-lymphadenectomy vs. lymphadenectomy and non-stoma vs. stoma) using the Fisher test. Risk factors for anastomotic leakage and its prognostic impact on survival were analyzed.

RESULTS

Overall rate of anastomotic leakage was 7.1%. Notably, the Non-lymphadenectomy subgroup had a lower anastomotic leakage rate of 3.0% compared to the lymphadenectomy subgroup (11.2%, P = 0.005). The use of protective stoma placement resulted in an anastomotic leakage rate of 5.5% regardless of lymphadenectomy compared to the Non-Stoma subgroup (7.5%, P = 0.78). Increased blood loss (odds ratio [OR] 1.04 per 100cc, 95% confidence interval [CI] 1.0001-1.09) and lymphadenectomy (OR 3.67, 95% CI 1.41-11.40) were associated with a higher risk of anastomotic leakage. Although anastomotic leakage demonstrated a numerical detrimental impact on median progression-free survival (PFS) (18 months with anastomotic leakage vs. 19 months with Non-anastomotic leakage, hazard ratio [HR] 0.86; 95% CI 0.5 to 1.4, P = 0.53) and median overall survival (OS) (31 months with anastomotic leakage vs. 58 months with Non-anastomotic leakage, HR 0.69; 95% CI 0.4 to 1.2, P = 0.17), the differences were not statistically significant.

CONCLUSION

Anastomotic leakage rates were lower in the Non-lymphadenectomy arm, the current standard of care. Blood loss and lymphadenectomy, as surrogate markers for extensive surgery, were associated with increased risk for anastomotic leakage. These findings highlight the importance of strategies to reduce surgical complexity and perioperative risk to improve clinical outcomes.

Impact of indocyanine green fluorescence angiography on surgeon action and anastomotic leak in colorectal resections. A systematic review and meta-analysis

BACKGROUND

Indocyanine green fluorescence angiography (ICGFA) during colorectal surgery either reassures surgeons regarding intestinal perfusion sufficiency or prompts changed surgical strategy by indicating unsuspected insufficiency. This study describes existing evidence supporting ICGFA use in colorectal surgery, particularly regarding impact on intraoperative decisions.

METHODS

Searches were performed on PubMed, ScienceDirect, Scopus, Web of Science, Cochrane Collaboration databases on 5th December 2023, updated to 19th August 2024. Full English language publications of clinical studies in human patients undergoing colorectal resection with primary anastomosis with the use of ICGFA to assess bowel perfusion intraoperatively, with a control group, were included. Pooling of anastomotic leak (AL) rates was performed for primary outcome analysis with odds ratio (OR) and number-needed-to-treat (NNT) calculated regarding leak reduction.

RESULTS

45 studies comprising 14,333 patients were included, with 7 randomised controlled trials (2911 patients). Overall, AL rate was 6.8%, 4.5% with ICGFA and 8.5% without (OR:0.47, p < 0.001, NNT 23), increasing to 9.5%, 7.5% and 11.6%, respectively, in randomised controlled trials (OR:0.62, p < 0.01, NNT 25). In rectal resections, AL rate was 4.7% with ICGFA vs 11.5% without (OR: 0.38, p < 0.0001). 26 studies performed ICGFA before and after anastomosis formation and 19 used ICGFA only prior to bowel transection, with no significant difference of AL rate reduction on subgroup testing. ICGFA prompted a change in surgical plan in 8.4% of thirty-four studies reporting this. Interestingly, in these studies, leak rates overall were 3.7% when ICGFA matched surgeon judgement versus 5.7% when it prompted change (OR 0.51, p < 0.0025), versus 7.7% without (OR 0.45, p < 0.0001). In rectal resections, these figures were 5%, 8.8% (OR 0.42, p = 0.01) and 12.0% (OR0.39, p < 0.0001), respectively.

CONCLUSIONS

ICGFA colorectal perfusion assessment is associated with lower anastomotic leak rates, especially when confirming surgeons' judgement, and may so stratify patients post-operatively regarding subsequent anastomotic leak rate.

Colorectal surgeons' perspectives on the efficacy of intraoperative bowel perfusion technology with a focus on indocyanine green fluorescence angiography

BACKGROUND

Level one evidence supports indocyanine green fluorescence angiography (ICGFA) use reducing anastomotic leak rates in colorectal surgery. We surveyed surgeons exploring perceptions and factors affecting its use in daily practice and adoption as routine standard of care.

METHODS

Validated electronic survey distributed via the Irish Association of Coloproctology, Royal College of Surgeons in Ireland, European Society of Surgical Oncology, European Association for Endoscopic Surgery, Milan Colorectal Congress and social media.

RESULTS

200 colorectal surgeons (143 consultants) responded. 147 (73.5%) surgeons already use ICGFA, with 90 (61.2%) using it routinely and 69 (46.9%) having a concomitant research interest. Strong clinical evidence base (83.5%) and protocol standardisation (78%) were overall rated most important for bowel perfusion technology with a majority of surgeons rating lack of standardisation and inter-user variability as challenges (similar between consultants and non-consultants). Lack of training and staff, reliability concerns and data security were perceived as significant barriers by selective users compared to non-users, and cost and operating time were perceived as significant barriers by selective users compared to routine users. Most surgeons (41.5%) ideated a number needed to treat (NNT) between 20 and 40 acceptable to advocate routine ICGFA use with 28% requiring a NNT < 20. Most surgeons (38.5%) indicate a per case cost savings of €250-500 supports routine use with 17% advocating it > €750.

CONCLUSIONS

With now a strong evidence base regarding clinical benefit, the survey respondents articulate remaining challenges for ICGFA as standard of care. Levels of expected benefit are largely in keeping with its reported performance.

The impact of indocyanine green fluorescence angiography (ICG-FA) on anastomotic leak rates and postoperative outcomes in colorectal anastomoses: a systematic review

BACKGROUND

Anastomotic leak (AL) is a major complication in colorectal surgery, significantly contributing to perioperative morbidity and mortality. Among strategies to prevent AL, Indocyanine Green Fluorescence Angiography (ICG-FA) has emerged as a promising method for assessing bowel perfusion intraoperatively. This systematic review evaluates the impact of ICG-FA on AL rates and other postoperative outcomes following colorectal anastomoses.

METHODS

A systematic search was conducted in PubMed, PubMed Central, MEDLINE, and Google Scholar, following PRISMA guidelines. Eligible studies included randomized controlled trials (RCTs), prospective cohort studies, and retrospective cohort studies comparing ICG-FA to controls in adult patients undergoing colorectal resections and anastomoses. Data on AL rates, intraoperative characteristics, and postoperative outcomes were extracted. Quality assessment was performed using the Newcastle-Ottawa Scale and the Revised Cochrane Risk-of-Bias Tool.

RESULTS

Sixteen studies (12 retrospective, 1 prospective, and 3 RCTs) involving 3231 patients (1562 ICG-FA and 1669 controls) were included. AL rates were significantly lower in the ICG-FA group (5.18%) compared to controls (11.50%) (p < 0.01). ICG-FA influenced surgical plans in 16.31% of cases. Operative time and ileostomy formation rates were comparable between groups. Reoperation, ileus, and wound infection rates showed minimal differences. Mortality rates were low in both groups (ICG-FA: 0.55%, control: 0.51%).

CONCLUSION

ICG-FA significantly reduces AL rates without increasing operative time or postoperative complications. This technique provides a reliable and safe assessment of bowel perfusion, supporting its integration into colorectal surgery protocols. Further high-quality RCTs are needed to confirm these findings and optimise its application.

Outcomes of loop ileostomy after rectal resection for cancer: A prospective observational multicenter snapshot study from Multidisciplinary Italian Study group for STOmas (MISSTO)

BACKGROUND

Diverting ileostomy is a common procedure in rectal cancer surgery, but it is sometimes associated with a nonnegligible rate of complications. The primary aim of this study was to analyze the incidence and types of stoma-related complications for ileostomy creation after rectal cancer resection. The secondary aims were to report the indications, the technical details, and the efficacy of stoma care provided by ostomy nurses.

METHODS

From 15 February to 31 December 2022, consecutive patients who underwent protective ileostomy after anterior rectal cancer resection were enrolled for prospective data collection at 45 Italian colorectal surgery centers. Univariate and multivariate analyses were performed to evaluate factors that influenced the occurrence of stoma-related complications.

RESULTS

In all, 287 patients were enrolled in the analysis. The short- and long-term postoperative stoma-related morbidity rates were 33.8% and 29.62%, respectively. The most frequent complications were dehydration (17.77%), peristomal skin dermatitis (13.59%), mucocutaneous separation (8.36%), and stoma retraction (4.18%). At the end of follow-up (median time 9 months), the overall stoma closure rate was 83.97% (241 patients), with a median time to stoma closure of 146 days (range 9-483 days). On multivariate analysis, the presence of a stoma nurse was a significant protective factor against stoma-related complications.

CONCLUSIONS

This study demonstrated that the creation of a protective ileostomy is associated to a nonnegligible rate of short-term and long-term postoperative stoma-related morbidity, higher than 25%. The most frequent complication is dehydration, and the presence of stoma-specialized nurses seems to be a protective factor for stoma-related complications. Moreover, more than 15% of protective stomas were not closed at the end of follow-up.

Fluorescence imaging in reducing anastomotic leak after left-sided colorectal resections: a systematic review and updated meta-analysis

BACKGROUND

The objective of this systematic review and meta-analysis was to pool randomized trials of patients undergoing left-sided colorectal anastomosis, comparing the use of fluorescence perfusion imaging versus visual inspection in reducing anastomotic leaks.

METHODS

Databases searched included PubMed, Cochrane Library, Scopus, CINHAL (EBSCO), and Google Scholar based on the concepts: randomized, colorectal, anastomotic leak, and fluorescence imaging. The risk of bias was assessed using RoB2 and the certainty of the evidence with the GRADE Pro tool. The analysis used the log odds ratio for dichotomous data with 95% confidence intervals. Back-transformation of the log odds to odds ratio was performed for the summary of findings. All syntheses used the Random-effects model.

RESULTS

Six randomized trials were included with 1949 patients and 204 events (leaks). Three trials included exclusively rectal cancer patients, while the other three involved benign and malignant pathologies of the sigmoid and rectum. The use of ostomy and preoperative radiation was variable. None of the studies had a high risk of bias. The pooled odds ratio for anastomotic leak reduction with Indocyanine Green (ICG) fluorescence was 0.586 (95% CI: 0.434-0.792). An absolute reduction of 4.7% in leak rates was observed, with no statistical heterogeneity (I2 = 0; p = 0.529). Due to clinical heterogeneity, the quality of evidence was rated moderate.

CONCLUSIONS

The use of ICG is associated with reduced leak rates following left-sided colorectal anastomosis with moderate confidence. ICG may be considered a standard of care given the clinically significant benefit in decreasing anastomotic leaks.

Optimal Indocyanine Green Dosage for Repetitive Angiography for Laparoscopic Colorectal Surgery

Background and Objectives: This study aimed to determine the minimal effective dose of indocyanine green (ICG) required for accurately assessing colonic perfusion during laparoscopic colorectal surgery using a laser-assisted laparoscopic near-infrared (NIR) camera system. Materials and Methods: In 15 patients with colorectal cancer undergoing right hemicolectomy, the left branch of the middle colic artery was preserved, and ICG angiography was performed in the transverse colon. To determine the optimal ICG dose, experimental doses of 0.01, 0.02, 0.03, 0.04, and 0.05 mg of ICG per patient's body weight (kg) were administered intravenously in each group. Additionally, a conventional dose of 0.2 mg/kg was administered in the same patients more than 30 min after the initial dose. For quantitative analysis, the fluorescent expression region was extracted, and fluorescence intensity was analyzed using automatic image processing. Analysis accessibility, T1/2MAX, perfusion time ratio, slope, artificial intelligence (AI)-based perfusion pattern analysis, and washout time were measured in 150 detailed regions of interest in each image. Results: Group 1 (0.01 mg/kg) showed significantly lower accessibility rates for quantitative analysis (48.0%) compared with Groups 2-5 (84.7-100%). The mean slope value in Group 1 was 3.7, which fell below the acceptable threshold (>4) and was significantly lower than that of the other groups (p < 0.001). An acceptable AI-based perfusion pattern was 14.2% in Group 1, significantly lower than in Groups 2-5 (66.4-100%). Washout time was significantly faster with minimal doses compared with conventional doses (39.0 ± 15.8 s vs. 117.5 ± 4.9 s, respectively, p < 0.001). Conclusions: This study supports the use of minimal ICG doses, ranging from 0.02 to 0.05 mg/kg, to optimize repetitive ICG angiography using a laser-assisted laparoscopic NIR camera.

[Modern approaches and technologies to prevent anastomotic leakage in the gastrointestinal tract]

The healing of gastrointestinal anastomoses is a complex biological process influenced by numerous factors. Various strategies to support healing and prevent anastomotic leakage (AL) exist, encompassing preoperative, intraoperative and postoperative measures. Preoperative interventions aim to optimize the patient and the tissue environment, particularly the gut microbiome. Intraoperative measures are technical in nature and include the choice of surgical access, the anastomotic technique and anastomotic reinforcement. Various procedures of the intraoperative diagnostics enable identification of such anastomoses requiring additional protective measures. Recently, indocyanine green (ICG) fluoroscopy has become established for evaluation of tissue perfusion, while newer techniques such as spectral microscopy offer promising possibilities. Postoperative diagnostic methods aim to identify potential AL as early as possible to enable initiation of therapeutic steps even before the onset of symptoms. These procedures range from various imaging techniques to innovative bioresorbable, pH-sensitive implants for early AL detection. Due to the multifactorial genesis of AL and the diverse technical possibilities, no single method will become established for prevention of AL. Instead, a combination of measures will ultimately lead to optimal anastomotic healing. The use of artificial intelligence and analyses based on the data promises a better interpretation of the vast amount of data and therefore to be able to provide general recommendations.

Inferior mesenteric artery preservation techniques in the treatment of diverticular disease: a systematic review of the literature

PURPOSE

The aim of this study is to analyze the impact of different surgical techniques used to preserve the inferior mesenteric artery on patient outcomes following left colonic resection.

METHODS

A search was conducted in PubMed, Embase and Web of Science, founding 4795 articles. The review was registered on PROSPERO (registration number: CRD42024572291).

RESULTS

Eleven articles published between 2001 and 2023, including 989 patients were the object of the present systematic review. Two hundred sixty-two patients (26.5%) underwent Valdoni's technique (Group A), which involves the skeletonization of the IMA, 272 (27.5%) underwent tubular resection (Group B), and 455 (46%) underwent peripheral dissection on sigmoid vessels (Group C). Laparoscopic surgery was predominant in Groups B (100%) and C (94.7%), while Group A had fewer laparoscopic procedures (44.6%). Patients in Group A experienced longer operative times (174.5 ± 27.4 min) and hospital stays (11.4 ± 3.6 days) compared to Groups B and C (165.9 min and 152.35 ± 46.9 min; 8.4 ± 5.7 days and 8.3 ± 3.6 days, respectively). Group A exhibited higher rates of anastomotic leakage (5%) compared to Group C (1.1%) and a higher incidence of bleeding (13%) compared to Group B (1.8%).

CONCLUSION

Valdoni's technique is less favourable for IMA preservation in left colon resection for diverticular disease. Peripheral dissection of sigmoid vessels or tubular resection is recommended for IMA preservation in this context.

A Green Lantern for the Surgeon: A Review on the Use of Indocyanine Green (ICG) in Minimally Invasive Surgery

Indocyanine green (ICG) fluorescence imaging has revolutionized surgical practice across various medical and surgical specialties. This article reviews the clinical applications of ICG in abdominal, urological, thoracic, and gynecological surgery. ICG fluorescence imaging has been widely adopted in general surgery for various applications, including perfusion assessment, intraoperative visualization of the ureter, and tumor localization. It is particularly valuable in evaluating anastomotic leaks and aiding in precise tumor resection during minimally invasive surgeries. Studies have shown mixed results on its effectiveness in reducing anastomotic leak rates, highlighting the need for further research. In thoracic surgery, ICG facilitates the identification and resection of pulmonary bullae, as well as the precise localization of pulmonary nodules during video-assisted surgery. In urology, ICG aids in localizing renal tumors and guiding selective arterial occlusion during partial nephrectomy. Its role in identifying the lymphatic pathway in prostate cancer and sentinel lymph node biopsy in gynecological cancer is also discussed. Despite its benefits, the use of ICG fluorescence faces challenges such as limited tissue penetration, the potential for false results, a lack of standardized protocols, and high equipment costs. Nonetheless, it remains a powerful tool that could improve surgical outcomes.