Intraoperative angiography with indocyanine green to assess anastomosis perfusion in patients undergoing laparoscopic colorectal resection: results of a multicenter randomized controlled trial

Quantitative fluorescence angiography aids novice and experienced surgeons in performing intestinal resection in well-perfused tissue

Background

Anastomotic leakage (AL) after gastrointestinal resection is a devastating complication with huge consequences for the patient. As AL is associated with poor blood supply, tools for objective assessment of perfusion are in high demand. Indocyanine green angiography (ICG-FA) and quantitative analysis of ICG-FA (q-ICG) seem promising. This study aimed to investigate whether ICG-FA and q-ICG could improve perfusion assessment performed by surgeons of different experience levels.

Methods

Thirteen small bowel segments with a varying degree of devascularization, including two healthy sham segments, were constructed in a porcine model. We recruited students, residents, and surgeons to perform perfusion assessment of the segments in white light (WL), with ICG-FA, and after q-ICG, all blinded to the degree of devascularization.

Results

Forty-five participants fulfilled the study (18 novices, 12 intermediates, and 15 experienced). ICG and q-ICG helped the novices correctly detect the healthy bowel segments to experienced surgeons’ level. ICG and q-ICG also helped novice surgeons to perform safer resections in healthy tissue compared with normal WL. The relative risk (RR) of leaving ischemic tissue in WL and ICG compared with q-ICG, even for experienced surgeons was substantial, intermediates (RR = 8.9, CI95% [4.0;20] and RR = 6.2, CI95% [2.7;14.1]), and experienced (RR = 4.7, CI95% [2.6;8.7] and RR = 4.0, CI95% [2.1;7.5]).

Conclusion

Q-ICG seems to guide surgeons, regardless of experience level, to safely perform resection in healthy tissue, compared with standard WL. Future research should focus on this novel tool’s clinical impact.

Dynamic Serosal Perfusion Assessment during Colorectal Resection Using Visible Light Spectroscopy

INTRODUCTION

Anastomotic leakage (AL) in colorectal surgery occurs with an incidence of up to 20%. Bowel perfusion is deemed to be one of the most important factors for anastomotic healing. However, not much is known about its variability during colorectal surgery and its impact on the outcome. Therefore, this study aims to evaluate serosal oxygen saturation patterns during colorectal resections with visible light spectroscopy (VLS).

MATERIALS AND METHODS

Bowel perfusion in patients undergoing left-sided colorectal resections was assessed at different timepoints during surgery using VLS on the colonic serosa. The primary outcome parameter was serosal oxygen saturation (StO2) at the anastomosis during different timepoints of surgery.

RESULTS

We included 50 patients who underwent colorectal resection for bowel cancer (58%) and diverticular disease (34%). StO2 at the proximal site of the anastomosis increased significantly throughout the surgery (mean difference 3.61%; 95% CI -6.22 to -1.00; p = 0.008). However, aberrancy from this identified perfusion pattern had no impact on the postoperative outcome.

CONCLUSION

During colorectal resections, we could demonstrate an increase of the colonic StO2 throughout surgery. Appearance of AL was not associated with lower StO2, underlining the multifactorial genesis of developing AL.

Defining indocyanine green fluorescence to assess anastomotic perfusion during gastrointestinal surgery: systematic review

Background

The aim of this systematic review was to identify all methods to quantify intraoperative fluorescence angiography (FA) of the gastrointestinal anastomosis, and to find potential thresholds to predict patient outcomes, including anastomotic leakage and necrosis.

Methods

This systematic review adhered to the PRISMA guidelines. A PubMed and Embase literature search was performed. Articles were included when FA with indocyanine green was performed to assess gastrointestinal perfusion in human or animals, and the fluorescence signal was analysed using quantitative parameters. A parameter was defined as quantitative when a diagnostic numeral threshold for patient outcomes could potentially be produced.

Results

Some 1317 articles were identified, of which 23 were included. Fourteen studies were done in patients and nine in animals. Eight studies applied FA during upper and 15 during lower gastrointestinal surgery. The quantitative parameters were divided into four categories: time to fluorescence (20 studies); contrast‐to‐background ratio (3); pixel intensity (2); and numeric classification score (2). The first category was subdivided into manually assessed time (7 studies) and software‐derived fluorescence–time curves (13). Cut‐off values were derived for manually assessed time (speed in gastric conduit wall) and derivatives of the fluorescence–time curves (F_max, T_1/2, TR and slope) to predict patient outcomes.

Conclusion

Time to fluorescence seems the most promising category for quantitation of FA. Future research might focus on fluorescence–time curves, as many different parameters can be derived and the fluorescence intensity can be bypassed. However, consensus on study set‐up, calibration of fluorescence imaging systems, and validation of software programs is mandatory to allow future data comparison.

ICG fluorescence imaging in colorectal surgery: a snapshot from the ICRAL study group

BACKGROUND

Fluorescence-guided visualization is a recently proposed technology in colorectal surgery. Possible uses include evaluating perfusion, navigating lymph nodes and searching for hepatic metastases and peritoneal spread. Despite the absence of high-level evidence, this technique has gained considerable popularity among colorectal surgeons due to its significant reliability, safety, ease of use and relatively low cost. However, the actual use of this technique in daily clinical practice has not been reported to date.

METHODS

This survey was conducted on April 2020 among 44 centers dealing with colorectal diseases and participating in the Italian ColoRectal Anastomotic Leakage (iCral) study group. Surgeons were approximately equally divided based on geographical criteria from multiple Italian regions, with a large proportion based in public (89.1%) and nonacademic (75.7%) centers. They were invited to answer an online survey to snapshot their current behaviors regarding the use of fluorescence-guided visualization in colorectal surgery. Questions regarding technological availability, indications and techniques, personal approaches and feelings were collected in a 23-item questionnaire.

RESULTS

Questionnaire replies were received from 37 institutions and partially answered by 8, as this latter group of centers do not implement fluorescence technology (21.6%). Out of the remaining 29 centers (78,4%), fluorescence is utilized in all laparoscopic colorectal resections by 72.4% of surgeons and only for selected cases by the remaining 27.6%, while 62.1% of respondents do not use fluorescence in open surgery (unless the perfusion is macroscopically uncertain with the naked eye, in which case 41.4% of them do). The survey also suggests that there is no agreement on dilution, dosing and timing, as many different practices are adopted based on personal judgment. Only approximately half of the surgeons reported a reduced leak rate with fluorescence perfusion assessment, but 65.5% of them strongly believe that this technique will become a minimum requirement for colorectal surgery in the future.

CONCLUSION

The survey confirms that fluorescence is becoming a widely used technique in colorectal surgery. However, both the indications and methods still vary considerably; furthermore, the surgeons' perceptions of the results are insufficient to consider this technology essential. This survey emphasizes the need for further research to reach recommendations based on solid scientific evidence.

The histopathological evaluation based on the indocyanine green fluorescence imaging of regional lymph node metastasis of splenic flexural colon cancer by near-infrared observation

PURPOSE

The purpose of this study was to investigate the relationship between the fluorescence on indocyanine green fluorescent imaging (ICG-FI) and the histopathological findings of regional lymph node (LN) metastasis of splenic flexural colon cancer.

METHODS

From July 2013 to December 2018, consecutive patients with splenic flexural colon cancer with a preoperative diagnosis of N0 who underwent laparoscopic surgery were enrolled. The distribution of cancer sites in metastatic LNs (completely/not completely occupied by metastatic foci) was evaluated with hematoxylin and eosin-stained preparations. We compared the relationship between the distribution of cancer site and fluorescence of paraffin block in metastatic LNs.

RESULTS

Seventy-two patients were enrolled, of whom 13 (18.1%) had metastatic LNs. A total of 25 metastatic LNs were evaluated. The median short axis of the occupied LNs was 4.5 mm, which was significantly larger than that of the non-occupied LNs (3.0 mm; p = 0.036). In the near-infrared observation of the paraffin block, the completely occupied LNs showed no fluorescence, regardless of the LN size, but 8 of 10 non-occupied LNs showed fluorescence (p < 0.001). Even the non-occupied LNs that showed fluorescence, the cancer site did not show fluorescence.

CONCLUSIONS

The occupied LNs showed no fluorescence, but 80% of the non-occupied LNs showed fluorescence. Even in non-occupied LNs that showed fluorescence, the cancer site did not show fluorescence. This demonstrated LN dissection should not be omitted, even if no fluorescence is noted on intraoperative ICG-FI.

Fluorescence-guided cancer surgery-A new paradigm

Fluorescence-guided surgery is an emerging and promising operative adjunct to assist the surgeon in various aspects of oncosurgery, ranging from assessing perfusion, identification, and characterization of tumors and peritoneal metastases, mapping of lymph nodes/leaks, and assistance for fluorescence-guided surgery (FGS). This study aims to provide an overview of principles, currently available dyes, platforms, and surgical applications and summarizes the available literature on the utility of FGS with a focus on abdomino-thoracic malignancies.

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

Reducing anastomotic leak (AL) continues to be a main focus in colorectal research. Several new technologies have been developed with an aim to reduce this from mechanical devices to advanced imaging techniques. Fluorescence angiography (FA) with indocyanine green (ICG) in colorectal surgery is now a well-established technique and may have a role in reducing AL. By using FA, we are able to have a visual representation of perfusion which aids intraoperative decision making. The main impact is change in the level of bowel transection at the proximal side of an anastomosis and provide a more objective and confident assessment of bowel perfusion. Previous studies have shown that routine FA use is safe and reproducible. Recent results from randomized control trials and meta-analyses show that FA use reduces the rate of anastomotic leak. The main limitation of FA is its lack of ability to quantify perfusion. Novel technologies are being developed that will quantify tissue perfusion and oxygenation. Overall, FA is a safe and feasible technique which may have a role in reducing AL.

Fluorescence-Based Quantification of Gastrointestinal Perfusion: A Step Towards an Automated Approach

Background: Qualitative fluorescence angiography (FA) provides insights into intestinal tissue perfusion, but today it is not yet accurate in predicting anastomotic leakage. To improve peroperative detection of impaired perfusion, quantified parameters should be investigated using a standardized method. The aim of this study was to develop a (semi)automated algorithm for comprehensive and convenient analysis of FA parameters. Materials and Methods: An analysis tool was developed for the extraction of quantified FA parameters. The start- and endpoint of intensity increase (T₀ and Tmax) were automatically detected in the intensity-time curves. Algorithm performance was measured against manual assignment of T₀ and Tmax by 9 independent observers in 18 in vivo generated test signals, using the intraclass correlation coefficient (ICC). Characteristics of parameter T1∕2 (time to 50% of maximal intensity) were analyzed in normally perfused small intestine of 32 subjects who underwent robotic laparoscopic surgery. Since ethical approval was not required under the Dutch law, the need for informed consent was waived. Results: Automated detection of T₀ and Tmax was successful in all subjects. Output of the algorithm had an excellent agreement with the median of the human observations: ICC = 0.95 (95% confidence interval: 0.86-0.96). Overall, T1∕2 had a median value of 5.1 (interquartile range = 2.4) seconds and a minimal and maximal value of 1.3 and 9.9 seconds, respectively. Conclusions: The presented method provided convenient data analysis in the search for effective FA quantification. Future research should expand the data to find adequate threshold values for peroperatively identifying insufficient perfusion and investigate the influence of physiological conditions.

Intra-operative assessment of left-sided colorectal anastomotic integrity: a systematic review of available techniques

AIM

Anastomotic leak (AL) after colorectal resection is associated with increased rates of morbidity and mortality: potential permanent stoma formation, increased local recurrence, reduced cancer-related survival, poor functional outcomes and associated quality of life. Techniques to reduce leak rates are therefore highly sought.

METHOD

A literature search was performed for published full text articles using PubMed, Cochrane and Scopus databases with a focus on colorectal surgery 1990-2020. Additional papers were detected by scanning references of relevant papers.

RESULTS

A total of 53 papers were included after a thorough literature search. Techniques assessed included leak tests, endoscopy, perfusion assessment and fluorescence studies. Air-leak testing remains the most commonly used method across Europe, due to ease of reproducibility and low cost. There is no evidence that this reduces the leak rate; however, identification of a leak intra-operatively provides the opportunity for either suture reinforcement or formal takedown with or without re-do of the anastomosis and consideration of diversion. Suture repair alone of a positive air-leak test is associated with an increased AL rate. The use of fluorescence studies to guide the site of anastomosis has demonstrated reduced leak rates in distal anastomoses, is safe, feasible and has a promising future.

CONCLUSION

Although over reliance on any assessment tool should be avoided, intra-operative techniques with the aim of reducing AL rates are increasingly being employed. Standardization of these methods is imperative for routine use. However, in the interim it is recommended that all anastomoses should be assessed intra-operatively for mechanical failure, particularly distal anastomoses.

Indocyanine green fluorescence angiography prevents anastomotic leakage in rectal cancer surgery: a systematic review and meta-analysis

BACKGROUND

The role of intraoperative use of indocyanine green (ICG) fluorescence angiography (ICGFA) to prevent anastomotic leakage (AL) in rectal cancer surgery remains controversial.

METHODS

The systematic review for studies evaluating ICGFA in patients undergoing rectal cancer surgery in PubMed, Embase, Web of Science, and the Cochrane Library was performed up to April 30, 2020. The primary outcome was the incidence of AL. The analysis was performed using RevMan v5.3 and Stata v12.0 software.

RESULTS

Eighteen studies comprising 4038 patients were included. In the present meta-analysis, intraoperative use of ICGFA markedly reduced AL rate (OR = 0.33; 95% CI: 0.24-0.45; P < 0.0001; I2 = 0%) in rectal cancer surgery, which was still significant in surgeries limited to symptomatic AL (OR = 0.44; 95% CI: 0.31-0.64; P < 0.0001; I2 = 22%). This intervention was also associated with shorter postoperative stays (MD = - 1.27; 95% CI: - 2.42 to - 0.13; P = 0.04; I2 = 60%). However, reoperation rate (OR = 0.61; 95% CI: 0.34-1.10; P = 0.10; I2 = 6%), ileus rate (OR = 1.30; 95% CI: 0.60-2.82; P = 0.51; I2 = 56%), and surgical site infection rate (OR = 1.40; 95% CI: 0.62-3.20; P = 0.42; I2 = 0%) were not significantly different between the two groups.

CONCLUSION

The use of ICGFA was associated with a lower AL rate after rectal cancer resection. However, more multi-center RCTs with large sample size are required to further verify the value of ICGFA in rectal cancer surgery.

[Risk factors associated with non-closure of defunctioning stoma in patients with rectal cancer: univariate and multivariate analysis]

OBJECTIVE

To identify the risk factors associated with non-closure of defunctioning stoma in patients with rectal cancer.

MATERIAL AND METHODS

A retrospective analysis included patients who underwent surgical treatment at the Ryzhikh National Medical Research Centre of Coloproctology for the period from March 2017 to August 2019. Inclusion criterion was anterior or low anterior resection followed by anastomosis and preventive stoma. Univariate and multivariate analysis enrolled 28 factors for identifying the risk factors of non-closure of defunctioning stoma.

RESULTS

There were 246 patients with rectal cancer. Intraoperative fluorescence angiography was applied in 145 cases to assess blood supply within the anastomosis and reduce the risk of anastomotic leakage. According to multivariate analysis, only two factors had significant influence on non-closure of preventive stoma - any grade of anastomotic leakage (OR 6.5; 95% CI 2.2-18.8, p=0.001) and rectal cancer stage IV (OR 7.2; 95% CI 1.9-27.6, p=0.004).

CONCLUSION

According to our data, permanent stoma is observed in 15% of patients.

Intraoperative perfusion assessment of the proximal colon by a visual grading system for safe anastomosis after resection in left-sided colorectal cancer patients

We aimed to evaluate the clinical feasibility of a new visual grading system. We included 50 patients who underwent resection of primary colorectal cancer. Before anastomosis, the marginal vessel was cut and the perfusion status was assessed by a visual grading system. The visual grading system is comprised of five grades according to the bleeding from the marginal vessel and is categorized into 4 groups: good (grade A and B), moderate (grade C), poor (grade D) and none (grade E). Colorectal anastomosis was performed only in the good and moderate groups. We compared postoperative outcomes between the good and moderate groups and analysed the factors affecting the perfusion grade. Among the patients, 48% were grade A, 12% were grade B, and 40% were grade C. There was no anastomotic leakage. Only one patient with grade C showed ischemic colitis and needed reoperation. Age was the only factor correlated with perfusion grade in multivariate analysis (OR 1.080, 95% CI 1.006-1.159, p = 0.034). The perfusion grades were significantly different between > 65 and < 65 year-old patients (> 65, A 29.2% B 12.5% C 58.3% vs. < 65, A 65.4% B 11.5% C 23.1%, p = 0.006). Our intraoperative perfusion assessment that uses a cutting method and a visual grading system is simple and useful for performing a safe anastomosis after colorectal resection. If the perfusion grade is better than grade C, an anastomosis can be performed safely. Age was found to be an important factor affecting the perfusion grade.

Evolving applications of fluorescence guided surgery in pediatric surgical oncology: A practical guide for surgeons

Fluorescence-guided surgery (FGS) is an increasingly available and popular method of visual field augmentation. The basic premise of FGS entails injection of fluorescent indocyanine green (ICG) and subsequent detection with a near-infrared (NIR) camera. For pediatric surgical oncologists, FGS remains experimental but is a promising modality for identifying tumor margins, locating metastases, performing sentinel lymph node biopsies, protecting peritumoral structures of interest, and facilitating reconstruction. Familiarity with basic ICG pharmacokinetics and NIR detection optics is critical for surgeons wishing to judiciously use FGS, as its success is firmly grounded in a thorough understanding of its capabilities and limitations. In this practical guide, we outline several well-described and innovative FGS applications by disease type, including their methods of administration, modes of detection, and typical ICG dosing paradigms. LEVEL OF EVIDENCE: V.

Fluorescence angiography guided resection of small bowel neuroendocrine neoplasms with mesenteric lymph node metastases

BACKGROUND

Surgery for small bowel neuroendocrine neoplasms (SB-NEN) might result in vascular compromise of the remaining bowel due to resection of lymph node metastases in close proximity to main mesenteric vessels. Fluorescence angiography (FA) has been described as a safe technique to assess perfusion during gastro-intestinal surgery. This study aimed to evaluate the potential value of intraoperative FA during surgery for SB-NEN.

METHODS

This study included patients undergoing surgery for SB-NEN of any stage. The planned level of transection was marked by the surgeon, after which FA using indocyanine green (ICG) was performed. The primary study outcome was change in management due to FA.

RESULTS

Ten consecutive patients with SB-NEN were included, all with metastatic lymph nodes close to main mesenteric vessels. FA use led to management changes in eight patients (80%); four patients had less bowel resected with a preserved length of 5-35 cm. The other four patients had more extended bowel resections with an additional length varying from 3 to 25 cm. The median postoperative stay was 4 days (interquartile range 4-6). No anastomotic leakage occurred.

CONCLUSION

This is the first known series describing preliminary results of FA during SB-NEN surgery. FA led to a management change in 80% of patients with better tailoring the extent of resection of small bowel. Structural implementation of FA to assess small bowel perfusion after dissection for small bowel NET results in change of management, either by preserving small bowel or resecting ill-perfused small bowel.

The significance of the time to arterial perfusion in intraoperative ICG angiography during colorectal surgery

BACKGROUND

Intraoperative indocyanine green angiography (ICG-A) is a promising tool to confirm blood supply; however, the assessment is difficult without clear demarcation. In this study, the clinical impact of the time to arterial perfusion (TAP) on anastomotic leakage (AL) was evaluated, especially in patients without ICG demarcation.

METHODS

The TAP was assessed using ICG-A during colorectal surgery in 110 patients. ICG demarcation required changing the transection line, and the TAP was measured at the new stump. The patients were divided into marginal flow (MF) and direct flow (DF) groups according to the arterial route. Delayed TAP was defined as the third quartile or slower TAP in each group.

RESULTS

Sixty-six patients (60%) were classified into the MF group, including 64 patients who underwent rectal or sigmoid resection with high ligation of the inferior mesenteric artery. The cut-off value of the delayed TAP in the MF group was significantly slower than that in the DF group (30 and 22 s, respectively, p < 0.001). In the entire cohort, the transection line was changed in 2 patients, resulting in no AL. Nevertheless, AL still developed in 6 patients (5.4%), 5 of whom were in the MF group, and delayed TAP was found in 5 of 6 patients. Delayed TAP was significantly associated with AL in the MF group (p = 0.046).

CONCLUSIONS

In patients without ICG demarcation, delayed TAP might be helpful for predicting the high-risk patients with AL in the MF group; however, performing diverting stoma or strictly careful observation might be a realistic reaction.

Inter-user variation in the interpretation of near infrared perfusion imaging using indocyanine green in colorectal surgery

INTRODUCTION

Despite increasing endorsement of near-infrared perfusion assessment using indocyanine green (ICG) during colorectal surgery, little work has yet been done regarding learning curve and interobserver variation most especially on surgical video reflective of real-world usage.

METHODS

Surgeons with established expertise in ICG usage were invited to participate in the study along with others without such experience including trainees. All participants completed an opinion questionnaire and interpreted video presentations of fluorescence angiograms in a variety of colorectal case scenarios. An interactive video platform (Mindstamp) enabled dynamic annotation. Statistical analysis of data was performed using Kruskal-Wallis and Mann-Whitney testing as well as Intraclass Correlation Coefficients and Fleiss Multi-rater Kappa Scoring.

RESULTS

Forty participants (six experts) completed questionnaire data and provided judgement of 14 videos (nine showing proximal colonic transection site perfusion, four showing completed anastomoses and one an acutely strangulated bowel). 70% felt > 10 cases were needed for competency in use with the majority of experts advocating > 50 (p < 0.05). Overall agreement among experts was "good" for videos showing colonic transection perfusion (versus "moderate" among in-experts) with experts clustering more distally. In contrast, there was no interpretation concordance among experts or in-experts when judging ICG perfusion sufficiency on a yes/no basis.

CONCLUSION

Significant experience is recommended before reliance on ICG perfusion angiograms. ICG fluorescence assessment is prone to variable interpretation and influenced by experience and, perhaps, knowledge of preassessment operative steps suggesting a role for objective flow analysis with artificial intelligence methods as the next phase of this technology.

Clinical role of fluorescence imaging in colorectal surgery - an updated review

INTRODUCTION

Colorectal surgery has markedly advanced due to the introduction of laparoscopic and robotic surgery. During the past 20 years, these two modalities have been further enhanced by fluorescence imaging.

AREAS COVERED

This article will review the common and novel uses for fluorophores in colorectal surgery, including tissue perfusion for anastomotic creation, ureter identification, lymphatic mapping, and tumor localization.

EXPERT OPINION

The versatility of this technology permeates through many aspects of colorectal procedures. The white light spectrum has historically been the only available modality to visualize tissue perfusion, tumor implants, and structures including the ureters and lymph nodes. The ability of the near-infrared spectrum to penetrate biologic tissues allows the identification of these structures with injection of fluorophores. The two most common intravenously utilized fluorophores are methylene blue and indocyanine green. Additionally, novel tumor marker-specific fluorophores are being investigated for purposes of cancer detection.

Indocyanine green fluorescent imaging on anastomotic leakage in colectomies: a network meta-analysis and systematic review

PURPOSE

The usage of indocyanine green (ICG) dye is commonly associated with decreased anastomotic leakage rates in colectomies. This study aims to perform a network meta-analysis to assess the usage of ICG fluorescence imaging in right-sided colectomies.

METHODS

Medline, Embase, Cochrane Trials, CNKI, and WanFang electronic databases were reviewed, and meta-analysis of proportions, comparative meta-analysis, and network meta-analysis were conducted in this review. Studies comparing ICG usage with conventional approaches of anastomosis were selected, with postoperative anastomotic leak rate being the primary outcome.

RESULTS

Ten articles were included, with a total of 675 patients involved, of which 515 patients underwent colorectal surgery with ICG. Anastomotic leak rates with ICG were estimated to be 1% (CI 0.00-0.04) and 3% (CI 0.01-0.06) for right and left procedures, respectively. No significant difference was observed in left-sided colectomies (OR 0.587; 95% CI 0.218-1.582; p = 0.292). There were nearly half the odds of anastomotic leakage when ICG was used in right-sided colectomies (OR 0.524; 95% CI 0.128-2.137).

CONCLUSION

With the ability to potentially avert postoperative anastomotic leakage, coupled with its minimal costs and side effects, administration of ICG in colectomies in centers where equipment is available should be encouraged.

Anastomosis Leak: Is There Still a Place for Indocyanine Green Fluorescence Imaging in Colon-Rectal Surgery? A Retrospective, Propensity Score-Matched Cohort Study

Anastomotic leakage (AL) represents one of the most relevant complications of colorectal cancer surgery. The aim of this study was to evaluate the utility of intraoperative indocyanine green (ICG) fluorescence imaging in the prevention of AL during laparoscopic colorectal surgery. Methods. We retrospectively analyzed 272 patients who underwent rectal and left colon surgery, consecutively enrolled between 2015 and 2019. Due to the heterogeneity of our groups, a propensity score matching (PSM) was performed with a 1:1 PSM cohort. Results. AL occurred in 36 (13.2%) patients. One hundred seventy-seven (65%) of them underwent an intraoperatory ICG test (ICG-group), whereas 95 patients (35%) did not receive the intraoperatory ICG test (no-ICG group). AL occurred in 10.8% of ICG group patients and in 17.8% of no-ICG group patients (P = 0.07). The ICG group registered significantly less type B and type C fistulas than the no-ICG group (57.9 vs 88.2%; P = .043). After PSM, the overall AL rate was less in the ICG group than the no-ICG group (9.3% vs 16%; P = 0.058), while type B and type C fistulas occurred in 5.48% in the ICG group vs 13.70% in the no-ICG group (P = 0.09). Univariate analysis demonstrated a protective effect of intraoperative ICG imaging against AL occurrence (odds ratio (OR: 0.66)). Conclusions. Hypoperfusion is a well-recognized cause of AL. The ICG assessment of colic vascularization is a simple, inexpensive, and side effects free method, which can sensibly reduce both overall AL and type B and type C fistulas when routinely used.

Intraoperative testing of colorectal anastomosis and the incidence of anastomotic leak: A meta-analysis

BACKGROUND

AL remains one of the most threatening complications in colorectal surgery. Significant efforts are put to understand the pathophysiological mechanisms involved in the development of leakage and to create the strategies to prevent it. We aimed to determine whether intraoperative testing of mechanical integrity and perfusion of colorectal anastomosis could reduce the incidence of AL.

METHODS

A systematic review and meta-analysis of papers published before November 2019 on PubMed, Scopus, Web of Science, and Cochrane Library databases and comparing intraoperative testing of the colorectal anastomosis with standard care were conducted. Odds ratios (ORs) and 95% confidence interval (CIs) were used to assess the association between intraoperative testing and AL.

RESULTS

A total of 23 studies totaling 7115 patients were included. Pooled analysis revealed intraoperative tests, for integrity (OR 0.52, 95% CI 0.34-0.82, P < .001) and perfusion (OR 0.40, 95% CI 0.22-0.752, P < .001) of the lower gastrointestinal tract anastomoses are associated with significantly lower AL rate.

CONCLUSIONS

Intraoperative testing for either integrity or perfusion of anastomoses both reduce the AL rate. Studies looking at the combination of these two testing methods of anastomosis, especially intraoperative endoscopy, and indocyanine green fluorescence angiography may be very promising to further reduction of the AL.

IMARI: multi-Interventional program for prevention and early Management of Anastomotic leakage after low anterior resection in Rectal cancer patIents: rationale and study protocol

Background

Anastomotic leakage (AL) is still a common and feared complication after low anterior resection (LAR) for rectal cancer. The multifactorial pathophysiology of AL and lack of standardised treatment options requires a multi-modal approach to improve long-term anastomotic integrity. The objective of the IMARI-trial is to determine whether the one-year anastomotic integrity rate in patients undergoing LAR for rectal cancer can be improved using a multi-interventional program.

Methods

IMARI is a multicentre prospective clinical effectiveness trial, whereby current local practice (control cohort) will be evaluated, and subsequently compared to results after implementation of the multi-interventional program (intervention cohort). Patients undergoing LAR for rectal cancer will be included. The multi-interventional program includes three preventive interventions (mechanical bowel preparation with oral antibiotics, tailored full splenic flexure mobilization and intraoperative fluorescence angiography using indocyanine green) combined with a standardised pathway for early detection and active management of AL. The primary outcome is anastomotic integrity, confirmed by CT-scan at one year postoperatively. Secondary outcomes include incidence of AL, protocol compliance and association with AL, temporary and permanent stoma rate, reintervention rate, quality of life and functional outcome. Microbiome analysis will be conducted to investigate the role of the rectal microbiome in AL.

In a Dutch nationwide study, the AL rate was 20%, with anastomotic integrity of 90% after one year. Based on an expected reduction of AL due to the preventive approaches of 50%, and increase of anastomotic integrity by a standardised pathway for early detection and active management of AL, we hypothesised that the anastomotic integrity rate will increase from 90 to 97% at one year. An improvement of 7% in anastomotic integrity at one year was considered clinically relevant. A total number of 488 patients (244 per cohort) are needed to detect this difference, with 80% statistical power.

Discussion

The IMARI-trial is designed to evaluate whether a multi-interventional program can improve long-term anastomotic integrity after rectal cancer surgery. The uniqueness of IMARI lies in the multi-modal design that addresses the multifactorial pathophysiology for prevention, and a standardised pathway for early detection and active treatment of AL.

Trial registration

Trialregister.nl (NL8261), January 2020.

Intra-operative fluorescence angiography is reproducible and reduces the rate of anastomotic leak after colorectal resection for cancer: a prospective case-matched study

AIM

Intra-operative fluorescence angiography (IOFA) with indocyanine green provides information on tissue perfusion that may help prevent an anastomotic leak (AL). The aim of this study was to assess the impact of IOFA on outcomes after left-sided colonic or low anterior resection with anastomosis for colorectal cancer.

METHODS

All patients with left-sided colonic or rectal cancer, operated between June 2017 and December 2018, were prospectively included. IOFA has been routinely implemented since May 2018. Reproducibility of IOFA, after a 1:1 matching for relevant clinical risk factors of AL, was studied in patients with IOFA (IOFA+) and without IOFA (IOFA-). Outcomes were compared in terms of postoperative events such as clinically relevant AL as the primary end-point.

RESULTS

In the IOFA+ group, changing of the initially planned colon transection due to inadequate perfusion occurred in five out of 46 patients (10.9%). Agreement between intra-operative assessment and postoperative blind review of IOFA was deemed strong (Cohen's kappa index 0.893, 95% CI 0.788-0.998, P < 0.001). Among 111 patients, 42 matched patients were included in each group. There was significantly more clinically relevant AL in the IOFA- group compared to the IOFA+ group (16.7% vs 2.4%, P = 0.026) involving significantly more anastomotic dehiscence which required re-intervention (19% vs 2.4%, P = 0.014). Additionally, more descending colon ischaemia/necrosis was observed in the IOFA- group compared with the IOFA+ group (9.5% vs 0%, P = 0.040).

CONCLUSION

In this prospective case-matched study, IOFA decreased the occurrence of clinically relevant AL due to necrosis of the descending colon or anastomosis. Upon blind review, perfusion assessment using IOFA was reproducible.

Intraoperative use of fluorescence with indocyanine green reduces anastomotic leak rates in rectal cancer surgery: an individual participant data analysis

BACKGROUND

Fluorescence imaging by means of Indocyanine green (ICG) has been applied to intraoperatively determine the perfusion of the anastomosis. The purpose of this Individual Participant Database meta-analysis was to assess the effectiveness in decreasing the incidence of anastomotic leak (AL) after rectal cancer surgery.

METHODS

We searched PubMed, Embase, Cochrane Library and ClinicalTrial.gov, EU Clinical Trials and ISRCTN registries on September 1st, 2019. We considered eligible those studies comparing the assessment of anastomotic perfusion during rectal cancer surgery by intraoperative use of ICG fluorescence compared with standard practice. We defined as primary outcome the incidence of AL at 30 days after surgery. The studies were assessed for quality by means of the ROBINS-I and the Cochrane risk tools. We calculated odds ratios (ORs) using the Individual patient data analysis, restricted to rectal lesions, according to original treatment allocation.

RESULTS

The review of the literature and international registries produced 15 published studies and 5 ongoing trials, for 9 of which the authors accepted to share individual participant data. 314 patients from two randomized trials, 452 from three prospective series and 564 from 4 non-randomized studies were included. Fluorescence imaging significantly reduced the incidence of AL (OR 0.341; 95% CI 0.220-0.530; p < 0.001), independent of age, gender, BMI, tumour and anastomotic distance from the anal verge and neoadjuvant therapy. Also, overall morbidity and reintervention rate were positively influenced by the use of ICG.

CONCLUSIONS

The incidence of AL may be reduced when ICG fluorescence imaging is used to assess the perfusion of a colorectal anastomosis. Limitations relate to the consistent number of non-randomized studies included and their heterogeneity in defining and assessing AL. Ongoing large randomized studies will help to determine the exact role of routine ICG fluorescence imaging may decrease the incidence of AL in surgery for rectal cancer.

Indocyanine Green-Enhanced Colorectal Surgery-between Being Superfluous and Being a Game-Changer

Nowadays, surgical innovations incorporate new technological conquests and must be validated by evidence-based medicine. The use of augmented reality-assisted indocyanine green (ICG) fluorescence has generated a myriad of intraoperative applications such as demonstration of key anatomical landmarks, sentinel lymph nodes, and real-time assessment of local blood flow. This paper presents a systematic review of the clinical evidence regarding the applications of ICG near-infrared (NIR) fluorescence in colorectal surgery. After we removed duplicate publications and screened for eligibility, a total of 36 articles were evaluated: 23 on perfusion assessment, 10 on lymph node mapping, and 3 on intraoperative identification of ureters. Lack of homogenous studies, low statistical power, and confounding evidence were found to be common amongst publications supporting the use of ICG in colorectal surgery, raising concerns over this seductive technique's cost efficiency and redundancy. The compiled data showed that ICG NIR fluorescence may be a game-changer in particular situations, as proven for low colorectal anastomosis or lateral pelvic lymph node dissection, but it remains controversial for routine use and sentinel lymph node assessment. Further randomized studies are needed to confirm these conclusions. Future research directions include tumor-targeted fluorescence imaging and digital software for quantitative evaluation of fluorescence.

Intraoperative fluorescence angiography with indocyanine green: retrospective evaluation and detailed analysis of our single-center 5-year experience focused on colorectal surgery

Objectives

Assessing bowel perfusion with indocyanine green fluorescence angiography (ICG-FA) shows positive effects on anastomotic healing in colorectal surgery.

Methods

A retrospective evaluation of 296 colorectal resections where we performed ICG-FA was undertaken from January 2014 until December 2018. Perfusion of the bowel ends measured with ICG-FA was compared to the visual assessment before and after performing the anastomosis. According to the observations, the operative strategy was confirmed or changed. Sixty-seven low anterior rectal resections (LARs) and 76 right hemicolectomies were evaluated statistically, as ICG-FA was logistically not available for every patient in our service and thus a control group for comparison resulted.

Results

The operative strategy based on the ICG-FA results was changed in 48 patients (16.2%), from which only one developed an anastomotic leakage (AL) (2.1%). The overall AL rate was calculated as 5.4%. Within the 67 patients with LAR, the strategy was changed in 11 patients (16.4%). No leakage was seen in those. In total three AL happened (4.5%), which was three times lower than the AL rate of 13.6% in the control group but statistically not significant. From the 76 right hemicolectomies a strategy change was undertaken in 10 patients (13.2%), from which only one developed an AL. This was the only AL reported in the whole group (1.3%), which was six times lower than the leakage rate of the control group (8.1%). This difference was statistically significant (p=0.032).

Conclusions

Based on the positive impact by ICG-FA on the AL rate, we established the ICG-FA into our clinical routine. Although randomized studies are still missing, ICG-FA can raise patient safety, with only about 10 min longer operating time and almost no additional risk for the patients.

Colonic perfusion assessment with indocyanine-green fluorescence imaging in anterior resections: a propensity score-matched analysis

BACKGROUND

Colonic perfusion is crucial for anastomotic healing and this could be evaluated intraoperatively using indocyanine-green fluorescence imaging (ICG FI). The aim of this study was to ascertain whether the use of ICG FI resulted in the reduction of anastomotic complications, i.e. AL and anastomotic stricture.

METHODS

Consecutive patients who underwent anterior resections or low anterior resections at our institution in the period from January 1st 2013 to December 31st 2018 were retrospectively reviewed. Surgery performed during the period from January 1st 2013 to December 31st 2015 did not involve the use of ICG FI (ICG-) while surgery during the period from January 1st 2016 to December 31st 2018 was performed with the use of ICG FI (ICG+). The anastomotic leakage rates of the two groups were compared after propensity score matching, taking into account the height of the anastomosis and any history of pelvic irradiation.

RESULTS

There was a total of 258 and 317 patients who had surgery with and without ICG FI, respectively. There were 253 patients in each group after propensity score matching. The overall anastomotic leakage rate was 3.6% and 7.9% for ICG+ and ICG-, respectively, (p = 0.035). Subgroup analysis showed that the use of ICG FI was significantly associated with a lower anastomotic leakage rate in total mesorectal excision (TME), 4.7% versus 11.6%, p = 0.043, but not in non-TME resections, 3.5% versus 2.4%, (p = 0.612). ICG FI, together with sex and anastomotic height, were independent predictors of anastomotic leakage.

CONCLUSIONS

The routine use of ICG FI was associated with a lower anastomotic leakage rate in anterior resections. The reduction in anastomotic leakage rate was mainly seen in TME.

A study investigating the perfusion of colorectal anastomoses using fluorescence angiography: results of the FLAG randomized trial

AIM

Our aim was to evaluate the efficacy of indocyanine green (ICG) fluorescence angiography (FA) in reducing the incidence of anastomotic leakage (AL) following colorectal anastomosis.

METHOD

A single-centre randomized trial was undertaken between 2018 and 2019. Those patients who underwent a stapled colorectal anastomosis were randomized 1:1 for ICG FA versus visual clinical assessment of blood perfusion of the anastomosed colon and rectal stump (non-ICG FA group). The primary end-point was to assess whether ICG FA was associated with a reduction in the incidence of AL. Secondary outcomes were the rate of postoperative complications and change in the level of bowel resection.

RESULTS

A total of 380 patients undergoing sigmoid and rectal resection were enrolled. After randomization, three patients were excluded. The results of 377 cases were available for analysis; 187 had ICG FA and 190 were in the non-ICG FA group. ICG FA identified impaired blood perfusion of the colon in 36 (19%) cases. An AL (grade A, B or C) developed in 48 patients: 17 (9.1%) in the ICG FA group and 31 (16.3%) in the non-ICG FA group (P = 0.04). ICG FA did not decrease the rate of AL of high anastomoses (9-15 cm from the anal verge), at 1.3% vs 4.6% in the non-ICG FA group (P = 0.37). In contrast, a decrease in AL rate was found for low (4-8 cm) colorectal anastomoses (14.4% in ICG FA vs 25.7% in the non-ICG FA group; P = 0.04).

CONCLUSION

ICG FA is associated with a reduction in AL following low anterior resection.

How to Prevent Anastomotic Leak in Colorectal Surgery? A Systematic Review

Anastomosis leakage (AL) after colorectal surgery is an embarrassing problem. It is associated with poor consequence. This review aims to summarize published evidence on prevention of AL after colorectal surgery and provide recommendations according to the Oxford Centre for Evidence-Based Medicine. We conducted bibliographic research on January 15, 2020, of PubMed, Cochrane Library, Embase, Scopus, and Google Scholar. We retained meta-analysis, reviews, and randomized clinical trials. We concluded that mechanical bowel preparation did not reduce AL. It seems that oral antibiotic or oral antibiotic with mechanical bowel preparation could reduce the risk of AL. The surgical approach did not affect the AL rate. The low ligation of the inferior mesenteric artery could reduce the AL rate. The mechanical anastomosis is superior to handsewn anastomosis only in case of right colectomies, with similar results in rectal surgery between the 2 anastomosis techniques. In the case of right colectomies, this anastomosis could be performed intracorporeally or extracorporeally with similar outcomes. The air leak test did not reduce AL. There is no interest of external drainage in colonic surgery but drains reduced the rate of AL and rate of reoperation after low anterior resection. The transanal tube reduced the rate of AL.

Noninvasive assessment of bowel blood perfusion using intraoperative laser speckle flowgraphy

PURPOSE

Laser speckle flowgraphy (LSFG) is a noninvasive method for quantitative evaluation of blood flow using the mean blur rate (MBR) as the blood flow index. We investigated whether LSFG can intraoperatively detect the demarcation line after vessel dissection and reduce the incidence of anastomotic leakage (AL).

METHODS

This study included 36 patients who underwent left-sided colorectal surgery. First, we compared the demarcation line (determined by LSFG) with the transection line (TL) at which the marginal vessels were divided. We then measured the MBR on both sides of the TL to determine where the MBR changed significantly. We investigated the presence or absence of significant differences between the MBR on the proximal side and that on the distal side of the TL. Finally, we retrospectively compared the patient characteristics and AL rates in the LSFG group (n = 36) and control group (n = 87).

RESULTS

In total, 58.3% (21/36) of the demarcation lines determined by LSFG matched the TL. The median distance between the demarcation line determined by LSFG and the TL was 0.0 mm (0.0-12.1 mm). The MBR sharply decreased at the TL in 80.6% (29/36) of cases. The median MBR was significantly lower on the distal than proximal side. The AL rate was not significantly lower in the LSFG group than in the control group.

CONCLUSION

LSFG accurately detected the demarcation line during surgery. However, LSFG did not reduce the incidence of AL.

Quantitative fluorescence angiography versus hyperspectral imaging to assess bowel ischemia: A comparative study in enhanced reality

BACKGROUND

Fluorescence-based enhanced reality is a software that provides quantitative fluorescence angiography by computing the fluorescence intensity time-to-peak after intravenous indocyanine green. Hyperspectral imaging is a contrast-free, optical imaging modality which measures tissue oxygenation.

METHODS

In 8 pigs, an ischemic bowel segment created by dividing the arcade branches was imaged using hyperspectral imaging and fluorescence-based enhanced reality. Tissue oxygenation values were acquired through a hyperspectral imaging system. Subsequently, fluorescence angiography was performed using a near-infrared laparoscopic camera after intravenous injection of 0.2 mg/kg of indocyanine green. The time-to-peak fluorescence signal was analyzed through a proprietary software to realize a perfusion map. This was overlaid onto real-time images to obtain fluorescence-based enhanced reality. Simultaneously, 9 adjacent regions of interest were selected and superimposed onto the real-time video, thereby obtaining hyperspectral-based enhanced reality. Fluorescence-based enhanced reality and hyperspectral-based enhanced reality were superimposed allowing a comparison of both imaging modalities. Local capillary lactate levels were sampled at the regions of interest. Two prediction models using the local capillary lactate levels were extrapolated based on both imaging systems.

RESULTS

For all regions of interest, the mean local capillary lactate levels were 4.67 ± 4.34 mmol/L, the mean tissue oxygenation was 45.9 ± 18.9%, and the mean time-to-peak was 10 ± 9.4 seconds. Pearson's test between fluorescence-based enhanced reality-time-to-peak and hyperspectral imaging-tissue oxygenation at the corresponding regions of interest gave an R = -0.66 (P < .0001). The hyperspectral imaging lactate prediction model proved more accurate than the fluorescence-based enhanced reality-based model (P < .0001).

CONCLUSION

Bowel perfusion was quantified using hyperspectral imaging and fluorescence angiography. Hyperspectral imaging yielded more accurate results than fluorescence angiography. Hyperspectral-based enhanced reality may prove to be a useful, contrast-free intraoperative tool to quantify bowel ischemia.

Indocyanine green fluorescence angiography to evaluate anastomotic perfusion in colorectal surgery

BACKGROUND

The aim of this study was to evaluate the efficacy of indocyanine green (ICG) fluorescence angiography with respect to the anastomotic leakage rate for patients undergoing colorectal operations.

METHODS

This prospective cohort involved patients who underwent colorectal surgery between August 2018 and September 2019. ICG was injected after colonic transection. Vascular perfusion was observed by ICG fluorescence system before completing anastomosis. Data was compared with those by subjective visual evaluation. The primary outcome was anastomotic leakage rate within 30 days from surgery.

RESULTS

A total of 131 patients were enrolled, of which ICG was injected in 63 of them. Demographic data were similar between the two groups. There were two (3.23%) and three (4.35%) anastomotic leaks in the ICG and non-ICG group respectively (p = 1.000). Change of resection plane occurred in one patient in the ICG group. There was no ICG related toxicity or adverse events.

CONCLUSION

ICG fluorescent imaging is a feasible and safe tool to assess colonic vascularisation for patients undergoing colorectal surgery. However, it did not significantly lower the anastomotic leakage rate. ICG should not be routinely used in colorectal surgery before an available large scale randomised controlled trial to prove any clinical benefits.

Indocyanine green fluorescence imaging to assess bowel perfusion during totally laparoscopic surgery for colon cancer

BACKGROUND

To retrospectively evaluate the feasibility and safety of intraoperative assessment of bowel perfusion in totally laparoscopic surgery for colon cancer using indocyanine green fluorescence imaging (IGFI).

METHODS

From October 2017 to June 2019, consecutive patients with colon cancer who underwent totally laparoscopic surgery were enrolled retrospectively and grouped into the IGFI group (n = 84) and control group (n = 105). In the IGFI group, indocyanine green (ICG) was injected intravenously, and the bowel perfusion was observed using a fluorescence camera system prior to and after completion of the anastomosis.

RESULTS

The two groups were demographically comparable. The IGFI group exhibited a significantly shorter operative time (p = 0.0374) while intraoperative blood loss did not significantly differ among the groups (p = 0.062). In the IGFI group, average time to perfusion fluorescence was 48.4 ± 14.0 s after ICG injection, and four patients (4.8%) were required to choose a more proximal point of resection due to the lack of adequate fluorescence at the point previously selected. There were no differences in terms of pathological outcomes, postoperative recovery and the postoperative complication rates between the groups (p>0.05).

CONCLUSION

IGFI shows promise as a safe and feasible tool to assess bowel perfusion during a totally laparoscopic surgery for colon cancer and may reduce the operative time.

Preventive strategies for anastomotic leakage after colorectal resections: A review

Anastomosis is a crucial step in radical cancer surgery. Despite being a daily practice in gastrointestinal surgery, anastomotic leakage (AL) stands as a frequent postoperative complication. Because of increased morbidity, mortality, combined with longer hospital stay, the rate of re-intervention, and poor oncological outcomes, AL is considered the most feared and life-threatening complication after colorectal resections. Furthermore, poor functional outcomes with a higher rate of a permeant stoma in 56% of patients this could negatively affect the patient’s quality of life. This a narrative review which will cover intraoperative anastomotic integrity assessment and preventive measures in order to reduce AL. Although the most important prerequisites for the creation of anastomosis is well-perfused and tension-free anastomosis, surgeons have proposed several preventive measures, which were assumed to reduce the incidence of AL, including antibiotic prophylaxis, intraoperative air leak test, omental pedicle flap, defunctioning stoma, pelvic drain insertion, stapled anastomosis, and general surgical technique. However, lack of clear evidence of which preventive measures is superior over the other combined with the fact that the decision remains based on the surgeon’s choice. Despite the advances in surgical techniques, AL remains a serious health problem associated with increased morbidity, mortality with additional cost. Many preventative measures were employed with no clear evidence supporting the superiority of stapled anastomosis over hand-Sewn anastomosis, coating of the anastomosis, or pelvic drain. Defunctioning stoma, when justified it could decrease the leakage-related complications and the incidence of reoperation. MBP combined with oral antibiotics still recommended.