Near-infrared fluorescence guided esophageal reconstructive surgery: A systematic review

Indocyanine green fluorescence video-angiography for flap perfusion assessment in head and neck reconstruction: a prospective study

PURPOSE

Managing postoperative complications is crucial in reconstructive surgery. Indocyanine green fluorescence video-angiography (ICGA) aids in assessing flap vascularization intraoperatively, potentially reducing complications.

METHODS

An ambispective study enrolled head and neck cancer patients undergoing ablative surgery with soft tissue reconstruction. An experimental arm (March 2021-May 2023) used ICGA, while a control arm (January 2017-December 2020) did not. Complications were graded by Clavien-Dindo classification. We also evaluated the effect of systemic inflammation on the sensitivity of ICGA in detecting hypoperfused areas of the flap.

RESULTS

Complications were less frequent in the experimental arm, both overall (11.4% vs. 36.4%) and major ones (Clavien-Dindo ≥ 3) (8.6% vs. 30.9%). ICGA showed a protective effect in univariate and multivariate analyses. Previous radiation and ICGA were independent predictors of major complications. ICGA altered the surgical strategy in 25.7% of cases.

CONCLUSIONS

Real-time perfusion assessment, particularly with ICGA, can improve outcomes in head and neck cancer patients undergoing soft tissue reconstruction by reducing complications. Further research with larger cohorts is warranted for validation.

Does Indocyanine Green Utilization during Esophagectomy Prevent Anastomotic Leaks? Systematic Review and Meta-Analysis

Background: Indocyanine Green (ICG) is a promising technique for the assessment of gastric conduit and anastomosis perfusion during esophagectomy. ICG integration may be helpful in minimizing the risk of anastomotic leak (AL). Literature evidence is sparse, while the real effect of ICG assessment on AL minimization remains unsolved. The aim of this systematic review and meta-analysis was to compare short-term outcomes between ICG-guided and non-ICG-guided (nICG) esophagogastric anastomosis during esophagectomy for cancer. Materials and Methods: PubMed, MEDLINE, Scopus, Web of Science, Cochrane Central Library, and ClinicalTrials.gov were queried up to 25 April 2024. Studies that reported short-term outcomes for ICG versus non-ICG-guided (nICG) anastomosis in patients undergoing esophagectomy were considered. Primary outcome was AL. Risk ratio (RR) and standardized mean difference (SMD) were utilized as effect size measures, whereas to assess relative inference we used 95% confidence intervals (95% CI). Results: Overall, 1399 patients (11 observational studies) were included. Overall, 576 (41.2%) underwent ICG gastric conduit assessment. The patients' ages ranged from 22 to 91 years, with 73% being male. The cumulative incidence of AL was 10.4% for ICG and 15.4% for nICG. Compared to nICG, ICG utilization was related to a reduced risk for postoperative AL (RR 0.48; 95% CI 0.23-0.99; p = 0.05). No differences were found in terms of pulmonary complications (RR 0.83), operative time (SMD -0.47), hospital length of stay (SMD -0.16), or 90-day mortality (RR 1.70). Conclusions: Our study seems to indicate a potential impact of ICG in reducing post-esophagectomy AL. However, because of limitations in the design of the included studies, allocation/reporting bias, variable definitions of AL, and heterogeneity in ICG use, caution is required to avoid potential overestimation of the ICG effect.

A Video-Based Procedure-Specific Competency Assessment Tool for Minimally Invasive Esophagectomy

Importance

Minimally invasive esophagectomy (MIE) is a complex procedure with substantial learning curves. In other complex minimally invasive procedures, suboptimal surgical performance has convincingly been associated with less favorable patient outcomes as assessed by peer review of the surgical procedure.

Objective

To develop and validate a procedure-specific competency assessment tool (CAT) for MIE.

Design, Setting, and Participants

In this international quality improvement study, a procedure-specific MIE-CAT was developed and validated. The MIE-CAT contains 8 procedural phases, and 4 quality components per phase are scored with a Likert scale ranging from 1 to 4. For evaluation of the MIE-CAT, intraoperative MIE videos performed by a single surgical team in the Esophageal Center East Netherlands were peer reviewed by 18 independent international MIE experts (with more than 120 MIEs performed). Each video was assessed by 2 or 3 blinded experts to evaluate feasibility, content validity, reliability, and construct validity. MIE-CAT version 2 was composed with refined content aimed at improving interrater reliability. A total of 32 full-length MIE videos from patients who underwent MIE between 2011 and 2020 were analyzed. Data were analyzed from January 2021 to January 2023.

Exposure

Performance assessment of transthoracic MIE with an intrathoracic anastomosis.

Main Outcomes and Measures

Feasibility, content validity, interrater and intrarater reliability, and construct validity, including correlations with both experience of the surgical team and clinical parameters, of the developed MIE-CAT.

Results

Experts found the MIE-CAT easy to understand and easy to use to grade surgical performance. The MIE-CAT demonstrated good intrarater reliability (range of intraclass correlation coefficients [ICCs], 0.807 [95% CI, 0.656 to 0.892] for quality component score to 0.898 [95% CI, 0.846 to 0.932] for phase score). Interrater reliability was moderate (range of ICCs, 0.536 [95% CI, -0.220 to 0.994] for total MIE-CAT score to 0.705 [95% CI, 0.473 to 0.846] for quality component score), and most discrepancies originated in the lymphadenectomy phases. Hypothesis testing for construct validity showed more than 75% of hypotheses correct: MIE-CAT performance scores correlated with experience of the surgical team (r = 0.288 to 0.622), blood loss (r = -0.034 to -0.545), operative time (r = -0.309 to -0.611), intraoperative complications (r = -0.052 to -0.319), and severe postoperative complications (r = -0.207 to -0.395). MIE-CAT version 2 increased usability. Interrater reliability improved but remained moderate (range of ICCs, 0.666 to 0.743), and most discrepancies between raters remained in the lymphadenectomy phases.

Conclusions and Relevance

The MIE-CAT was developed and its feasibility, content validity, reliability, and construct validity were demonstrated. By providing insight into surgical performance of MIE, the MIE-CAT might be used for clinical, training, and research purposes.

Current applications of indocyanine green (ICG) in abdominal, gynecologic and urologic surgery: a meta-review and quality analysis with use of the AMSTAR 2 instrument

BACKGROUND

Indocyanine green (ICG) is an injectable fluorochrome that has recently gained popularity as a means of assisting intraoperative visualization during laparoscopic and robotic surgery. Many systematic reviews and meta-analyses have been published. We conducted a meta-review to synthesize the findings of these studies.

METHODS

PubMed and Embase were searched to identify systematic reviews and meta-analyses coping with the uses of ICG in abdominal operations, including Metabolic Bariatric Surgery, Cholecystectomy, Colorectal, Esophageal, Gastric, Hepato-Pancreato-Biliary, Obstetrics and Gynecology (OG), Pediatric Surgery, Surgical Oncology, Urology, (abdominal) Vascular Surgery, Adrenal and Splenic Surgery, and Interdisciplinary tasks, until September 2023. We submitted the retrieved meta-analyses to qualitative analysis based on the AMSTAR 2 instrument.

RESULTS

We identified 116 studies, 41 systematic reviews (SRs) and 75 meta-analyses (MAs), spanning 2013-2023. The most thoroughly investigated (sub)specialties were Colorectal (6 SRs, 25 MAs), OG (9 SRs, 15 MAs), and HPB (4 SRs, 12 MAs). Interestingly, there was high heterogeneity regarding the administered ICG doses, routes, and timing. The use of ICG offered a clear benefit regarding anastomotic leak prevention, particularly after colorectal and esophageal surgery. There was no clear benefit regarding sentinel node detection after OG. According to the AMSTAR 2 tool, most meta-analyses ranked as "critically low" (34.7%) or "low" (58.7%) quality. There were only five meta-analyses (6.7%) that qualified as "moderate" quality, whereas there were no "high" quality reviews.

CONCLUSIONS

Regardless of the abundance of pertinent literature and reviews, surgeons should be cautious when interpreting their results on ICG use in abdominal surgery. Future reviews should focus on ensuring methodological vigor; establishing clear protocols of ICG dose, route of administration, and timing; and improving reporting quality. Other sources of data (e.g., registries) and novel methods of data analysis (e.g., machine learning) might also contribute to an enhanced role of ICG as a decision-making tool in surgery.

A novel imaging technology to assess tissue oxygen saturation and its correlation with indocyanine green in the gastric conduit during thoracic esophagectomy

BACKGROUND

Anastomotic leakage in esophagectomy is a serious complication, and assessing blood perfusion in the conduit can help minimize this risk. Indocyanine green is the most widely used method to assess tissue blood flow; however, this technique has disadvantages. Evaluating tissue oxygen saturation in the gastric conduit during thoracic esophagectomy compared with indocyanine green blood perfusion assessment addresses these disadvantages and can be performed easily and repeatedly.

METHODS

This was a prospective study of patients with esophageal cancer who underwent thoracic esophagectomy. Intraoperative tissue oxygen saturation and indocyanine green measurements were obtained to determine the anastomotic site and to compare the correlation between the 2 methods. Tissue oxygen saturation and indocyanine green values were obtained at the tip of the gastric conduit, the demarcation line indicating visible perfusion, and the end of the right gastroepiploic artery.

RESULTS

Fifty-seven patients were enrolled in this study; 3 developed anastomotic leakage, and all 3 underwent robotic thoracic surgery. The tissue oxygen saturation value decreased gradually toward the tip of the conduit, as did congestion, and was significantly decreased at the tip compared with the value at the demarcation line (P = .001). Mean tissue oxygen saturation differed significantly between the leakage and no-leakage groups at the anastomosis site (P = .04). We found a negative correlation between tissue oxygen saturation and indocyanine green values at the end of the right gastroepiploic artery (r = -0.361; P = .03).

CONCLUSION

Tissue oxygen saturation imaging was useful in determining the anastomotic site and addressed the disadvantages associated with indocyanine green.

Current status of indocyanine green fluorescent angiography in assessing perfusion of gastric conduit and oesophago-gastric anastomosis

Anastomotic leak (AL) remains a significant complication after esophagectomy. Indocyanine green fluorescent angiography (ICG-FA) is a promising and safe technique for assessing gastric conduit (GC) perfusion intraoperatively. It provides detailed visualization of tissue perfusion and has demonstrated usefulness in oesophageal surgery. GC perfusion analysis by ICG-FA is crucial in constructing the conduit and selecting the anastomotic site and enables surgeons to make necessary adjustments during surgery to potentially reduce ALs. However, anastomotic integrity involves multiple factors, and ICG-FA must be combined with optimization of patient and procedural factors to decrease AL rates. This review summarizes ICG-FA's current applications in assessing esophago-gastric anastomosis perfusion, including qualitative and quantitative analysis and different imaging systems. It also explores how fluorescent imaging could decrease ALs and aid clinicians in utilizing ICG-FA to improve esophagectomy outcomes.

Intraoperative assessment of anastomotic blood supply using indocyanine green fluorescence imaging following esophagojejunostomy or esophagogastrostomy for gastric cancer

Objective

This retrospective study aimed to evaluate the feasibility and safety of intraoperative assessment of anastomotic blood supply in patients undergoing esophagojejunostomy or esophagogastrostomy for gastric cancer using Indocyanine Green Fluorescence Imaging (IGFI).

Materials and methods

From January 2019 to October 2021, we conducted a retrospective analysis of patients who had undergone laparoscopic gastrectomy for the treatment of gastric cancer. The patients were consecutively enrolled and categorized into two study groups: the Indocyanine Green Fluorescence Imaging (IGFI) group consisting of 86 patients, and the control group comprising 92 patients. In the IGFI group, intravenous administration of Indocyanine Green (ICG) was performed, and we utilized a fluorescence camera system to assess anastomotic blood supply both before and after the anastomosis.

Results

The demographic characteristics of patients in both groups were found to be comparable. In the IGFI group, the mean time to observe perfusion fluorescence was 26.3 ± 12.0 seconds post-ICG injection, and six patients needed to select a more proximal resection point due to insufficient fluorescence at their initial site of choice. Notably, the IGFI group exhibited a lower incidence of postoperative anastomotic leakage, with no significant disparities observed in terms of pathological outcomes, postoperative recovery, or other postoperative complication rates when compared to the control group (p > 0.05).

Conclusion

This study underscores the potential of IGFI as a dependable and pragmatic tool for the assessment of anastomotic blood supply following esophagojejunostomy or esophagogastrostomy for gastric cancer. The use of IGFI may potentially reduce the occurrence of postoperative anastomotic leakage.

[Indocyanine green in delayed esophageal reconstruction after previous extirpation]

Advanced chemo- and radiotherapy makes it possible to expand the cohort of patients who can undergo surgical treatment for esophageal cancer. Optimization of perioperative approach, diagnosis and modern options for complications reduced early postoperative mortality after esophagectomy. Conduit ischemia with failure of esophageal-gastric or esophageal-intestinal anastomosis is one of the most serious complications. To minimize the risk of anastomotic leakage and graft necrosis in these patients, various methods of intraoperative assessment of graft viability are being investigated. Near-infrared fluorescence imaging with indocyanine green is valuable for real time assessment of graft perfusion. To date, fluorescence imaging is analyzed regarding perfusion of the gastric stalk after esophagectomy. However, there are still few or no data on this method for analysis of colonic conduit perfusion. The absence of plastic material for gastrointestinal reconstruction is the most dangerous moment in case of ischemia and necrosis of colonic graft. We present our first case of delayed retrosternal esophageal repair using intraoperative indocyanine green fluorescence imaging for assessment of conduit perfusion.

The use of indocyanine green (ICYG) angiography intraoperatively to evaluate gastric conduit perfusion during esophagectomy: does it impact surgical decision-making?

BACKGROUND

Ischemia is known to be a major contributor for anastomotic leaks and indocyanine green (ICYG) fluorescence angiography has been utilized to assess perfusion. Experienced esophageal surgeons have clinically assessed the gastric conduit with acceptable outcomes for years. We sought to examine the impact of ICYG in a surgeon's decision-making during esophagectomy.

METHODS

We queried a prospectively maintained database to identify patients who underwent robotic esophagectomy. Time to initial perfusion, time to maximum perfusion, and residual ischemia were measured and used as a guide to resection of residual stomach. During esophagectomy the surgeon identified the anticipated line of ischemic demarcation (LOD) prior to ICYG injection. The distance between the surgeon's LOD and ICYG LOD was measured.

RESULTS

We identified 312 patients who underwent robotic esophagectomy, 251 without ICYG and 61 with ICGY. There were no differences in age, sex, race, body mass index, histology, stage, or neoadjuvant therapy use between groups. The incidence of anastomotic leak did not differ between groups (non-ICYG, 5.2% vs. ICYG, 6.6%), p = 0.67. The initial perfusion time was ≥ 10 s and max perfusion was > 25 s in all the patients in the ICYG that developed anastomotic leaks. All patients were noted to have at least 1 cm of residual gastric ischemia. Fifteen patients underwent independent surgeon evaluation of the ischemic LOD prior to ICYG. Differential distances were noted in 12 (80%) patients with a mean distance between surgical line of demarcation and ICYG LOD of 0.77 cm.

CONCLUSION

While the implementation of ICYG during esophagectomy demonstrates no significant improvements in anastomotic leak rates compared to historical controls, surgeon's decision-making is impacted in 80% of cases resulting in additional resection of the gastric conduit. Elevated times to initial perfusion and maximum perfusion were associated with increased gastric ischemia and anastomotic leaks.

Alternative intraoperative optical imaging modalities for fluorescence angiography in gastrointestinal surgery: spectral imaging and imaging photoplethysmography

INTRODUCTION

Intraoperative near-infrared fluorescence angiography with indocyanine green (ICG-FA) is a well-established modality in gastrointestinal surgery. Its main drawback is the application of a fluorescent agent with possible side effects for patients. The goal of this review paper is the presentation of alternative, non-invasive optical imaging methods and their comparison with ICG-FA.

MATERIAL AND METHODS

The principles of ICG-FA, spectral imaging, imaging photoplethysmography (iPPG), and their applications in gastrointestinal surgery are described based on selected published works.

RESULTS

The main applications of the three modalities are the evaluation of tissue perfusion, the identification of risk structures, and tissue segmentation or classification. While the ICG-FA images are mainly evaluated visually, leading to subjective interpretations, quantitative physiological parameters and tissue segmentation are provided in spectral imaging and iPPG. The combination of ICG-FA and spectral imaging is a promising method.

CONCLUSIONS

Non-invasive spectral imaging and iPPG have shown promising results in gastrointestinal surgery. They can overcome the main drawbacks of ICG-FA, i.e. the use of contrast agents, the lack of quantitative analysis, repeatability, and a difficult standardization of the acquisition. Further technical improvements and clinical evaluations are necessary to establish them in daily clinical routine.

Fluorescent Imaging in Visceral Surgery: Current Opportunities and Future Perspectives

Background

Fluorescent imaging using indocyanine green (FI-ICG) has become quite popular in the past century, giving the surgeon various pre- and intraoperative approaches in visceral surgery. Nevertheless, several aspects and pitfalls of using the technology need to be addressed.

Summary

This article focused on the applications of FI-ICG in esophageal and colorectal surgery as this is where the clinical relevance is most important. Important benchmark studies were summarized to explain the background. In addition, dosage, the timing of application, and future perspectives - especially quantification methods - were the article's content.

Key Message

There are currently encouraging data on the use of FI-ICG, particularly concerning perfusion assessment to reduce anastomotic leakage, although its use is mainly subjective. The optimal dosage remains unclear; for perfusion evaluation, it should be around 0.1 mg/kg body weight. Moreover, the quantification of FI-ICG opens new possibilities, so that reference values may be available in the future. However, in addition to perfusion measurement, the detection of additional hepatic lesions such as liver metastases or lesions of peritoneal carcinomatosis is also possible. A standardization of FI-ICG and further studies are needed to fully utilize FI-ICG.

Perfusion assessment by fluorescence time curves in esophagectomy with gastric conduit reconstruction: a prospective clinical study

BACKGROUND

Intraoperative perfusion assessment with indocyanine green fluorescence angiography (ICG-FA) may reduce postoperative anastomotic leakage rates after esophagectomy with gastric conduit reconstruction. This study evaluated quantitative parameters derived from fluorescence time curves to determine a threshold for adequate perfusion and predict postoperative anastomotic complications.

METHODS

This prospective cohort study included consecutive patients who underwent FA-guided esophagectomy with gastric conduit reconstruction between August 2020 and February 2022. After intravenous bolus injection of 0.05-mg/kg ICG, fluorescence intensity was registered over time by PINPOINT camera (Stryker, USA). Fluorescent angiograms were quantitatively analyzed at a region of interest of 1 cm diameter at the anastomotic site on the conduit using tailor-made software. Extracted fluorescence parameters were both inflow (T₀, T_max, F_max, slope, Time-to-peak) as outflow parameters (T_90% and T_80%). Anastomotic complications including anastomotic leakage (AL) and strictures were documented. Fluorescence parameters in patients with AL were compared to those without AL.

RESULTS

One hundred and three patients (81 male, 65.7 ± 9.9 years) were included, the majority of whom (88%) underwent an Ivor Lewis procedure. AL occurred in 19% of patients (n = 20/103). Both time to peak as T_max were significantly longer for the AL group in comparison to the non-AL group (39 s vs. 26 s, p = 0.04 and 65 vs. 51 s, p = 0.03, respectively). Slope was 1.0 (IQR 0.3-2.5) and 1.7 (IQR 1.0-3.0) for the AL and non-AL group (p = 0.11). Outflow was longer in the AL group, although not significantly, T_90% 30 versus 15 s, respectively, p = 0.20). Univariate analysis indicated that T_max might be predictive for AL, although not reaching significance (p = 0.10, area under the curve 0.71) and a cut-off value of 97 s was derived, with a specificity of 92%.

CONCLUSION

This study demonstrated quantitative parameters and identified a fluorescent threshold which could be used for intraoperative decision-making and to identify high-risk patients for anastomotic leakage during esophagectomy with gastric conduit reconstruction. A significant predictive value remains to be determined in future studies.

Preservation of remnant esophagus during total pharyngolaryngectomy in a patient with previous subtotal esophagectomy: a case report

Background

With the improved survival rate of patients with esophageal cancer, secondary cancers, including pharyngolaryngeal cancer, have become a problem. Phanryngolaryngeal cancer surgery often requires esophagogastric anastomosis resection in patients with a previous history of subtotal esophagectomy. Owing to adhesions, especially surrounding the esophagogastric anastomosis, caused by the initial surgery, the second surgery might cause postoperative complications.

Case presentation

A 65-year-old man was diagnosed with early stage esophageal squamous cell carcinoma and underwent endoscopic mucosal dissection. However, the histopathological depth of the tumor was pT1b, and additional treatment was required. After administration of the neoadjuvant chemotherapy, he underwent thoracoscopic esophagectomy and retrosternum reconstruction via a gastric tube (pT1N3M0 stage III). Eight months after the first surgery, tumor recurrences were observed at the anastomosis and left cervical lymph node. Definitive chemoradiotherapy was performed for the recurrences, and complete response was achieved. Seven months after chemoradiotherapy, he was diagnosed with hypopharyngeal squamous cell carcinoma in the right piriform fossa (cT2N2bM0 stage IVA), and salvage surgery was chosen as treatment. The surgical findings revealed strong adhesion around the remnant esophagus, which was difficult to dissect from surrounding tissue and was associated with a risk of breaking of the anastomosis. However, indocyanine green fluorescence imaging findings indicated sufficient blood flow to preserve the remnant esophagus, including the anastomosis, even after the interruption of blood flow from the proximal side of the esophagus by total pharyngolaryngectomy. Finally, approximately 4 cm of the remnant esophagus was preserved, and the free jejunum reconstruction with cervical vascular anastomosis was performed. Moreover, the patient was discharged without complications on postoperative day 38. After 10 months of the second surgery, a metastatic lymph node was observed in the right neck. Immune checkpoint inhibitors and chemotherapy were administered, and the patient is alive and under treatment 1.5 years after the second surgery.

Conclusions

Blood supply to the remnant cervical esophagus was thought to be from the gastric conduit over the anastomosis and surrounding capillaries. Thus, the preservation of the remnant esophagus can be considered in total pharyngolaryngectomy even after < 2 years of esophagectomy by blood flow evaluation using indocyanine green fluorescence.

Preservation of remnant esophagus during total pharyngolaryngectomy in a patient with previous subtotal esophagectomy: a case report

BACKGROUND

With the improved survival rate of patients with esophageal cancer, secondary cancers, including pharyngolaryngeal cancer, have become a problem. Phanryngolaryngeal cancer surgery often requires esophagogastric anastomosis resection in patients with a previous history of subtotal esophagectomy. Owing to adhesions, especially surrounding the esophagogastric anastomosis, caused by the initial surgery, the second surgery might cause postoperative complications.

CASE PRESENTATION

A 65-year-old man was diagnosed with early stage esophageal squamous cell carcinoma and underwent endoscopic mucosal dissection. However, the histopathological depth of the tumor was pT1b, and additional treatment was required. After administration of the neoadjuvant chemotherapy, he underwent thoracoscopic esophagectomy and retrosternum reconstruction via a gastric tube (pT1N3M0 stage III). Eight months after the first surgery, tumor recurrences were observed at the anastomosis and left cervical lymph node. Definitive chemoradiotherapy was performed for the recurrences, and complete response was achieved. Seven months after chemoradiotherapy, he was diagnosed with hypopharyngeal squamous cell carcinoma in the right piriform fossa (cT2N2bM0 stage IVA), and salvage surgery was chosen as treatment. The surgical findings revealed strong adhesion around the remnant esophagus, which was difficult to dissect from surrounding tissue and was associated with a risk of breaking of the anastomosis. However, indocyanine green fluorescence imaging findings indicated sufficient blood flow to preserve the remnant esophagus, including the anastomosis, even after the interruption of blood flow from the proximal side of the esophagus by total pharyngolaryngectomy. Finally, approximately 4 cm of the remnant esophagus was preserved, and the free jejunum reconstruction with cervical vascular anastomosis was performed. Moreover, the patient was discharged without complications on postoperative day 38. After 10 months of the second surgery, a metastatic lymph node was observed in the right neck. Immune checkpoint inhibitors and chemotherapy were administered, and the patient is alive and under treatment 1.5 years after the second surgery.

CONCLUSIONS

Blood supply to the remnant cervical esophagus was thought to be from the gastric conduit over the anastomosis and surrounding capillaries. Thus, the preservation of the remnant esophagus can be considered in total pharyngolaryngectomy even after < 2 years of esophagectomy by blood flow evaluation using indocyanine green fluorescence.

The role of intraoperative hyperspectral imaging (HSI) in colon interposition after esophagectomy

BACKGROUND

Colon conduit is an alternative approach to reconstructing the alimentary tract after esophagectomy. Hyperspectral imaging (HSI) has been demonstrated to be effective for evaluating the perfusion of gastric conduits, but not colon conduits. This is the first study to describe this new tool addressing image-guided surgery and supporting esophageal surgeons to select the optimal colon segment for the conduit and anastomotic site intraoperatively.

PATIENTS AND METHODS

Of 10 patients, eight who underwent reconstruction with a long-segment colon conduit after esophagectomy between 01/05/2018 and 01/04/2022 were included in this study. HSI was recorded at the root and tip of the colon conduit after clamping the middle colic vessels, allowing us to evaluate the perfusion and appropriate part of the colon segment.

RESULTS

Anastomotic leak (AL) was detected in only one (12.5%) of all the enrolled patients (n = 8). None of the patients developed conduit necrosis. Only one patient required re-anastomosis on postoperative day 4. No patient needed conduit removal, esophageal diversion, or stent placement. There was a change in the anastomosis site to proximal in two patients intraoperatively. There was no need to change the side of colon conduit intraoperatively in any patient.

CONCLUSION

HSI is a promising and novel intraoperative imaging tool to objectively assess the perfusion of the colon conduit. It helps the surgeon to define the best perfused anastomosis site and the side of colon conduit in this type of operation.

The impact of nitroglycerine and volume on gastric tube microperfusion assessed by indocyanine green fluorescence imaging

The influence of hypervolemia and intraoperative administration of nitroglycerine on gastric tube microperfusion remains unclear The present study aimed to investigate the impact of different hemodynamic settings on gastric tube microperfusion quantified by fluorescence imaging with Indocyanine green (ICG-FI) as a promising tool for perfusion evaluation. Three groups with seven pigs each were formed using noradrenaline, nitroglycerin, and hypervolemia for hemodynamic management, respectively. ICG-FI, hemodynamic parameters, and transit-time flow measurement (TTFM) in the right gastroepiploic artery were continuously assessed. Fluorescent microspheres (FM) were administered, and the partial pressure of tissue oxygen was quantified. The administration of nitroglycerine and hypervolemia were both associated with significantly impaired microperfusion compared to the noradrenaline group quantified by ICG-FI. Even the most minor differences in microperfusion could be sufficiently predicted which, however, could not be represented by the mean arterial pressure measurement. Histopathological findings supported these results with a higher degree of epithelial damage in areas with impaired perfusion. The values measured by ICG-FI significantly correlated with the FM measurement. Using tissue oxygenation and TTFM for perfusion measurement, changes in microperfusion could not be comprehended. Our results support current clinical practice with restrictive volume and catecholamine administration in major surgery. Hypervolemia and continuous administration of nitroglycerine should be avoided.

Current Issues and Future Technologies in Esophageal Cancer Surgery

Gastrointestinal surgery has evolved rapidly in recent years, with laparoscopic techniques being implemented as the standard procedure and robotic surgery becoming increasingly important [...].

Evaluation of inter-user variability in indocyanine green fluorescence angiography to assess gastric conduit perfusion in esophageal cancer surgery

Indocyanine Green Fluorescence Angiography (ICGFA) has been deployed to tackle malperfusion-related anastomotic complications. This study assesses variations in operator interpretation of pre-anastomotic ICGFA inflow in the gastric conduit. Utilizing an innovative online interactive multimedia platform (Mindstamp), esophageal surgeons completed a baseline opinion-practice questionnaire and proceeded to interpret, and then digitally assign, a distal transection point on 8 ICGFA videos of esophageal resections (6 Ivor Lewis, 2 McKeown). Annotations regarding gastric conduit transection by ICGFA were compared between expert users versus non-expert participants using ImageJ to delineate longitudinal distances with Shapiro Wilk and t-tests to ascertain significance. Expert versus non-expert correlation was assessed via Intraclass Correlation Coefficients (ICC). Thirty participants (13 consultants, 6 ICGFA experts) completed the study in all aspects. Of these, a high majority (29 participants) stated ICGFA should be used routinely with most (21, including 5/6 experts) stating that 11-50 cases were needed for competency in interpretation. Among users, there were wide variations in dosing (0.05-3 mg/kg) and practice impact. Agreement regarding ICGFA video interpretation concerning transection level among experts was 'moderate' (ICC = 0.717) overall but 'good' (ICC = 0.871) among seven videos with Leave One Out (LOO) exclusion of the video with highest disagreement. Agreement among non-experts was moderate (ICC = 0.641) overall and in every subgroup including among consultants (ICC = 0.626). Experts choose levels that preserved more gastric conduit length versus non-experts in all but one video (P = 0.02). Considerable variability exists with ICGFA interpretation and indeed impact. Even adept users may be challenged in specific cases. Standardized training and/or computerized quantitative fluorescence may help better usage.

[Intraoperative fluorescence-guided perfusion assessment using indocyanine green-Increased safety in gastrointestinal anastomoses?]

Insufficiency of gastrointestinal anastomoses represents a relevant risk of morbidity and mortality for affected patients. The perfusion quality of the ends of the intestine is the decisive parameter for ensuring sufficient healing of an anastomosis. Intraoperative fluorescence-guided perfusion assessment with indocyanine green is increasingly being used in modern visceral surgery to evaluate tissue perfusion prior to the fashioning of gastrointestinal anastomoses. This technique provides the possibility to distinguish between adequately and inadequately perfused tissue in order to place the anastomosis in the region with the best possible perfusion. Thus, surgeons have a measuring instrument that enables an objective assessment of the perfusion quality of the tissue to be undertaken in addition to a purely subjective macroscopic visual assessment, in order to achieve a better functional result for the patients. Currently, however, the value of this technique has not yet been conclusively clarified. The aim of this review article is to characterize the benefits of intraoperative fluorescence-guided perfusion assessment and to classify it with respect to its significance for routine clinical practice.

Qualitative features of esophageal fluorescence angiography and anastomotic outcomes in children

BACKGROUND

Indocyanine green (ICG) is commonly used to assess perfusion, but quality defining features are lacking. We sought to establish qualitative features of esophageal ICG perfusion assessments, and develop an esophageal anastomotic scorecard to risk-stratify anastomotic outcomes.

METHODS

Single institution, retrospective analysis of children with an intraoperative ICG perfusion assessment of an esophageal anastomosis. Qualitative perfusion features were defined and a perfusion score developed. Associations between perfusion and clinical features with poor anastomotic outcomes (PAO, leak or refractory stricture) were evaluated with logistic and time-to-event analyses. Combining significant features, we developed and tested an esophageal anastomotic scorecard to stratify PAO risk.

RESULTS

From 2019 to 2021, 53 children (median age 7.4 months) underwent 55 esophageal anastomoses. Median (IQR) follow-up was 14 (10-19.9) months; mean (SD) perfusion score was 13.2 (3.4). Fifteen (27.3%) anastomoses experienced a PAO and had significantly lower mean perfusion scores (11.3 (3.3) vs 14.0 (3.2), p = 0.007). Unique ICG perfusion features, severe tension, and primary or rescue traction-induced esophageal lengthening [Foker] procedures were significantly associated with PAO on both logistic and Cox regression. The scorecard (range 0-7) included any Foker (+2), severe tension (+1), no arborization on either segment (+1), suture line hypoperfusion >twice expected width (+2), and segmental or global areas of hypoperfusion (+1). A scorecard cut-off >3 yielded a sensitivity of 73% and specificity of 93% (AUC 0.878 [95%CI 0.777 to 0.978]) in identifying a PAO.

CONCLUSIONS

A scoring system comprised of qualitative ICG perfusion features, tissue quality, and anastomotic tension can help risk-stratify esophageal anastomotic outcomes accurately.

LEVELS OF EVIDENCE

Diagnostic - II.

Application of Indocyanine Green Enhanced Fluorescence in Esophageal Surgery: A Mini Review

Despite recent technological innovations and the development of minimally invasive surgery, esophagectomy remains an operation burdened with severe postoperative complications. Fluorescence imaging, particularly using indocyanine green (ICG), offers the ability to address a number of issues faced during esophagectomy. The three main indications for the intraoperative use of ICG during esophagectomy are visualization of conduit vascular supply, allow identification of sentinel nodes and visualization of the thoracic duct. The purpose of this mini review is to present an overview of current practice in fluorescence imaging utilizing ICG during esophagectomy, as well as to demonstrate how this technology can guide lymphadenectomy and reduce surgical morbidity such as anastomotic leaking and chylothorax.

Indocyanine Green Fluorescence Using in Conduit Reconstruction for Patients With Esophageal Cancer to Improve Short-Term Clinical Outcome: A Meta-Analysis

Objectives

This meta-analysis evaluated the short-term safety and efficacy of indocyanine green (ICG) fluorescence in gastric reconstruction to determine a suitable anastomotic position during esophagectomy.

Methods

The Preferred Reporting Items for Systematic Reviews and Meta-Analyzes 2020 (PRISMA) were followed for this analysis.

Results

A total of 9 publications including 1,162 patients were included. The operation time and intraoperative blood loss were comparable in the ICG and control groups. There was also no significant difference in overall postoperative mortality, reoperation, arrhythmia, vocal cord paralysis, pneumonia, and surgical wound infection. The ICG group had a 2.66-day reduction in postoperative stay. The overall anastomotic leak (AL) was 17.6% (n = 131) in the control group and 4.5% (n = 19) in the ICG group with a relative risk (RR) of 0.29 (95% CI 0.18–0.47). A subgroup analysis showed that the application of ICG in cervical anastomosis significantly reduced the incidence of AL (RR of 0.31, 95% CI 0.18–0.52), but for intrathoracic anastomosis, the RR 0.35 was not significant (95% CI 0.09–1.43). Compared to an RR of 0.35 in publications with a sample size of <50, a sample size of >50 had a lower RR of 0.24 (95% CI 0.12–0.48). Regarding intervention time of ICG, the application of ICG both before and after gastric construction had a better RR of 0.25 (95% CI 0.07–0.89).

Conclusions

The application of ICG fluorescence could effectively reduce the incidence of AL and shorten the postoperative hospital stay for patients undergoing cervical anastomosis but was not effective for patients undergoing intrathoracic anastomosis. The application of ICG fluorescence before and after gastric management can better prevent AL.

Systematic Review Registration

PROSPERO, CRD:42021244819.

Quantification of gastric tube perfusion following esophagectomy using fluorescence imaging with indocyanine green

INTRODUCTION

Anastomotic leakage (AL) remains a prevalent and life-threatening complication after esophagectomy. Gastric tube perfusion assessment using indocyanine green fluorescence imaging (ICG-FI) has been published in several studies and appears to be a promising tool to reduce AL rates by changing the surgical approach, namely by an intraoperative evaluation of the anastomosis localization.

METHODS

In this study, gastric tube perfusion was quantified by using ICG-FI in 20 high-risk patients undergoing esophagectomy. From a time-dependent fluorescence intensity curve, the following three parameters were evaluated: slope of fluorescence intensity (SFI), background subtracted peak fluorescence intensity (BSFI), and time to slope (TTS).

RESULTS

The values between pyloric region and tip showed a similar downward trend and SFI and BSFI significantly correlated with the distance to the pyloric region. SFI and BSFI were significantly decreased at the tip of the gastric tube. The placement of anastomosis in an area with homogenous fluorescence pattern was correlated with no AL in 92.9% of cases. An inhomogeneous fluorescence pattern at anastomotic site was a risk factor for the occurrence of an AL (p < 0.05). Reduction of perfusion up to 32% using SFI and up to 23% using BSFI was not associated with AL.

CONCLUSION

ICG-FI can be used to quantify the gastric tube perfusion by calculating SFI, BSFI, and TTS. The anastomosis should be created in areas with homogeneous fluorescence pattern. A reduction in blood flow of up to 32% can be accepted without causing an increased rate of insufficiency.

Is Prophylactic Cervical Drainage Effective in Patients Undergoing McKeown Esophagectomy Reconstructed Through the Retrosternal Route with Two-Field Lymphadenectomy?

BACKGROUND

McKeown esophagectomy with two-field lymphadenectomy is the treatment of choice for oncologic esophagectomy. A cervical drain is placed in cases after modern two-field lymph node dissection (M2FD) to provide information on anastomotic leakage. However, the necessity of prophylactic cervical drainage during surgery remains unknown. This study aimed to clarify the clinical significance of cervical drainage in patients who underwent McKeown esophagectomy with M2FD.

METHODS

A total of 293 patients underwent McKeown surgery with two-field lymphadenectomy at our institute between January 2013 and December 2019. We compared the day of drain removal, amount of drainage volume, and the appearance of drainage fluid between patients with and without anastomotic leakage.

RESULTS

McKeown esophagectomy reconstructed through the retrosternal route is 203 patients (69.3%) of all. Nineteen patients (6.5%) experienced anastomotic leakage. The amount of cervical drain discharge was comparable between patients with and without anastomotic leakage. In addition, no purulent or salivary discharge was observed in patients with anastomotic leakage. There was no difference in the median day of drain removal between the groups. The initial clinical findings for the diagnosis of anastomotic leakage were surgical site infection in 10 (52.6%), fever in 5 (26.3%), prolonged inflammation in a blood test in 3 (15.8%), and bloody discharge from the chest tube in 1 (5.3%). There was no mortality due to any cause.

CONCLUSION

A prophylactic cervical drain may not be mandatory in patients with esophageal cancer undergoing McKeown esophagectomy reconstructed through the retrosternal route with two-field lymphadenectomy.

Indocyanine green (ICG) fluorescence imaging for prevention of anastomotic leak in totally minimally invasive Ivor Lewis esophagectomy: a systematic review and meta-analysis

BACKGROUND

Indocyanine green (ICG) fluorescence imaging is an emerging technology that might help decreasing anastomotic leakage (AL) rates. The aim of this study was to determine the usefulness of ICG fluorescence imaging for the prevention of AL after minimally invasive esophagectomy with intrathoracic anastomosis.

METHODS

A systematic literature review of the MEDLINE and Cochrane databases was performed to identify all articles on totally minimally invasive Ivor Lewis esophagectomy. Studies were then divided into two groups based on the use or not of ICG for perfusion assessment. Primary outcome was anastomotic leak. Secondary outcomes included operative time, ICG-related adverse reactions, and mortality rate. A meta-analysis was conducted to estimate the overall weighted proportion and its 95% confidence interval (CI) for main outcomes.

RESULTS

A total of 3,171 patients were included for analysis: 381 (12%) with intraoperative ICG fluorescence imaging and 2,790 (88%) without ICG. Mean patients' age and proportion of males were similar between groups. Mean operative time was also similar between both groups (ICG: 354.8 vs. No-ICG: 354.1 minutes, P = 0.52). Mean ICG dose was 12 mg (5-21 mg). No ICG-related adverse reactions were reported. AL rate was 9% (95% CI, 5-17%) and 9% (95% CI, 7-12%) in the ICG and No-ICG groups, respectively. The risk of AL was similar between groups (odds ratio 0.85, 95% CI 0.53-1.28, P = 0.45). Mortality was 3% (95% CI, 1-9%) in patients with ICG and 2% (95% CI, 2-3%) in those without ICG. Median length of hospital stay was also similar between groups (ICG: 13.6 vs. No-ICG: 11.2 days, P = 0.29).

CONCLUSION

The use of ICG fluorescence imaging for perfusion assessment does not seem to reduce AL rates in patients undergoing minimally invasive esophagectomy with intrathoracic anastomosis.

A novel imaging technology to assess oxygen saturation of the gastric conduit in thoracic esophagectomy

BACKGROUND

Real-time evaluation of blood perfusion is important when selecting the site of anastomosis during thoracic esophagectomy. This study investigated a novel imaging technology that assesses tissue oxygen saturation (StO2) in the gastric conduit and examined its efficacy.

METHODS

Fifty-one patients undergoing thoracic esophagectomy for esophageal cancer who underwent intraoperative StO2 endoscopic imaging to assess the gastric conduit for the optimal site of anastomosis were examined. Efficacy of oxygen saturation imaging and patient outcomes were analyzed.

RESULTS

All 51 patients underwent esophagectomy without intraoperative problems. Mean StO2 in the gastric tube was highest at the pre-pylorus area and then gradually decreased proceeding toward the tip. StO2 was well preserved in areas supplied by the right gastroepiploic artery but low in other areas. Anastomotic sites were selected based on StO2 imaging and tension considerations; most were located within 3 cm of the end of the right gastroepiploic artery. Three patients developed postoperative anastomotic leakage (5.8%). Mean StO2 at the point of anastomosis was significantly lower in the patients who experienced leakage than in those who did not (P = 0.04).

CONCLUSION

Intraoperative endoscopic StO2 imaging is useful in esophageal cancer patients undergoing thoracic esophagectomy to determine the optimal site for anastomosis to minimize the risk of anastomotic leakage.

Near-Infrared Fluorescence Image-Guided Surgery in Esophageal and Gastric Cancer Operations

Background

Near-infrared fluorescence image-guided surgery helps surgeons to see beyond the classical eye vision. Over the last few years, we have witnessed a revolution which has begun in the field of image-guided surgery.

Purpose, and Research design

Fluorescence technology using indocyanine green (ICG) has shown promising results in many organs, and in this review article, we wanted to discuss the 6 main domains where fluorescence image-guided surgery is currently used for esophageal and gastric cancer surgery.

Study sample and data collection

Visualization of lymphatic vessels, tumor localization, fluorescence angiography for anastomotic evaluation, thoracic duct visualization, tracheal blood flow analysis, and sentinel node biopsy are discussed.

Conclusions

It seems that this technology has already found its place in surgery. However, new possibilities and research avenues in this area will probably make it even more important in the near future.

Near-infrared fluorescence imaging with indocyanine green to assess the blood supply of the reconstructed gastric conduit to reduce anastomotic leakage after esophagectomy: a literature review

The blood supply of the right gastroepiploic artery after esophagectomy with gastric tube reconstruction is essential for avoiding anastomotic leakage. Near-infrared fluorescence (NIRF) imaging with indocyanine green is widely used to assess the blood supply because it can visualize it in real-time during navigation surgery. However, there is no established protocol for this modality. One reason for this lack of protocol is that NIRF provides subjective information. This study aimed to evaluate NIRF quantification. We conducted a literature review of risk factors for anastomotic leakage after esophagectomy, NIRF procedures, NIRF quantification, and new methods to compensate for NIRF limitations. Major methods for the quantification of NIRF include measuring the blood flow speed, visualization time, and fluorescence intensity. The cutoff value for the blood flow speed is 2.07 cm/s, and that for the visualization time is 30-90 s. Although the time-intensity curve provided patterns of change in the blood flow, it did not show an association with anastomotic leakage. However, to compensate for the limitations of NIRF, new devices have been reported that can assess tissue oxygenation perfusion, organ hemoglobin concentration, and microcirculation.

Clinical utility of near-infrared perfusion assessment of the gastric tube during Ivor Lewis esophagectomy

BACKGROUND

Anastomotic leakage (AL) after Ivor Lewis esophagectomy with intrathoracic anastomosis carries a significant morbidity. Adequate perfusion of the gastric tube (GT) is an important predictor of anastomotic integrity. Recently, near infrared fluorescent (NIRF) imaging using indocyanine green (ICG) was introduced in clinical practice to evaluate tissue perfusion. We evaluated the feasibility and efficacy of GT indocyanine green angiography (ICGA) after Ivor Lewis esophagectomy.

METHODS

This retrospective analysis used data from a prospectively kept database of consecutive patients who underwent Ivor Lewis (IL) esophagectomy with GT construction for cancer between January 2016 and December 2020. Relevant outcomes were feasibility, ICGA complications and the impact of ICGA on AL.

RESULTS

266 consecutive IL patients were identified who matched the inclusion criteria. The 115 patients operated with perioperative ICGA were compared to a control group in whom surgery was performed according to the standard of care. ICGA perfusion assessment was feasible and safe in all 115 procedures and suggested a poorly perfused tip in 56/115 (48.7%) cases, for which additional resection was performed. The overall AL rate was 16% (43/266), with 12% (33/266) needing an endoscopic our surgical intervention and 6% (17/266) needing ICU support. In univariable and multivariable analyses, ICGA was not correlated with the risk of AL (ICGA:14.8% vs non-ICGA:17.2%, p = 0.62). However, poor ICGA perfusion of the GT predicted a higher AL rate, despite additional resection of the tip (ICGA poorly perfused: 19.6% vs ICG well perfused: 10.2%, p = 0.19).

CONCLUSIONS

ICGA is safe and feasible, but did not result in a reduction of AL. The interpretation and necessary action in case of perioperative presence of ischemia on ICGA have yet to be determined. Prospective randomized trials are warranted to analyze its benefit on AL in esophageal surgery. Trial registration Ethical approval for a prospective esophageal surgery database was granted by the Ethical committee of the Ghent University Hospital. Belgian registration number: B670201111232. Ethical approval for this retrospective data analysis was granted by our institutional EC. Registration number: BC-09216.

Fluorescence-based bowel anastomosis perfusion evaluation: results from the IHU-IRCAD-EAES EURO-FIGS registry

BACKGROUND

Anastomotic leakage (AL) is one of the dreaded complications following surgery in the digestive tract. Near-infrared fluorescence (NIRF) imaging is a means to intraoperatively visualize anastomotic perfusion, facilitating fluorescence image-guided surgery (FIGS) with the purpose to reduce the incidence of AL. The aim of this study was to analyze the current practices and results of NIRF imaging of the anastomosis in digestive tract surgery through the EURO-FIGS registry.

METHODS

Analysis of data prospectively collected by the registry members provided patient and procedural data along with the ICG dose, timing, and consequences of NIRF imaging. Among the included upper-GI, colorectal, and bariatric surgeries, subgroup analysis was performed to identify risk factors associated with complications.

RESULTS

A total of 1240 patients were included in the study. The included patients, 74.8% of whom were operated on for cancer, originated from 8 European countries and 30 hospitals. A total of 54 surgeons performed the procedures. In 83.8% of cases, a pre-anastomotic ICG dose was administered, and in 60.1% of cases, a post-anastomotic ICG dose was administered. A significant difference (p < 0.001) was found in the ICG dose given in the four pathology groups registered (range: 0.013-0.89 mg/kg) and a significant (p < 0.001) negative correlation was found between the ICG dose and BMI. In 27.3% of the procedures, the choice of the anastomotic level was guided by means of NIRF imaging which means that in these cases NIRF imaging changed the level of anastomosis which was first decided based on visual findings in conventional white light imaging. In 98.7% of the procedures, the use of ICG partly or strongly provided a sense of confidence about the anastomosis. A total of 133 complications occurred, without any statistical significance in the incidence of complications in the anastomoses, whether they were ICG-guided or not.

CONCLUSION

The EURO-FIGS registry provides an insight into the current clinical practice across Europe with respect to NIRF imaging of anastomotic perfusion during digestive tract surgery.

Influence of Damaged Stomach on Anastomotic Leakage following Cervical Esophagogastrostomy in Patients with Esophageal Cancer

BACKGROUND

Anastomotic leakage (AL) is one of the most common complications after esophagectomy. Although some patients have a history of peptic ulcers or other prior stomach diseases, the influence of a damaged stomach (DS) on AL incidence remains unclear. Therefore, we investigated the association between DS and incidence of AL in patients who underwent esophagectomy.

PATIENTS AND METHODS

Between 2015 and 2019, a total of 447 consecutive patients who underwent cervical esophagogastrostomy using gastric tube following esophagectomy were enrolled. DS was defined on the basis of endoscopic findings of ulcers or scars due to medical history or prior treatment. We compared the incidence of AL between patients with DS and those with a healthy stomach (HS). Univariate and multivariate logistic regression analyses were used to identify factors that could predict AL incidence.

RESULTS

Fifty-one patients (11.4%) had DS. Causes of DS included peptic ulcer (n = 36), endoscopic resection for early gastric cancer (n = 9), percutaneous endoscopic gastrostomies (n = 5), and post-chemotherapy scar for gastric malignant lymphoma (n = 1). Overall, AL occurred in 35 patients (7.8%). The incidence of AL in the DS group was significantly higher than in the HS group (15.7 vs. 6.8%, p = 0.03). DS was one of the independent predictive factors for AL (odds ratio, 2.75; 95% confidence interval, 1.10-6.92; p = 0.03) on multivariate analysis. Further, the diseases in the lower third of the conduit were associated with AL.

CONCLUSIONS

Presence of DS can predict AL in patients who underwent cervical esophagogastrostomy after esophagectomy.

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.

Fluorescence-guided surgery of the esophagus

The use of indocyanine green (ICG) fluorescence near-infrared (NIR) imaging during gastrointestinal surgery has surged in recent years. Its use in esophageal surgery is actively being studied both in the clinical setting and in the lab. NIR imaging has several important applications in esophageal surgery including assessing perfusion of the gastrointestinal-esophageal anastomosis, lymphatic drainage and tracheal blood flow after mediastinal dissection. This is a review of the modern literature summarizing the current knowledge on fluorescence-guided surgery of the esophagus.

The evaluation of the gastric tube blood flow by indocyanine green fluorescence angiography during esophagectomy: a multicenter prospective study

OBJECTIVE

We determined the anastomotic site during gastric tube reconstruction in esophagectomy according to the "90-to 60-s rule" using indocyanine green (ICG) fluorescence angiography. We evaluated its safety and efficacy in a prospective multicenter setting.

METHODS

We enrolled 129 patients who underwent subtotal esophagectomy for esophageal cancer. ICG fluorescence angiography was performed after making a wide gastric tube, and the time from the initial enhancement of the right gastroepiploic artery to the tip of the gastric tube was used as a parameter. Esophago-gastro anastomosis was made at the area that was enhanced within 90 s (preferably within 60 s). The enhancement time and the incidence of anastomotic leakage were compared.

RESULTS

In all cases, anastomosis was made at the site enhanced within 90 s. Anastomotic leakage was found in only 4 (3.1%) of 129 cases; specifically, it was detected in 3 (2.4%) of 126 cases whose anastomotic site was enhanced within 60 s and in 1 (33.3%) of 3 cases where the enhancement time exceeded 60 s (p = 0.09).

CONCLUSIONS

Determining the anastomotic site using the 90-to 60-s rule with ICG imaging in gastric tube reconstruction helps reduce the rate of anastomotic leakage.

Association between indocyanine green fluorescence blood flow speed in the gastric conduit wall and superior mesenteric artery calcification: predictive significance for anastomotic leakage after esophagectomy

BACKGROUND

Near-infrared fluorescence using indocyanine green (ICG) has been applied as a real-time navigation tool to observe blood flow in gastric conduit wall after esophagectomy. Atherosclerosis might impair the blood flow of the systemic organs. The aim of the study was to investigate the significances of ICG blood flow speed in the gastric conduit wall and atherosclerotic calcification for the prediction of anastomotic leakage after esophagectomy.

METHODS

The 109 esophageal cancer patients were prospectively enrolled. ICG fluorescence blood flow speed in the gastric conduit wall and abdominal aortic calcification index (ACI), celiac artery (CA) calcification, and superior mesenteric artery (SMA) calcification were determined. Then, the correlation between ICG fluorescence blood flow speed and anastomotic leakage as well as ACI, CA, and SMA calcification were evaluated.

RESULTS

Anastomotic leakage occurred in 15 patients. ACI ranged from 0 to 65. CA calcification and SMA calcification were present in 25 and 12 patients. Multivariate analysis demonstrated that ICG fluorescence blood flow speed in the gastric conduit wall of 2.07 cm/s or less (P < 0.001) and SMA calcification (P = 0.026) were the significant independent predictors of anastomotic leakage. Only SMA calcification was significantly associated with ICG fluorescence blood flow speed in the gastric conduit wall (P = 0.026).

CONCLUSIONS

This study demonstrated that ICG fluorescence blood flow speed in the gastric conduit wall can predict anastomotic leakage after esophagectomy and microvascular perfusion of capillary vessels of the gastric conduit might be impaired by systemic atherosclerosis.

Indocyanine green perfusion assessment of the gastric conduit in minimally invasive Ivor Lewis esophagectomy

BACKGROUND

Anastomotic leak is a serious complication following esophagectomy. The aim of the study was to report our experience with indocyanine green fluorescence angiography (ICG-FA)-PINPOINT® assisted minimally invasive Ivor Lewis esophagectomy (MILE) and assess factors associated with anastomotic leak.

METHODS

We reviewed consecutive patients undergoing MILE from 2013 to 2018. Intraoperative real-time assessment of gastric conduit was performed using ICG-FA with PINPOINT®. Perfusion was categorized as good perfusion (brisk ICG visualization to conduit tip) or non-perfusion (any demarcation along the conduit).

RESULTS

100 patients (81 males, median age 68 [60-72]) underwent MILE for malignancy in 96 patients and benign disease in 4 patients. There were six anastomotic leaks all managed with endoscopic stent placement. There was no intraoperative mortality and no 30-day mortality in leak patients. Patients with a leak were more likely to be overweight with BMI > 25 (100% versus 53%, p = 0.03), have pre-existing diabetes (50% versus 13%, p = 0.04), and have higher intraoperative estimated blood loss (260 mL [95-463] versus 75 mL [48-150], p = 0.03). Anastomotic leaks occurred more frequently in the non-perfusion (67%) versus the good perfusion category (33%, p = 0.03). By multivariable analysis, diabetes (odds ratio [OR] 6.42; p = 0.04) and non-perfusion (OR 6.60; p = 0.04) were independently associated with leak.

CONCLUSION

Intraoperative use of ICG-FA may be a useful adjunct to assess perfusion of the gastric conduit with non-perfusion being independently associated with a leak. While perfusion plays an important role in anastomotic integrity, development of a leak is multifactorial, and ICG-FA should be used in conjunction with the optimization of patient and procedural components to minimize leak rates. Prospective, randomized studies are required to validate the interpretation, efficacy, and application of this novel technology in minimally invasive esophagectomies.

Indocyanine green fluorescence imaging for subtotal esophagectomy due to esophageal stenosis after acute esophageal necrosis: a report of two cases

Although esophageal stricture after acute esophageal necrosis (AEN) is often refractory to dilation therapy, there have been few reports of surgical intervention. We report two rare cases of successful subtotal esophagectomy and esophagogastrostomy for esophageal strictures after AEN using indocyanine green (ICG) fluorescence imaging. In case 1, emergent esophagogastroduodenoscopy (EGD) in a 56-year-old man with coffee-ground emesis revealed black esophageal mucosa in the middle to lower esophagus, indicating AEN. Despite conservative therapy, an esophageal stricture developed after 2 weeks. Repeated endoscopic balloon dilation (EBD) did not resolve the stenosis; esophagectomy was thus performed approximately 6 months after AEN onset. We evaluated the blood flow to the esophagus using ICG fluorescence imaging to determine the proximal surgical resection line. The postoperative course was uneventful. In case 2, an 81-year-old woman with upper gastrointestinal bleeding with hematemesis and chest pain was diagnosed with AEN by EGD and was treated with conservative therapy. An esophageal stricture developed after 3 weeks, and repeated EBD was ineffective. Approximately 2 months after AEN onset, she underwent esophagectomy using ICG fluorescence imaging. The postoperative course was uneventful. Considering that AEN is a blood flow disorder, ICG fluorescence imaging is a useful technology to prevent surgical morbidity.

Quantitative serosal and mucosal optical imaging perfusion assessment in gastric conduits for esophageal surgery: an experimental study in enhanced reality

Introduction/objective

Gastric conduit (GC) is used for reconstruction after esophagectomy. Anastomotic leakage (AL) incidence remains high, given the extensive disruption of the gastric circulation. Currently, there is no reliable method to intraoperatively quantify gastric perfusion. Hyperspectral imaging (HSI) has shown its potential to quantify serosal StO2. Confocal laser endomicroscopy (CLE) allows for automatic mucosal microcirculation quantification as functional capillary density area (FCD-A). The aim of this study was to quantify serosal and mucosal GC’s microperfusion using HSI and CLE. Local capillary lactate (LCL) served as biomarker.

Methods

GC was formed in 5 pigs and serosal StO2% was quantified at 3 regions of interest (ROI) using HSI: fundus (ROI-F), greater curvature (ROI-C), and pylorus (ROI-P). After intravenous injection of sodium-fluorescein (0.5 g), CLE-based mucosal microperfusion was assessed at the corresponding ROIs, and LCLs were quantified via a lactate analyzer.

Results

StO2 and FCD-A at ROI-F (41 ± 10.6%, 3.3 ± 3.8, respectively) were significantly lower than ROI-C (68.2 ± 6.7%, p value: 0.005; 18.4 ± 7, p value: 0.01, respectively) and ROI-P (72 ± 10.4%, p value: 0.005; 15.7 ± 3.2 p value: 0.001). LCL value at ROI-F (9.6 ± 4.7 mmol/L) was significantly higher than at ROI-C (2.6 ± 1.2 mmol/L, p value: 0.04) and ROI-P (2.6 ± 1.3 mmol/L, p value: 0.04). No statistically significant difference was found in all metrics between ROI-C and ROI-P. StO2 correlated with FCD-A (Pearson’s r = 0.67). The LCL correlated negatively with both FCD-A (Spearman’s r =  − 0.74) and StO2 (Spearman’s r =  −  0.54).

Conclusions

GC formation causes a drop in serosal and mucosal fundic perfusion. HSI and CLE correlate well and might become useful intraoperative tools.

Quantitative fluorescence-guided perfusion assessment of the gastric conduit to predict anastomotic complications after esophagectomy

BACKGROUND

Fluorescence angiography (FA) assesses anastomotic perfusion during esophagectomy with gastric conduit reconstruction, but its interpretation is subjective. This study evaluated time to fluorescent enhancement in the gastric conduit, with the aim to determine a threshold to predict postoperative anastomotic complications.

METHODS

In a prospective cohort study, all consecutive patients undergoing esophagectomy with gastric conduit reconstruction from July 2018 to October 2019 were included. FA was performed before anastomotic reconstruction following injection of indocyanine green (ICG). During FA, the following time points were recorded: ICG injection, first fluorescent enhancement in the lung, at the base of the gastric conduit, at the planned anastomotic site, and at ICG watershed or in the tip of the gastric conduit. Anastomotic complications including anastomotic leakage and clinically relevant strictures were documented.

RESULTS

Eighty-four patients were included, the majority (67 out of 84, 80%) of which underwent an Ivor Lewis procedure. After a median follow-up of 297 days, anastomotic leakage was observed in 12 out of 84 (14.3%) and anastomotic stricture in 12 out of 82 (14.6%). Time between ICG injection and enhancement in the tip was predictive for anastomotic leakage (P = 0.174, area under the curve = 0.731), and a cut-off value of 98 seconds was derived (specificity: 98%). All times to enhancement at the planned anastomotic site and ICG watershed were significantly predictive for the occurrence of a stricture, however area under the curves were <0.7.

CONCLUSIONS

The identified fluorescent threshold can be used for intraoperative decision making or to identify potentially high-risk patients for anastomotic leakage after esophagectomy with gastric conduit reconstruction.

Fluorescence Image-Based Evaluation of Gastric Tube Perfusion during Esophagogastrostomy

During esophagectomy and esophagogastrostomy, the prediction of anastomotic leakage relies on the operating surgeon's tactile or visual diagnosis. Therefore, anastomotic leaks are relatively unpredictable, and new intraoperative evaluation methods or tools are essential. A fluorescence imaging system enables visualization over a wide region of interest, and provides intuitive information on perfusion intraoperatively. Surgeons can choose the best anastomotic site of the gastric tube based on fluorescence images in real time during surgery. This technology provides better surgical outcomes when used with an optimal injection dose and timing of indocyanine green.

Subtotal gastrectomy for gastric tube cancer using intraoperative indocyanine green fluorescence method

INTRODUCTION

Currently, the frequency of evaluating the flow of a reconstructed gastric tube using indocyanine green (ICG) fluorescence has been increasing. However, it has been difficult to decide on the operation method for patients with gastric tube cancer (GTC). We herein report a case in which ICG was effective in a patient with resection of GTC.

PRESENTATION OF CASE

An 83-year-old man underwent subtotal esophagectomy with gastric tube reconstruction via the retrosternal route for esophageal cancer and right hemicolectomy for ascending colon cancer 16 years earlier. Postoperatively, the proximal part of the gastric tube had poor blood flow. Therefore, the patient underwent proximal-side resection of the gastric tube. Thereafter, free jejunal graft reconstruction was performed. The patient had not developed recurrence at that point. Recently, the patient visited the hospital complaining of nausea and chest discomfort. Upper gastrointestinal endoscopy revealed a type 0-IIa + IIc lesion located around the pylorus. A biopsy showed adenocarcinoma. Based on these findings, the patient was diagnosed with gastric tube cancer (cT1bN0M0StageI). The invasion depth of the cancer was predicted to be widespread submucosal invasion. Therefore, the patient underwent surgery. Intraoperatively, we evaluated the flow of the gastric tube after clamping the right gastroepiploic artery using ICG fluorescence. As a result, the flow of the gastric tube was deemed insufficient. Consequently, subtotal gastrectomy was performed with preservation of the right gastroepiploic artery via Roux-en-Y reconstruction.

DISCUSSION

ICG fluorescence is useful for evaluating the flow of the gastric tube helping to decide the operating method.

CONCLUSION

We herein report a case of subtotal gastrectomy for GTC using intraoperative ICG fluorescence.

[Fluorescence angiography for esophageal anastomoses : Perfusion evaluation of the gastric conduit with indocyanine green]

BACKGROUND

The incidence of esophageal cancer continues to increase. Despite increasing experience in esophageal surgery and perioperative management, anastomotic leakage remains a frequent and severe complication.

OBJECTIVE

The aim of this article is to demonstrate the current role of fluorescence angiography (FA) with indocyanine green (ICG) in the assessment of esophageal anastomoses. The main focus is on the evaluation of the perfusion situation.

MATERIAL AND METHODS

A systematic search was carried out in PubMed and Medline on FA and ICG, especially with respect to current subjective and objective interpretation approaches of FA against the background of own research.

RESULTS

The rate of anastomotic leakage remains high despite modern surgical procedures. Assessment of neoesophageal perfusion with FA can significantly reduce the rate of anastomotic leakage. At present, FA is mostly subjectively applied in small case studies. The study situation is heterogeneous. Randomized studies do not so far exist.

CONCLUSION

The use of FA with ICG is suitable for evaluation of perfusion of the gastric tube. The implementation is simple and can be standardized. Prospective, randomized trials and objective quantification are needed in the future in order to clarify the potential of the technique.