Intraoperative laser fluorescence angiography in colorectal surgery: a noninvasive analysis to reduce the rate of anastomotic leakage

Intraoperative Thermal Imaging for Evaluating Blood Perfusion During Laparoscopic Colorectal Surgery

BACKGROUND

Anastomotic leakage is a feared complication of anterior resection for rectal cancer. Among the various factors reported to be involved in the occurrence of anastomotic leakage, blood perfusion of the remnant intestine is one of the most important. Recently, the usefulness of evaluating blood perfusion using indocyanine green (ICG) has been reported. We therefore aimed to show that measuring intestinal temperature using thermography is useful for evaluating blood perfusion. The authors also investigated the relation between intestinal temperatures and the ICG fluorescence time (FT).

MATERIALS AND METHODS

Altogether, 45 patients who underwent laparoscopic anterior resection for rectal cancer between July 2017 and September 2018 were enrolled in this study. ICG FT and intestinal temperature were measured after the mesenteric dissection.

RESULT

The temperature boundary could be easily identified using thermographic images. The temperature of the residual intestinal tract was significantly higher than that of the resected intestinal tract at the planned separation line (29.9 vs. 27.3°C). In addition, there was an inverse correlation between the ICG FT and the temperature of the residual intestine.

CONCLUSION

Intestinal temperature measurement through thermography is a useful new tool for evaluating intestinal blood perfusion.

Preliminary Use of Indocyanine Green Fluorescence Angiography and Value in Predicting the Vascular Supply of Tissues Needed to Perform Cloacal, Anorectal Malformation, and Hirschsprung Reconstructions

INTRODUCTION

 Reconstructive techniques for cloaca, anorectal malformations (ARM), and Hirschsprung disease (HD) may require intestinal flaps on vascular pedicles for vaginal reconstruction and/or colonic pull-throughs. Visual assessment of tissue perfusion is typically the only modality used. We investigated the utility of intraoperative indocyanine green fluorescence angiography (ICG-FA) and hypothesized that it would be more accurate than the surgeon's eye.

MATERIALS AND METHODS

 Thirteen consecutive patients undergoing cloacal reconstruction (9), HD (3), and ARM repair (1) underwent ICG-FA laser SPY imaging to assess colonic, rectal, vaginal, and neovaginal tissue perfusion following intraoperative visual clinical assessment. Operative findings were correlated with healing at 6 weeks, 3 months, and 1 year postoperatively.

RESULTS

 ICG-FA resulted in a change in the operative plan in 4 of the 13 (31%) cases. In three cases, ICG-FA resulted in the distal bowel being transected at a level (>10 cm) higher than originally planned, and in one case the distal bowel was discarded, and the colostomy used for pull-through.

CONCLUSION

 ICG-FA correctly identified patients who might have developed a complication from poor tissue perfusion. Employing this technology to assess rectal or neovaginal pull-throughs in cloacal reconstructions, complex HD, and ARM cases may be a valuable technology.

Clinical utility of transanal indocyanine green near-infrared fluorescence imaging for evaluation of colorectal anastomotic perfusion

BACKGROUND

Although indocyanine green (ICG) fluorescence imaging has been reported to be useful for assessing colorectal perfusion, unstable quantification remains an issue. We performed ICG fluorescence observation from the luminal side and examined the usefulness of the transanal approach.

METHODS

A total of 69 patients who underwent left-side colon surgery were enrolled in this cohort study. After the anastomosis had been constructed, ICG 0.2 mg/kg was injected intravenously. The anastomotic site was then observed by a scope inserted transanally. The following items were examined in the areas of the anastomotic site with the highest- and lowest-fluorescence intensity: maximum fluorescence (Fmax), time from ICG injection to Fmax (Tmax), time from start of dyeing to Fmax (ΔT), and the contrast pattern of the mucosa.

RESULTS

Anastomotic leakage (AL) occurred in nine cases. Tmax and ΔT values of the lowest-fluorescence area in the distal intestine showed significant differences in the cases with AL (P = 0.015 and P = 0.040, respectively). Regarding the contrast pattern of the mucosa of the lowest-fluorescence area in the proximal and distal intestine, the patients in whom the vessels were not depicted in the area had a significantly higher incidence of AL than those in whom vessels were depicted in the area (P = 0.031 and P = 0.030, respectively). Some of the areas in which vessels were not depicted by ICG fluorescence observation from the luminal side corresponded to the points of leakage. There were heterogeneous changes that might not be grasped by observation from the serosal side.

CONCLUSION

Transanal ICG fluorescence imaging can evaluate perfusion over the entire circumference of the anastomosis in detail and aid in assessing the risk of AL. Therefore, the examination of the detailed low-perfusion area enables us to take measures for AL and to search for safer operative managements.

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.

Validation of quantitative assessment of indocyanine green fluorescent imaging in a one-vessel model

Objectives

Evaluation of intestinal perfusion remains subjective and depends on the surgeon´s individual experience. Intraoperative quality assessment of tissue perfusion with indocyanine green (ICG) fluorescence using a near-infrared camera system has been described in different ways and for different indications. The aim of the present study was to evaluate fluorescent imaging (FI) in the quantitative assessment of intestinal perfusion in a gastric tube model in pigs and to compare the results to results obtained with florescent microspheres (FM), the gold standard for tissue perfusion.

Methods

Seven pigs (56.0±3.0 kg), both males and females, underwent gastric tube formation after transection and ligation of the gastric arteries, except the right gastroepiploic artery, to avoid collateral blood flow.

After baseline assessment (T0), hypotension (T1) was induced by propofol (Karampinis et al 2017) (< 60 mmHg). Then, propofol was paused to obtain normotension (T2, Mean arterial pressure (MAP) 60–90 mmHg). Finally, hypertension (T3, MAP>90 mmHg) was induced by norepinephrine.

Measurements were performed in three regions of interest (ROIs) under standardized conditions: the fundus (D1), corpus (D2), and prepyloric area (D3). Hemodynamic parameters and transit-time flow measurement (TTFM) in the right gastroepiploic artery were continuously assessed. FI, FM and the partial pressure of tissue oxygen (TpO₂) were quantified in each ROI.

Results

The study protocol could successfully be performed during stable hemodynamics. Flow in the gastroepiploic artery measured by transit time flow measurement (TTFM) was related to hemodynamic changes between the measurements, indicating improved blood flow with increasing MAP. The distal part of the gastric tube (D1) showed significantly (p<0.05) impaired perfusion compared to the proximal parts D3 and D2 using FM. ICG-FI also showed the highest values in D3 and the lowest values in D1 at all hemodynamic levels (T1-T3; p<0,05).

Conclusion

Visual and quantitative assessment of gastric tube perfusion is feasible in an experimental setting using ICG-FI. This might be a promising tool for intraoperative assessment during visceral surgery in the future.

Incidence and risk factors for fluorescence abnormalities on near-infrared imaging using indocyanine green in stapled functional end-to-end anastomosis in laparoscopic colectomy

PURPOSE

Recently, several studies have suggested that near-infrared (NIR) imaging using indocyanine green (ICG) may contribute to the reduction of anastomotic leakage (AL) after colorectal cancer (CRC) surgery. However, few reports have focused on the usefulness of NIR imaging for AL after stapled functional end-to-end anastomosis (stapled FEEA). The purpose of this study was to clarify the frequency of fluorescence abnormalities on NIR imaging, in cases reconstructed with stapled FEEA.

METHODS

This retrospective study included patients with colon or appendiceal cancer who underwent laparoscopic colectomy with stapled FEEA reconstruction between March 2016 and August 2019.

RESULTS

A total of 400 patients who were managed at our three institutions were included in the present study. The rate of Clavien-Dindo (CD) grade > III AL was 1.0% (4/400). The median length of postoperative hospital stay was 7 days (IQR 25-75th percentile 6-8 days). In 11 patients (2.8%), the transection line was changed by NIR imaging, due to fluorescence abnormalities. The rate of transverse colon involvement in anastomosis was significantly higher in cases with fluorescence abnormalities than in cases with normal fluorescence (p = 0.035).

CONCLUSIONS

The frequency of fluorescence abnormalities on NIR was 2.8% in cases of colon resection with reconstruction by using stapled FEEA. There was a probability of abnormal fluorescence on NIR in cases where the transverse colon was involved in the anastomosis. This means that NIR may have potential benefit in such cases.

TRIAL REGISTRATION

UMIN000039977.

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.

The sigmoidea ima artery: A player in colonic ischemia?

INTRODUCTION

The sigmoidea ima artery is defined as the lowest sigmoid artery, which forms the distal end of the marginal artery by linking with the superior rectal artery. It supplies the rectosigmoid junction, which is a critical area for ischemia. The aim of the present study was to delineate the area supplied by the inferior mesenteric artery with special consideration of the sigmoidea ima artery.

MATERIALS AND METHODS

The inferior mesenteric artery was dissected from its origin to the bifurcation of the superior rectal artery in 30 cadavers (15 male, 15 female). Vessel length and distance to the promontory were measured for each branch.

RESULTS

There were two manifestations of the sigmoidea ima artery, irrespective of the branching pattern of the inferior mesenteric artery. It originated below the promontory in 25 cases (83.3%) and above it in three (10%). It did not derive from the superior rectal artery in two cases (6.7%). In these 16.7%, the marginal artery was absent near the rectosigmoid junction.

CONCLUSIONS

We suggest the terms "arteria sigmoidea ima pelvina" and "arteria sigmoidea ima abdominalis" for the two variants. The terms "arteria marginalis pelvina" and "arteria marginalis abdominalis" could be applied in clinical practice. An abdominal marginal artery could be considered a risk factor for colonic ischemia in colorectal resections and abdominal aortic aneurysm repair. Both variants should be considered when pre- and intra-operative perfusion measurements are interpreted.

Prospective Study Comparing Clinical vs Indocyanine Green Fluorescence-Based Assessment of Line of Transection in Robotic Rectal Cancer Surgery-Indian Study

Anastomotic leakage continues to be the most feared postoperative complications in rectal surgery with negative impact on both short- and long-term outcomes. Fortunately, new surgical strategies have helped to offset this complication and improve surgical outcomes. Traditionally, perfusion is assessed by intraoperative visual judgment by the surgeon. These subjective methods lack predictive accuracy resulting in either excess or insufficient colonic resection. Indocyanine green (ICG) fluorescence has shown promise in identifying the adequacy of perfusion. After injection of ICG, the system projected high-resolution near-infrared real-time images of blood flow in mesentery and bowel wall. This novel imaging method is used intraoperatively for taking real-time informed decisions. We conducted a single institutional prospective study to identify the feasibility of ICG identification of vascularity of anastomotic site and its impact on the change of plan of surgical management in robotic rectal cancer surgery. Between September 2017 and April 2019, fifty patients undergoing robotic rectal cancer surgery were included in the study. The aim was to analyze the feasibility and clinical benefit of intraoperative near-infrared fluorescence imaging in determining the line of transection in comparison with the traditional method. Line of proximal transection of the bowel subjectively assessed by the surgical team was marked point B and that after ICG injection was marked point A if moved proximally and point C if moved distally. The vascular anatomy was clearly identified with no intraoperative or injection-related adverse effects. Of the 50 patients, the line of transaction remained the same in 6 patients (12%). Based on the fluorescence imaging, the surgical team opted for further proximal change of the transection line up to an "adequate" fluorescent portion in 3 patients (6%) and distally in 41 patients (82%). ICG-based infrared image-guided localization gives a real-time image of colon vascularity possibly affecting anastomotic leak. The ICG fluorescence imaging system is a simple, safe, and useful technique, performed within a short time, and it enables visual evaluation of the blood flow in the intestinal tract prior to anastomosis. Larger studies are needed before this can become the standard of care.

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.

A prospective study of real-time identification of line of transection in robotic colorectal cancer surgery by ICG

Colorectal cancer is the second most common cancer in women and the third most common cancer in men in the world. Surgical resection is the gold standard treatment and minimally invasive surgery remains the standard of care. Anastomotic leakage is one of the most feared postoperative complications in colorectal surgery. Although several factors have been identified as possible causes of anastomotic leakage (i.e., surgical techniques, patient risk factors, suture material or devices), the complete pathogenesis is still unclear. The reported leak rate ranges from 1 to 30% and increases as the anastomosis is more distal. To date the most widely used methods to assess tissue perfusion includes the surgeon intraoperative visual judgement based on the colour; bleeding edges of resected margins; pulsation and temperature, thereby resulting in either excess or insufficient colonic resection. Earlier studies in colorectal surgery have suggested that assessment of tissue perfusion by the clinical judgment of the operating surgeon underestimated the risk of anastomotic leakage. Indocyanine green (ICG) is a intravenous dye which has shown promise in identifying the bowel vascularity real time. Earlier studies on colorectal cancer have shown that ICG based detection of bowel vascularity is technically possible and has reduced the anastomotic leak rates in 16.7% of patients. We conducted a prospective study on patients with ICG guided bowel perfusion during robotic colorectal cancer surgery. The method is technically easy, reproducible and safe. This technique has changed the intraoperative decision in 88% of patients. Larger studies are needed before this can become the standard of care.

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.

The Use of Enhanced Technologies in Robotic Surgery and Its Impact on Outcomes in Rectal Cancer: A Systematic Review

The main advantage of the robotic approach is the surgical precision that the technology offers. It is particularly useful in rectal cancer as this is a technically challenging procedure. The technological advantage of the robot leads to better postoperative outcomes. Apart from the 3D vision and endowrist instrumentation in comparison to laparoscopy, the options of using fluorescence imaging, endowrist stapler, and table motion have revolutionised the way of performing an anterior resection. Thus, the true benefit of these advances will be the quality of the surgery, which leads to better postoperative outcomes. This article focuses on the current status of applications of new modalities and technology development in robotic rectal surgery. A systematic literature search was performed using PubMed, MEDLINE, and cochrane database. The studies included were considered based on the following (1) articles written in English, (2) full text is available, (3) whether the topic is related to the use of novel technologies during robotic rectal surgery, and (4) sample: adult patients and malignant rectal disease. The primary end point was to analyse the current use of technological advances in robotic rectal surgery. Only a few studies are currently available on the use of these different technologies in robotic colorectal surgery. Many of these reports describe promising results, although with short-term outcomes. The use of technologies in robotic colorectal surgery is safe and feasible and can be used together to improve short-term outcomes. Intraoperative fluorescence angiography has demonstrated to reduce the rate of anastomotic leak, whereas the robotic stapler and the table motion simplify anatomic resection.

The impact of near-infrared angiography and proctoscopy after rectosigmoid resection and anastomosis performed during surgeries for gynecologic malignancies

OBJECTIVES

Reducing anastomotic leak rates after rectosigmoid resection and anastomosis is a priority in patients undergoing gynecologic oncology surgery. Therefore, we investigated the implications of performing near-infrared angiography (NIR) via proctoscopy to assess anastomotic perfusion at the time of rectosigmoid resection and anastomosis.

METHODS

We identified all patients who underwent rectosigmoid resection and anastomosis for a gynecologic malignancy between January 1, 2013 and December 31, 2018. NIR proctoscopy was assessed via the PINPOINT Endoscopic Imaging System (Stryker).

RESULTS

A total of 410 patients were identified, among whom NIR was utilized in 133 (32.4%). There were no statistically significant differences in age, race, BMI, type of malignancy, surgery, histology, FIGO stage, hypertension, diabetes, or preoperative chemotherapy between NIR and non-NIR groups. All cases of rectosigmoid resection underwent stapled anastomosis. The anastomotic leak rate was 2/133 (1.5%) in the NIR cohort compared with 13/277 (4.7%) in the non-NIR cohort (p = 0.16). Diverting ostomy was performed in 9/133 (6.8%) NIR and 53/277 (19.9%) non-NIR patients (p < 0.001). Postoperative abscesses occurred in 8/133 (6.0%) NIR and 44/277 (15.9%) non-NIR patients (p = 0.004). The NIR cohort had significantly fewer post-operative interventional procedures (12/133, 9.0% NIR vs. 55/277, 19.9% non-NIR, p = 0.006) and significantly fewer 30-day readmissions (14/133, 10.5% NIR vs. 61/277, 22% non-NIR, p = 0.004).

CONCLUSIONS

NIR proctoscopy is a safe tool for assessing anastomotic rectal perfusion after rectosigmoid resection and anastomosis, with a low anastomotic leak rate of 1.5%. Its potential usefulness should be evaluated in randomized trials in patients undergoing gynecologic cancer surgery.

Near-infrared fluorescent solid material for visualizing indwelling devices implanted for medical use

BACKGROUND

In clinical practice, various devices are implanted into the body for medical reasons. As X-ray fluoroscopy is necessary to visualize medical devices implanted into the body, the development of a less-invasive visualization method is highly desired. This study aimed to investigate the clinical applicability of our novel solid material that emits near-infrared fluorescence.

METHODS

We developed a solid resin material that emits near-infrared fluorescence. This material incorporates a near-infrared fluorescent pigment, with quantum yield ≥ 20 times than that of indocyanine green. It can be sterilized for medical treatment. This resin material is designed to be molded into a catheter and inserted into the body with an endoscope clip. In this preclinical experiment using a swine model, the resin material was embedded into the body of the swine and visualized with a near-infrared fluorescence camera system.

RESULTS

Endoscopic clips were placed in the mucosa of the stomach, esophagus, and large intestine, and the indwelling ureteral catheters were successfully visualized by near-infrared fluorescence laparoscopy.

CONCLUSIONS

We confirmed the tissue permeability of the fluorescence emitted by our novel near-infrared fluorescent material and the possibility of its clinical application. This material may allow visualization of devices embedded in the body.

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.

Preoperative anaemia and thrombocytopenia are associated with venous thromboembolism complications after colorectal resection

BACKGROUND

Earlier studies have shown that abnormal levels of haemoglobin and platelets may be associated with worse post-operative outcomes. We aim to compare the rates of venous thromboembolism (VTE), anastomotic leak and other complications in patients post-colorectal resection with normal and abnormal levels of haemoglobin and platelets.

METHODS

We performed a retrospective review of 1610 patients from July 2010 to June 2015 in a single colorectal unit. Our primary outcome was the rate of VTE and anastomotic leak in anaemic and thrombocytopenic patients. Secondary outcomes included length of stay, 30-day mortality, return to theatre, transfusion rates and Clavien-Dindo classification complications.

RESULTS

VTE complications were more common in anaemic patients, and this difference became more pronounced with the severity of anaemia. Other complications such as length of stay >2 weeks occurred more frequently in anaemic and thrombocytopenic patients. A trend towards higher rates of 30-day mortality and anastomotic leak was noted in patients with anaemia and thrombocytopenia.

CONCLUSION

Anaemia and thrombocytopenia are associated with worse outcomes including length of stay, anastomotic leak, VTE and 30-day mortality.

Advances in image enhancement for sarcoma surgery

The recurrence rate of soft tissue and bone sarcomas strongly correlates to the status of the surgical margin after excision, yet excessive removal of tissue may lead to distinct, otherwise avoidable morbidity. Therefore, adequate margination of sarcomas both pre- and intra-operatively is a clinical necessity that has not yet fully been met. Current guidance for soft-tissue sarcomas recommends an ultrasound scan followed by magnetic resonance imaging (MRI). For bone sarcomas, two plane radiographs are required, followed similarly by an MRI scan. The introduction of more precise imaging modalities may reduce the morbidity associated with sarcoma surgery; the PET-CT and PET-MRI approaches in particular demonstrating high clinical efficacy. Despite advancements in the accuracy in pre-operative imaging, translation of an image to surgical margins is difficult, regularly resulting in wider resection margins than required. For soft tissue sarcomas there is currently no standard technique for image guided resections, while for bone sarcomas fluoroscopy may be used, however margins are not easily discernible during the surgical procedure. Near infra-red (NIR) fluorescence guided surgery offers an intra-operative modality through which complete tumour resection with adequate tumour-free margins may be achieved, while simultaneously minimising surgical morbidity. NIR imaging presents a potentially valuable adjunct to sarcoma surgery. Early reports indicate that it may be able to provide the surgeon with helpful information on anatomy, perfusion, lymphatic drainage, tumour margins and metastases. The use of NIR fluorochromes have also been demonstrated to be well tolerated by patients. However, prior to widespread implementation, studies related to cost-effectiveness and the development of protocols are essential. Nevertheless, NIR imaging may become ubiquitous in the future, carrying the potential to transform the surgical management of sarcoma.

HYPerspectral Enhanced Reality (HYPER): a physiology-based surgical guidance tool

BACKGROUND

HSI is an optical technology allowing for a real-time, contrast-free snapshot of physiological tissue properties, including oxygenation. Hyperspectral imaging (HSI) has the potential to quantify the gastrointestinal perfusion intraoperatively. This experimental study evaluates the accuracy of HSI, in order to quantify bowel perfusion, and to obtain a superposition of the hyperspectral information onto real-time images.

METHODS

In 6 pigs, 4 ischemic bowel loops were created (A, B, C, D) and imaged at set time points (from 5 to 360 min). A commercially available HSI system provided pseudo-color maps of the perfusion status (StO2, Near-InfraRed perfusion) and the tissue water index. An ad hoc software was developed to superimpose HSI information onto the live video, creating the HYPerspectral-based Enhanced Reality (HYPER). Seven regions of interest (ROIs) were identified in each bowel loop according to StO2 ranges, i.e., vascular (VASC proximal and distal), marginal vascular (MV proximal and distal), marginal ischemic (MI proximal and distal), and ischemic (ISCH). Local capillary lactates (LCL), reactive oxygen species (ROS), and histopathology were measured at the ROIs. A machine-learning-based prediction algorithm of LCL, based on the HSI-StO2%, was trained in the 6 pigs and tested on 5 additional animals.

RESULTS

HSI parameters (StO2 and NIR) were congruent with LCL levels, ROS production, and histopathology damage scores at the ROIs discriminated by HYPER. The global mean error of LCL prediction was 1.18 ± 1.35 mmol/L. For StO2 values > 30%, the mean error was 0.3 ± 0.33.

CONCLUSIONS

HYPER imaging could precisely quantify the overtime perfusion changes in this bowel ischemia model.

Impact of intraoperative indocyanine green fluorescence angiography on anastomotic leakage after laparoscopic sphincter-sparing surgery for malignant rectal tumors

PURPOSE

Whether indocyanine green fluorescence angiography (ICG-FA) during rectal surgery is effective in reducing anastomotic leakage remains unclear. This study aimed to investigate the effect of intraoperative ICG-FA on anastomotic leakage after sphincter-sparing surgery for malignant rectal tumors.

METHODS

This was a retrospective, single-center cohort study conducted on 852 consecutive patients who underwent laparoscopic sphincter-sparing surgery from January 2007 to June 2017 at our institution. The incidence of anastomotic leakage was compared between patients who underwent ICG-FA to determine the proximal resection margin and those in whom this technique was not performed, using logistic regression analysis, including propensity score.

RESULTS

A total of eight patients were excluded (one patient with previous low anterior resection and seven patients who underwent simultaneous resection for other primary cancers), resulting in 844 patients being analyzed. Before propensity score matching, 141 patients (16.7%) who underwent ICG-FA were compared with 703 patients (83.3%) in whom ICG-FA was not performed. The incidence of anastomotic leakage was 2.8% (4/141) in the ICG-FA group and 12.4% (87/703) in the control group (p = 0.001). After propensity score matching (n = 420), the patient characteristics between the two groups were well balanced, and the incidence of anastomotic leakage was 2.8% (4/141) in the ICG-FA group and 13.6% (38/279) in the control group (p = 0.001). Logistic regression analyses using propensity score showed that patients who underwent ICG-FA had significantly lower odds of anastomotic leakage.

CONCLUSION

Intraoperative ICG-FA is a promising method to reduce anastomotic leakage after laparoscopic rectal surgery.

A Modified Side-to-Side Anastomosis Using a Circular Stapler Reduces Anastomotic Leakage in Colonic Surgery

Background. Anastomotic leakage (AL) remains one of the serious complications after colonic surgery. Method. A prospective interventional study to assess a modified technique of creating the ileocolic, colic-colic, and colorectal side-to-side anastomoses using a circular stapler. The primary endpoint was to evaluate the safety and efficacy of this technique in the reduction of AL. Computed tomography scan was performed when AL was clinically suspected. Result. One hundred and forty-five patients who underwent colonic resection between January 2015 and August 2018 were included. One patient underwent surgery for severe inflammatory bowel disease, and the others underwent surgery for colonic cancer. The procedures were open surgeries, including right hemicolectomy (n = 79 [54.5%]), left hemicolectomy (n = 29 [20%]), sigmoidectomy (n = 30 [20.7%]), and transverse colectomy (n = 7 [4.8%]). In 23 patients with ascending colonic obstruction, emergency right colectomy with primary anastomosis was performed. Two surgeons performed the operations (52.4% and 47.6%, respectively), and intraoperative blood loss was 50 to 100 mL. The operative time was 160 to 240 minutes. There was no mortality postoperatively, and 26 (17.9%) patients developed complications. One patient who underwent transverse colonic cancer resection developed a clinical AL (0.7%). After ileostomy, the patient was discharged with no other serious complication. The median of postoperative hospital stay was 8 days (range = 5-18 days). Conclusion. This modified technique is a safe and efficient method for anastomotic configuration in colonic surgery.

[Splenic flexure mobilization in surgery for rectal cancer]

Nowadays, the issue of splenic flexure mobilization (SFM) in anterior and low anterior rectal resection for rectal cancer is still debatable. This stage is important because dissection results tension-free anastomosis and excision of specimen of enough length with adequate number of harvested lymph nodes. However, literature review confirmed the absence of agreement regarding reduced incidence of colorectal anastomotic leakage and improved long-term oncologic outcomes after SFM. Opinion about selective approach to this procedure is becoming more common. Therefore, randomized trials are necessary to determine a need for routine SFM or indications for selective approach to SFM in anterior rectal resection for rectal cancer.

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

BACKGROUND

Insufficient vascular supply is one of the main causes of anastomotic leak in colorectal surgery. Intraoperative indocyanine-green (ICG) angiography has been shown to provide information on tissue perfusion, identifying a well-perfused location for colonic and rectal transections, and thus possibly reducing the leak rate. Aim of this study was to evaluate the usefulness of intraoperative assessment of anastomotic perfusion using ICG angiography in patients undergoing left-sided colon or rectal resection with colorectal anastomosis.

METHODS

This randomized trial involved 252 patients undergoing laparoscopic left-sided colon and rectal resection randomized 1:1 to intraoperative ICG or to subjective visual evaluation of the bowel perfusion without ICG. The primary aim was to assess whether ICG angiography could lead to a reduction in anastomotic leak rate. Secondary outcomes were possible changes in the surgical strategy and postoperative morbidity.

RESULTS

After randomization, 12 patients were excluded. Accordingly, 240 patients were included in the analysis; 118 were in the study group, and 122 in the control group. ICG angiography showed insufficient perfusion of the colic stump, which led to extended bowel resection in 13 cases (11%). An anastomotic leak developed in 11 patients (9%) in the control group and in 6 patients (5%) in the study group (p = n.s.).

CONCLUSIONS

Intraoperative ICG fluorescent angiography can effectively assess vascularization of the colic stump and anastomosis in patients undergoing colorectal resection. This method led to further proximal bowel resection in 13 cases, however, there was no statistically significant reduction of anastomotic leak rate in the ICG arm.

CLINICAL TRIAL

ClinicalTrials.gov NCT02662946.

Recurrence of rectal anastomotic leakage following stoma closure: assessment of risk factors

AIM

In patients with a previous history of rectal anastomotic leakage (AL), the surgical indications and timing for closure of a diverting stoma have to be carefully judged. Even if AL has apparently healed before stoma closure, re-leakage may occur after closure. The aim of this study was to determine the incidence and risk factors for recurrent AL following stoma closure. We also examined the treatment strategies aiming to minimize the risk of recurrent AL.

METHODS

From January 2009 to December 2016, 1008 patients underwent sphincter-saving surgery [low anterior resection, all-sphincter-preserving rectal resection with hand-sewn coloanal anastomosis (CAA) and intersphincteric resection (ISR)] for primary rectal cancer with curative intent at our hospital. A total of 69 patients with AL with a Clavien-Dindo Grade III or more who subsequently underwent closure of a diverting stoma were retrospectively reviewed for this study.

RESULTS

The incidence of recurrent leakage after stoma closure in this series was 13% overall with an incidence of 25% in the CAA/ISR group and 5% in the low anterior resection group. Significant risk factors included hand-sewn anastomosis (P = 0.0257) compared to stapled anastomosis, ischaemia at the anastomotic site as the cause of initial AL (P < 0.001) and a shorter interval between confirmation of healing and stoma closure (P = 0.00952).

CONCLUSION

Ischaemia at the anastomotic site was the main risk factor for recurrent leakage, particularly after CAA/ISR. Additional treatment options before stoma closure should be considered to avoid re-leakage in such cases.

Clinical application and technical standardization of indocyanine green (ICG) fluorescence imaging in pediatric minimally invasive surgery

PURPOSE

We reported our preliminary experience using ICG fluorescence in pediatric minimally invasive surgery (MIS) with the aim to standardize indications, dose, timing, and modality of administration of ICG according to different organs.

METHODS

ICG technology was adopted in 46 MIS procedures performed in our unit over the last 18 months: 30 left varicocele repairs; 5 cholecystectomies in obese adolescents; 3 tumor excisions; 3 nephrectomies; 2 partial nephrectomies; 3 lymphoma excisions. ICG solution was injected intravenously in all cases except for varicocelectomy in which it was injected into the testis. The ICG injection was performed intra-operatively in all cases except for cholecystectomy in which it was injected 18 h prior to the procedure.

RESULTS

All procedures were completed laparoscopically without conversions or intra-operative complications. No adverse or allergic reactions to ICG were reported.

CONCLUSION

Our preliminary experience showed that ICG fluorescence is a safe, useful, and versatile technique to adopt in pediatric MIS to achieve a better identification of anatomy and an easier surgical dissection or resection in challenging cases. Currently, the main indications are varicocelectomy, difficult cholecystectomy, tumor excision, nephrectomy, and partial nephrectomy. The main limitation is the needing of a special equipment to use ICG technology.

Visualization and quantification of anastomotic perfusion in colorectal surgery using near-infrared fluorescence

BACKGROUND

Anastomotic leakage (AL) is one of the most troublesome complications in colorectal surgery. Recently, near-infrared fluorescence (NIRF) imaging has been used intraoperatively to detect sentinel lymph nodes and visualize the blood supply at the region of interest (ROI). The aim of this study was to evaluate the role of visualization and quantification of bowel perfusion around the anastomosis using NIRF system in predicting AL.

METHODS

A prospective study was conducted on patients who had laparoscopic surgery for colorectal cancer at our institution. Perfusion of the anastomosis was evaluated with NIRF imaging after intravenous injection of indocyanine green (ICG). The time course of fluorescence intensity was recorded by an imaging analyzer We measured the time from ICG injection to the beginning of fluorescence (T₀), maximum intensity (I_max), time to reach I_max (T_max), time to reach I_max 50% ([Formula: see text]) and slope (S) after the anastomosis.

RESULTS

Tumor locations were as follows; cecum: 2, ascending colon: 2, transverse colon: 7, descending colon: 1, sigmoid colon: 2, rectosigmoid colon: 3 and rectum: 6 (one case with synchronous cancer). All operations were performed laparoscopically. Four patients were diagnosed with or suspected to have AL (2 patients with grade B anastomotic leakage after low anterior resection, 1 patient with minor leakage in transverse colon resection and 1 patient needing re-anastomosis intraoperatively in transverse colon resection). T₀ was significantly longer in the AL group than in patients without AL (64.3 ± 27.6 and 18.2 ± 6.6 s, p = 2.2 × 10^-3).

CONCLUSIONS

Perfusion of the anastomosis could be successfully visualized and quantified using NIRF imaging with ICG. T₀ might be a useful parameter for prediction of AL.

[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.

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.

Near-infrared fluorescence angiography for intra-operative assessment of pedicled omentoplasty for filling of a pelvic cavity: a pilot study

BACKGROUND

During creation of a pedicled omentoplasty, blood flow to segments of the omentum might become compromised. If unrecognized, this can lead to omental necrosis. The purpose of this study was to investigate the potential added intra-operative value of the use of fluorescence angiography (FA) with indocyanine green (ICG) to assess omental perfusion.

METHODS

All consecutive patients undergoing a pedicled omentoplasty in a 6-month period (April 1 2018-October 1 2018) in a University hospital were included. The primary outcome was change in management due to FA. Secondary outcomes included the amount of additionally resected omentum, added surgical time, and quantitative fluorescent values (time to fluorescent enhancement, contrast quantification).

RESULTS

Fifteen patients had pelvic surgery with omentoplasty and FA. Change in management occurred in 12 patients (80%) and consisted of resecting a median of 44 g (range 12-198 g) of poorly perfused omental areas that were not visible by conventional white light. The median added surgical time for the use of FA and subsequent management was 8 min (range 3-39 min). The first fluorescent signal in the omental tissue appeared after a median of 20 s (range 9-37 s) after injection of ICG. The median signal-to-baseline ratio was 23.7 (interquartile range 12.2-29.7) in well perfused and 2.5 (interquartile range 1.7-4.0) in poorly perfused tissue.

CONCLUSIONS

FA of a pedicled omentoplasty allows a real-time assessment of omental perfusion and leads to change in management in 80% of the cases in this pilot study. These findings support the conduct of larger studies to determine the impact on patient outcome in this setting.

In vivo validation of a miniaturized electrochemical oxygen sensor for measuring intestinal oxygen tension

Recent advances in the fields of electronics and microfabrication techniques have led to the development of implantable medical devices for use within the field of precision medicine. Monitoring visceral surface tissue O₂ tension (PTo2) by means of an implantable sensor is potentially useful in many clinical situations, including the perioperative management of patients undergoing intestinal resection and anastomosis. This concept could provide a means by which treatment could be tailored to individual patients. This study describes the in vivo validation of a novel, miniaturized electrochemical O₂ sensor to provide real-time data on intestinal PTo2. A single O₂ sensor was placed onto the serosal surface of the small intestine of anesthetized rats that were exposed to ischemic (superior mesenteric artery occlusion) and hypoxemic (alterations in inspired fractional O₂ concentrations) insults. Control experiments demonstrated that the sensors can function and remain stable in an in vivo environment. Intestinal PTo2 decreased following superior mesenteric artery occlusion and with reductions in inspired O₂ concentrations. These results were reversible after reinstating blood flow or by increasing inspired O₂ concentrations. We have successfully developed an anesthetized rat intestinal ischemic and hypoxic model for validation of a miniaturized O₂ sensor to provide real-time measurement of intestinal PTo2. Our results support further validation of the sensors in physiological conditions using a large animal model to provide evidence of their use in clinical applications where monitoring visceral surface tissue O₂ tension is important.NEW & NOTEWORTHY This is the first report of real-time continuous measurements of intestinal oxygen tension made using a microfabricated O₂ sensor. Using a developed rodent model, we have validated this sensor's ability to accurately measure dynamic and reversible changes in intestinal oxygenation that occur through ischemic and hypoxemic insults. Continuous monitoring of local intestinal oxygenation could have value in the postoperative monitoring of patients having undergone intestinal surgery.

Assessment of Anastomotic Perfusion in Left-Sided Robotic Assisted Colorectal Resection by Indocyanine Green Fluorescence Angiography

Background

Indocyanine green fluorescent angiography (IcGA) has been used with success in guiding intraoperative management to prevent colorectal anastomotic complications. Prior studies in open and laparoscopic colorectal surgery, such as PILLAR II, have demonstrated a low anastomotic leak rate (1.4%). As the minimally invasive approach progresses from laparoscopic to robotic approach, the effect and safety of IcGA in assessing anastomotic perfusion in the latter deserve further investigation.

Methods

The objective of the study was to determine the safety of IcGA in guiding intraoperative management of robotic assisted colorectal resection via perfusion assessment. The design was single-surgeon, retrospective case-control study. 74 patients underwent left-sided robotic assisted colorectal resection and anastomosis with IcGA guidance. 30 historical controls underwent left-sided robotic assisted colorectal resection and anastomosis without IcGA. Clinical, demographic, operative, and outcome variables were tabulated.

Results

In the control group, 1 patient suffered a postoperative anastomotic stricture requiring no surgery, and 1 patient suffered an anastomotic dehiscence requiring return to the operating room. There were no anastomotic complications in the IcGA group, including 4 patients who underwent a change in the chosen level of anastomosis based on intraoperative IcGA.

Conclusion

IcGA is safe to use as demonstrated by the very low rate of complications in this case series. It is also safe to rely on to guide re-resection and recreation of an anastomosis intraoperatively by demonstration of blood flow. This may help offset the loss of tactile feedback and assessment of tension in the robotic platform.

The Risk Factor of Anastomotic Hypoperfusion in Colorectal Surgery

BACKGROUND

Inadequate blood flow is an important risk factor for anastomotic leakage. Indocyanine green (ICG) fluorescence imaging allows intraoperative assessment of intestinal blood flow. This study determined the risk factor of anastomotic hypoperfusion in colorectal surgery using ICG fluorescence imaging.

METHODS

This study included 74 consecutive patients who underwent colorectal surgery between April 2017 and March 2018. ICG was injected intravenously after dividing the mesentery and central vessels along the planned transection line, but before completing the anastomosis. Intraoperative blood flow was evaluated using ICG fluorescence imaging. With regard to the patient-, tumor-, and surgery-related factors, anastomotic perfusion was evaluated based on the changed transection line and prolonged (more than 60 s) perfusion time.

RESULTS

Intraoperative ICG fluorescence imaging was performed in all patients, and no adverse events were associated with ICG injection. Based on the perfusion assessment, we changed the transection line in six patients (8.1%). The prolonged perfusion time was observed in nine patients (12.2%). The postoperative course was uneventful in 63 (85.1%) patients, but one patient (1.4%) had postoperative anastomotic leakage. The changed transection line was significantly associated with anticoagulation therapy (P = 0.029). Well-known risk factors, including surgical site, sex, smoking, blood loss, operative time, and preoperative chemoradiotherapy, were not related to the changed transection line. Prolonged ICG perfusion time was not associated with any patient-, tumor-, or surgery-related factors.

CONCLUSIONS

The evaluation of intraoperative blood flow using ICG fluorescence imaging may be able to detect anastomotic hypoperfusion, and anticoagulation therapy is a risk factor of anastomotic hypoperfusion in colorectal surgery.

A standardized use of intraoperative anastomotic testing in colorectal surgery in the new millennium: is technology taking over? A systematic review and network meta-analysis

BACKGROUND

Anastomotic leakage (AL) remains the most challenging complication following colorectal resection. There are several tests that can be used to test anastomotic integrity intraoperatively including air leak testing (ALT) and intraoperative colonoscopy (IOC). Indocyanine green (ICG) can be used to visualise blood supply to the bowel used in the anastomosis. However, there is no consensus internationally regarding routine use and which technique is superior. The aim of this study was to determine which intraoperative anastomotoic leak test (IALT) was most effective in reducing AL.

METHODS

A systematic review and network meta-analysis were performed. An electronic systematic search was performed using Pubmed, CENTRAL, and Web of Science, of studies comparing ALT, IOC, and ICG. The inclusion criteria were as follows: (a) patients must have had colorectal surgery with formation of an anastomosis; (b) studies must have compared one or more IALTs; (c) and studies must have clear research methodology.

RESULTS

Eleven articles totalling 3844 patients met the inclusion criteria and were included in this meta-analysis. Point estimation showed that the AL rate in the control group (no IALT) was significantly higher when compared to the ICG group (RR 0.44; Crl 0.14-0.87) and higher, but without reaching statistical significance, when compared to ALT (RR 0.53; Crl 0.21-1.30) and IOC (RR 0.49; Crl 0.10-1.80). Indirect comparison showed that the AL rate in the ICG group was lower, when compared to both ALT (RR 0.44; Crl 0.14-0.87) and IOC (RR 0.44; Crl 0.14-0.87).

CONCLUSIONS

This study suggests that intraoperative testing for a good blood supply using ICG may reduce the AL rate following colorectal surgery.

Fluorescence techniques in adrenal surgery

This chapter describes the use of fluorescence via indocyanine green (ICG) in minimally invasive adrenal surgery (laparoscopic and robotic). ICG is a non-toxic dye that can aid identification of vascular structures and parenchymal tissue planes in real time. The primary utility of ICG fluorescence in adrenal surgery is to help delineate the margins of resection, to guide a more precise operation. In particular, for patients with bilateral adrenal disease or a heredity associated with high risk of recurrence (e.g., VHL, MEN2a) this may facilitate subtotal adrenal resection (e.g., cortical sparing adrenalectomy), obviating the incidence of iatrogenic adrenal insufficiency and its numerous sequelae including lifelong hormone supplementation, osteoporosis and risk of Addisonian crisis.

[Hyperspectral imaging of gastrointestinal anastomoses]

INTRODUCTION

Anastomotic insufficiency (AI) remains the most feared surgical complication in gastrointestinal surgery, which is closely associated with a prolonged inpatient hospital stay and significant postoperative mortality. Hyperspectral imaging (HSI) is a relatively new medical imaging procedure which has proven to be promising in tissue identification as well as in the analysis of tissue oxygenation and water content. Until now, no data exist on the in vivo HSI analysis of gastrointestinal anastomoses.

METHODS

Intraoperative images were obtained using the TIVITA™ tissue system HSI camera from Diaspective Vision GmbH (Pepelow, Germany). In 47 patients who underwent gastrointestinal surgery with esophageal, gastric, pancreatic, small bowel or colorectal anastomoses, 97 assessable recordings were generated. Parameters obtained at the sites of the anastomoses included tissue oxygenation (StO₂), the tissue hemoglobin index (THI), near-infrared (NIR) perfusion index, and tissue water index (TWI).

RESULTS

Obtaining and analyzing the intraoperative images with this non-invasive imaging system proved practicable and delivered good results on a consistent basis. A NIR gradient along and across the anastomosis was observed and, furthermore, analysis of the tissue water and oxygenation content showed specific changes at the site of anastomosis.

CONCLUSION

The HSI method provides a non-contact, non-invasive, intraoperative imaging procedure without the use of a contrast medium, which enables a real-time analysis of physiological anastomotic parameters, which may contribute to determine the "ideal" anastomotic region. In light of this, the establishment of this methodology in the field of visceral surgery, enabling the generation of normal or cut off values for different gastrointestinal anastomotic types, is an obvious necessity.

The significance of intraoperative fluorescence angiography in miniinvasive low rectal resections

Introduction

Anastomotic leak is a very serious complication in colorectal surgery. Tissue perfusion of the anastomosis plays an integral role in its multifactorial etiology. Fluorescence angiography using indocyanine green allows visualization of perfusion in real time.

Aim

To evaluate the effectiveness of intraoperative fluorescence angiography as a tool to decrease the incidence of anastomotic leak after laparoscopic or robotic low resection of the rectum for cancer.

Material and methods

Intraoperative fluorescence angiography was performed sequentially in 50 patients during low rectal resection for cancer with total mesorectal excision, primary anastomosis and protective ileostomy using laparoscopic or robotic technique. The results were compared to a historical control group of 50 patients with the same procedure without the use of fluorescence angiography.

Results

The patient sets were comparable in basic demographic and clinical parameters. Intraoperative visualization of perfusion by fluorescence angiography was achieved in all patients without unwanted side-effects. In 6 (12%) patients, the resection line was adjusted based on the fluorescence angiography. The incidence of anastomotic leak was insignificantly lower in the group with fluorescence angiography (18% vs. 10%), which led to significantly shorter hospital stay. Other postoperative complications were comparable between the two groups.

Conclusions

Fluorescence angiography using indocyanine green is a safe and effective method with the potential of reducing anastomotic leak during minimally invasive low resection of the rectum for cancer.

Application of laser speckle contrast imaging in laparoscopic surgery

Anastomotic leakage is a worldwide problem in gastrointestinal surgery which seems to be related to the state of microcirculation. Laser speckle contrast imaging (LSCI) could give surgeons insight in the state of microcirculation to attune the site of anastomosis. This work studies the feasibility of LSCI as a tool for this purpose. An experimental setup was developed using a commercially available laparoscopic video system. Laser speckle contrast imaging is capable of detecting ischemic areas on the large intestine. Further research and development are required before adaptation of this technique in the operating room.