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

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.

Surgical considerations for the "perfect" colorectal anastomosis

A technically sound colorectal anastomosis is paramount in optimising outcomes and reducing complications such as anastomotic leak which can lead to prolonged hospital stay, repeated operations, stoma formation, anastomotic stricture formation and even mortality in patients. Therefore, thorough consideration should be given to all aspects of its construct, from its basic mechanical configuration to subsequent evaluation of anastomosis integrity and perfusion. Risk factors for anastomotic leakage are well established and are usually classified into modifiable and non-modifiable risk factors. In this review article, we will focus on and discuss the modifiable surgical risk factors and how the authors incorporate latest evidence and surgical principles in creating a "perfect" colorectal anastomosis. We review the latest evidence on the proper mechanical construct of a colorectal anastomosis, enhanced recovery after surgery (ERAS), high versus low ligation of inferior mesenteric artery (IMA), routine splenic flexure mobilisation (SFM), the use of indocyanine green (ICG), as well as methods used for the evaluation of the anastomosis integrity. New adjuncts described in the literature to reinforce anastomoses are also discussed. In summary, meticulous technique with nuanced refinements based on our understanding of surgical principles, together with the adoption of relevant new technologies, are essential in our strive towards the "perfect" colorectal anastomosis.

Intraoperative bowel perfusion assessment methods and their effects on anastomotic leak rates: meta-analysis

BACKGROUND

Anastomotic leak is one of the most feared complications of colorectal surgery, and probably linked to poor blood supply to the anastomotic site. Several technologies have been described for intraoperative assessment of bowel perfusion. This systematic review and meta-analysis aimed to evaluate the most frequently used bowel perfusion assessment modalities in elective colorectal procedures, and to assess their associated risk of anastomotic leak. Technologies included indocyanine green fluorescence angiography, diffuse reflectance spectroscopy, laser speckle contrast imaging, and hyperspectral imaging.

METHODS

The review was preregistered with PROSPERO (CRD42021297299). A comprehensive literature search was performed using Embase, MEDLINE, Cochrane Library, Scopus, and Web of Science. The final search was undertaken on 29 July 2022. Data were extracted by two reviewers and the MINORS criteria were applied to assess the risk of bias.

RESULTS

Some 66 eligible studies involving 11 560 participants were included. Indocyanine green fluorescence angiography was most used with 10 789 participants, followed by diffuse reflectance spectroscopy with 321, hyperspectral imaging with 265, and laser speckle contrast imaging with 185. In the meta-analysis, the total pooled effect of an intervention on anastomotic leak was 0.05 (95 per cent c.i. 0.04 to 0.07) in comparison with 0.10 (0.08 to 0.12) without. Use of indocyanine green fluorescence angiography, hyperspectral imaging, or laser speckle contrast imaging was associated with a significant reduction in anastomotic leak.

CONCLUSION

Bowel perfusion assessment reduced the incidence of anastomotic leak, with intraoperative indocyanine green fluorescence angiography, hyperspectral imaging, and laser speckle contrast imaging all demonstrating comparable results.

Assessment of Colorectal Anastomosis with Intraoperative Colonoscopy: Its Role in Reducing Anastomotic Complications

The use of intraoperative colonoscopy (IOC) to evaluate the integrity of newly created anastomosis has been advocated by some surgeons. However, whether direct visualization of fresh anastomosis can help reduce anastomotic problems is still unclear. This study investigates the impact of immediate endoscopic assessment of colorectal anastomosis on anastomotic problems. This is a retrospective study conducted at a single center. Among six hundred forty-nine patients who underwent stapled anastomosis for left-sided colorectal cancer, the anastomotic complications were compared between patients who underwent IOC and those who did not. Additionally, patients with subsequent intervention after the IOC were compared to those without the intervention. Twenty-seven patients (5.0%) developed anastomotic leakage, and six (1.1%) experienced anastomotic bleeding postoperatively. Of the patients with IOC, 70 patients received reinforcement sutures to secure anastomotic stability. Of 70 patients, 39 patients showed abnormal findings in IOC. Thirty-seven patients (94.9%) who underwent reinforcement sutures did not develop postoperative anastomotic problems. This study demonstrates that IOC assessment with reinforcement sutures does not imminently reduce the rate of anastomotic complications. However, its use may play a role in detecting early technical failure and preventing postoperative anastomotic complications.

Novel Modality of Endoluminal Anastomotic Integrity Assessment with Fluoroangiography After Left-sided Colorectal Resections

BACKGROUND

Several methods have been described for the intraoperative evaluation of colorectal anastomotic integrity. Technological evolution has allowed to progress from basic mechanical methods to the use of more sophisticated techniques. This study describes a novel endoluminal modality of colorectal anastomotic assessment through the use of a Disposable Rigid Scope Introducer (DRSI) also allowing for intraoperative endoluminal perfusion evaluation by indocyanine green (ICG) fluoroangiography in patients undergoing left-sided colorectal resection.

METHODS

The DRSI consists of an endoluminal introducer device made up of an insertion tube and port connected to an insufflation bulb to manually insufflate the sigmoid and rectum and is compatible with any laparoscopic camera, also allowing for ICG fluoroangiography for perfusion purposes.

RESULTS

The DRSI was successfully used to assess anastomotic integrity after left-sided colorectal resections performed in 16 consecutive patients. The DRSI allowed to visualize by fluoroangiography the quality of tissue perfusion at the anastomotic site in all cases, contributing to the decision of avoiding loop ileostomies in low rectal resections. In 2 cases, the DRSI showed the presence of significant anastomotic bleeding which was successfully controlled by laparoscopic suture placement. No adverse event resulted from the use of this device.

CONCLUSIONS

The DRSI combines direct endoluminal visualization of the anastomosis together with real-time evaluation of its blood flow. This device holds great potential for prompt intraoperative detection of anastomotic alterations, possibly reducing the risk of postoperative anastomotic bleeding or leaks related to mechanical construction/perfusion issues. Potential advantages of this device warrant larger cohort studies and prospective randomized trials.

In vivo evaluation of a hyperspectral imaging system for minimally invasive surgery (HSI-MIS)

BACKGROUND

Hyperspectral Imaging (HSI) is a reliable and safe imaging method for taking intraoperative perfusion measurements. This is the first study translating intraoperative HSI to an in vivo laparoscopic setting using a CE-certified HSI-system for minimally invasive surgery (HSI-MIS). We aim to compare it to an established HSI-system for open surgery (HSI-Open).

METHODS

Intraoperative HSI was done using the HSI-MIS and HSI-Open at the Region of Interest (ROI). 19 patients undergoing gastrointestinal resections were analyzed in this study. The HSI-MIS-acquired images were aligned with those from the HSI-Open, and spectra and parameter images were compared pixel-wise. We calculated the Mean Absolute Error (MAE) for Tissue Oxygen Saturation (StO₂), Near-Infrared Perfusion Index (NIR-PI), Tissue Water Index (TWI), and Organ Hemoglobin Index (OHI), as well as the Root Mean Squared Error (RMSE) over the whole spectrum. Our analysis of parameters was optimized using partial least squares (PLS) regression. Two experienced surgeons carried out an additional color-change analysis, comparing the ROI images and deciding whether they provided the same (acceptable) or different visual information (rejected).

RESULTS

HSI and subsequent image registration was possible in 19 patients. MAE results for the original calculation were StO_{2 orig.} 17.2% (± 7.7%)_, NIR-PI_orig. 16.0 (± 9.5), TWI_orig. 18.1 (± 7.9), OHI_orig. 14.4 (± 4.5). For the PLS calculation, they were StO_{2 PLS} 12.6% (± 5.2%), NIR-PI_PLS 10.3 (± 6.0), TWI_PLS 10.6 (± 5.1), and OHI_PLS 11.6 (± 3.0). The RMSE between both systems was 0.14 (± 0.06). In the color-change analysis; both surgeons accepted more images generated using the PLS method.

CONCLUSION

Intraoperative HSI-MIS is a new technology and holds great potential for future applications in surgery. Parameter deviations are attributable to technical differences and can be reduced by applying improved calculation methods. This study is an important step toward the clinical implementation of HSI for minimally invasive surgery.

Bowel Rest with Total Parenteral Nutrition as an Alternative to Diverting Ileostomy in High-Risk Colorectal Anastomosis: A Pilot Study

Anastomotic leakage remains the most feared complication in colorectal surgery. Various intraoperative tests evaluate bowel perfusion and mechanical integrity of the colorectal anastomosis. These tests reduce the risk of postoperative anastomotic leakage; however, the incidence remains high. Diverting loop ileostomy mitigates the damage if anastomotic leakage occurs. Nevertheless, ileostomy has a significant rate of complications, reducing patients’ quality of life, and requiring an additional operation. We evaluated six consecutive cases where bowel rest with total parenteral nutrition was used instead of diverting loop ileostomy. All colorectal anastomoses were at high risk of postoperative anastomotic leakage. Total parenteral nutrition was administered for the first seven days postoperatively. There were no serious complications during the recovery period, and no clinical postoperative anastomotic leakage was detected. All patients tolerated total parenteral nutrition. Bowel rest with total parenteral nutrition may be a feasible option in high-risk left-sided colorectal anastomosis and a possible alternative to a preventive loop ileostomy. Further studies are necessary to evaluate it on a larger scale.

Comprehensive testing of colorectal anastomosis: results of prospective observational cohort study

BACKGROUND

Anastomotic leakage remains one of the most threatening complications in colorectal surgery. Intraoperative testing of anastomosis may reduce the postoperative anastomotic leakage rates. This study aimed to investigate a novel comprehensive intraoperative colorectal anastomosis testing technique to detect the failure of the anastomosis construction and to reduce the risk of postoperative leak.

METHODS

This multi-centre prospective cohort pilot study included 60 patients who underwent colorectal resection with an anastomosis at or below 15 cm from the anal verge. Comprehensive trimodal testing consisted of indocyanine green fluorescence angiography, tension testing, air-leak, and methylene blue leak tests to evaluate the perfusion, tension, and mechanical integrity of the anastomosis.

RESULTS

Ten (16.7%) patients developed an anastomotic leakage. Trimodal test was positive in 16 (26.6%) patients and the operative plan was changed for all of them. Diverting ileostomy was performed in 14 (87.5%) patients. However, two (12.5%) patients still developed clinically significant anastomotic leakage (Grade B). Forty-four (73.4%) patients had a negative trimodal test, preventive ileostomy was performed in 19 (43.2%), and five (11.4%) patients had clinically significant anastomotic leakage (Grade B and C).

CONCLUSION

Trimodal testing identifies anastomoses with initial technical failure where reinforcement of anastomosis or diversion can lead to an acceptable rate of anastomotic leakage. Identification of well-performed anastomosis could allow a reduction of ileostomy rate by two-fold. However, anastomotic leakage rate remains high in technically well-performed anastomoses.

Indocyanine green fluorescence-guided laparoscopic removal of infected mesh with chronic sinus formation after inguinal mesh plug repair

Chronic mesh infection with sinus formation is usually amenable to open method with dye. Recently, intraoperative real-time fluorescent imaging has been applied to various organs but not to mesh infection. A 72-year-old man with the history of two times removal of infected mesh was referred for groin bulge with purulent discharge. Laparoscopy assisted infected mesh removal was undertaken using intraoperative real-time fluorescent imaging with indocyanine green injection via the sinus orifice. We experienced the first case of the infected mesh with chronic sinus formation treated by the help of intraoperative indocyanine green fluorescent. This method is simple and easy to apply for laparoscopic assisted removal of chronic mesh infection with sinus.