The utility of indocyanine green fluorescence imaging during robotic adrenalectomy

Impact of indocyanine green on decision making for performing laparoscopic cortical sparing adrenalectomy

BACKGROUND

Indocyanine green imaging (ICG) is an expansion technology that can contribute to the development of demanding techniques such as cortical-sparing adrenalectomy (CSA). The aim of this study was to determine in which cases CSA should be performed and when total adrenalectomy should be performed instead based on ICG fluorescence. Here, we present our experience through a series of cases and videos.

METHODS

Prospective and descriptive study on patients with surgical adrenal lesions who were proposed for CSA using ICG with near-infrared fluorescence imaging in our center. A first bolus of 6,25 mg ICG was administered intravenously upon exposure of the retroperitoneal plane. Fluorescence was visualized using a Storz® NIR/ICG endoscopic system.

RESULTS

Seven patients were proposed for CSA. After the application of ICG, a change in attitude was carried out in 71.4% of the cases (five of seven). In the two patients in whom CSA could be performed, the adrenal remnants were functional, and the resection margins of the surgical specimens were free of disease. The reasons why partial adrenalectomy could not be completed, and a total adrenalectomy was decided instead were the presence of a tumor located very close to the adrenal vein that prevented a correct remnant volume (n = 4) and one case of isofluorescent tumor with the adrenal parenchyma.

CONCLUSION

ICG fluorescence guidance could help in the decision making to select patients intraoperatively for successful cortical preservation.

Fluorescence and tracers in surgery: the coming future

The revolution that we are seeing in the world of surgery will determine the way we understand surgical approaches in coming years. Since the implementation of minimally invasive surgery, innovations have constantly been developed to allow the laparoscopic approach to go further and be applied to more and more procedures. In recent years, we have been in the middle of another revolutionary era, with robotic surgery, the application of artificial intelligence and image-guided surgery. The latter includes 3D reconstructions for surgical planning, virtual reality, holograms or tracer-guided surgery, where ICG-guided fluorescence has provided a different perspective on surgery. ICG has been used to identify anatomical structures, assess tissue perfusion, and identify tumors or tumor lymphatic drainage. But the most important thing is that this technology has come hand in hand with the potential to develop other types of tracers that will facilitate the identification of tumor cells and ureters, as well as different light beams to identify anatomical structures. These will lead to other types of systems to assess tissue perfusion without the use of tracers, such as hyperspectral imaging. Combined with the upcoming introduction of ICG quantification, these developments represent a real revolution in the surgical world. With the imminent implementation of these technological advances, a review of their clinical application in general surgery is timely, and this review serves that aim.

Augmenting Laparoscopic Surgery with Fluorescence Imaging

Minimally invasive endoscopic surgery is growing in veterinary medicine, in large part, due to the advantages associated with reduced pain, potential for decreased complications, and increased visualization of structures through magnification and illumination. With advancing technologies, we can now improve upon natural "white light" endoscopy with fluorescence-guided imaging. Near-infrared (NIR) cameras allow for real-time, high-definition visualization of vessels, anatomic structures, and perfusion. New uses of NIR technologies during laparoscopy are continuing to grow for vascular, lymphatic, and oncologic-related techniques. Limitations exist, and future efforts need to determine optimal dosing, tissue-specific fluorophores, and veterinary-specific techniques.

Indocyanine green dye and its application in gastrointestinal surgery: The future is bright green

Indocyanine green (ICG) is a water-soluble fluorescent dye that is minimally toxic and widely used in gastrointestinal surgery. ICG facilitates anatomical identification of structures (e.g., ureters), assessment of lymph nodes, biliary mapping, organ perfusion and anastomosis assessment, and aids in determining the adequacy of oncological margins. In addition, ICG can be conjugated to artificially created antibodies for tumour markers, such as carcinoembryonic antigen for colorectal, breast, lung, and gastric cancer, prostate-specific antigen for prostate cancer, and cancer antigen 125 for ovarian cancer. Although ICG has shown promising results, the optimization of patient factors, dye factors, equipment, and the method of assessing fluorescence intensity could further enhance its utility. This review summarizes the clinical application of ICG in gastrointestinal surgery and discusses the emergence of novel dyes such as ZW-800 and VM678 that have demonstrated appropriate pharmacokinetic properties and improved target-to-background ratios in animal studies. With the emergence of robotic technology and the increasing reporting of ICG utility, a comprehensive review of clinical application of ICG in gastrointestinal surgery is timely and this review serves that aim.

Exploring the Applications of Indocyanine Green in Robot-Assisted Urological Surgery: A Comprehensive Review of Fluorescence-Guided Techniques

This comprehensive review aims to explore the applications of indocyanine green (ICG) in robot-assisted urological surgery through a detailed examination of fluorescence-guided techniques. An extensive literature search was conducted in PubMed/MEDLINE, EMBASE and Scopus, using keywords such as "indocyanine green," "ICG", "NIRF", "Near Infrared Fluorescence", "robot-assisted", and "urology". Additional suitable articles were collected by manually cross-referencing the bibliography of previously selected papers. The integration of the Firefly^® technology in the Da Vinci^® robotic system has opened new avenues for the advancement and exploration of different urological procedures. ICG is a fluorophore widely used in near-infrared fluorescence-guided techniques. The synergistic combination of intraoperative support, safety profiles and widespread availability comprises an additional asset that empowers ICG-guided robotic surgery. This overview of the current state of the art illustrates the potential advantages and broad applications of combining ICG-fluorescence guidance with robotic-assisted urological surgery.

European Association for Endoscopic Surgery (EAES) consensus on Indocyanine Green (ICG) fluorescence-guided surgery

BACKGROUND

In recent years, the use of Indocyanine Green (ICG) fluorescence-guided surgery during open and laparoscopic procedures has exponentially expanded across various clinical settings. The European Association of Endoscopic Surgery (EAES) initiated a consensus development conference on this topic with the aim of creating evidence-based statements and recommendations for the surgical community.

METHODS

An expert panel of surgeons has been selected and invited to participate to this project. Systematic reviews of the PubMed, Embase and Cochrane libraries were performed to identify evidence on potential benefits of ICG fluorescence-guided surgery on clinical practice and patient outcomes. Statements and recommendations were prepared and unanimously agreed by the panel; they were then submitted to all EAES members through a two-rounds online survey and results presented at the EAES annual congress, Barcelona, November 2021.

RESULTS

A total of 18,273 abstracts were screened with 117 articles included. 22 statements and 16 recommendations were generated and approved. In some areas, such as the use of ICG fluorescence-guided surgery during laparoscopic cholecystectomy, the perfusion assessment in colorectal surgery and the search for the sentinel lymph nodes in gynaecological malignancies, the large number of evidences in literature has allowed us to strongly recommend the use of ICG for a better anatomical definition and a reduction in post-operative complications.

CONCLUSIONS

Overall, from the systematic literature review performed by the experts panel and the survey extended to all EAES members, ICG fluorescence-guided surgery could be considered a safe and effective technology. Future robust clinical research is required to specifically validate multiple organ-specific applications and the potential benefits of this technique on clinical outcomes.

The Role of Intraoperative Indocyanine Green (ICG) and Preoperative 3-Dimensional (3D) Reconstruction in Laparoscopic Adrenalectomy: A Propensity Score-matched Analysis

BACKGROUND

Laparoscopic adrenalectomy (LA) is considered the "gold standard" treatment of adrenal lesions that are often coincidentally diagnosed during the radiologic workup of other diseases. This study aims to evaluate the intraoperative role of indocyanine green (ICG) fluorescence associated with preoperative 3-dimensional reconstruction (3DR) in laparoscopic adrenalectomy in terms of perioperative outcomes. To our knowledge, this is the first prospective case-controlled report comparing these techniques.

MATERIALS AND METHODS

All consecutive patients aged≥18 and undergoing laparoscopic transperitoneal adrenalectomy for all adrenal masses from January 1, 2019 to January 31, 2022 were prospectively enrolled. Patients undertaking standard LA and those undergoing preoperative 3D reconstruction and intraoperative ICG fluorescence were matched through a one-on-one propensity score matching analysis (PSM) for age, gender, BMI, CCI score, ASA score, lesion histology, tumor side, and lesion diameter. Differences in operative time, blood loss, intraoperative and postoperative complications, conversion rate, and length of stay were analyzed.

RESULTS

After propensity score matching analysis, we obtained a cohort of 36 patients divided into 2 groups of 18 patients each. The operative time and intraoperative blood loss were shorter in patients of the 3DR group ( P =0,004 and P =0,004, respectively). There was no difference in terms of length of stay, conversion rate, and intraoperative and postoperative complications between the 2 groups.

CONCLUSIONS

The use of intraoperative ICG in LA and preoperative planning with 3DR images is a safe and useful addition to surgery. Furthermore, we observed a reduction in terms of operating time and intraoperative blood loss.

Adrenal Near-Infrared Autofluorescence

Context

Parathyroid tissue is one of the few tissues to have strong near-infrared (NIR) autofluorescence, which has been exploited to improve intraoperative parathyroid identification. The US Food and Drug Administration has approved 2 devices for this purpose. Adrenal glands can be difficult to distinguish from surrounding fat, an issue during total adrenalectomy.

Objective

We hypothesized adrenal tissue may also possess considerable NIR autofluorescence.

Methods

Resected patient adrenal specimens were examined after robotic adrenalectomy with an NIR camera intraoperatively. Patients did not receive fluorescent dye. Images were taken of both gross and sectioned specimens. Post hoc image analysis was performed with ImageJ software. Confocal microscopy was performed on selected tissues using immunofluorescence and hematoxylin-eosin staining.

Results

Resected tissue was examined from 22 patients undergoing surgery for pheochromocytomas (6), primary aldosteronism (3), adrenocorticotropin-independent hypercortisolism (10), and a growing or suspicious mass (3). Normal adrenal tissue demonstrated strong NIR autofluorescence. The intensity ratio compared to background (set as 1) for gross images was 2.03 ± 0.51 (P < .0001) compared to adjacent adipose of 1.24 ± 0.18. Autofluorescence from adrenal tumors was also detected at variable levels of intensity. Cortisol-producing tumors had the highest fluorescence ratio of 3.01 ± 0.41. Confocal imaging localized autofluorescence to the cytosol, with the highest intensity in the zona reticularis followed by the zona fasciculata.

Conclusion

Normal and abnormal adrenal tissues possess natural NIR autofluorescence. Highest autofluorescence levels were associated with cortisol-producing tumors. Confocal imaging demonstrated the highest intensity in the zona reticularis. NIR cameras may have the potential to improve identification of adrenal tissue during surgery.

Indocyanine green (ICG) fluorescence guide for the use and indications in general surgery: recommendations based on the descriptive review of the literature and the analysis of experience

Indocyanine Green is a fluorescent substance visible in near-infrared light. It is useful for the identification of anatomical structures (biliary tract, ureters, parathyroid, thoracic duct), the tissues vascularization (anastomosis in colorectal, esophageal, gastric, bariatric surgery, for plasties and flaps in abdominal wall surgery, liver resection, in strangulated hernias and in intestinal ischemia), for tumor identification (liver, pancreas, adrenal glands, implants of peritoneal carcinomatosis, retroperitoneal tumors and lymphomas) and sentinel node identification and lymphatic mapping in malignant tumors (stomach, breast, colon, rectum, esophagus and skin cancer). The evidence is very encouraging, although standardization of its use and randomized studies with higher number of patients are required to obtain definitive conclusions on its use in general surgery. The aim of this literature review is to provide a guide for the use of ICG fluorescence in general surgery procedures.

Minimally Invasive Partial vs. Total Adrenalectomy for the Treatment of Unilateral Primary Aldosteronism: A Systematic Review and Meta-Analysis

BACKGROUND

This systematic review and metanalysis was conducted to assess differences between perioperative and functional outcomes in patients undergoing minimally-invasive partial (mi-PA) and total adrenalectomy (mi-TA) for unilateral primary aldosteronism (uPHA).

MATERIAL AND METHODS

Multiple scientific databases (PUBMED, Web of Science, and Cochrane Library) were searched up to November 2021 for surgical series comparing mi-PA vs. mi-TA for uPHA according to the PRISMA statement. Primary outcomes of interest were perioperative and functional outcomes.

RESULTS

Overall, a total of 802 patients from six eligible studies were identified, with mi-PA and mi-TA performed in 40.4% (n = 324) and 59.6% (n = 478) of cases, respectively. No differences were recorded between the two groups according to number of transfusions, EBL and Clavien-Dindo complications ≥2. Similarly, no differences in clinical success, persistence of postoperative hypokalemia and improvement in HTN were reported between mi-PA and mi-TA.

CONCLUSIONS

In a uPHA setting, mi-PA and mi-TA provide comparable perioperative and functional outcomes despite the use of mi-PA remains limited to patients with small adenoma size, or hereditary/bilateral disease. Due to limited use of standardized reporting criteria in most of current series, the quest for a superiority of mi-PA over mi-TA in the treatment of uPHA still remains open.

A narrative review of fluorescence imaging in robotic-assisted surgery

Objective

In this review, we provide examples of applications of fluorescence imaging in urologic, gynecologic, general, and endocrine surgeries.

Background

While robotic-assisted surgery has helped increase the availability of minimally invasive procedures across surgical specialties, there remains an opportunity to reduce adverse events associated with open, laparoscopic, and robotic-assisted methods. In 2011, fluorescence imaging was introduced as an option to the da Vinci Surgical System, and has been standard equipment since 2014. Without interfering with surgical workflow, this fluorescence technology named Firefly^® allows for acquisition and display of near-infrared fluorescent signals that are co-registered with white light endoscopic images. As a result, robotic surgeons of all specialties have been able to explore the clinical utility of fluorescence guided surgery.

Methods

Literature searches were performed using the PubMed and MEDLINE databases using the keywords "robotic-assisted fluorescence surgery", "ICG robotic surgery", and "fluorescence guided surgery" covering the years 2011-2020.

Conclusions

Real-time intraoperative fluorescence guidance has shown great potential in helping guide surgeons in both simple and complex surgical interventions. Indocyanine green is one of the most widely-used imaging agents in fluorescence guided surgery, and other targeted, near-infrared imaging agents are in various stages of development. Fluorescence is becoming a reliable tool that can help surgeons in their decision-making process in some specialties, while explorations continue in others.

A visual quantification of tissue distinction in robotic transabdominal lateral adrenalectomy: comparison of indocyanine green and conventional views

BACKGROUND

Recent studies have reported the feasibility of indocyanine green fluorescence imaging of adrenal tumors to guide dissection. Although the adrenal has been reported to concentrate the dye more than surrounding tissues, the amount of tissue distinction and how this compares with conventional vision has not been quantified before. The aim of this study is to quantify this distinction using color analysis.

METHODS

This was an institutional review board-approved retrospective study. By excluding adrenal cortical carcinoma, metastasis and pheochromocytoma, video recordings of 50 patients who underwent robotic transabdominal lateral adrenalectomy with indocyanine green (ICG) imaging for adrenocortical tumors between August 2015 and May 2018 were reviewed. Using a color analysis software, the pixel intensity of adrenal tumors versus adjacent retroperitoneal tissues was calculated for conventional red, green and blue, as well as indocyanine green (ICG) scales. Statistical analysis was performed using ANOVA.

RESULTS

A total of 50 patients underwent unilateral robotic transabdominal lateral adrenalectomy. All procedures were completed robotically without a conversion to laparoscopy or open. Morbidity was 4%. Measured pixel intensity of adrenal tumors was higher than adjacent retroperitoneal tissues for all conventional color and ICG modes (p < 0.0001), with the gradient being more pronounced for ICG green versus conventional red, green and blue modes.

CONCLUSIONS

To our knowledge this is the first study attempting to encode tissue planes in robotic adrenalectomy. The results show that the visual contrast distinction observed between adrenal and adjacent retroperitoneal tissues can be quantified using pixel intensity. ICG enabled the distinction of tissue planes with a wider gradient compared to conventional RGB view, quantifying its subjective benefits reported in prior studies.

Robotic approach for partial adrenalectomy

Although safe and feasible, partial adrenalectomy is not a widespread procedure. Endorsement of robotic technologies and fluorescence techniques in adrenal surgery might help develop partial adrenalectomy and could avoid unnecessary total adrenalectomies. When performed in selected cases, partial adrenalectomy is associated with good postoperative outcomes comparable with those reported after total adrenalectomy. It has been hypothesized that one of the advantages of the robotic approach in adrenal-sparing surgery is to reduce manipulation of the gland allowing preservation of the vascularization of the residual adrenal, overcoming some limits when performing a laparoscopic conventional approach. A major drawback of the robotic surgery is its cost, but the overcost due to the use of the robotic system could be balanced by the execution of a high number of partial adrenalectomies leading to fewer life-long replacement steroid treatment. Partial adrenalectomy could become the recommended management for small benign and hormonal active adrenal tumors. Indocyanine green fluorescence (IGF) also seems to be a useful technique to help surgeons identify the adrenal gland and to locate small tumors from the normal adrenal tissue in difficult patients. It is likely that the use of a robotic approach associated with IGF may extend indications of partial adrenalectomy in the years to come.

Robot-assisted adrenalectomy: state of the art

Currently, laparoscopic adrenalectomy is worldwide considered the gold standard technique. Both transperitoneal and retroperitoneal approaches have proved their efficacy with excellent outcomes. Since the introduction of da Vinci System (Intuitive Surgical, Sunnyvale, CA), robotic surgery has made many steps forward gaining progressively more diffusion in the field of general and endocrine surgery. The robotic technique offers advantages to overcome some laparoscopic shortcomings (rigid instruments, loss of 3D vision, unstable camera). Indeed, the robotic system is provided of stereoscopic 3D-magnified vision, additional degree of freedom, tremor-filtering technology and a stable camera. Recently, several case series have demonstrated the feasibility and the safety of robot-assisted adrenalectomy in high-volume centers with outcomes comparable to laparoscopic adrenalectomy. Notwithstanding, the technical advantages of the robotic system have not yet demonstrated significant improvements in terms of outcomes to undermine laparoscopic adrenalectomy. Moreover, robotic adrenalectomy harbor inherits drawbacks, such as longer operative time and elevated costs, that limit its use. In particular, the high cost associated with the use of the robotic system is primarily related to the purchase and the maintenance of the unit, the high instruments cost and the longer operative time. Notably, these aspects make robotic adrenalectomy up to 2.3 times more costly than laparoscopic adrenalectomy. This literature review summarizes the current available studies and provides an overview about the robotic scenario including applicability, technical details and surgical outcomes.

Intraoperative imaging for remnant viability assessment in bilateral posterior retroperitoneoscopic partial adrenalectomy in an experimental model

BACKGROUND

A surgical approach preserving functional adrenal tissue allows biochemical cure while avoiding the need for lifelong steroid replacement. The aim of this experimental study was to evaluate the impact of intraoperative imaging during bilateral partial adrenalectomy on remnant perfusion and function.

METHODS

Five pigs underwent bilateral posterior retroperitoneoscopic central adrenal gland division (9 divided glands, 1 undivided). Intraoperative perfusion assessment included computer-assisted quantitative fluorescence imaging, contrast-enhanced CT, confocal laser endomicroscopy (CLE) and local lactate sampling. Specimen analysis after completion adrenalectomy (10 adrenal glands) comprised mitochondrial activity and electron microscopy.

RESULTS

Fluorescence signal intensity evolution over time was significantly lower in the cranial segment of each adrenal gland (mean(s.d.) 0·052(0·057) versus 0·133(0·057) change in intensity per s for cranial versus caudal parts respectively; P = 0·020). Concordantly, intraoperative CT in the portal phase demonstrated significantly lower contrast uptake in cranial segments (P = 0·031). In CLE, fluorescein contrast was observed in all caudal segments, but in only four of nine cranial segments (P = 0·035). Imaging findings favouring caudal perfusion were congruent, with significantly lower local capillary lactate levels caudally (mean(s.d.) 5·66(5·79) versus 11·58(6·53) mmol/l for caudal versus cranial parts respectively; P = 0·008). Electron microscopy showed more necrotic cells cranially (P = 0·031). There was no disparity in mitochondrial activity (respiratory rates, reactive oxygen species and hydrogen peroxide production) between the different segments.

CONCLUSION

In a model of bilateral partial adrenalectomy, three intraoperative imaging modalities consistently discriminated between regular and reduced adrenal remnant perfusion. By avoiding circumferential dissection, mitochondrial function was preserved in each segment of the adrenal glands. Surgical relevance Preservation of adrenal tissue to maintain postoperative function is essential in bilateral and hereditary adrenal pathologies. There is interindividual variation in residual adrenocortical stress capacity, and the minimal functional remnant size is unknown. New intraoperative imaging technologies allow improved remnant size and perfusion assessment. Fluorescence imaging and contrast-enhanced intraoperative CT showed congruent results in evaluation of perfusion. Intraoperative imaging can help to visualize the remnant vascular supply in partial adrenalectomy. Intraoperative assessment of perfusion may foster maximal functional tissue preservation in bilateral adrenal pathologies and procedures.

Indocyanine green fluorescence imaging for robotic adrenalectomy

Despite the novel and innovative developments in minimal invasive platforms and the expanding indications regarding adrenal surgery, surgeons are still confronted with some obstacles. The use of intraoperative indocyanine green aims to overcome these problems, but there is still limited data and ongoing debates in terms of robot-assisted adrenal surgery. The aim of this article is to discuss the benefit of indocyanine green fluorescence imaging for robot-assisted adrenalectomy and provide up-to date data.

Laparoscopic partial adrenalectomy using near-infrared imaging: the initial experience

INTRODUCTION

To present our initial clinical experience with laparoscopic partial adrenalectomy using indocyanine green dye with near-infrared fluorescence imaging.

MATERIAL AND METHODS

A total of eight patients underwent transperitoneal laparoscopic partial adrenalectomy using indocyanine green dye with near-infrared fluorescence imaging in our clinic. After 5 mg intravenous indocyanine green dye administration, we resected the mass under the guidance of near-infrared fluorescence imaging and white light visualization in an effort to completely excise the mass while sparing uninvolved adrenal tissue.

RESULTS

Seven patients underwent unilateral and one patient underwent bilateral laparoscopic partial adrenalectomy. The median tumor size was 43 mm. The surgery was successfully performed with negative margins in all patients. The tumors were hypofluorescent relative to normal adrenal tissue with indocyanine green dye with near-infrared fluorescence imaging in patients with Cushing's syndrome, aldosteronoma, and adrenal cyst. However, pheochromocytoma and angiomyolipoma were noted to be isoflourorescent and hyperfluorescent relative to normal adrenal parenchyma, respectively.

CONCLUSIONS

Laparoscopic partial adrenalectomy using intraoperative indocyanine green dye with near-infrared fluorescence imaging seems to be safe and feasible. This technology may ultimately be helpful in resecting lesions with more precise surgical margins by identifying the vascular structure during laparoscopic partial adrenalectomy. Abbreviations: LTA: Laparoscopic total adrenalectomy; LPA:Laparoscopic partial adrenalectomy; ICG: Indocynanine green; NIRF: Near-infrared fluorescence; HPA: Hypothalamic-pituitary-adrenal.

Indocyanine green fluorescence imaging during partial adrenalectomy

BACKGROUND

Indocyanine green (ICG) fluorescence imaging represents an emerging technology that facilitates the assessment of tissue vascularity, tissue distinction, and tumor localization during surgery. The aim of this study was to investigate the potential role of ICG imaging during laparoscopic partial adrenalectomy.

METHODS

Indocyanine fluorescence imaging was carried out during laparoscopic partial adrenalectomy for bilateral pheochromocytoma and bilateral Cushing's syndrome. A first bolus of 5 mg ICG was applied intravenously upon exposure of the retroperitoneal plane to identify the adrenal borders. The fluorescence was visualized using a Storz^® NIR/ICG endoscopic system. As the camera of this system detects NIR light as a blue signal, the well-vascularized adrenal tissue was expected to show a strong fluorescence in the blue color channel in contrast to the surrounding adipose tissue. Following partial adrenalectomy, a second bolus of 5 mg ICG was applied intravenously to evaluate the vascularity of the remaining adrenal tissue.

RESULTS

We investigated six adrenal glands from three patients undergoing bilateral partial adrenalectomy. The indication for surgery was pheochromocytoma in two patients and Cushing's syndrome with bilateral adenomas in one patient. Regarding left adrenalectomies, ICG imaging was helpful in visualizing the adrenal borders and the adrenal vein. Further, it facilitated the identification of the hypofluorescent pheochromocytoma and to resect the entire tumor. On the right side, due to the more apparent anatomy, ICG imaging did not contribute to the conduct of the operation. Four adrenal remnants showed a strong vascularization and two remnants were only reasonably vascularized.

CONCLUSION

ICG fluorescence may be helpful in guiding partial adrenalectomy and assessing the vascularity of remaining adrenal tissue.

Fluorescence-enabled assessment of adrenal gland localization and perfusion in posterior retroperitoneoscopic adrenal surgery in a preclinical model

BACKGROUND

The posterior retroperitoneoscopic adrenal access represents a challenge in orientation and working space creation. The aim of this experimental acute study was to evaluate the impact of computer-assisted quantitative fluorescence imaging on adrenal gland identification and assessment of intraoperative remnant perfusion for adrenal resection in the posterior retroperitoneoscopic approach.

METHODS

Six pigs underwent simultaneous (n = 5) or sequential (n = 1) bilateral posterior retroperitoneoscopic adrenalectomy (n = 12). Fluorescence imaging was obtained via intravenous administration of 3 mL of Indocyanine Green (ICG) and by switching the camera systems to near-infrared mode (D-LIGHT P, KARL STORZ; Germany). Fluorescence-based visualization of adrenal glands before vascular division (n = 4), after the main vascular pedicle ligation (negative control, n = 1) or after adrenal resection (n = 7), was followed by completion adrenalectomy. The fluorescence signal intensity dynamics were recorded and analyzed using proprietary software. For each pixel, the slope of fluorescence signal intensity evolution over time was translated into a color-coded perfusion cartography, which was superimposed onto real-time images obtained with the corresponding left and right camera systems. Quantitative fluorescence signal analysis in the regions of interest (ROIs) served to assess adrenal remnant perfusion in divided adrenal glands.

RESULTS

In the retroperitoneum, the vascular anatomy was illuminated in fluorescence imaging first. The adrenal glands were promptly highlighted after primary intravenous ICG administration (n = 9) or showed a fluorescence signal intensity increase upon reinjection (n = 3). Quantitative fluorescence analysis showed a statistically significant difference between perfused and ischemic segments in divided glands (p = 0.0156).

CONCLUSIONS

Fluorescence imaging provides real-time guidance during minimally invasive adrenal surgery. Prior to dissection, it allows to easily discriminate the adrenal gland from surrounding retroperitoneal structures. After adrenal gland division, ICG injection associated with a computer-assisted quantitative analysis helps to distinguish between well-perfused and ischemic segments. Further studies are underway to establish the correlation between remnant perfusion and viability.

Best practices in near-infrared fluorescence imaging with indocyanine green (NIRF/ICG)-guided robotic urologic surgery: a systematic review-based expert consensus

PURPOSE

The aim of the present study is to investigate the impact of the near-infrared (NIRF) technology with indocyanine green (ICG) in robotic urologic surgery by performing a systematic literature review and to provide evidence-based expert recommendations on best practices in this field.

METHODS

All English language publications on NIRF/ICG-guided robotic urologic procedures were evaluated. We followed the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analyses) statement to evaluate PubMed^®, Scopus^® and Web of Science™ databases (up to April 2019). Experts in the field provided detailed pictures and intraoperative video-clips of different NIRF/ICG-guided robotic surgeries with recommendations for each procedure. A unique QRcode was generated and linked to each underlying video-clip. This new exclusive feature makes the present the first "dynamic paper" that merges text and figure description with their own video providing readers an innovative, immersive, high-quality and user-friendly experience.

RESULTS

Our electronic search identified a total of 576 papers. Of these, 36 studies included in the present systematic review reporting the use of NIRF/ICG in robotic partial nephrectomy (n = 13), robotic radical prostatectomy and lymphadenectomy (n = 7), robotic ureteral re-implantation and reconstruction (n = 5), robotic adrenalectomy (n = 4), robotic radical cystectomy (n = 3), penectomy and robotic inguinal lymphadenectomy (n = 2), robotic simple prostatectomy (n = 1), robotic kidney transplantation (n = 1) and robotic sacrocolpopexy (n = 1).

CONCLUSION

NIRF/ICG technology has now emerged as a safe, feasible and useful tool that may facilitate urologic robotic surgery. It has been shown to improve the identification of key anatomical landmarks and pathological structures for oncological and non-oncological procedures. Level of evidence is predominantly low. Larger series with longer follow-up are needed, especially in assessing the quality of the nodal dissection and the feasibility of the identification of sentinel nodes and the impact of these novel technologies on long-term oncological and functional outcomes.

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.

Indocyanine Green (ICG) in Urologic Surgery

Indocyanine green (ICG) is a dye used for fluorescent-guided surgery. This review article addresses the recent surge in reported uses of ICG in various surgical fields and provides a comprehensive and up to date review of the uses of ICG in urologic surgery.

The Utility of Intraoperative Near Infrared Fluorescence (NIR) Imaging with Indocyanine Green (ICG) for the Assessment of Kidney Allograft Perfusion

Background

Near infrared light (NIR) fluorescence imaging with indocyanine green (ICG) has been used in various aspects of surgery, such as in the assessment of vascular anastomosis, tissue perfusion, and the identification of lymph nodes. In this study we evaluated the utility of NIR/ICG fluorescence imaging in kidney transplantation.

Materials and Methods

NIR/ICG imaging was used to assess allograft perfusion in n=1 living donor (LDRT) and n=2 deceased donor (DDRT) renal transplantations, performed in February 2017. The allograft arterial and venous anastomoses were done end-to-side to the corresponding recipient external iliacs, and ureteroneocystostomies were performed for urinary reconstructions. After completion of vascular anastomosis, ICG was given as intravenous bolus at 0.3mg/kg, followed by visual assessment of tissue perfusion and vascular anastomoses at 1-minute interval using fluorescence imaging (KARL STORZ NIR/ICG System).

Results

Homogenous global fluorescence of the allograft and vascular anastomosis was observed in all 3 cases. Immediate postoperative perfusion studies showed patent inflow and outflow vessels and well perfused transplanted kidneys. Immediate graft function was observed in 2 recipients (1 LDRT and 1 DDRT). One session of haemodialysis was performed in 1 DDRT recipient, for high serum potassium in the immediate postoperative setting, who otherwise had good urine output and serially declining serum creatinine.

Conclusions

NIR/ICG fluorescence imaging can be useful in renal transplantation for the intraoperative assessment of allograft perfusion, especially in complex cases with multiple renal arteries and vascular reconstructions.

Characterization of fluorescence patterns exhibited by different adrenal tumors: Determining the indications for indocyanine green use in adrenalectomy

BACKGROUND

A number of small studies have reported the use of indocyanine green imaging during adrenalectomy. Nevertheless, imaging properties of different tumors and the indications for indocyanine green imaging use in adrenalectomy have not been defined.

METHODS

This is an Institutional Review Board-approved retrospective review of a prospectively maintained database. Consenting patients underwent indocyanine green imaging fluorescence-guided robotic adrenalectomy. Fluorescence patterns of adrenal tumors were assessed. Multivariate logistic regression was performed to determine the best clinical applications.

RESULTS

One hundred patients with Cushing syndrome (n = 29), pheochromocytoma (n = 24), primary hyperaldosteronism (n = 23), nonsecreting adrenocortical adenoma (n = 9), and other tumors (n = 15) underwent robotic adrenalectomy through lateral transabdominal (n = 77) and posterior retroperitoneal (n = 23) approaches. Mean tumor size was 3.6 cm and mean body mass index 33. A total of 74% of the tumors were hyperfluorescent compared with the surrounding retroperitoneal tissues, whereas the remaining 26% were nonfluorescent. Hyperfluorescence was predicted by adrenocortical tissue origin but not by demographic characteristics or tumor size. The contrast distinction between the tumor and the retroperitoneum was better, similar, or inferior on indocyanine green fluoresced compared with the nonfluoresced view in 41%, 27%, and 32% of patients, respectively. The utility was best for adrenocortical adenomas removed through a lateral transabdominal approach. Indocyanine green fluorescence imaging was used to confirm remnant viability in all 4 patients undergoing cortical-sparing adrenalectomy for pheochromocytoma (n = 2), adrenal cyst (n = 1), and lymphatic malformation (n = 1).

CONCLUSION

Adrenal tumors have different patterns of indocyanine green fluorescence based on histologic origin. Indocyanine green confers the highest utility for adrenocortical tumors removed through a lateral transabdominal approach and cortical-sparing adrenalectomy.

A practical guide for the use of indocyanine green and methylene blue in fluorescence-guided abdominal surgery

Near-infrared (NIR) fluorescence imaging is gaining clinical acceptance over the last years and has been used for detection of lymph nodes, several tumor types, vital structures and tissue perfusion. This review focuses on NIR fluorescence imaging with indocyanine green and methylene blue for different clinical applications in abdominal surgery with an emphasis on oncology, based on a systematic literature search. Furthermore, practical information on doses, injection times, and intraoperative use are provided.

Fluorescence-Guided Surgery

Surgical resection of cancer remains an important treatment modality. Despite advances in preoperative imaging, surgery itself is primarily guided by the surgeon’s ability to locate pathology with conventional white light imaging. Fluorescence-guided surgery (FGS) can be used to define tumor location and margins during the procedure. Intraoperative visualization of tumors may not only allow more complete resections but also improve safety by avoiding unnecessary damage to normal tissue which can also reduce operative time and decrease the need for second-look surgeries. A number of new FGS imaging probes have recently been developed, complementing a small but useful number of existing probes. In this review, we describe current and new fluorescent probes that may assist FGS.

Oncologic Procedures Amenable to Fluorescence-guided Surgery

OBJECTIVE

Although fluorescence imaging is being applied to a wide range of cancers, it remains unclear which disease populations will benefit greatest. Therefore, we review the potential of this technology to improve outcomes in surgical oncology with attention to the various surgical procedures while exploring trial endpoints that may be optimal for each tumor type.

BACKGROUND

For many tumors, primary treatment is surgical resection with negative margins, which corresponds to improved survival and a reduction in subsequent adjuvant therapies. Despite unfavorable effect on patient outcomes, margin positivity rate has not changed significantly over the years. Thus, patients often experience high rates of re-excision, radical resections, and overtreatment. However, fluorescence-guided surgery (FGS) has brought forth new light by allowing detection of subclinical disease not readily visible with the naked eye.

METHODS

We performed a systematic review of clinicatrials.gov using search terms "fluorescence," "image-guided surgery," and "near-infrared imaging" to identify trials utilizing FGS for those received on or before May 2016.

INCLUSION CRITERIA

fluorescence surgery for tumor debulking, wide local excision, whole-organ resection, and peritoneal metastases.

EXCLUSION CRITERIA

fluorescence in situ hybridization, fluorescence imaging for lymph node mapping, nonmalignant lesions, nonsurgical purposes, or image guidance without fluorescence.

RESULTS

Initial search produced 844 entries, which was narrowed down to 68 trials. Review of literature and clinical trials identified 3 primary resection methods for utilizing FGS: (1) debulking, (2) wide local excision, and (3) whole organ excision.

CONCLUSIONS

The use of FGS as a surgical guide enhancement has the potential to improve survival and quality of life outcomes for patients. And, as the number of clinical trials rise each year, it is apparent that FGS has great potential for a broad range of clinical applications.

The use of near-infrared fluorescence imaging in endocrine surgical procedures

Near-infrared fluorescence imaging in endocrine surgery is a new, yet highly investigated area. It involves indocyanine green use as well as parathyroid autofluorescence. Several groups have described their technique and reported on the observed utility. However, there is no consensus on technical details. Furthermore, the correlation between intraoperative findings and postoperative outcomes is unclear. With this study, we aim to review the current literature on fluorescence imaging and share our insights on technical details.

Advances in fluorescent-image guided surgery

Fluorescence imaging is increasingly gaining intraoperative applications. Here, we highlight a few recent advances in the surgical use of fluorescent probes.