Fluorescence techniques in adrenal surgery

A Comparison of Near-Infrared Autofluorescence Findings in Benign Versus Malignant Adrenal Tumors

BACKGROUND

Many adrenal tumors are deemed radiologically indeterminate and surgically removed. Adrenal tissue, like parathyroid glands, exhibits near-infrared autofluorescence (NIRAF) properties. This study was designed to investigate the potential of NIRAF to differentiate benign versus malignant adrenal tumors.

METHODS

Patients undergoing adrenalectomy between October 2021 and May 2023 were prospectively studied. Adrenalectomy specimens were inspected with NIRAF imaging. Specimen autofluorescence (AF) characteristics were recorded. Comparisons were made between different tumor types and a logistic regression model was constructed to differentiate benign versus malignant tumors. A receiver operating characteristic curve was used to identify an optimal AF threshold differentiating benign versus malignant tumors.

RESULTS

A total of 108 adrenal specimens were examined: adrenocortical adenomas/other benign lesions (n = 72), pheochromocytomas (n = 18), adrenocortical neoplasms of uncertain behavior (n = 4), and malignant tumors (n = 14). A significant difference in normalized AF intensity was identified when comparing adrenocortical adenomas (3.08 times background) with pheochromocytomas (1.95, p = 0.001) and malignant tumors (1.11, p < 0.0001). The Area Under the Curve differentiating benign vs malignant tumors was 0.87, with an optimal normalized AF threshold at 1.93.

CONCLUSIONS

Different adrenal pathologies exhibit diverse AF properties. These findings suggest a potential intraoperative utility of NIRAF in predicting benign versus malignant nature for radiologically indeterminate adrenal tumors.

Persistent and recurrent hyperparathyroidism - Attitude

BACKGROUND

Despite parathyroidectomy represents the curative treatment for primary hyperparathyroidism (pHPT) in up to 98% of patients, persistent hyperparathyroidism (perHPT) and recurrent hyperparathyroidism (rHPT) rates are reported in 22% and 10%, respectively. Indications for reoperation must be balanced with the higher risk of postoperative complications. The aim of this review is summarizing the current evidence in terms of preoperative assessment and surgical approach in patients with perHPT and rHPT.

METHODS

Operations for pHPT between 1997 and 2023 in our center were analyzed and patients with perHPT and rPTH at time of referral were included.

RESULTS

Among 1730 parathyroidectomies for pHPT, 85 patients underwent revisional surgery. Eleven and 74 out of these 85 cases were due to perHPT and rHPT, respectively.

CONCLUSIONS

Prior to reoperation, biochemical assessment and localization methods should always be performed to properly plan surgical strategy. Surgical experience represents the primary determinant in achieving effective disease control.

The utility of fluorescence imaging in detecting primary and metastatic small bowel carcinoid tumors

BACKGROUND

Our aim was to investigate utility of indocyanine green (ICG) and autofluorescence (AF) imaging in detection of small bowel primary and metastatic carcinoids.

METHODS

Using Institutional Review Board approval, ICG and AF imaging of small bowel carcinoids was performed. Imaging findings were prospectively recorded in operating room and compared with conventional imaging, surgical exploration and pathologic findings.

RESULTS

There were 16 patients with 23 primary small bowel tumors, 27 mesenteric lymph nodes, 36 liver metastases and 2 peritoneal nodules. Carcinoid tumors exhibited brighter AF signals compared to background. AF imaging was superior to both DOTATATE PET and surgeon inspection/palpation in demonstrating small bowel primaries. Utility for metastatic lymph nodes and peritoneal metastases was limited. Superficial liver metastases exhibited brighter fluorescence compared to background on both ICG and AF imaging.

CONCLUSIONS

This is the largest study assessing utility of near-infrared fluorescence imaging in detection of small bowel carcinoids. Our results show promise in the utilization fluorescence imaging to detect occult primary tumors and superficial liver metastases.

The Wonder Dye: Uses and Implications of Indigocyanine Green in Various Surgeries

Indigocyanine green (ICG) is a fluorophore dye that has been extensively used in recent modern times for bioimaging in numerous surgeries to aid in easier identification of occult and often tricky-to-find anatomical structures. Surgery becomes complex and challenging due to multiple anatomical anomalies, pathological fibrosis, obesity, or previous surgeries. To overcome these obstacles in surgery, the surgeon yearns to know the structures present beyond their white light vision so that while dissecting the organ, they can avoid injuring the critical systems in the vicinity of dissection. Near-infrared (NIR) imaging aids in visualising the tissues at depth/in the area of dissection, thereby preventing any possible surgical catastrophes due to them inadvertently damaging surrounding vital structures. Various advantages in surgeries like gastric sleeve surgery, lymph node and tumour detection, localisation of ureters and biliary tracts, and intraoperative tissue perfusion of flaps have been described in this study. This review article aims to compile a short list of utilities of ICG with NIR imaging in various surgical interventions. The merits and demerits of this imaging technique have been noted. The study points out the uses of ICG fluorescence imaging under different surgical fronts. This review article concludes by comparing the results of studies performed by various authors. Results have been compared to conventional surgical modalities.

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.

Impact of Current Technology in Laparoscopic Adrenalectomy: 20 Years of Experience in the Treatment of 254 Consecutive Clinical Cases

BACKGROUND

Laparoscopic adrenalectomy (LA), which avoids large abdomen incisions, is considered the gold standard technique for the treatment of benign small- and medium-size adrenal masses (<6 cm) and weighing < 100 g. A trascurable mortality and morbidity rate, short hospitalization and patient rapid recovery are the main advantages compared to traditional surgery. During the past decade, a new surgical technology has been developed that expedites a "clipless" adrenalectomy. Here, the authors analyze a clinical series of 254 consecutive patients who were affected by adrenal gland neoplasms and underwent LA by the transabdominal lateral approach over the two last decades. A literature review is also presented.

METHODS

Preoperative, intraoperative and postoperative data from 254 patients who underwent LA between January 2003 and December 2022 were retrospectively collected and reviewed. Diagnosis was obtained on the basis of clinical examination, laboratory values and imaging techniques. Doxazosin was preoperatively administered in the case of pheochromocytoma (PCC) while spironolactone and potassium were employed to treat Conn's disease. The same surgeon (CG) performed all the LA and utilized the same laparoscopic transabdominal lateral approach. Different dissection tools-ultrasonic, bipolar or mixed scissors-and hemostatic agents were used during this period. The following results were obtained: 254 patients were included in the study; functioning tumors were diagnosed in 155 patients, 52 patients were affected by PCCs, 55 by Conn's disease, 48 by Cushing's disease. Surgery mean operative time was 137.33 min (range 100-180 min) during the learning curve adrenalectomies and 98.5 min (range 70-180) in subsequent procedures. Mean blood loss was respectively 160.2 mL (range 60-280) and 96.98 mL (range 50-280) in the first 30 procedures and the subsequent ones. Only three conversions (1.18%) to open surgery occurred. No mortality or postoperative major complications were observed, while minor complications occurred in 19 patients (3.54%). In 153 out of 155 functioning neoplasms, LA was effective in the normalization of the endocrine profile. According to our experience, a learning curve consisting of 30 cases was identified. In fact, a lower operative time and a lower complication rate was reported following 30 LA.

CONCLUSIONS

LA is a safe procedure, even for masses larger than 6 cm and PCCs. Undoubtedly, the development of surgical technology has made it possible reducing operative times, performing a "clipless" adrenalectomy and extending the indications in the treatment of more complex patients. A multidisciplinary team, in referral high-volume centers, is recommended in the management of adrenal pathology. A 30-procedure learning curve is necessary to improve surgical outcomes.

Outcome of Partial Adrenalectomy in MEN2 Syndrome: Personal Experience and Systematic Review of Literature

Background: Partial adrenalectomy (PA) is an alternative option to total adrenalectomy for the treatment of hereditary pheochromocytoma (PHEO) to preserve cortical function and avoid life-long steroid replacement. The aim of this review is to summarize current evidence in terms of clinical outcome, recurrence, and corticosteroid therapy implementation after PA for MEN2-PHEOs. Material and Methods: From a total of 931 adrenalectomies (1997-2022), 16 of the 194 patients who underwent surgical treatment of PHEO had MEN2 syndrome. There were six patients scheduled for PA. MEDLINE^®, EMBASE^®, Web of Science, and Cochrane Library were searched for English studies from 1981 to 2022. Results: Among six patients who underwent PA for MEN2-related PHEO in our center, we reported two with bilateral synchronous disease and three with metachronous PHEOs. One recurrence was registered. Less than 20 mg/day Hydrocortison therapy was necessary in 50% of patients after bilateral procedures. Systematic review identified 83 PA for MEN2-PHEO. Bilateral synchronous PHEO, metachronous PHEO and disease recurrence were reported in 42%, 26%, and 4% of patients, respectively. Postoperative steroid implementation was necessary in 65% of patients who underwent bilateral procedures. Conclusions: PA seems to be a safe and valuable option for the treatment of MEN2-related PHEOs, balancing the risk of disease recurrence with the need for corticosteroid therapy.

The new robotic platform Hugo™ RAS for lateral transabdominal adrenalectomy: a first world report of a series of five cases

Robotic assisted surgery is the most rapidly developing field of minimally invasive surgery. Its wide diffusion has led to the development and standardization of robotic-assisted approaches also for adrenalectomy. In this study, we present the first five robotic-assisted lateral transabdominal adrenalectomies performed with the new Hugo RAS™ system (Medtronic, Minneapolis, MN, USA). After an official training course of the surgical team, five consecutive patients scheduled for unilateral adrenalectomy, underwent robotic-assisted operations in our institution. Patients that were candidates for partial adrenalectomy were excluded. A description of the operating theatre, robotic arms and docking setup is provided. Four female and one male patient underwent lateral transabdominal adrenalectomy, three for lesions on the left side and two on the right. Median lesion size was 3.9 cm (range: 30-90) and preoperative diagnosis was Cushing's syndrome in three patients, an adrenal cystic lesion and a pheochromocytoma. The median docking time was 5 min (range: 5-8) and the median console time was 55 min (range: 29-108). Procedures were performed without intraoperative complications and no conversions or additional ports were needed. System's function and docking were uneventful. Based on our initial experience, adrenalectomy with the Hugo™ system is feasible. This study provides technical notes for other centres that wish to perform robotic-assisted adrenalectomies with the Hugo™ RAS as well as general information and our preliminary insights on this new platform.

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.

PARTIAL ADRENALECTOMY - HOW FAR CAN WE GO?

Organ preservation and functional resections are the mainstays of most surgical sub-specialties at the present time. This is even more evident in endocrine surgery, where the product of secretion of these petit organs is of paramount importance. Partial adrenalectomy and cortical sparing techniques have evolved to actually compete with total adrenalectomy, the historical gold standard treatment. Much refined imaging techniques can readily identify smaller adrenal lesions that can be addressed surgically or percutaneously given the indication. The trend towards partial adrenalectomy is straightforward in bilateral disease where steroid replacement can be avoided while for unilateral disease, normal hormonal levels can be obtained. The reviewed publications offer deep insight into the advancement of partial or cortical sparing adrenal procedures from pioneering work to large cohort studies.

Real-time tissue perfusion assessment using fluorescence imaging topography scanning system: A preclinical investigation

BACKGROUND AND OBJECTIVES

We previously developed a real-time fluorescence imaging topography scanning (RFITS) system for intraoperative multimodal imaging, image-guided surgery, and dynamic surgical navigation. The RFITS can capture intraoperative fluorescence, color reflectance, and surface topography concurrently and offers accurate registration of multimodal images. The RFITS prototype is a promising system for multimodal image guidance and intuitive 3D visualization. In the current study, we investigated the capability of the RFITS system in intraoperative fluorescence vascular angiography for real-time assessment of tissue perfusion.

STUDY DESIGN/MATERIALS AND METHODS

We conducted ex vivo imaging of fluorescence perfusion in a soft casting life-sized human brain phantom. Indocyanine green (ICG) solutions diluted in dimethyl sulfoxide (DMSO) and human serum were injected into the brain phantom through the vessel simulating tube (2 ± 0.2 mm inner diameter) by an adjustable flow peristaltic pump. To demonstrate the translational potential of the system, an ICG/DMSO solution was perfused into blood vessels of freshly harvested porcine ears (n = 9, inner diameter from 0.56 to 1.27 mm). We subsequently performed in vivo imaging of fluorescence-perfused vascular structures in rodent models (n = 10). 5 mg/ml ICG solutions prepared in sterile water were injected via the lateral tail vein. All targets were imaged by the RFITS prototype at a working distance of 350-400 mm.

RESULTS

3D visualization of 10 µg/ml ICG-labeled continuous moving serum in the brain phantom was obtained at an average signal-to-background ratio (SBR) of 1.74 ± 0.03. The system was able to detect intravenously diffused fluorescence in porcine tissues with an average SBR of 2.23 ± 0.22. The RFITS prototype provided real-time monitoring of tissue perfusion in rats after intravenous (IV) administration of ICG. The maximum fluorescence intensity (average SBR = 1.94 ± 0.16, p < 0.001) was observed at T_peak of ~30 seconds after the ICG signal was first detected (average SBR = 1.19 ± 0.13, p < 0.01).

CONCLUSIONS

We have conducted preclinical studies to demonstrate the feasibility of applying the RFITS system in real-time fluorescence angiography and tissue perfusion assessment. Our system provides fluorescence/color composite images for intuitive visualization of tissue perfusion with 3D perception. The findings pave the way for future clinical translation.

Detection of near-infrared autofluorescence from adrenal neoplasms: An initial experience

BACKGROUND AND OBJECTIVES

Fluorescence from adrenal tumors can be detected with near-infrared imaging after injection with indocyanine green. However, it is unknown if adrenal tumors exhibit autofluorescence. The aim of this study was to determine whether adrenal tumors emit near-infrared autofluorescence (NIRAF).

METHODS

This was a prospective study of patients who underwent minimally invasive adrenalectomy at a tertiary center. Intraoperative images were analyzed to detect NIRAF with a 750 nm camera. Descriptive and comparative statistical analyses were performed.

RESULTS

Twenty-five adrenalectomies were examined. Only 11 tumors (44%), that originated from the cortex exhibited autofluorescence. A contrast distinction between the tumor and retroperitoneum was observed in 23 patients, whereas a contrast distinction between the tumor and normal adrenocortical tissue was seen in 12 patients. The overall fluorescence intensity of adrenal tumors was found to be variable and ranging between 0.3 and 5.6 times that of the background tissue. Pheochromocytoma, malignancy and adrenal cyst did not demonstrate NIRAF.

CONCLUSION

This is the first study to show that adrenocortical tissue can demonstrate NIRAF. The pattern of fluorescence was similar to that observed after indocyanine green injection in our historical experience. NIRAF has a potential to be used as an intraoperative optical adjunct during adrenalectomy.

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.

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.