A narrative review of fluorescence imaging in robotic-assisted surgery

The Rise of Molecular Image-Guided Robotic Surgery

Following early acceptance by urologists, the use of surgical robotic platforms is rapidly spreading to other surgical fields. This empowerment of surgical perception via robotic advances occurs in parallel to developments in intraoperative molecular imaging. Convergence of these efforts creates a logical incentive to advance the decades-old image-guided robotics paradigm. This yields new radioguided surgery strategies set to optimally exploit the symbiosis between the growing clinical translation of robotics and molecular imaging. These strategies intend to advance surgical precision by increasing dexterity and optimizing surgical decision-making. In this state-of-the-art review, topic-related developments in chemistry (tracer development) and engineering (medical device development) are discussed, and future scientific robotic growth markets for molecular imaging are presented.

Recent Advances in Robotic Surgery for Urologic Tumors

This review discusses recent advances in robotic surgery for urologic tumors, focusing on three key areas: robotic systems, assistive technologies, and artificial intelligence. The Da Vinci SP system has enhanced the minimally invasive nature of robotic surgeries, while the Senhance system offers advantages such as tactile feedback and eye-tracking capabilities. Technologies like 3D reconstruction combined with augmented reality and fluorescence imaging aid surgeons in precisely identifying the anatomical relationships between tumors and surrounding structures, improving surgical efficiency and outcomes. Additionally, the development of artificial intelligence lays the groundwork for automated robotics. As these technologies continue to evolve, we are entering an era of minimally invasive, precise, and intelligent robotic surgery.

Advances of surgical robotics: image-guided classification and application

Surgical robotics application in the field of minimally invasive surgery has developed rapidly and has been attracting increasingly more research attention in recent years. A common consensus has been reached that surgical procedures are to become less traumatic and with the implementation of more intelligence and higher autonomy, which is a serious challenge faced by the environmental sensing capabilities of robotic systems. One of the main sources of environmental information for robots are images, which are the basis of robot vision. In this review article, we divide clinical image into direct and indirect based on the object of information acquisition, and into continuous, intermittent continuous, and discontinuous according to the target-tracking frequency. The characteristics and applications of the existing surgical robots in each category are introduced based on these two dimensions. Our purpose in conducting this review was to analyze, summarize, and discuss the current evidence on the general rules on the application of image technologies for medical purposes. Our analysis gives insight and provides guidance conducive to the development of more advanced surgical robotics systems in the future.

Development of a plant-based surgical training model for fluorescence-guided cancer surgery

BACKGROUND

Fluorescence-guided surgery (FGS) can help surgeons to discriminate tumor tissue from adjacent normal tissues using fluorescent tracers.

METHODS

We developed a surgical training model, manufactured using sustainable vegetable organic material with indocyanine green (ICG)-containing "tumor." Surgeons evaluated the model with both the closed-field and endoscopic fluorescence imaging devices and assessed its efficacy to identify residual tumor after enucleation using electrocautery.

RESULTS

Strong correlations of fluorescence were obtained at all working distance (3, 5, 7, and 10 cm), showing the robustness of fluorescence signal for the closed-field and endoscopic fluorescence imaging devices. The higher fluorescence signals were obtained in the wound bed in the closed-field fluorescence imaging device and the residual tumor could be clearly identified by fluorescence endoscopy.

CONCLUSIONS

Our FGS training model may provide experience for surgeons unfamiliar with optical surgery and subsequent tissue interactions. The model seemed particularly helpful in teaching surgeons the principles of FGS.

Intraoperative Fluorescent Navigation of the Ureters, Vessels, and Nerves during Robot-Assisted Sacrocolpopexy

In this study, we aimed to demonstrate the feasibility and safety of navigating the ureters, middle sacral artery (MSA), and superior hypogastric nerve (SHN) using indocyanine green (ICG) and near-infrared fluorescence (NIRF) imaging during robot-assisted sacrocolpopexy (RSCP). Overall, 15 patients who underwent RSCP for apical vaginal prolapse were retrospectively enrolled. All patients underwent cystoscopic intraureteric instillation of 5 cc ICG (2.5 mg/mL) before RSCP and intravenous injection of 3 cc ICG during presacral dissection and mesh fixation. In all patients, the fluorescent right ureter was clearly identified in real time. The MSA was visualized on ICG-NIRF images in 80% (13/15) of patients. The mean time from ICG injection to MSA visualization was 43.7 s; the mean duration of the arterial phase was 104.3 s. Fluorescent SHN was detected in 73.3% (11/15) of patients. The time from ICG injection to SHN fluorescence was 48.4 s; the duration of fluorescence was 177.2 s. There was no transfusion, iatrogenic ureteral injury, or bowel or urinary dysfunction. Our results indicated that intraoperative ureter, MSA, and SHN mapping using ICG-NIRF images during RSCP is a valuable and safe technique to avoid iatrogenic ureteral, vascular, and neural injuries and to simplify surgical procedures. Nonetheless, further studies are required.

Fluorescence imaging-guided surgery: current status and future directions

Surgery is one of the most important paradigms for tumor therapy, while fluorescence imaging (FI) offers real-time intraoperative guidance, greatly boosting treatment prognosis. The imaging fidelity heavily relies on not only imaging facilities but also probes for imaging-guided surgery (IGS). So far, a great number of IGS probes with emission in visible (400-700 nm) and near-infrared (NIR 700-1700 nm) windows have been developed for pinpointing disease margins intraoperatively. Herein, the state-of-the-art fluorescent probes for IGS are timely updated, with a special focus on the fluorescent probes under clinical examination. For a better demonstration of the superiority of NIR FI over visible FI, both imaging modalities are critically compared regarding signal-to-background ratio, penetration depth, resolution, tissue autofluorescence, photostability, and biocompatibility. Various types of fluorescence IGS have been summarized to demonstrate its importance in the medical field. Furthermore, the most recent progress of fluorescent probes in NIR-I and NIR-II windows is summarized. Finally, an outlook on multimodal imaging, FI beyond NIR-II, efficient tumor targeting, automated IGS, the use of AI and machine learning for designing fluorescent probes, and the fluorescence-guided da Vinci surgical system is given. We hope this review will stimulate interest among researchers in different areas and expedite the translation of fluorescent probes from bench to bedside.

A Minimally Invasive Robotic Tissue Palpation Device

OBJECTIVE

Robot-assisted minimally invasive surgery remains limited by the absence of haptic feedback, which surgeons routinely rely on to assess tissue stiffness. This limitation hinders surgeons' ability to identify and treat abnormal tissues, such as tumors, during robotic surgery.

METHODS

To address this challenge, we developed a robotic tissue palpation device capable of rapidly and non-invasively quantifying the stiffness of soft tissues, allowing surgeons to make objective and data-driven decisions during minimally invasive procedures. We evaluated the effectiveness of our device by measuring the stiffness of phantoms as well as lung, heart, liver, and skin tissues obtained from both rats and swine.

RESULTS

Results demonstrated that our device can accurately determine tissue stiffness and identify tumor mimics. Specifically, in swine lung, we determined elastic modulus (E) values of 9.1 ± 2.3, 16.8 ± 1.8, and 26.0 ± 3.6 kPa under different internal pressure of the lungs (PIP) of 2, 25, and 45 cmH2O, respectively. Using our device, we successfully located a 2-cm tumor mimic embedded at a depth of 5 mm in the lung subpleural region. Additionally, we measured E values of 33.0 ± 5.4, 19.2 ± 2.2, 33.5 ± 8.2, and 22.6 ± 6.0 kPa for swine heart, liver, abdominal skin, and muscle, respectively, which closely matched existing literature data.

CONCLUSION/SIGNIFICANCE

Results suggest that our robotic palpation device can be utilized during surgery, either as a stand-alone or additional tool integrated into existing robotic surgical systems, to enhance treatment outcomes by enabling accurate intraoperative identification of abnormal tissue.

Fluorescence guidance using near-infrared fluorescent clips in robotic rectal surgery: a case series

PURPOSE

Tattoo markings are often used as preoperative markers for colorectal cancer. However, scattered ink markings adversely affect tumor site recognition intraoperatively; therefore, interventions for rectal cancer may lead to an inaccurate distal resection margin (DRM) and incomplete total mesorectal excision (TME). This is the first case series of fluorescence-guided robotic rectal surgery in which near-infrared fluorescence clips (NIRFCs) were used to localize rectal cancer lesions.

METHODS

We enrolled 20 consecutive patients who underwent robotic surgery for rectal cancer between December 2022 and December 2023 in the current study. The primary endpoints were the rate of intraoperative clip detection and its usefulness for marking the tumor site. Secondary endpoints were oncological assessments, including DRM and the number of lymph nodes.

RESULTS

Clip locations were confirmed in 17 of 20 (85%) patients. NIRFCs were not detected in 3 out of 7 patients who underwent preoperative chemoradiation therapy. No adverse events, including bleeding or perforation, were observed at the time of clipping, and no clips were lost. The median DRM was 55 mm (range, 22-86 mm) for rectosigmoid (Rs), 33 mm (range, 16-60 mm) for upper rectum (Ra), and 20 mm (range, 17-30 mm) for low rectum (Rb). The median number of lymph nodes was 13 (range, 10-21).

CONCLUSION

The rate of intraoperative clip detection, oncological assessment, including DRM, and the number of lymph nodes indicate that the utility of fluorescence-guided methods with NIRFCs is feasible for rectal cancer.

Microsurgery Robots: Applications, Design, and Development

Microsurgical techniques have been widely utilized in various surgical specialties, such as ophthalmology, neurosurgery, and otolaryngology, which require intricate and precise surgical tool manipulation on a small scale. In microsurgery, operations on delicate vessels or tissues require high standards in surgeons' skills. This exceptionally high requirement in skills leads to a steep learning curve and lengthy training before the surgeons can perform microsurgical procedures with quality outcomes. The microsurgery robot (MSR), which can improve surgeons' operation skills through various functions, has received extensive research attention in the past three decades. There have been many review papers summarizing the research on MSR for specific surgical specialties. However, an in-depth review of the relevant technologies used in MSR systems is limited in the literature. This review details the technical challenges in microsurgery, and systematically summarizes the key technologies in MSR with a developmental perspective from the basic structural mechanism design, to the perception and human-machine interaction methods, and further to the ability in achieving a certain level of autonomy. By presenting and comparing the methods and technologies in this cutting-edge research, this paper aims to provide readers with a comprehensive understanding of the current state of MSR research and identify potential directions for future development in MSR.

Safety and efficacy of indocyanine green near-infrared fluorescent imaging-guided lymph node dissection during robotic gastrectomy for gastric cancer: a systematic review and meta-analysis

BACKGROUND

In Asia, particularly, robotic gastrectomy has grown in popularity as a treatment for stomach cancer. Indocyanine green (ICG) and near-infrared (NIR) fluorescent imaging technology has been reported for robotic gastrectomy. However, the clinical value still should be further evaluated. In this meta-analysis, we investigated the safety and efficacy of ICG near-infrared fluorescent imaging-guided lymph node (LN) dissection during robotic gastrectomy.

MATERIAL AND METHODS

Through July 2022, systematic searches of PubMed, Embase, Web of Science, and the Cochrane Library were conducted to find studies comparing ICG fluorescence imaging with conventional treatment in patients with gastric cancer. The current meta-analysis was performed according to the preferred reporting items for systematic review and meta-analysis guidelines. A pooled analysis was performed for the available data regarding the number of lymph node dissections, other operative outcomes and postoperative complications. R studio software 4.2.2 was used for this meta-analysis.

RESULTS

This analysis includes five studies with a total of 312 gastric cancer patients (128 in the ICG group and 184 in the non-ICG group). In this meta-analysis, the number of retrieved LNs in the ICG group was significantly higher (weighted mean difference [WMD] = 8.80, 95% confidence intervals [CI]: 4.37-13.22, p < 0.05) than that in the non-ICG group with moderate heterogeneity (p < 0.0001, I2=53.3%). Intraoperative blood loss and postoperative complications were all comparable and without significant heterogeneity. Additionally, ICG near-infrared fluorescent imaging was associated with a reduced operative time (WMD= -11.85, 95% CI: -22.40 to -1.30, p < 0.05) with low heterogeneity (p = 0.027, I2= 2.1%).

CONCLUSIONS

ICG near-infrared fluorescent imaging-guided lymphadenectomy was considered to be safe and effective in robotic gastrectomy. ICG was used to increase the number of LNs harvested while reducing operative time without increasing intraoperative blood loss or postoperative complications.

Intraoperative Fluorescent Ureter Visualization in Complex Laparoscopic or Robotic-Assisted Gynecologic Surgery

This study aimed to demonstrate the feasibility of ureteral navigation using intraoperative indocyanine green (ICG) and near-infrared fluorescence (NIRF) imaging during complex laparoscopic or robot-assisted gynecologic surgery (LRAGS). Twenty-six patients at high risk of ureteral injury with complex pelvic pathology (CPP) due to pelvic organ prolapse (POP), multiple myomas, large intraligamentary or cervical myoma, severe pelvic adhesions, or cervical atresia underwent LRAGS. All patients underwent cystoscopic intraureteral ICG instillation before LRAGS and ureteral navigation under NIRF imaging intraoperatively. Both ureteral pathways were identified from the pelvic brim downwards through NIRF imaging in all patients, even though some were not visualized under the white light mode. The fluorescent ureters were visualized immediately after the beginning of surgery and typically lasted for >5 h during surgery. There were no cases of iatrogenic ureteral injury. The hemoglobin decrement was 1.47 ± 1.13 g/dL, and no transfusion was required. In our study, both ureters in all patients were identified with ICG-NIRF imaging during LRAGS, and these techniques made surgeries easier and safer. Despite the CPP, there was no ureteral injury or transfusion following surgery. Further prospective studies are needed to introduce intraoperative ureteral guidelines for ICG-NIRF imaging during LRAGS with CPP.

[Extended Reality (XR) - Applications in Thoracic Surgery]

Extended reality (XR) includes the sub-terms of virtual reality (VR), augmented reality (AR) and mixed reality (MR) and describes interactive and immersive technologies that replace the real world with digital elements or seamlessly extend it with such approaches. XR thus offers a very wide range of possible applications in medicine. In surgery, and thoracic surgery in particular, XR technologies can be harnessed for treatment planning, navigation, training, and patient information. Such applications are increasingly being tested and need to be evaluated. We provide an overview of the status quo of technical development, current surgical applications of XR, and look into the future of the medical XR landscape with integration of artificial intelligence (AI).

Robot-Assisted Surgery in the Treatment of Gynecological Carcinoma and Malignancies: Introduction to the da Vinci Robotic Surgery System

Robotic surgery is a surgical intervention that was developed from traditional manual surgeries because of the intrusive procedures it uses. It is now accomplished in hospitals worldwide, and comprehensive programs for the application of technology in the management of gynecological cancer are being developed. Robotic surgery should be straightforwardly compared with manual and traditional laparoscopy to see if the higher indirect costs are justified by some improvements in patient studies. This paper aims to evaluate the procedure of robotic surgery and its implementation in gynecological cancer to verify its safeness, practicability, and effectiveness. A higher chance of infections is usually in classical surgery, particularly in comparison to laparoscopic or robotic surgery. Surgical and hospital stay are much less with any of these new technologies than the aforementioned; however, the drawbacks are the scarcity of robot systems, their high price, and the realization that it is only appropriate in learning institutions with infrastructure and highly skilled surgeons. In conclusion, tissue engineering constitutes a significant discovery and approach for treating gynecological cancer with improved methods than some other types of traditional surgery, and it will likely become dominant technology shortly.

Effectiveness of fluorescence-guided methods using near-infrared fluorescent clips of robotic colorectal surgery: a case report

BACKGROUND

This is the first report on the application of the Da Vinci-compatible near-infrared fluorescent clips (NIRFCs) as tumor markers to localize colorectal cancer lesions during robotic surgery. In laparoscopic and robotic colorectal surgeries, the accuracy of tumor marking is a critical issue that remains unresolved. This study aimed to determine the accuracy of NIRFCs in localizing tumors for intestinal resection. Indocyanine green (ICG) was also used to verify the feasibility of safely performing an anastomosis.

CASE PRESENTATION

A patient diagnosed with rectal cancer was scheduled to undergo a robot-assisted high anterior resection. During colonoscopy 1 day prior to the surgery, four Da Vinci-compatible NIRFCs were placed intraluminally 90° around the lesion. The locations of the Da Vinci-compatible NIRFCs were confirmed using firefly technology, and ICG staining was performed before cutting the oral side of the tumor. The locations of the Da Vinci-compatible NIRFCs and the intestinal resection line were confirmed. Moreover, sufficient margins were obtained.

CONCLUSIONS

In robotic colorectal surgery, fluorescence guidance with firefly technology offers two advantages. First, it has an oncological advantage, because marking with the Da Vinci-compatible NIRFCs allows for real-time monitoring of the lesion location. This enables sufficient intestinal resection by grasping the lesion precisely. Second, it reduces the risk of postoperative complications, because ICG evaluation with firefly technology prevents postoperative anastomotic leakage. Fluorescence guidance in robot-assisted surgery is useful. In the future, the application of this technique should be evaluated for lower rectal cancer.

Current Status of Robotic Gastrointestinal Surgery

Development of surgical support robots began in the 1980s as a navigation and auxiliary device for endoscopic surgery. For remote surgery on the battlefield, a master-slave-type surgical support robot was developed, in which a console surgeon operates the robot at will. The da Vinci surgical system, which currently dominates the global robotic surgery market, received United States Food and Drug Administration and regulatory approval in Japan in 2000 and 2009 respectively. The latest, fourth generation, da Vinci Xi has a good field of view via a three-dimensional monitor, highly operable forceps, a motion scale function, and a tremor-filtered articulated function. Gastroenterological tract robotic surgery is safe and minimally invasive when accessing and operating on the esophagus, stomach, colon, and rectum. The learning curve is said to be short, and robotic surgery will likely be standardized soon. Therefore, robotic surgery training should be systematized for young surgeons so that it can be further standardized and later adapted to a wider range of surgeries. This article reviews current trends and potential developments in robotic surgery.

Near-infrared ray catheter and indocyanine green via nephrostomy in delayed robotic reconstruction of injured ureter: A case report

Delayed surgical reconstruction of iatrogenic ureteral injuries is often a challenging procedure because spreading scar tissue impedes accurate identification and dissection of the injured ureter. We report a novel real-time navigation system using a ureteral near-infrared ray catheter (NIRC) and indocyanine green (ICG) via nephrostomy in delayed robot-assisted ureteral reconstruction. A female patient presented with complete obstruction of the right upper ureter after gynecological surgery with extensive lymphadenectomy. A nephrostomy tube was urgently placed, and surgical repair was performed. A straight NIRC was placed in the right ureter up to the obstruction point. ICG was administered via nephrostomy. Near-infrared light could clearly visualize the ureter and renal pelvis encased in scar tissue. The ureter and renal pelvis were dissected and successfully anastomosed. We found that near-infrared navigation using ureteral NIRC and ICG via nephrostomy was valuable for delayed laparoscopic reconstruction of the injured ureter.

Intraoperative fluorescence imaging in esophagectomy and its application to the robotic platform: a narrative review

Background and Objective

Robotic-assisted esophagectomy is an approach to minimally invasive esophagectomy (MIE) that has demonstrated equivalent or improved outcomes relative to open and other minimally invasive techniques. The robotic approach also allows unique opportunities to improve complications following esophagectomy through use of enhanced visualization tools, including intraoperative fluorescence imaging. In this review, we summarize the specific uses of intraoperative fluorescence imaging as an adjunct tool during esophagectomy and discuss its application to the robotic platform.

Methods

A literature search was conducted via PubMed in February 2022 with the following keywords: esophagectomy, esophageal cancer, infrared, near-infrared (NIR) and fluorescence. Peer-reviewed academic journal articles published in English between 2000 and 2021 were included.

Key Content and Findings

There is a growing body of literature evaluating the use of intraoperative fluorescence imaging in robotic-assisted esophagectomy. This includes assessment of gastric conduit perfusion, including feasibility, creation of the gastroesophageal anastomosis, and qualification of perfusion, along with lymphatic mapping and identification of critical anatomy. These tools are uniquely leveraged using the robotic platform to standardize and quantify key technical aspects of the operation.

Conclusions

Intraoperative fluorescence imaging provides the opportunity to assess perfusion and identify anatomy for more precise and patient-specific dissection and reconstruction. Among all the operative techniques for esophagectomy, robotic-assisted esophagectomy is uniquely suited to utilize these imaging modalities to optimize outcomes and minimize risk associated with esophagectomy.

Morphological Characteristics, Hemoglobin Content, and Membrane Mechanical Properties of Red Blood Cell Delivery Systems

Red blood cell (RBC)-based systems are under extensive development as platforms for the delivery of various biomedical agents. While the importance of the membrane biochemical characteristics in relation to circulation kinetics of RBC delivery systems has been recognized, the membrane mechanical properties of such carriers have not been extensively studied. Using optical methods in conjunction with image analysis and mechanical modeling, we have quantified the morphological and membrane mechanical characteristics of RBC-derived microparticles containing the near-infrared cargo indocyanine green (ICG). We find that these particles have a significantly lower surface area, volume, and deformability as compared to normal RBCs. The residual hemoglobin has a spatially distorted distribution in the particles. The membrane bending modulus of the particles is about twofold higher as compared to normal RBCs and exhibits greater resistance to flow. The induced increase in the viscous characteristics of the membrane is dominant over the elastic and entropic effects of ICG. Our results suggest that changes to the membrane mechanical properties are a result of impaired membrane-cytoskeleton attachment in these particles. We provide a mechanistic explanation to suggest that the compromised membrane-cytoskeleton attachment and altered membrane compositional and structural asymmetry induce curvature changes to the membrane, resulting in mechanical remodeling of the membrane. These findings highlight the importance of membrane mechanical properties as an important criterion in the design and engineering of future generations of RBC-based delivery systems to achieve prolonged circulation.

Contemporary Management of Locally Advanced and Recurrent Rectal Cancer: Views from the PelvEx Collaborative

Pelvic exenteration is a complex operation performed for locally advanced and recurrent pelvic cancers. The goal of surgery is to achieve clear margins, therefore identifying adjacent or involved organs, bone, muscle, nerves and/or vascular structures that may need resection. While these extensive resections are potentially curative, they can be associated with substantial morbidity. Recently, there has been a move to centralize care to specialized units, as this facilitates better multidisciplinary care input. Advancements in pelvic oncology and surgical innovation have redefined the boundaries of pelvic exenterative surgery. Combined with improved neoadjuvant therapies, advances in diagnostics, and better reconstructive techniques have provided quicker recovery and better quality of life outcomes, with improved survival This article provides highlights of the current management of advanced pelvic cancers in terms of surgical strategy and potential future developments.