Endoscopic Imaging System

Clinical Background

Laparoscopic and endoscopic procedures have become the gold standard for many surgical interventions due to their minimally invasive nature, reduced postoperative pain, shorter hospital stays, and faster recovery times compared to traditional open surgery. However, these procedures present certain challenges, such as limited visibility and difficulty in identifying crucial anatomical structures, which can lead to complications and suboptimal outcomes.

Traditionally, surgeons have relied on their visual inspection and experience to identify vital structures, assess tissue perfusion, and detect abnormalities during laparoscopic and endoscopic procedures. However, this approach is highly subjective and may not provide an adequate evaluation of the surgical field, particularly in cases with distorted anatomy, inflammation, or previous surgeries.

To address these challenges, endoscopic fluorescence imaging systems have been developed to enhance visualization during minimally invasive surgery. These systems employ near-infrared (NIR) fluorescence imaging, which uses a fluorescent dye (e.g., indocyanine green) and specialized camera systems to provide real-time visualization of various physiological processes, such as blood flow, tissue perfusion, and lymphatic drainage. The primary goal of these systems is to improve the identification of critical structures, assess organ viability, and detect abnormalities that may not be visible under standard white light imaging.

The use of endoscopic fluorescence imaging systems has the potential to:

• Reduce the risk of iatrogenic injuries by improving the identification of vital structures, such as blood vessels, bile ducts, and ureters.
• Assess tissue perfusion and organ viability, enabling surgeons to make informed decisions regarding resection margins and anastomotic sites.
• Identify sentinel lymph nodes and lymphatic drainage patterns, aiding in cancer staging and guiding the extent of lymph node dissection.
• Detect occult tumors and delineate tumor margins, facilitating complete resection and reducing the risk of local recurrence.

Endoscopic fluorescence imaging systems address the limitations of traditional visual inspection during laparoscopic and endoscopic procedures by providing real-time, objective visualization of critical anatomical structures and physiological processes. These systems have the potential to improve surgical outcomes, reduce complications, and enhance patient safety in minimally invasive surgery.

Near-infrared fluorescence (NIRF) imaging using indocyanine green (ICG) dye has emerged as a promising complementary technique for intraoperative visualization of endometriosis lesions. NIRF provides real-time images that allow accurate surgical guidance. The robotic surgical 3D scope also improves depth perception and visualization of endometriosis compared to conventional 2D laparoscopy. Combining fluorescent intraoperative imaging with robotic surgery is a logical progression to enhance perioperative tissue visualization.

Near-infrared fluorescence imaging with indocyanine green (ICG): This technique involves the intravenous injection of ICG, which is then visualized using a specialized camera system. It allows for real-time assessment of tissue perfusion, identification of vital structures (e.g., bile ducts, ureters), and detection of sentinel lymph nodes. Studies have demonstrated its potential to reduce complications and improve surgical outcomes.

Fluorescence-guided lymph node mapping: This method uses ICG or other fluorescent dyes to identify sentinel lymph nodes and map lymphatic drainage patterns. It has been applied in various cancer surgeries, including colorectal, gastric, and gynecological malignancies, to guide the extent of lymph node dissection and improve staging accuracy.

Fluorescence-guided tumor detection: Fluorescent dyes, such as 5-aminolevulinic acid (5-ALA) and ICG, have been used to detect occult tumors and delineate tumor margins during laparoscopic and endoscopic procedures. This approach has shown promise in improving complete resection rates and reducing local recurrence in various malignancies, such as colorectal, gastric, and bladder cancers.

Recent small case series have reported the potential benefits of robotic NIRF-ICG imaging in detecting peritoneal and deep endometriosis lesions that were not visible with conventional white light. The endometriotic lesions fluoresce as green islands surrounded by lighter areas of fibrosis. The inherent neovascularization in endometriosis may make lesions more recognizable with ICG, which binds to plasma proteins and remains in the vascular system after IV injection. NIRF can penetrate several millimeters into tissue, allowing identification of structures not yet directly exposed on the surface. These preliminary studies suggest robotic NIRF-ICG imaging is a safe technique that may help surgeons better visualize, diagnose and treat endometriosis with minimal risk.

Several new methods have been recently developed to enhance visualization and improve outcomes in laparoscopic and endoscopic procedures:

Alternative Options

Several alternative diagnostic and new methods are available for conditions typically managed with laparoscopic or endoscopic procedures:

Hyperspectral imaging (HSI): HSI is an emerging technology that captures and processes information from across the electromagnetic spectrum. It has been applied in laparoscopic and endoscopic procedures to assess tissue oxygenation, differentiate between normal and diseased tissues, and detect ischemia. HSI has the potential to provide real-time, objective assessment of tissue viability and guide surgical decision-making.

Confocal laser endomicroscopy (CLE): CLE is a high-resolution imaging technique that allows for real-time, in vivo microscopic visualization of tissues during endoscopic procedures. It has been used to differentiate between benign and malignant lesions, assess tumor margins, and guide targeted biopsies. CLE has shown promise in improving diagnostic accuracy and reducing the need for unnecessary biopsies in various gastrointestinal and urological conditions.

These new methods represent significant advancements in laparoscopic and endoscopic imaging, offering surgeons additional tools to enhance visualization, improve diagnostic accuracy, and guide surgical decision-making. As these technologies continue to evolve and become more widely adopted, they have the potential to further improve patient outcomes and reduce complications in minimally invasive surgery.

In the meantime, conventional 2D laparoscopy uses a standard laparoscopic camera system to provide real-time visible light imaging during surgical procedures. Conventional 2D laparoscopy is a well-established alternative visualization option for minimally invasive surgery. It provides surgeons with a flat, 2D view of the surgical field.

Comparable Advantages of Conventional 2D laparoscopy:

• Mature technology with wide clinical applications and low equipment costs
• Doctors have high familiarity and do not require additional training
• Image processing is relatively simple

Comparable Disadvantages:

• Lack of depth information may affect the accuracy of certain complex surgeries
• May increase the surgeon’s visual fatigue, especially during prolonged surgeries

Medical management: In some cases, medical therapy can be an alternative to surgical intervention. For example, proton pump inhibitors and H2 receptor blockers can be used to treat gastroesophageal reflux disease (GERD) and peptic ulcer disease, while antibiotics and anti-inflammatory agents can be used to manage acute diverticulitis.

Radiological interventions: Image-guided interventions, such as percutaneous drainage of abscesses or collections, can be an alternative to surgical drainage in selected cases. Embolization techniques can be used to control gastrointestinal bleeding, while stenting can be employed to manage obstructive conditions, such as malignant biliary or colonic obstruction.

Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD): These techniques involve the removal of superficial gastrointestinal lesions and early-stage cancers through an endoscope, avoiding the need for more invasive surgical resection. EMR and ESD have been widely used in the management of early esophageal, gastric, and colorectal neoplasms.

Endoscopic ablation therapies: Various endoscopic ablation techniques, such as radiofrequency ablation, cryoablation, and photodynamic therapy, can be used to treat precancerous lesions and early-stage cancers in the gastrointestinal tract. These methods offer a less invasive alternative to surgical resection in selected cases.

Endoscopic retrograde cholangiopancreatography (ERCP): ERCP is a diagnostic and therapeutic procedure that allows for the evaluation and treatment of pancreatic and biliary disorders. It can be used to remove gallstones from the bile ducts, place stents to relieve obstructions, and perform tissue sampling for diagnostic purposes, potentially avoiding the need for surgical intervention in some cases.

Endoscopic ultrasound (EUS): EUS combines endoscopy and ultrasound imaging to provide detailed visualization of the gastrointestinal tract and adjacent structures. It can be used to diagnose and stage gastrointestinal cancers, assess submucosal lesions, and guide fine-needle aspiration for tissue sampling. EUS has become an essential tool in the diagnostic workup of various gastrointestinal conditions, often complementing or replacing surgical exploration.

Capsule endoscopy: This non-invasive diagnostic method involves swallowing a small, wireless camera capsule that captures images of the gastrointestinal tract as it passes through. Capsule endoscopy is primarily used to evaluate the small intestine, which is difficult to access with conventional endoscopy, and can help diagnose conditions such as obscure gastrointestinal bleeding, Crohn’s disease, and small bowel tumors.

These alternative diagnostic and treatment methods have expanded the options available for managing various gastrointestinal conditions, offering less invasive approaches that can reduce the need for surgical intervention in selected cases. However, the choice of treatment modality depends on factors such as the specific condition, disease stage, patient characteristics, and available expertise. A multidisciplinary approach involving gastroenterologists, surgeons, radiologists, and oncologists is often necessary to determine the most appropriate management strategy for each individual patient.

Performance and Safety Endpoints

Claim or Benefit	Safety (S) and Performance (P) Objectives	Acceptance Criteria with Justification
Enhanced Visualization; Surgical Decision Support; Safety Improvements	Enhanced Visualization (S, P): – Improved identification of anatomical structures – Successful imaging rate – Low conversion rates to open surgery Visualization of tumor boundaries during minimally invasive surgery   Safety Improvements: – Low ICG-related AEs – Reduced bile duct injury or Anastomotic leak rates – Low Complications	Based on literature study, Safety (S) and Performance (P) acceptance criteria are: Visualization Quality: Biliary Structure Visualization [Keeratibharat, 2021]: from 70.9 to 96.3% depending on the anatomical structure. Successful imaging rate [Zhang et al., 2022; Barnes et al. (2018); Liu et al. (2023)]: Structure-dependent, rates ranging from 75% to 100% Visualization of tumor boundaries [Achterberg et al., 2024; Achterberg et al., 2020; Aoki et al., 2018]: Negative margin rates with ICG were 92.4% for colorectal liver metastases (CRLM), 100% for neuroendocrine tumor (NET) liver metastases, and 92% for various liver metastases Surgical Decision Support: Conversion to open surgery rate: ≤15.5/10,000 [Dip et al., 2021] Safety Acceptance Criteria: ICG-related Adverse Events: ICG-related complications: ≤0.3% [Agnus et al., 2020] No severe allergic reactions reported Procedure-related Complications: Bile duct injury rate: ≤6.2/10,000 [Dip et al., 2021] Anastomotic leak rate: ≤10% with fluorescence imaging [Skrovina et al., 2020] Other Complications: Clavien-Dindo Classification: Minor complications: ≤31% Major complications: ≤19% [Pather et al., 2022]

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Literature Search Period: 2020 – 2024 | Search Time: June. 2024 | Next review/update: June. 2025