Laparoscopic Fluorescence Imaging System Research Articles

Clinical value of fluorescent cholangiography for the infraportal type of right posterior bile duct

Background The infraportal type of the right posterior bile duct (infraportal RPBD) is a well-known anatomical variation that increases the potential risk of intraoperative biliary injury. The aim of this study is to clarify the clinical value of fluorescent cholangiography during single-incision laparoscopic cholecystectomy (SILC) for patients with infraportal RPBD. Material and methods Our procedure for SILC utilized the SILS-Port, and another 5-mm forceps was inserted via an umbilical incision. A laparoscopic fluorescence imaging system developed by Karl Storz Endoskope was utilized for fluorescent cholangiography. Between July 2010 and March 2022, 41 patients with infraportal RPBD underwent SILC. We conducted retrospective reviews of patient data, focusing on the clinical value of fluorescent cholangiography. Results Thirty-one patients underwent fluorescent cholangiography during SILC, but the remaining ten did not. Only one patient who did not undergo fluorescent cholangiography developed an intraoperative biliary injury. The detectability of infraportal RPBD before and during the dissection of Calot’s triangle was 16.1% and 45.2%, respectively. These visible infraportal RPBDs were characterized as connections to the common bile duct. The confluence pattern of infraportal RPBD significantly influenced its detectability during the dissection of Calot’s triangle (p < 0.001). Conclusions The application of fluorescent cholangiography can lead to safe SILC, even for patients with infraportal RPBD. Its benefit is emphasized when infraportal RPBD is connected to the common bile duct.

Real-time ureteral identification with novel, versatile, and inexpensive catheter.

Although ureteral catheters and ureteral fluorescence methods have been investigated to avoid ureteral injury, they have not been standardized for procedural complexity and safety to the living body. A near-infrared (NIR) fluorescence ureteral catheter made of fluorescent resin was jointly developed for non-invasive detection of ureters. The aims of this study were to (1) evaluate its bench-top performance and (2) assert its safety and potential usefulness in a series of animal models. [Bench-top study]: Confirmed stimulation of NIR fluorescence catheter by NIR light was investigated with the use of a laparoscopic fluorescence imaging system. Additionally, the influence of imaging distance and shielding objects, such as 1.5-mm sliced pig loin with multiple sheets, was also evaluated. [Performance study]: The safety and potential usefulness of fluorescence catheter was evaluated in five pigs. Non-fluorescence and fluorescence ureteral catheters were alternatively placed in the animals' left and right ureters. The ImageJ software was used in all experiments to quantify fluorescence signal and the signal-to-background ratio. [Bench-top study]: The fluorescence ureteral catheter was successfully identified at all distances. Its fluorescence decreased in inverse proportion to distance and to the intervening shield thickness (p < 0.01). When shields were present, catheter position could not be recognized with non-fluorescence catheters, but with fluorescence catheters they could be recognized. [Performance study]: Fluorescence catheter's ability to fluoresce at all distances was confirmed (p < 0.01). No individual differences (p = 0.21) or left/right ureter differences (p = 0.79) were observed. The fluorescence of the fluorescence catheter decreased in inverse proportion to distance (p < 0.01). The new fluorescence ureter catheter investigated shows promising performance in providing ureteral identification with high specificity during laparoscopic surgery.

Applications of a laparoscopic fluorescence imaging system during open hepatectomy: Tumor/ and segment identification, cholangiography, and angiography

Applications of a laparoscopic fluorescence imaging system during open hepatectomy: Tumor/ and segment identification, cholangiography, and angiography

Does Indocyanine Green Cholangiography Identify Critical View of Safety Earlier in Laparoscopic Cholecystectomy ? Results from a Randomised Control Study in University Malaya Medical Centre

Introduction: Indocyanine green (ICG) cholangiography helps identify biliary structures during laparoscopic cholecystectomy (LC). Our study aims to determine if ICG cholangiography assisted LC (ICG –LC) could reach critical view of safety (CVS) earlier compared to conventional white light LC. Method: Patients were randomly grouped into ICG-LC and LC. ICG was administered intravenously to patients preoperatively in the ICG-LC group. Laparoscopic fluorescence imaging system was used during dissection of Calot’s triangle in this group. Duration of time from gallbladder retraction until identification of CVS for each group was measured. All surgeries were performed by the same surgeon and the intraoperative difficulty was rated arbitrarily from level 1 being least difficult to level 4 being most difficult. The data was compared and analysed. Result: Fifty two patients were randomised, 24 patients in ICG-LC and 28 in LC group. There was no significant difference in the median time to identification of CVS in the overall analysis, which was 22 minutes in ICG-LC group and 18 minutes in LC group (p value 0.556). In the subgroup analysis, both ICG-LC and LC group recorded a median time of 13 minutes to reach CVS in level 1 difficulty cholecystectomy, while level 2 was 21 minutes in the ICG- LC group compared to 17 minutes in the LC group (p value 0.662). In level 3, ICG-LC took 41 minutes compared to 38 minutes in LC (p value 0.346). Median time for ICG-LC was faster for Level 4 where it took 48 minutes compared to 54.5 minutes in LC (p value 0.221). No major adverse events were recorded. Conclusion: Use of ICG does not shorten duration of CVS identification. The longer duration taken with ICG could be attributed to more careful dissection from aided visualised anatomy. ICG may be useful to identify CVS earlier for difficult gallbladders but further study is needed.

Near-infrared fluorescence laparoscopy of the cystic duct and cystic artery: first experience with two new preclinical dyes in a pig model

BackgroundImaging techniques that enhance visualisation of the anatomy may help prevent bile duct injury. Near-Infrared Fluorescence Imaging is such a technique. Previous experiments with ICG have shown that illumination of the extra-hepatic bile ducts is feasible. Yet, there is room for improvement in the visualisation of the target as compared to the background. Experiments with IRDye® 800CW show promising results. However, this dye is too expensive for routine clinical use. The aim of this study is to test the first applicability of two newly developed preclinical dyes regarding intraoperative imaging of the cystic duct and cystic artery, compared with IRDye® 800CW.MethodsLaparoscopic cholecystectomy was performed in three pigs, using a laparoscopic fluorescence imaging system. Each pig received 6 mg of one of the fluorescent dyes (1 mg/mL; IRDye® 800CW, IRDye® 800BK or IRDye® 800NOS) by intravenous injection. Intraoperative recognition of the biliary system and cystic artery was registered at set time points. All procedures were digitally recorded, and the target to background ratio (TBR) was determined to assess the fluorescence signal.ResultsWith all three fluorescent dyes, the cystic artery was directly visualised. For the visualisation of the cystic duct, 15, 34 and 30 min were needed using IRDye® 800BK, IRDye® 800NOS and IRDye® 800CW, respectively. The maximum TBR of the cystic duct was the highest with IRDye® 800NOS (4.20) after 36 min, compared to 2.45 for IRDye® 800BK and 2.15 for IRDye® 800CW, both after 45 min. There were no adverse events.ConclusionIRDye® 800BK and IRDye® 800NOS seem to be good alternatives for IRDye® 800CW for the visualisation of the cystic duct and cystic artery in pigs.

Application of Fluorescent Cholangiography for Determination of the Resection Line During a Single-Incision Laparoscopic Cholecystectomy for a Benign Lesion of the Cystic Duct: Preliminary Experience.

To avoid bile leakage from the stump of a cystic duct that is closed at edematous and/or involved areas, the decision regarding the location of the resection line during a laparoscopic cholecystectomy for benign lesions extending into the cystic duct is important and requires technical ingenuity. For these situations, we used fluorescent cholangiography. Our procedure for single-incision laparoscopic cholecystectomy utilized the SILS-Port, and an additional pair of 5-mm forceps was inserted via an umbilical incision. As a fluorescence source, 1 mL of indocyanine green was intravenously injected after endotracheal intubation of patients in the operating room. A laparoscopic fluorescence imaging system developed by Karl Storz Endoskope was utilized for fluorescent cholangiography. Fluorescent cholangiography could be used to identify the border of the lesion in the cystic duct. According to the fluorescent cholangiography results, a location for the resection line of the cystic duct could be identified; therefore, the planned resection was successful and produced a histologically negative margin. Application of fluorescent cholangiography in the determination of the location of the resection line location during a laparoscopic cholecystectomy for benign lesions of the cystic duct should be widely accepted.

子宮頸癌手術におけるインドシアニングリーンを用いた蛍光色素による腹腔鏡下センチネルリンパ節同定法

Objective: Radical hysterectomy with pelvic lymphadenectomy is standard therapy for cervical cancer. The standard surgical lymph node assessment is a systematic lymphadenectomy, but the procedure is associated with lymphedema and lymphocysts. A sentinel lymph node (SLN) is the first node draining the lymphatic flow from a primary tumor. If the SLN is negative for metastasis, nodes after the SLN are also considered to be negative. We report our experience using a new laparoscopic fluorescence imaging system with indocyanine green (ICG) for SLN detection with cervical cancer.Methods: Participants included 12 patients treated from April 2014 to April 2015. Median age was 41.8 years (range, 27-56years) and median body mass index was 20.2 kg/m2 (range, 15-31 years). Patients underwent SLN mapping by intracervical injection of ICG at 3 and 9 o'clock positions. Following SLN mapping, radical hysterectomy and pelvic lymphadenectomy was performed. Result: Median SLN count was 2.8 (range, 1-7). The overall and bilateral detection rate was 100% (12/12) and 83% (10/12), respectively. Positive SLNs were identified in 2 of 12 patients (16%). SLNs were identifided in the external iliac, internal iliac, obturator and common iliac regions and sensitivity, specificity and NPV were all 100%. Conclusions: Fluorescence imaging using ICG is a feasible and safe method for SLN detection. In the future, this technique may represent a useful treatment for patients with early cervical cancer.

Optimisation of Fluorescence Guidance During Robot-assisted Laparoscopic Sentinel Node Biopsy for Prostate Cancer

BackgroundThe hybrid tracer was introduced to complement intraoperative radiotracing towards the sentinel nodes (SNs) with fluorescence guidance. ObjectiveImprove in vivo fluorescence-based SN identification for prostate cancer by optimising hybrid tracer preparation, injection technique, and fluorescence imaging hardware. Design, setting, and participantsForty patients with a Briganti nomogram–based risk >10% of lymph node (LN) metastases were included. After intraprostatic tracer injection, SN mapping was performed (lymphoscintigraphy and single-photon emission computed tomography with computed tomography (SPECT-CT)). In groups 1 and 2, SNs were pursued intraoperatively using a laparoscopic gamma probe followed by fluorescence imaging (FI). In group 3, SNs were initially located via FI. Compared with group 1, in groups 2 and 3, a new tracer formulation was introduced that had a reduced total injected volume (2.0ml vs 3.2ml) but increased particle concentration. For groups 1 and 2, the Tricam SLII with D-Light C laparoscopic FI (LFI) system was used. In group 3, the LFI system was upgraded to an Image 1 HUB HD with D-Light P system. InterventionHybrid tracer-based SN biopsy, extended pelvic lymph node dissection, and robot-assisted radical prostatectomy. Outcome measurements and statistical analysisNumber and location of the preoperatively identified SNs, in vivo fluorescence-based SN identification rate, tumour status of SNs and LNs, postoperative complications, and biochemical recurrence (BCR). Results and limitationsMean fluorescence-based SN identification improved from 63.7% (group 1) to 85.2% and 93.5% for groups 2 and 3, respectively (p=0.012). No differences in postoperative complications were found. BCR occurred in three pN0 patients. ConclusionsStepwise optimisation of the hybrid tracer formulation and the LFI system led to a significant improvement in fluorescence-assisted SN identification. Preoperative SPECT-CT remained essential for guiding intraoperative SN localisation. Patient summaryIntraoperative fluorescence-based SN visualisation can be improved by enhancing the hybrid tracer formulation and laparoscopic fluorescence imaging system.

Near-infrared fluorescence laparoscopy of the cystic duct and artery in pigs: performance of a preclinical dye.

Near-infrared fluorescence laparoscopy after intravenous indocyanine green (ICG) administration has been proposed as a promising surgical imaging technique for real-time visualization of the extrahepatic bile ducts and arteries in clinical laparoscopic cholecystectomies. However, optimization of this new technique with respect to the imaging system combined with the fluorophore is desirable. The performance of a preclinical near-infrared dye, CW800-CA, was compared with that of ICG for near-infrared fluorescence laparoscopy of the cystic duct and artery in pigs. Laparoscopic cholecystectomy was performed in six pigs (average weight, 35 kg) using a commercially available laparoscopic fluorescence imaging system. The fluorophores CW800-CA and ICG (both 800 nm fluorescent dyes) were administered by intravenous injection in four and two pigs, respectively. CW800-CA was administered in three different doses (consecutively 0.25, 1, and 3 mg); ICG was intravenously injected (2.5 mg) for comparison. Intraoperative recognition of the biliary structures was recorded at set time points. The target-to-background ratio was determined to quantify the fluorescence signal of the designated tissues. A clinically proven dose of 2.5 mg of ICG resulted in a successful fluorescence delineation of both the cystic duct and artery. In the CW800-CA-injected pigs a clear visualization of the cystic duct and artery was obtained after administration of 3 mg of CW800-CA. Time from injection until fluorescence identification of the cystic duct was reduced when CW800-CA was used compared with ICG (11.5 minutes versus 21.5 minutes, respectively). CW800-CA provided clearer illumination of the cystic artery, in terms of target-to-background ratio. As well as ICG, CW800-CA can be applied for fluorescence identification of the cystic artery and duct using a commercially available laparoscopic fluorescence imaging system. Fluorescence cholangiography of the cystic duct can be obtained earlier after intravenous injection of CW800-CA, compared with ICG. These findings increase the possibilities of use and of optimization of this imaging technique.

Application of a New Dye for Near-Infrared Fluorescence Laparoscopy of the Ureters

Ureteral injury during laparoscopic colorectal surgery is a rare but serious complication with a reported incidence rate of 0.66%. The early detection and prevention of ureteral injury is clinically relevant and important. The successful use of preclinical near-infrared fluorophore CW800-CA for real-time intraoperative identification of the anatomical course of the ureters with the use of a laparoscopic fluorescence imaging system is reported. The usefulness of this new imaging technique was explored in two 35-kg pigs. Intravenous CW800-CA was administered 10 minutes before fluorescence imaging was conducted with the use of a commercially available laparoscopic fluorescence imaging system. A dose of 1 mg/mL CW800-CA (bolus injection of 3 mL) provided clear delineation of the course of both ureters by using the fluorescence mode of the laparoscope. There were no adverse reactions to the injected dye. Near-infrared fluorescence laparoscopy of the ureters, following intravenous CW800-CA administration, is easily applicable and provides real-time identification of the course of the ureters.

Visualization of subcapsular hepatic malignancy by indocyanine-green fluorescence imaging during laparoscopic hepatectomy

Although laparoscopic hepatectomy has increasingly been used to treat cancers in the liver, the accuracy of intraoperative diagnosis may be inferior to that of open surgery because the ability to visualize and palpate the liver surface during laparoscopy is relatively limited. Fluorescence imaging has the potential to provide a simple compensatory diagnostic tool for identification of cancers in the liver during laparoscopic hepatectomy. In 17 patients who were to undergo laparoscopic hepatectomy, 0.5 mg/kg body weight of indocyanine green (ICG) was administered intravenously within the 2 weeks prior to surgery. Intraoperatively, a laparoscopic fluorescence imaging system obtained fluorescence images of its surfaces during mobilization of the liver. In all, 16 hepatocellular carcinomas (HCCs) and 16 liver metastases (LMs) were resected. Of these, laparoscopic ICG fluorescence imaging identified 12 HCCs (75%) and 11 LMs (69%) on the liver surfaces distributed over Couinaud's segments 1-8, including the 17 tumors that had not been identified by visual inspections of normal color images. The 23 tumors that were identified by fluorescence imaging were located closer to the liver surfaces than another nine tumors that were not identified by fluorescence imaging (median [range] depth 1 [0-5] vs. 11 [8-30] mm; p < 0.001). Like palpation during open hepatectomy, laparoscopic ICG fluorescence imaging enables real-time identification of subcapsular liver cancers, thus facilitating estimation of the required extent of hepatic mobilization and determination of the location of an appropriate hepatic transection line.

Optimization of near-infrared fluorescence cholangiography for open and laparoscopic surgery

During laparoscopic cholecystectomy, common bile duct (CBD) injury is a rare but severe complication. To reduce the risk of injury, near-infrared (NIR) fluorescent cholangiography using indocyanine green (ICG) has recently been introduced as a novel method of visualizing the biliary system during surgery. To date, several studies have shown feasibility of this technique; however, liver background fluorescence remains a major problem during fluorescent cholangiography. The aim of the current study was to optimize ICG dose and timing for NIR cholangiography using a quantitative intraoperative camera system during open hepatopancreatobiliary (HPB) surgery. Subsequently, these results were validated during laparoscopic cholecystectomy using a laparoscopic fluorescence imaging system. Twenty-seven patients who underwent NIR imaging using the Mini-FLARE image-guided surgery system during open HPB surgery were analyzed to assess optimal dosage and timing of ICG administration. ICG was intravenously injected preoperatively at doses of 5, 10, and 20 mg, and imaged at either 30 min (early) or 24 h (delayed) post-injection. Next, the optimal doses found for early and delayed imaging were applied to two groups of seven patients (n = 14) undergoing laparoscopic NIR fluorescent cholangiography during laparoscopic cholecystectomy. Median liver-to-background contrast was 23.5 (range 22.1–35.0), 16.8 (range 11.3–25.1), 1.3 (range 0.7–7.8), and 2.5 (range 1.3–3.6) for 5 mg/30 min, 10 mg/30 min, 10 mg/24 h, and 20 mg/24 h, respectively. Fluorescence intensity of the liver was significantly lower in the 10 mg delayed-imaging dose group compared with the early imaging 5 and 10 mg dose groups (p = 0.001), which resulted in a significant increase in CBD-to-liver contrast ratio compared with the early administration groups (p < 0.002). These findings were qualitatively confirmed during laparoscopic cholecystectomy. This study shows that a prolonged interval between ICG administration and surgery permits optimal NIR cholangiography with minimal liver background fluorescence.

Visualisation of the Lymph Node Pathway in Real Time by Laparoscopic Radioisotope- and Fluorescence-guided Sentinel Lymph Node Dissection in Prostate Cancer Staging

To investigate the feasibility of visualizing lymphatic drainage of the prostate using indocyanine green. The results were compared with standard radio-guided sentinel lymph node dissection and validated by extended pelvic lymph node dissection. From March 2010 to October 2011, (99m)Tc-labelled colloid (18 hours before surgery) and indocyanine green (immediately before surgery) were injected transrectally into the prostate of 26 consecutive patients. A dedicated laparoscopic fluorescence imaging system and a commercially available laparoscopic γ-probe were used. Lymphatic vessels were visualized in real time and followed to identify the sentinel lymph node. All detected hot spots (fluorescent signals and/or radioactivity) were considered as sentinel lymph nodes, dissected, and removed. Each specimen of excised tissue was labeled according to its anatomic position and whether it was positive for radioactivity or fluorescence. Every patient underwent laparoscopic extended pelvic lymph node dissection and radical prostatectomy. Five-hundred eighty-two lymph nodes (median 22, range 11-36) were removed. Two characteristic drainage patterns were identified: one was associated with the medial umbilical ligament and the other with the internal iliac region. A direct connection with para-aortic lymph nodes was found in 3 patients. A single solitary micrometastasis was visualized by fluorescence navigation alone. A strong correlation was established between radioactive and fluorescent lymph nodes. Compared with radio-guided sentinel lymph node dissection alone, additional fluorescence-guided sentinel lymph node dissection demonstrated a further 120 lymph nodes. Using the described technique of fluorescence navigation, not only lymph nodes but also lymphatic vessels are visualized in real time. The technique appears to be as effective as sentinel lymph node dissection but easier to apply.