Use of fluorescence imaging and indocyanine green during laparoscopic cholecystectomy: Results of an international Delphi survey.

BACKGROUND: Published empirical data have increasingly suggested that using near-infrared fluorescence cholangiography during laparoscopic cholecystectomy markedly increases biliary anatomy visualization. The technology is rapidly evolving, and different equipment and doses may be used. We aimed to identify areas of consensus and nonconsensus in the use of incisionless near-infrared fluorescent cholangiography during laparoscopic cholecystectomy. METHODS: A 2-round Delphi survey was conducted among 28 international experts in minimally invasive surgery and near-infrared fluorescent cholangiography in 2020, during which respondents voted on 62 statements on patient preparation and contraindications (n = 12); on indocyanine green administration (n = 14); on potential advantages and uses of near-infrared fluorescent cholangiography (n = 18); comparing near-infrared fluorescent cholangiography with intraoperative x-ray cholangiography (n = 7); and on potential disadvantages of and required training for near-infrared fluorescent cholangiography (n = 11). RESULTS: Expert consensus strongly supports near-infrared fluorescent cholangiography superiority over white light for the visualization of biliary structures and reduction of laparoscopic cholecystectomy risks. It also offers other advantages like enhancing anatomic visualization in obese patients and those with moderate to severe inflammation. Regarding indocyanine green administration, consensus was reached that dosing should be on a milligrams/kilogram basis, rather than as an absolute dose, and that doses >0.05 mg/kg are necessary. Although there is no consensus on the optimum preoperative timing of indocyanine green injections, the majority of participants consider it important to administer indocyanine green at least 45 minutes before the procedure to decrease the light intensity of the liver. CONCLUSION: Near-infrared fluorescent cholangiography experts strongly agree on its effectiveness and safety during laparoscopic cholecystectomy and that it should be used routinely, but further research is necessary to establish optimum timing and doses for indocyanine green.

Consensus Conference Statement on the General Use of Near-infrared Fluorescence Imaging and Indocyanine Green Guided Surgery: Results of a Modified Delphi Study.

BACKGROUND: In recent decades, the use of near-infrared light and fluorescence-guidance during open and laparoscopic surgery has exponentially expanded across various clinical settings. However, tremendous variability exists in how it is performed. OBJECTIVE: In this first published survey of international experts on fluorescence-guided surgery, we sought to identify areas of consensus and nonconsensus across 4 areas of practice: fundamentals; patient selection/preparation; technical aspects; and effectiveness and safety. METHODS: A Delphi survey was conducted among 19 international experts in fluorescence-guided surgery attending a 1-day consensus meeting in Frankfurt, Germany on September 8th, 2019. Using mobile phones, experts were asked to anonymously vote over 2 rounds of voting, with 70% and 80% set as a priori thresholds for consensus and vote robustness, respectively. RESULTS: Experts from 5 continents reached consensus on 41 of 44 statements, including strong consensus that near-infrared fluorescence-guided surgery is both effective and safe across a broad variety of clinical settings, including the localization of critical anatomical structures like vessels, detection of tumors and sentinel nodes, assessment of tissue perfusion and anastomotic leaks, delineation of segmented organs, and localization of parathyroid glands. Although the minimum and maximum safe effective dose of ICG were felt to be 1 to 2 mg and >10 mg, respectively, there was strong consensus that determining the optimum dose, concentration, route and timing of ICG administration should be an ongoing research focus. CONCLUSIONS: Although fluorescence imaging was almost unanimously perceived to be both effective and safe across a broad range of clinical settings, considerable further research remains necessary to optimize its use.

Nerve autofluorescence in near-ultraviolet light markedly enhances nerve visualization in vivo.

BACKGROUND: During surgery, surgeons must accurately localize nerves to avoid injuring them. Recently, we have discovered that nerves fluoresce in near-ultraviolet light (NUV) light. The aims of the current study were to determine the extent to which nerves fluoresce more brightly than background and vascular structures in NUV light, and identify the NUV intensity at which nerves are most distinguishable from other tissues. METHODS: We exposed sciatic nerves within the posterior thigh in five 250-300 gm Wistar rats, then observed them at four different NUV intensity levels: 20%, 35%, 50%, and 100%. Brightness of fluorescence was measured by fluorescence spectroscopy, quantified as a fluorescence score using Image-J software, and statistically compared between nerves, background, and both an artery and vein by unpaired Student's t tests with Bonferroni adjustment to accommodate multiple comparisons. Sensitivity, specificity, and accuracy were calculated for each NUV intensity. RESULTS: At 20, 35, 50, and 100% NUV intensity, fluorescence scores for nerves versus background tissues were 117.4 versus 40.0, 225.8 versus 88.0, 250.6 versus 121.4, and 252.8 versus 169.4, respectively (all p < 0.001). Fluorescence scores plateaued at 50% NUV intensity for nerves, but continued to rise for background. At 35%, 50%, and 100% NUV intensity, a fluorescence score of 200 was 100% sensitive, specific, and accurate identifying nerves. At 100 NUV intensity, artery and vein scores were 61.8 and 60.0, both dramatically lower than for nerves (p < 0.001). CONCLUSIONS: At all NUV intensities ≥ 35%, a fluorescence score of 200 is 100% accurate distinguishing nerves from other anatomical structures in vivo.

Randomized Trial of Near-infrared Incisionless Fluorescent Cholangiography.

BACKGROUND: Incisionless near-infrared fluorescent cholangiography (NIFC) is emerging as a promising tool to enhance the visualization of extrahepatic biliary structures during laparoscopic cholecystectomies. METHODS: We conducted a single-blind, randomized, 2-arm trial comparing the efficacy of NIFC (n = 321) versus white light (WL) alone (n = 318) during laparoscopic cholecystectomy. Using the KARL STORZ Image1 S imaging system with OPAL1 technology for NIR/ICG imaging, we evaluated the detection rate for 7 biliary structures-cystic duct (CD), right hepatic duct (RHD), common hepatic duct, common bile duct, cystic common bile duct junction, cystic gallbladder junction (CGJ), and accessory ducts -before and after surgical dissection. Secondary calculations included multivariable analysis for predictors of structure visualization and comparing intergroup biliary duct injury rates. RESULTS: Predissection detection rates were significantly superior in the NIFC group for all 7 biliary structures, ranging from 9.1% versus 2.9% to 66.6% versus 36.6% for the RHD and CD, respectively, with odds ratios ranging from 2.3 (95% CI 1.6-3.2) for the CGJ to 3.6 (1.6-9.3) for the RHD. After dissection, similar intergroup differences were observed for all structures except CD and CGJ, for which no differences were observed. Significant odds ratios ranged from 2.4 (1.7-3.5) for the common hepatic duct to 3.3 (1.3-10.4) for accessory ducts. Increased body mass index was associated with reduced detection of most structures in both groups, especially before dissection. Only 2 patients, both in the WL group, sustained a biliary duct injury. CONCLUSIONS: In a randomized controlled trial, NIFC was statistically superior to WL alone visualizing extrahepatic biliary structures during laparoscopic cholecystectomy. REGISTRATION NUMBER: NCT02702843.

Increased identification of parathyroid glands using near infrared light during thyroid and parathyroid surgery.

BACKGROUND: Parathyroid gland (PG) identification during thyroid and parathyroid surgery is challenging. Accidental parathyroidectomy increases the rate of postoperative hypocalcaemia. Recently, autofluorescence with near infrared light (NIRL) has been described for PG visualization. The aim of this study is to analyze the increased rate of visualization of PGs with the use of NIRL compared to white light (WL). MATERIALS AND METHODS: All patients undergoing thyroid and parathyroid surgery were included in this study. PGs were identified with both NIRL and WL by experienced head and neck surgeons. The number of PGs identified with NIRL and WL were compared. The identification of PGs was correlated to age, sex, and histopathological diagnosis. RESULTS: Seventy-four patients were included in the study. The mean age was 48.4 (SD ±13.5) years old. Mean PG fluorescence intensity (47.60) was significantly higher compared to the thyroid gland (22.32) and background (9.27) (p < 0.0001). The mean number of PGs identified with NIRL and WL were 3.7 and 2.5 PG, respectively (p < 0.001). The difference in the number of PGs identified with NIRL and WL and fluorescence intensity was not related to age, sex, or histopathological diagnosis, with the exception of the diagnosis of thyroiditis, in which there was a significant increase in the number of PGs visualized with NIRL (p = 0.026). CONCLUSION: The use of NIRL for PG visualization significantly increased the number of PGs identified during thyroid and parathyroid surgery, and the differences in fluorescent intensity among PGs, thyroid glands, and background were not affected by age, sex, and histopathological diagnosis.