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BackgroundFluorescence-based enhanced reality (FLER) is a computer-based quantification method of fluorescence angiographies to evaluate bowel perfusion. The aim of this prospective trial was to assess the clinical feasibility and to correlate FLER with metabolic markers of perfusion, during colorectal resections.MethodsFLER analysis and visualization was performed in 22 patients (diverticulitis n = 17; colorectal cancer n = 5) intra- and extra-abdominally during distal and proximal resection, respectively. The fluorescence signal of indocyanine green (0.2 mg/kg) was captured using a near-infrared camera and computed to create a virtual color-coded cartography. This was overlaid onto the bowel (enhanced reality). It helped to identify regions of interest (ROIs) where samples were subsequently obtained. Resections were performed strictly guided according to clinical decision. On the surgical specimen, samplings were made at different ROIs to measure intestinal lactates (mmol/L) and mitochondria efficiency as acceptor control ratio (ACR).ResultsThe native (unquantified) fluorescent signal diffused to obvious ischemic areas during the distal appreciation. Proximally, a lower diffusion of ICG was observed. Five anastomotic complications occurred. The expected values of local capillary lactates were correlated with the measured values both proximally (3.62 ± 2.48 expected vs. 3.17 ± 2.8 actual; rho 0.89; p = 0.0006) and distally (4.5 ± 3 expected vs. 4 ± 2.5 actual; rho 0.73; p = 0.0021). FLER values correlated with ACR at the proximal site (rho 0.76; p = 0.04) and at the ischemic zone (rho 0.71; p = 0.01). In complicated cases, lactates at the proximal resection site were higher (5.8 ± 4.5) as opposed to uncomplicated cases (2.45 ± 1.5; p = 0.008). ACR was reduced proximally in complicated (1.3 ± 0.18) vs. uncomplicated cases (1.68 ± 0.3; p = 0.023).ConclusionsFLER allows to image the quantified fluorescence signal in augmented reality and provides a reproducible estimation of bowel perfusion (NCT02626091).

BackgroundClinical evaluation of the demarcation line separating ischemic from non-ischemic liver parenchyma may be challenging. Hyperspectral imaging (HSI) is a noninvasive imaging modality, which combines a camera with a spectroscope and allows quantitative imaging of tissue oxygenation. Our group developed a software to overlay HSI images onto the operative field, obtaining HSI-based enhanced reality (HYPER). The aim of the present study was to evaluate the accuracy of HYPER to identify the demarcation line after a left vascular inflow occlusion during an anatomical left hepatectomy.Materials and methodsIn the porcine model (n = 3), the left branches of the hepatic pedicle were ligated. Before and after vascular occlusion, HSI images based on tissue oxygenation (StO2), obtained through the Near-Infrared index (NIR index), were regularly acquired and superimposed onto RGB video. The demarcation line was marked on the liver surface with electrocautery according to HYPER. Local lactates were measured on blood samples from the liver surface in both ischemic and perfused segments using a strip-based device. At the same areas, confocal endomicroscopy was performed.ResultsAfter ligation, HSI demonstrated a significantly lower oxygenation (NIR index) in the left medial lobe (LML) (0.27% ± 0.21) when compared to the right medial lobe (RML) (58.60% ± 12.08; p = 0.0015). Capillary lactates were significantly higher (3.07 mmol/L ± 0.84 vs. 1.33 ± 0.71 mmol/L; p = 0.0356) in the LML versus RML, respectively. Concordantly, confocal videos demonstrated the absence of blood flow in the LML and normal perfusion in the RML.ConclusionsHYPER has made it possible to correctly identify the demarcation line and quantify surface liver oxygenation. HYPER could be an intraoperative tool to guide perfusion-based demarcation line assessment and segmentation.

IntroductionNear-infrared fluorescence cholangiography (NIRF-C) is a popular application of fluorescence image-guided surgery (FIGS). NIRF-C requires near-infrared optimized laparoscopes and the injection of a fluorophore, most frequently Indocyanine Green (ICG), to highlight the biliary anatomy. It is investigated as a tool to increase safety during cholecystectomy. The European registry on FIGS (EURO-FIGS: www.euro-figs.eu) aims to obtain a snapshot of the current practices of FIGS across Europe. Data on NIRF-C are presented.MethodsEURO-FIGS is a secured online database which collects anonymized data on surgical procedures performed using FIGS. Data collected for NIRF-C include gender, age, Body Mass Index (BMI), pathology, NIR device, ICG dose, ICG timing of administration before intraoperative visualization, visualization (Y/N) of biliary structures such as the cystic duct (CD), the common bile duct (CBD), the CD-CBD junction, the common hepatic duct (CHD), Visualization scores, adverse reactions to ICG, operative time, and surgical complications.ResultsFifteen surgeons (12 European surgical centers) uploaded 314 cases of NIRF-C during cholecystectomy (cholelithiasis n = 249, cholecystitis n = 58, polyps n = 7), using 4 different NIR devices. ICG doses (mg/kg) varied largely (mean 0.28 ± 0.17, median 0.3, range: 0.02–0.62). Similarly, injection-to-visualization timing (minutes) varied largely (mean 217 ± 357; median 57), ranging from 1 min (direct intragallbladder injection in 2 cases) to 3120 min (n = 2 cases). Visualization scores before dissection were significantly correlated, at univariate analysis, with ICG timing (all structures), ICG dose (CD-CBD), device (CD and CD-CBD), surgeon (CD and CD-CBD), and pathology (CD and CD-CBD). BMI was not correlated. At multivariate analysis, pathology and timing remained significant factors affecting the visualization scores of all three structures, whereas ICG dose remained correlated with HD visualization only.ConclusionsThe EURO-FIGS registry has confirmed a wide disparity in ICG dose and timing in NIRF-C. EURO-FIGS can represent a valuable tool to promote and monitor FIGS-related educational and consensus activities in Europe.

Background Modern chemotherapy achieves the shrinking of colorectal cancer liver metastases (CRLM) to such extent that they may disappear from radiological imaging. Disappearing CRLM rarely represents a complete pathological remission and have an important risk of recurrence. Augmented reality (AR) consists in the fusion of real-time patient images with a computer-generated 3D virtual patient model created from pre-operative medical imaging. The aim of this prospective pilot study is to investigate the potential of AR navigation as a tool to help locate and surgically resect missing CRLM. Methods A 3D virtual anatomical model was created from thoracoabdominal CT-scans using customary software (VR RENDER ® , IRCAD). The virtual model was superimposed to the operative field using an Exoscope (VITOM ® , Karl Storz, Tüttlingen, Germany). Virtual and real images were manually registered in real-time using a video mixer, based on external anatomical landmarks with an estimated accuracy of 5 mm. This modality was tested in three patients, with four missing CRLM that had sizes from 12 to 24 mm, undergoing laparotomy after receiving pre-operative oxaliplatin-based chemotherapy. Results AR display and fine registration was performed within 6 min. AR helped detect all four missing CRLM, and guided their resection. In all cases the planned security margin of 1 cm was clear and resections were confirmed to be R0 by pathology. There was no postoperative major morbidity or mortality. No local recurrence occurred in the follow-up period of 6–22 months. Conclusions This initial experience suggests that AR may be a helpful navigation tool for the resection of missing CRLM.

Telesurgery, a cutting-edge field at the intersection of medicine and technology, holds immense promise for enhancing surgical capabilities, extending medical care, and improving patient outcomes. In this scenario, this article explores the landscape of technical and ethical considerations that highlight the advancement and adoption of telesurgery. Network considerations are crucial for ensuring seamless and low-latency communication between remote surgeons and robotic systems, while technical challenges encompass system reliability, latency reduction, and the integration of emerging technologies like artificial intelligence and 5G networks. Therefore, this article also explores the critical role of network infrastructure, highlighting the necessity for low-latency, high-bandwidth, secure and private connections to ensure patient safety and surgical precision. Moreover, ethical considerations in telesurgery include patient consent, data security, and the potential for remote surgical interventions to distance surgeons from their patients. Legal and regulatory frameworks require refinement to accommodate the unique aspects of telesurgery, including liability, licensure, and reimbursement. Our article presents a comprehensive analysis of the current state of telesurgery technology and its potential while critically examining the challenges that must be navigated for its widespread adoption.

Iatrogenic ureteral injuries (IUI) occur in 0.5–1.3% of cases during abdominal surgery. If not recognized intraoperatively, IUI increase morbidity/mortality. A universally accepted method to prevent IUI is lacking. Near-infrared fluorescent imaging (NIRF), penetrating deeper than normal light within the tissue, might be useful, therefore ureter visualization combining NIRF with special dyes (i.e. IRDye 800BK) is promising. Aim of this work is to evaluate the detection of ureters using stents coated with a novel biocompatible fluorescent material (NICE: near-infrared coating of equipment), during laparoscopy. female pigs underwent placement of NICE-coated stents (NS). NIRF was performed, and fluorescence intensity (FI) was computed. Successively, 0.15 mg/kg of IRDye 800BK was administered intravenously, and FI was computed at different timepoints. Ureter visualization using NS only was further assessed in a human cadaver. Both methods allowed in vivo ureter visualization, with equal FI. However, NS were constantly visible whereas IRDye 800BK allowed visualization exclusively during the ureteral peristaltic phases. In the human cadaver, NS provided excellent ureter visualization in its natural anatomical position. NS provided continuous ureteral visualization with similar FI as the IRDye 800BK, which exclusively allowed intermittent visualization, dependent on ureteral peristalsis. NS might prove useful to visualize ureters intraoperatively, potentially preventing IUI.

BackgroundIntraoperative localization of endoluminal lesions is can be difficult during laparoscopy. Preoperative endoscopic marking is therefore necessary. Current methods include submucosal tattooing using visible dyes, which in case of transmural injection can impair surgical dissection. Tattooing using indocyanine green (ICG) coupled to intraoperative near-infrared (NIR) laparoscopy has been described. ICG is only visible under NIR-light, therefore, it doesn’t impair the surgical workflow under white light even if there is spillage. However, ICG tattoos have rapid diffusion and short longevity. We propose fluorescent over-the-scope clips (FOSC), using a novel biocompatible fluorescent paint, as durable lesion marking.MethodsIn six pigs, gastric and colonic endoscopic tattoos using 0.05 mg/mL of ICG and markings using the fluorescent OSC were performed (T0). Simultaneously, NIR laparoscopy was executed. Follow-up laparoscopies were conducted at postoperative day (POD) 4–6 (T1) and POD 11–12 (T2). During laparoscopy, fluorescence intensity was assessed. In one human cadaver, FOSC was used to mark a site on the stomach and on the sigmoid colon, respectively. Intraoperative detection during NIR laparoscopy was assessed.ResultsGastric and colonic ICG tattooing and OSC markings were easily visible using NIR laparoscopy on T0. All FOSC were visible at T1 and T2 in both stomach and colon, whereas the ICG tattooing at T1 was only visible in the stomach of 2 animals and in the colon of 3 animals. At T2, tattoos were not visible in any animal. FOSC were still visible in both stomach and colon of the human cadaver at 10 days.ConclusionEndoscopic marking using FOSC can be an efficient and durable alternative to standard methods.

BackgroundHSI is an optical technology allowing for a real-time, contrast-free snapshot of physiological tissue properties, including oxygenation. Hyperspectral imaging (HSI) has the potential to quantify the gastrointestinal perfusion intraoperatively. This experimental study evaluates the accuracy of HSI, in order to quantify bowel perfusion, and to obtain a superposition of the hyperspectral information onto real-time images.MethodsIn 6 pigs, 4 ischemic bowel loops were created (A, B, C, D) and imaged at set time points (from 5 to 360 min). A commercially available HSI system provided pseudo-color maps of the perfusion status (StO2, Near-InfraRed perfusion) and the tissue water index. An ad hoc software was developed to superimpose HSI information onto the live video, creating the HYPerspectral-based Enhanced Reality (HYPER). Seven regions of interest (ROIs) were identified in each bowel loop according to StO2 ranges, i.e., vascular (VASC proximal and distal), marginal vascular (MV proximal and distal), marginal ischemic (MI proximal and distal), and ischemic (ISCH). Local capillary lactates (LCL), reactive oxygen species (ROS), and histopathology were measured at the ROIs. A machine-learning-based prediction algorithm of LCL, based on the HSI-StO2%, was trained in the 6 pigs and tested on 5 additional animals.ResultsHSI parameters (StO2 and NIR) were congruent with LCL levels, ROS production, and histopathology damage scores at the ROIs discriminated by HYPER. The global mean error of LCL prediction was 1.18 ± 1.35 mmol/L. For StO2 values > 30%, the mean error was 0.3 ± 0.33.ConclusionsHYPER imaging could precisely quantify the overtime perfusion changes in this bowel ischemia model.

BackgroundIn laparoscopic cholecystectomy (LC), achievement of the Critical View of Safety (CVS) is commonly advocated to prevent bile duct injuries (BDI). However, BDI rates remain stable, probably due to inconsistent application or a poor understanding of CVS as well as unreliable reporting. Objective video reporting could serve for quality auditing and help generate consistent datasets for deep learning models aimed at intraoperative assistance. In this study, we develop and test a method to report CVS using videos.MethodLC videos performed at our institution were retrieved and the video segments starting 60 s prior to the division of cystic structures were edited. Two independent reviewers assessed CVS using an adaptation of the doublet view 6-point scale and a novel binary method in which each criterion is considered either achieved or not. Feasibility to assess CVS in the edited video clips and inter-rater agreements were evaluated.ResultsCVS was attempted in 78 out of the 100 LC videos retrieved. CVS was assessable in 100% of the 60-s video clips. After mediation, CVS was achieved in 32/78(41.03%). Kappa scores of inter-rater agreements using the doublet view versus the binary assessment were as follows: 0.54 versus 0.75 for CVS achievement, 0.45 versus 0.62 for the dissection of the hepatocystic triangle, 0.36 versus 0.77 for the exposure of the lower part of the cystic plate, and 0.48 versus 0.79 for the 2 structures connected to the gallbladder.ConclusionsThe present study is the first to formalize a reproducible method for objective video reporting of CVS in LC. Minute-long video clips provide information on CVS and binary assessment yields a higher inter-rater agreement than previously used methods. These results offer an easy-to-implement strategy for objective video reporting of CVS, which could be used for quality auditing, scientific communication, and development of deep learning models for intraoperative guidance.

The number of robot-assisted minimally invasive surgeries is increasing annually, together with the need for dedicated and effective training. Surgeons need to learn how to address the novel control modalities of surgical instruments and the loss of haptic feedback, which is a common feature of most surgical robots. High-fidelity physical simulation has proved to be a valid training tool, and it might help in fulfilling these learning needs. In this regard, a high-fidelity sensorized simulator of vascular structures was designed, fabricated and preliminarily validated. The main objective of the simulator is to train novices in robotic surgery to correctly perform vascular resection procedures without applying excessive strain to tissues. The vessel simulator was integrated with soft strain sensors to quantify and objectively assess manipulation skills and to provide real-time feedback to the trainee during a training session. Additionally, a portable and user-friendly training task board was produced to replicate anatomical constraints. The simulator was characterized in terms of its mechanical properties, demonstrating its realism with respect to human tissues. Its face, content and construct validity, together with its usability, were assessed by implementing a training scenario with 13 clinicians, and the results were generally positive.