Ultrasound-guided robotic surgical procedures: a systematic review

INTRODUCTION

Ultrasound has been nicknamed "the surgeon's stethoscope". The advantages of laparoscopic ultrasound beyond a substitute for the sense of touch are considerable, especially for robotic surgery. Being able to see through parenchyma and into vascular structures enables to avoid unnecessary dissection by providing a thorough assessment at every stage without the need for contrast media or ionising radiation. The limitations of restricted angulation and access within the abdominal cavity during laparoscopy can be overcome by robotic handling of miniaturised ultrasound probes and the use of various and specific frequencies will meet tissue- and organ-specific characteristics. The aim of this systematic review was to assess the reported applications of intraoperative ultrasound-guided robotic surgery and to outline future perspectives.

METHODS

The study adhered to the PRISMA guidelines. PubMed, Google Scholar, ScienceDirect and ClinicalTrials.gov were searched up to October 2023. Manuscripts reporting data on ultrasound-guided robotic procedures were included in the qualitative analysis.

RESULTS

20 studies met the inclusion criteria. The majority (53%) were related to the field of general surgery during liver, pancreas, spleen, gallbladder/bile duct, vascular and rectal surgery. This was followed by other fields of oncological surgery (42%) including urology, lung surgery, and retroperitoneal lymphadenectomy for metastases. Among the studies, ten (53%) focused on locating tumoral lesions and defining resection margins, four (15%) were designed to test the feasibility of robotic ultrasound-guided surgery, while two (10.5%) aimed to compare robotic and laparoscopic ultrasound probes. Additionally two studies (10.5%) evaluated the robotic drop-in probe one (5%) assessed the hepatic tissue consistency and another one (5%) aimed to visualize the blood flow in the splenic artery.

CONCLUSION

The advantages of robotic instrumentation, including ergonomics, dexterity, and precision of movements, are of relevance for robotic intraoperative ultrasound (RIOUS). The present systematic review demonstrates the virtue of RIOUS to support surgeons and potentially reduce minimally invasive procedure times.

Combining preoperative C-reactive protein values with the Tokyo Guidelines 2018 grading criteria can enhance the prediction of surgical difficulty in early laparoscopic cholecystectomy for acute cholecystitis

BACKGROUND

Early laparoscopic cholecystectomy (ELC) is the standard treatment for acute cholecystitis (AC). However, predicting the difficulty of this procedure remains challenging. The present study aimed to develop an improved prediction model for surgical difficulty during ELC, surpassing the current Tokyo Guidelines 2018 (TG18) grading system.

METHODS

We analyzed data from 201 consecutive patients who underwent ELC for AC between 2019 and 2021. Surgical difficulty was defined as the failure to achieve the critical view of safety (non-CVS). We developed a scoring system by conducting multivariate analysis on demographics, symptoms, laboratory data, and radiographic findings. The predictive accuracy of our scoring system was compared to that of the TG18 grading system (Grade I vs. Grade II/III).

RESULTS

Through multivariate logistic regression analysis, a novel scoring system was formulated. This system incorporated preoperative C-reactive protein (CRP) values (≥5: 1 pt, ≥10: 2 pts, ≥15: 3 pts) and TG18 grading score (duration >72 h: 1 pt, image criteria for Grade II AC: 1 pt). Our model, a cutoff score of ≥3, exhibited a significantly elevated area under the curve (AUC) of 0.721 compared to the TG18 grading system alone (AUC 0.609) (p = 0.001).

CONCLUSION

Combining preoperative CRP values with TG18 grading criteria can enhance the accuracy of predicting intraoperative difficulty in ELC for AC.

Design and preliminary validation of a high-fidelity vascular simulator for robot-assisted manipulation

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.

Technical and ethical considerations in telesurgery

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.

Machine learning models to predict success of endoscopic sleeve gastroplasty using total and excess weight loss percent achievement: a multicentre study

BACKGROUND

The large amount of heterogeneous data collected in surgical/endoscopic practice calls for data-driven approaches as machine learning (ML) models. The aim of this study was to develop ML models to predict endoscopic sleeve gastroplasty (ESG) efficacy at 12 months defined by total weight loss (TWL) % and excess weight loss (EWL) % achievement. Multicentre data were used to enhance generalizability: evaluate consistency among different center of ESG practice and assess reproducibility of the models and possible clinical application. Models were designed to be dynamic and integrate follow-up clinical data into more accurate predictions, possibly assisting management and decision-making.

METHODS

ML models were developed using data of 404 ESG procedures performed at 12 centers across Europe. Collected data included clinical and demographic variables at the time of ESG and at follow-up. Multicentre/external and single center/internal and temporal validation were performed. Training and evaluation of the models were performed on Python's scikit-learn library. Performance of models was quantified as receiver operator curve (ROC-AUC), sensitivity, specificity, and calibration plots.

RESULTS

Multicenter external validation: ML models using preoperative data show poor performance. Best performances were reached by linear regression (LR) and support vector machine models for TWL% and EWL%, respectively, (ROC-AUC: TWL% 0.87, EWL% 0.86) with the addition of 6-month follow-up data. Single-center internal validation: Preoperative data only ML models show suboptimal performance. Early, i.e., 3-month follow-up data addition lead to ROC-AUC of 0.79 (random forest classifiers model) and 0.81 (LR models) for TWL% and EWL% achievement prediction, respectively. Single-center temporal validation shows similar results.

CONCLUSIONS

Although preoperative data only may not be sufficient for accurate postoperative predictions, the ability of ML models to adapt and evolve with the patients changes could assist in providing an effective and personalized postoperative care. ML models predictive capacity improvement with follow-up data is encouraging and may become a valuable support in patient management and decision-making.

Initial experience of robotically assisted endometriosis surgery with a novel robotic system: first case series in a tertiary care center

Endometriosis is a benign disease requiring surgery if medical treatment can not achieve symptom control. Laparoscopy remains the gold standard and robotic assistance can be beneficial in complex cases. Robot-assisted radical endometriosis excision using the Hugo™ RAS system is a novel approach. The aim of this study is to describe its setting and outcomes in a series of patients in a robotic surgery center. Endometriosis patients who consecutively underwent robot-assisted surgery with the Hugo™ RAS system (Medtronic, USA) were retrospectively enrolled. Disease-specific symptoms before and after surgery, endometriosis stage, as well as perioperative and intraoperative variables including system setup were collected. Early post-operative complications (< 30 days) and follow-up (up to 3 months) were reported. All procedures were completed robotically. Port placement followed the "bridge" configuration with a "compact" docking. The median operative time was 186.5 min (IQR 174-220), the median estimated blood loss 50 ml (IQR 0-100). An intraoperative complication occurred in one patient (6.6%), a bladder laceration with postoperative antibiotic treatment. The median lenght of hospital stay (LOS) was 3 days (IQR 3-4). Surgery achieved a statistically significant decrease in symptoms: mean dysmenorrhea (9.50 ± 0.83 versus 1.7 ± 2.26; p = 0.001), dyschezia (4.27 ± 3.61 versus 2.40 ± 2.92; p = 0.026), dysuria (2.73 ± 3.39 versus 1.87 ± 2.41; p = 0.358), dyspareunia (6.53 ± 3.15 versus 2.93 ± 2.89; p = 0.002) and chronic pelvic pain (8.8 ± 1.20 versus 3.20 ± 2.39; p = 0.001). The integration of this platform in the described configuration was safe with regular perioperative outcomes and significant improvement in symptoms. Prospective comparative studies with a larger cohort and longer follow-up are needed to assess potential advantages over the current gold standard.

Weakly Supervised Temporal Convolutional Networks for Fine-Grained Surgical Activity Recognition

Automatic recognition of fine-grained surgical activities, called steps, is a challenging but crucial task for intelligent intra-operative computer assistance. The development of current vision-based activity recognition methods relies heavily on a high volume of manually annotated data. This data is difficult and time-consuming to generate and requires domain-specific knowledge. In this work, we propose to use coarser and easier-to-annotate activity labels, namely phases, as weak supervision to learn step recognition with fewer step annotated videos. We introduce a step-phase dependency loss to exploit the weak supervision signal. We then employ a Single-Stage Temporal Convolutional Network (SS-TCN) with a ResNet-50 backbone, trained in an end-to-end fashion from weakly annotated videos, for temporal activity segmentation and recognition. We extensively evaluate and show the effectiveness of the proposed method on a large video dataset consisting of 40 laparoscopic gastric bypass procedures and the public benchmark CATARACTS containing 50 cataract surgeries.

TRandAugment: temporal random augmentation strategy for surgical activity recognition from videos

PURPOSE

Automatic recognition of surgical activities from intraoperative surgical videos is crucial for developing intelligent support systems for computer-assisted interventions. Current state-of-the-art recognition methods are based on deep learning where data augmentation has shown the potential to improve the generalization of these methods. This has spurred work on automated and simplified augmentation strategies for image classification and object detection on datasets of still images. Extending such augmentation methods to videos is not straightforward, as the temporal dimension needs to be considered. Furthermore, surgical videos pose additional challenges as they are composed of multiple, interconnected, and long-duration activities.

METHODS

This work proposes a new simplified augmentation method, called TRandAugment, specifically designed for long surgical videos, that treats each video as an assemble of temporal segments and applies consistent but random transformations to each segment. The proposed augmentation method is used to train an end-to-end spatiotemporal model consisting of a CNN (ResNet50) followed by a TCN.

RESULTS

The effectiveness of the proposed method is demonstrated on two surgical video datasets, namely Bypass40 and CATARACTS, and two tasks, surgical phase and step recognition. TRandAugment adds a performance boost of 1-6% over previous state-of-the-art methods, that uses manually designed augmentations.

CONCLUSION

This work presents a simplified and automated augmentation method for long surgical videos. The proposed method has been validated on different datasets and tasks indicating the importance of devising temporal augmentation methods for long surgical videos.

How Much Is Enough? A Surgical Perspective on Imaging Modalities to Estimate Function and Volume of the Future Liver Remnant before Hepatic Resection

Liver resection is the first curative option for most hepatic primary and secondary malignancies. However, post-hepatectomy liver failure (PHLF) still represents a non-negligible postoperative complication, embodying the most frequent cause of hepatic-related mortality. In the absence of a specific treatment, the most effective way to deal with PHLF is its prevention through a careful preoperative assessment of future liver remnant (FLR) volume and function. Apart from the clinical score and classical criteria to define the safe limit of resectability, new imaging modalities have shown their ability to assist surgeons in planning the best operative strategy with a precise estimation of the FLR amount. New technologies leading to liver and tumor 3D reconstruction may guide the surgeon along the best resection planes combining the least liver parenchymal sacrifice with oncological appropriateness. Integration with imaging modalities, such as hepatobiliary scintigraphy, capable of estimating total and regional liver function, may bring about a decrease in postoperative complications. Magnetic resonance imaging with hepatobiliary contrast seems to be predominant since it simultaneously integrates hepatic function and volume information along with a precise characterization of the target malignancy.

Near-infrared cholangiography can increase the chance of success in laparoscopic approaches to common bile duct stones, even with previous abdominal surgery

BACKGROUND

The treatment of common bile duct (CBD) stones with minimally invasive surgery (MIS) is more technical demanding than laparoscopic cholecystectomy (LC), especially in patients with history of previous abdominal surgery, cholangitis or cholecystitis. Near-infrared (NIR) cholangiography via systemic or biliary tree administration of indocyanine green (ICG), which enhances the visualization of the biliary tree anatomy, may increase the reassurance of CBD localization. The aim of this study was to identify the benefit of near-infrared cholangiography for laparoscopic common bile duct exploration (LCBDE).

METHODS

Three groups of CBD stone patients were included in this retrospective study depending on the surgical methods: 1) open choledocholithotomy (OCC), 2) laparoscopic choledocholithotomy (LCC), and 3) near-infrared cholangiography-assisted laparoscopic choledocholithotomy (NIR-CC). For the NIR-CC group, either 3 ml (concentration: 2.5 mg/mL) of ICG were intravenously administered or 10 ml (concentration: 0.125 mg/mL) of ICG were injected directly into the biliary tree. The enhancement rate of the cystic duct (CD), CBD, the upper and lower margin of the CBD were compared using white light image.

RESULTS

A total of 187 patients with a mean age of 68.3 years were included (OCC, n = 56; LCC, n = 110; NIR-CC, n = 21). The rate of previous abdominal surgery was significantly lower in the LCC group. The conversion rate was similar between the LCC and the NIR CC groups (p = 0.746). The postoperative hospital stay was significantly longer in the OCC group. No differences in morbidity and mortality were found between the three groups. In the NIR-CC group, the localization of CBD was as high as 85% compared to 24% with white light imaging.

CONCLUSIONS

Near-infrared cholangiography helps increase the chance of success in minimally invasive approaches to CBD stones even in patients with previous abdominal surgeries, without increasing the rate of conversion.

Live laparoscopic video retrieval with compressed uncertainty

Searching through large volumes of medical data to retrieve relevant information is a challenging yet crucial task for clinical care. However the primitive and most common approach to retrieval, involving text in the form of keywords, is severely limited when dealing with complex media formats. Content-based retrieval offers a way to overcome this limitation, by using rich media as the query itself. Surgical video-to-video retrieval in particular is a new and largely unexplored research problem with high clinical value, especially in the real-time case: using real-time video hashing, search can be achieved directly inside of the operating room. Indeed, the process of hashing converts large data entries into compact binary arrays or hashes, enabling large-scale search operations at a very fast rate. However, due to fluctuations over the course of a video, not all bits in a given hash are equally reliable. In this work, we propose a method capable of mitigating this uncertainty while maintaining a light computational footprint. We present superior retrieval results (3%-4% top 10 mean average precision) on a multi-task evaluation protocol for surgery, using cholecystectomy phases, bypass phases, and coming from an entirely new dataset introduced here, surgical events across six different surgery types. Success on this multi-task benchmark shows the generalizability of our approach for surgical video retrieval.

Deep sedation versus orotracheal intubation for endoscopic sleeve gastroplasty (ESG): preliminary experience

BACKGROUND

Endoscopic sleeve gastroplasty (ESG) is an emerging bariatric procedure currently performed under general anaesthesia with orotracheal intubation (OTI). Several studies have shown the feasibility of advanced endoscopic procedures under deep sedation (DS) without impacting patient outcomes or adverse event rates. Our goal was to perform an initial comparative analysis of ESG in DS with ESG under OTI.

METHODS

A prospective institutional registry was reviewed for ESG patients between 12/2016 and 1/2021. Patients were stratified into OTI or DS cohorts, and the 1st 50 cases performed in each cohort were included for comparability. Univariate analysis was performed on demographics, intraoperative, and postoperative outcomes (up to 90 days). Multivariate analyses evaluated the relationship between anesthesia type, preclinical and clinical variables.

RESULTS

Of the 50 DS patients, 21(42%) underwent primary and 29 (58%) revisional surgery. There was no significant differences in Mallampati score across groups. No DS patient required intubation. DS patients were younger (p = 0.006) and lower BMI (p = 0.002) than OTI. As expected, DS patients overall and in the primary subgroup had shorter operative time (p ≤ 0.001 and p = 0.003, respectively) and higher rates (84% DS vs. 20% OTI, p ≤ 0.001) of ambulatory procedures. There were no significant differences in the sutures used between groups (p = 0.616). DS patients required less postoperative opioids (p ≤ 0.001) and antiemetics (p = 0.006) than OTI. There were no significant differences in 3-month postoperative weight loss across cohorts. There was no rehospitalization in either group. In primary ESG cases, we found DS patients were more likely younger (p = 0.006), female (p = 0.001), and had a lower BMI (p = 0.0027).

CONCLUSIONS

ESG under DS is safe and feasible in select patients. We found DS safely increased rates of outpatient care, reduced use of opioids and antiemetics, and provided the same results of postoperative weight loss. Patient selection for DS may be more clearer for durable weight loss.

Early laparoscopic cholecystectomy for acute cholecystitis following the Tokyo Guidelines 2018: a prospective single-center study of 201 consecutive cases

BACKGROUND

Early laparoscopic cholecystectomy (ELC) for acute cholecystitis (AC) poses multiple challenges. The Tokyo Guidelines 2018 (TG18) eliminated the time limit (< 72 h) and expanded the surgical indication to severe AC. This study aimed to evaluate the clinical outcomes of ELC for AC following the TG18 in a single high-volume center.

METHODS

From 2019 to 2021, we managed all AC patients with a TG18 flowchart and prospectively enrolled those who underwent ELC within 7 days of symptom onset. The primary outcome was overall morbidity, with a comparison between mild (Grade I) and moderate/severe (Grade II/III) AC.

RESULTS

During the study period, 201 patients underwent ELC was for Grade I (56.2%), II (40.3%), and III (3.5%) ACs. Mean age was 69 ± 15.2 years and time to surgery from symptom onset was 0 (12.9%), 1-3 (66.7%), and 4-7 days (20.4%). Mean operative time and blood loss were 118.9 ± 42.7 min and 57.8 ± 99.4 mL, respectively. The critical view of safety (CVS) was achieved in 76.1% of patients, and bailout procedures were performed in 21.4%. There were no open conversions or bile duct injuries. Major morbidities (Clavien-Dindo classification ≥ IIIa) were observed in 5.5% of cases and mortality in 0.5%. Comparing Grades II/III to Grade I, operative time was longer (112.3 vs. 127.3 min, p = 0.014), blood loss was higher (40.3 vs. 80.1 mL, p = 0.005), the CVS rate was lower (83.2 vs. 67.0%, p = 0.012), and the major morbidity rate was higher (1.8 vs. 10.2%, p = 0.012). In the subgroup analysis of Grade II/III, there were no significant differences in major morbidities (p = 0.288) between the two groups (0-3 vs. 4-7 days).

CONCLUSION

ELC for AC following TG18 is feasible with low morbidity rates. However, ELC for Grade II/III ACs remains challenging, and surgeons must carefully assess intraoperative difficulties and surgical risks before proceeding.

Partial Hepatic Vein Occlusion and Venous Congestion in Liver Exploration Using a Hyperspectral Camera: A Proposal for Monitoring Intraoperative Liver Perfusion

INTRODUCTION

The changes occurring in the liver in cases of outflow deprivation have rarely been investigated, and no measurements of this phenomenon are available. This investigation explored outflow occlusion in a pig model using a hyperspectral camera.

METHODS

Six pigs were enrolled. The right hepatic vein was clamped for 30 min. The oxygen saturation (StO₂%), deoxygenated hemoglobin level (de-Hb), near-infrared perfusion (NIR), and total hemoglobin index (THI) were investigated at different time points in four perfused lobes using a hyperspectral camera measuring light absorbance between 500 nm and 995 nm. Differences among lobes at different time points were estimated by mixed-effect linear regression.

RESULTS

StO₂% decreased over time in the right lateral lobe (RLL, totally occluded) when compared to the left lateral (LLL, outflow preserved) and the right medial (RML, partially occluded) lobes (p < 0.05). De-Hb significantly increased after clamping in RLL when compared to RML and LLL (p < 0.05). RML was further analyzed considering the right portion (totally occluded) and the left portion of the lobe (with an autonomous draining vein). StO₂% decreased and de-Hb increased more smoothly when compared to the totally occluded RLL (p < 0.05).

CONCLUSIONS

The variations of StO₂% and deoxy-Hb could be considered good markers of venous liver congestion.

Simultaneous, Multi-Channel, Near-Infrared Fluorescence Visualization of Mesenteric Lymph Nodes Using Indocyanine Green and Methylene Blue: A Demonstration in a Porcine Model

Near-infrared fluorescence (NIRF) image-guided surgery is a useful tool that can help reduce perioperative complications and improve tissue recognition. Indocyanine green (ICG) dye is the most frequently used in clinical studies. ICG NIRF imaging has been used for lymph node identification. However, there are still many challenges in lymph node identification by ICG. There is increasing evidence that methylene blue (MB), another clinically applicable fluorescent dye, can also be useful in the intraoperative fluorescence-guided identification of structures and tissues. We hypothesized that MB NIRF imaging could be used for lymph node identification. The aim of this study was to evaluate the feasibility of intraoperative lymph node fluorescence detection using intravenously (IV) administered MB and compare it to ICG via a camera that has two dedicated near-infrared (NIR) channels. Three pigs were used in this study. ICG (0.2 mg/kg) was administered via a peripheral venous catheter followed by immediate administration of MB (0.25 mg/kg). NIRF images were acquired as video recordings at different time points (every 10 min) over an hour using the QUEST SPECTRUM^® 3 system (Quest Medical Imaging, Middenmeer, The Netherlands), which has two dedicated NIR channels for simultaneous intraoperative fluorescence guidance. The 800 nm channel was used to capture ICG fluorescence and the 700 nm channel was used for MB. The target (lymph nodes and small bowel) and the background (vessels-free field of the mesentery) were highlighted as the regions of interest (ROIs), and corresponding fluorescence intensities (FI) from these ROIs were measured. The target-to-background ratio (TBR) was then computed as the mean FI of the target minus the mean FI of the background divided by the mean FI of the background. In all included animals, a clear identification of lymph nodes was achieved at all time points. The mean TBR of ICG in lymph nodes and small bowel was 4.57 ± 1.00 and 4.37 ± 1.70, respectively for the overall experimental time. Regarding MB, the mean TBR in lymph nodes and small bowel was 4.60 ± 0.92 and 3.27 ± 0.62, respectively. The Mann-Whitney U test of the lymph node TBR/small bowel TBR showed that the TBR ratio of MB was statistically significantly higher than ICG. The fluorescence optical imaging technology used allows for double-wavelength assessment. This feasibility study proves that lymph nodes can be discriminated using two different fluorophores (MB and ICG) with different wavelengths. The results suggest that MB has a promising potential to be used to detect lymphatic tissue during image-guided surgery. Further preclinical trials are needed before clinical translation.

Fluorescence-based sentinel lymph node mapping and lymphography evaluation: results from the IHU-IRCAD-EAES EURO-FIGS registry

BACKGROUND

The identification of metastatic lymph nodes is one of the most important prognostic factors in gastrointestinal (GI) cancers. Near-infrared fluorescence (NIRF) imaging has been successfully used in GI tumors to detect the lymphatic pathway and the sentinel lymph node (SLN), facilitating fluorescence image-guided surgery (FIGS) with the purpose to achieve a correct nodal staging. The aim of this study was to analyze the current results of NIRF SLN navigation and lymphography through data collected in the EURO-FIGS registry.

METHODS

Prospectively collected data regarding patients and ICG-guided lymphadenectomies were analyzed. Additional analyses were performed to identify predictors of metastatic SLN and determinants of fluorescence positivity and nodal metastases outside the boundaries of standard lymphadenectomies.

RESULTS

Overall, 188 patients were included by 18 surgeons from 10 different centers. Colorectal cancer was the most reported pathology (77.7%), followed by gastric (19.1%) and esophageal tumors (3.2%). ICG was injected with higher doses (p < 0.001) via extraparietal side (63.3%), and with higher volumes (p < 0.001) via endoluminal side (36.7%). Overall, NIRF SLN navigation was positive in 75.5% of all cases and 95.5% of positive SLNs were retrieved, with a metastatic rate of 14.7%. NIRF identification of lymph nodes outside standard lymphatic stations occurred in 52.1% of all cases, 43.8% of which were positive for metastatic involvement. Positive NIRF SLN identification was an independent predictor of metastasis outside standard lymphatic stations (OR = 4.392, p = 0.029), while BMI independently predicted metastasis in retrieved SLNs (OR = 1.187, p = 0.013). Lower doses of ICG were protective against NIRF identification outside standard of care lymphadenectomy (OR = 0.596, p = 0.006), while higher volumes of ICG were predictive of metastatic involvement outside standard of care lymphadenectomy (OR = 1.597, p = 0.001).

CONCLUSIONS

SLN mapping helps identifying potentially metastatic lymph nodes outside the boundaries of standard lymphadenectomies. The EURO-FIGS registry is a valuable tool to share and analyze European surgeons' practices.

Quantification of bowel ischaemia using real-time multispectral Single Snapshot Imaging of Optical Properties (SSOP)

BACKGROUND

Single snapshot imaging of optical properties (SSOP) is a relatively new non-invasive, real-time, contrast-free optical imaging technology, which allows for the real-time quantitative assessment of physiological properties, including tissue oxygenation (StO2). This study evaluates the accuracy of multispectral SSOP in quantifying bowel ischaemia in a preclinical experimental model.

METHODS

In six pigs, an ischaemic bowel segment was created by dividing the arcade branches. Five regions of interest (ROIs) were identified on the bowel loop, as follows: ROI 1: central ischaemic; ROI 2: left marginal; ROI 3: left vascularised; ROI 4: right marginal; and ROI 5: right vascularised. The Trident imaging system, specifically developed for real-time tissue oxygenation imaging using SSOP, was used to image before (T0) and after ischaemia induction. Capillary and systemic lactates were measured at each time point (T0, T15, T30, T45, T60), as well as StO2 values acquired by means of SSOP (SSOP-StO2).

RESULTS

The mean value of SSOP-StO2 in ROI 1 was 30.08 ± 6.963 and was significantly lower when compared to marginal ROIs (ROI 2 + ROI 4: 45.67 ± 10.02 p =  < 0.0001), and to vascularised ROIs (ROI 3 + ROI 5: 48.08 ± 7.083 p =  < 0.0001). SSOP-StO2 was significantly correlated with normalised lactates r = - 0.5892 p < 0.0001 and with histology r =- 0.6251 p = 0.0002.

CONCLUSION

Multispectral SSOP allows for a contrast-free accurate assessment of small bowel perfusion identifying physiological tissue oxygenation as confirmed with perfusion biomarkers.

Hyperspectral Imaging in Major Hepatectomies: Preliminary Results from the Ex-Machyna Trial

Ischemia-reperfusion injury during major hepatic resections is associated with high rates of post-operative complications and liver failure. Real-time intra-operative detection of liver dysfunction could provide great insight into clinical outcomes. In the present study, we demonstrate the intra-operative application of a novel optical technology, hyperspectral imaging (HSI), to predict short-term post-operative outcomes after major hepatectomy. We considered fifteen consecutive patients undergoing major hepatic resection for malignant liver lesions from January 2020 to June 2021. HSI measures included tissue water index (TWI), organ hemoglobin index (OHI), tissue oxygenation (StO₂%), and near infrared (NIR). Pre-operative, intra-operative, and post-operative serum and clinical outcomes were collected. NIR values were higher in unhealthy liver tissue (p = 0.003). StO₂% negatively correlated with post-operative serum ALT values (r = -0.602), while ΔStO₂% positively correlated with ALP (r = 0.594). TWI significantly correlated with post-operative reintervention and OHI with post-operative sepsis and liver failure. In conclusion, the HSI imaging system is accurate and precise in translating from pre-clinical to human studies in this first clinical trial. HSI indices are related to serum and outcome metrics. Further experimental and clinical studies are necessary to determine clinical value of this technology.

Automatic optical biopsy for colorectal cancer using hyperspectral imaging and artificial neural networks

BACKGROUND

Intraoperative identification of cancerous tissue is fundamental during oncological surgical or endoscopic procedures. This relies on visual assessment supported by histopathological evaluation, implying a longer operative time. Hyperspectral imaging (HSI), a contrast-free and contactless imaging technology, provides spatially resolved spectroscopic analysis, with the potential to differentiate tissue at a cellular level. However, HSI produces "big data", which is impossible to directly interpret by clinicians. We hypothesize that advanced machine learning algorithms (convolutional neural networks-CNNs) can accurately detect colorectal cancer in HSI data.

METHODS

In 34 patients undergoing colorectal resections for cancer, immediately after extraction, the specimen was opened, the tumor-bearing section was exposed and imaged using HSI. Cancer and normal mucosa were categorized from histopathology. A state-of-the-art CNN was developed to automatically detect regions of colorectal cancer in a hyperspectral image. Accuracy was validated with three levels of cross-validation (twofold, fivefold, and 15-fold).

RESULTS

32 patients had colorectal adenocarcinomas confirmed by histopathology (9 left, 11 right, 4 transverse colon, and 9 rectum). 6 patients had a local initial stage (T1-2) and 26 had a local advanced stage (T3-4). The cancer detection performance of the CNN using 15-fold cross-validation showed high sensitivity and specificity (87% and 90%, respectively) and a ROC-AUC score of 0.95 (considered outstanding). In the T1-2 group, the sensitivity and specificity were 89% and 90%, respectively, and in the T3-4 group, the sensitivity and specificity were 81% and 93%, respectively.

CONCLUSIONS

Automatic colorectal cancer detection on fresh specimens using HSI, using a properly trained CNN is feasible and accurate, even with small datasets, regardless of the local tumor extension. In the near future, this approach may become a useful intraoperative tool during oncological endoscopic and surgical procedures, and may result in precise and non-destructive optical biopsies to support objective and consistent tumor-free resection margins.

Ten years of IRCAD, Barretos, SP, Brazil

Minimally invasive surgery represented a significant milestone in modern surgery; however, continuous innovation and the emergence of new technologies pose new challenges in terms of surgical learning curves since new interventions are associated with increased surgical complexity and a higher risk of complications. For this reason, surgeons are aware of the beneficial effects of "learning before doing" and the importance of safely implementing new surgical procedures in order to obtain better patient outcomes. Considered the largest Latin American training center in minimally invasive surgery, IRCAD Barretos, São Paulo, Brazil, makes it possible to acquire surgical skills through training in different and the most complex areas of medicine, providing the experience of real and simulated situations, with focus on innovation. The center possesses state-of-the-art infrastructure and technology, with a very high-level teaching staff and an affectionate and hospitable reception. Since its inauguration, in 2011, the center has already qualified numerous professionals and has placed the country in a privileged position in terms of surgical knowledge. The present article describes the activities developed over these ten years of the institute in Brazil as the largest training center for surgeons of the continent in order to address the importance of surgical skills training.

Computer-Assisted Differentiation between Colon-Mesocolon and Retroperitoneum Using Hyperspectral Imaging (HSI) Technology

Complete mesocolic excision (CME), which involves the adequate resection of the tumor-bearing colonic segment with “en bloc” removal of its mesocolon along embryological fascial planes is associated with superior oncological outcomes. However, CME presents a higher complication rate compared to non-CME resections due to a higher risk of vascular injury. Hyperspectral imaging (HSI) is a contrast-free optical imaging technology, which facilitates the quantitative imaging of physiological tissue parameters and the visualization of anatomical structures. This study evaluates the accuracy of HSI combined with deep learning (DL) to differentiate the colon and its mesenteric tissue from retroperitoneal tissue. In an animal study including 20 pig models, intraoperative hyperspectral images of the sigmoid colon, sigmoid mesentery, and retroperitoneum were recorded. A convolutional neural network (CNN) was trained to distinguish the two tissue classes using HSI data, validated with a leave-one-out cross-validation process. The overall recognition sensitivity of the tissues to be preserved (retroperitoneum) and the tissues to be resected (colon and mesentery) was 79.0 ± 21.0% and 86.0 ± 16.0%, respectively. Automatic classification based on HSI and CNNs is a promising tool to automatically, non-invasively, and objectively differentiate the colon and its mesentery from retroperitoneal tissue.

In Vivo Imaging Evaluation of Fluorescence Intensity at Tail Emission of Near-Infrared-I (NIR-I) Fluorophores in a Porcine Model

Over the last decade fluorescence-guided surgery has been primarily focused on the NIR-I window. However, the NIR-I window has constraints, such as limited penetration and scattering. Consequently, exploring the performance of NIR-I dyes at longer wavelengths (i.e., the NIR-II window) is crucial to expanding its application. Two fluorophores were used in three pigs to identify the mean fluorescence intensity (MFI) using two commercially available NIR-I and NIR-II cameras. The near-infrared coating of equipment (NICE) was used to identify endoluminal surgical catheters and indocyanine green (ICG) for common bile duct (CBD) characterization. The NIR-II window evaluation showed an MFI of 0.4 arbitrary units (a.u.) ± 0.106 a.u. in small bowel NICE-coated catheters and an MFI of 0.09 a.u. ± 0.039 a.u. in gastric ones. In CBD characterization, the ICG MFI was 0.12 a.u. ± 0.027 a.u., 0.18 a.u. ± 0.100 a.u., and 0.22 a.u. ± 0.041 a.u. at 5, 35, and 65 min, respectively. This in vivo imaging evaluation of NIR-I dyes confirms its application in the NIR-II domain. To the best of our knowledge, this is the first study assessing the MIF of NICE in the NIR-II window using a commercially available system. Further comparative trials are necessary to determine the superiority of NIR-II imaging systems.

Automatic surgical phase recognition in laparoscopic inguinal hernia repair with artificial intelligence

BACKGROUND

Because of the complexity of the intra-abdominal anatomy in the posterior approach, a longer learning curve has been observed in laparoscopic transabdominal preperitoneal (TAPP) inguinal hernia repair. Consequently, automatic tools using artificial intelligence (AI) to monitor TAPP procedures and assess learning curves are required. The primary objective of this study was to establish a deep learning-based automated surgical phase recognition system for TAPP. A secondary objective was to investigate the relationship between surgical skills and phase duration.

METHODS

This study enrolled 119 patients who underwent the TAPP procedure. The surgical videos were annotated (delineated in time) and split into seven surgical phases (preparation, peritoneal flap incision, peritoneal flap dissection, hernia dissection, mesh deployment, mesh fixation, peritoneal flap closure, and additional closure). An AI model was trained to automatically recognize surgical phases from videos. The relationship between phase duration and surgical skills were also evaluated.

RESULTS

A fourfold cross-validation was used to assess the performance of the AI model. The accuracy was 88.81 and 85.82%, in unilateral and bilateral cases, respectively. In unilateral hernia cases, the duration of peritoneal incision (p = 0.003) and hernia dissection (p = 0.014) detected via AI were significantly shorter for experts than for trainees.

CONCLUSION

An automated surgical phase recognition system was established for TAPP using deep learning with a high accuracy. Our AI-based system can be useful for the automatic monitoring of surgery progress, improving OR efficiency, evaluating surgical skills and video-based surgical education. Specific phase durations detected via the AI model were significantly associated with the surgeons' learning curve.

New Intraoperative Imaging Tools and Image-Guided Surgery in Gastric Cancer Surgery

Innovations and new advancements in intraoperative real-time imaging have gained significant importance in the field of gastric cancer surgery in the recent past. Currently, the most promising procedures include indocyanine green fluorescence imaging (ICG-FI) and hyperspectral imaging or multispectral imaging (HSI, MSI). ICG-FI is utilized in a broad range of clinical applications, e.g., assessment of perfusion or lymphatic drainage, and additional implementations are currently investigated. HSI is still in the experimental phase and its value and clinical relevance require further evaluation, but initial studies have shown a successful application in perfusion assessment, and prospects concerning non-invasive tissue and tumor classification are promising. The application of machine learning and artificial intelligence technologies might enable an automatic evaluation of the acquired image data in the future. Both methods facilitate the accurate visualization of tissue characteristics that are initially indistinguishable for the human eye. By aiding surgeons in optimizing the surgical procedure, image-guided surgery can contribute to the oncologic safety and reduction of complications in gastric cancer surgery and recent advances hold promise for the application of HSI in intraoperative tissue diagnostics.

International survey among surgeons on laparoscopic right hemicolectomy: the gap between guidelines and reality

Introduction

To assess the current approaches and perioperative treatments of laparoscopic right hemicolectomy (LRHC) and to highlight similarities and differences with international guidelines and scientific evidence, we conducted a survey for surgeons across the globe.

Methods

All digestive and colorectal surgeons registered with the database of the Research Institute against Digestive Cancer (IRCAD) were invited to take part in the survey via email and through the social media networks of IRCAD.

Results

There were a total of 440 respondents from 78 countries. Most surgeons worked in the European region (38.6%) followed by the Americas (34.1%), the Eastern Mediterranean region (13.0%), the South-East Asian region (5.9%), the Western Pacific region (4.8%), and Africa (3.2%) respectively. Over half of the respondents performed less than 25% of right hemicolectomies laparoscopically where 4 ports are usually used by 68% of the surgeons. The medial-to-lateral, vessel-first approach is the approach most commonly used (74.1%). The most common extraction site was through a midline incision (53%) and an abdominal drain tube is routinely used by 52% of the surgeons after surgery. A total of 68.6% of the responding surgeons perform the majority of the anastomoses extracorporeally. Finally, we found that the majority of responders (60.7%) routinely used mechanical bowel preparations prior to LRHC.

Conclusion

Regarding several topics related to LRHC care, a discrepancy was observed between the current medical practice and the recommendations from RCTs and international guidelines and significant regional differences were observed.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00464-022-09044-w.

Single Snapshot Imaging of Optical Properties (SSOP) for Perfusion Assessment during Gastric Conduit Creation for Esophagectomy: An Experimental Study on Pigs

Simple Summary

Anastomotic leak is the most dangerous complication occurring after esophagectomy and its relationship with inadequate visceral perfusion is widely recognized. Currently, the adequate perfusion of the gastric conduit is intraoperatively assessed by surgeons using subjective indicators (e.g., serosal color or pulsatile flow of vessels). During the last decades, several innovative optical techniques based on the interaction of light with tissue have been developed to monitor perfusion in esophagogastric surgery. However, these innovative approaches are characterized by a lack of video rate and reproducibility. They also provide operator-dependent results and lengthen the surgical workflow. Single Snapshot imaging of Optical Properties (SSOP) is an optical technique, which can overcome such limitations, providing quantitative information on the optical properties of biological tissues over a large field of view. It is the first study to demonstrate the accuracy of SSOP in the quantification of serosal StO₂% in a porcine gastric conduit model.

Abstract

Anastomotic leakage (AL) is a serious complication occurring after esophagectomy. The current knowledge suggests that inadequate intraoperative perfusion in the anastomotic site contributes to an increase in the AL rate. Presently, clinical estimation undertaken by surgeons is not accurate and new technology is necessary to improve the intraoperative assessment of tissue oxygenation. In the present study, we demonstrate the application of a novel optical technology, namely Single Snapshot imaging of Optical Properties (SSOP), used to quantify StO₂% in an open surgery experimental gastric conduit (GC) model. After the creation of a gastric conduit, local StO₂% was measured with a preclinical SSOP system for 60 min in the antrum (ROI-A), corpus (ROI-C), and fundus (ROI-F). The removed region (ROI-R) acted as ischemic control. ROI-R had statistically significant lower StO₂% when compared to all other ROIs at T15, T30, T45, and T60 (p < 0.0001). Local capillary lactates (LCLs) and StO₂% correlation was statistically significant (R = −0.8439, 95% CI −0.9367 to −0.6407, p < 0.0001). Finally, SSOP could discriminate resected from perfused regions and ROI-A from ROI-F (the future anastomotic site). In conclusion, SSOP could well be a suitable technology to assess intraoperative perfusion of GC, providing consistent StO₂% quantification and ROIs discrimination.

Fluorescence-based bowel anastomosis perfusion evaluation: results from the IHU-IRCAD-EAES EURO-FIGS registry

BACKGROUND

Anastomotic leakage (AL) is one of the dreaded complications following surgery in the digestive tract. Near-infrared fluorescence (NIRF) imaging is a means to intraoperatively visualize anastomotic perfusion, facilitating fluorescence image-guided surgery (FIGS) with the purpose to reduce the incidence of AL. The aim of this study was to analyze the current practices and results of NIRF imaging of the anastomosis in digestive tract surgery through the EURO-FIGS registry.

METHODS

Analysis of data prospectively collected by the registry members provided patient and procedural data along with the ICG dose, timing, and consequences of NIRF imaging. Among the included upper-GI, colorectal, and bariatric surgeries, subgroup analysis was performed to identify risk factors associated with complications.

RESULTS

A total of 1240 patients were included in the study. The included patients, 74.8% of whom were operated on for cancer, originated from 8 European countries and 30 hospitals. A total of 54 surgeons performed the procedures. In 83.8% of cases, a pre-anastomotic ICG dose was administered, and in 60.1% of cases, a post-anastomotic ICG dose was administered. A significant difference (p < 0.001) was found in the ICG dose given in the four pathology groups registered (range: 0.013-0.89 mg/kg) and a significant (p < 0.001) negative correlation was found between the ICG dose and BMI. In 27.3% of the procedures, the choice of the anastomotic level was guided by means of NIRF imaging which means that in these cases NIRF imaging changed the level of anastomosis which was first decided based on visual findings in conventional white light imaging. In 98.7% of the procedures, the use of ICG partly or strongly provided a sense of confidence about the anastomosis. A total of 133 complications occurred, without any statistical significance in the incidence of complications in the anastomoses, whether they were ICG-guided or not.

CONCLUSION

The EURO-FIGS registry provides an insight into the current clinical practice across Europe with respect to NIRF imaging of anastomotic perfusion during digestive tract surgery.

Intraoperative Guidance Using Hyperspectral Imaging: A Review for Surgeons

Hyperspectral imaging (HSI) is a novel optical imaging modality, which has recently found diverse applications in the medical field. HSI is a hybrid imaging modality, combining a digital photographic camera with a spectrographic unit, and it allows for a contactless and non-destructive biochemical analysis of living tissue. HSI provides quantitative and qualitative information of the tissue composition at molecular level in a contrast-free manner, hence making it possible to objectively discriminate between different tissue types and between healthy and pathological tissue. Over the last two decades, HSI has been increasingly used in the medical field, and only recently it has found an application in the operating room. In the last few years, several research groups have used this imaging modality as an intraoperative guidance tool within different surgical disciplines. Despite its great potential, HSI still remains far from being routinely used in the daily surgical practice, since it is still largely unknown to most of the surgical community. The aim of this study is to provide clinical surgeons with an overview of the capabilities, current limitations, and future directions of HSI for intraoperative guidance.

Robotic endoscopic cooperative surgery for colorectal tumors: a feasibility study (with video)

BACKGROUND

Laparoscopic endoscopic cooperative colorectal surgery (LECS-CR) is a promising technique to achieve full-thickness resection of colorectal tumors. This approach has shown good rates of complete resection and low local recurrence, especially for large laterally spreading tumors, which are difficult to remove via endoscopy alone. However, it is often difficult to prevent peritoneal leakage of intestinal content, causing infections and risks of cancer spreading. It was hypothesized that a robotic assistance could make the procedure easier and decrease intestinal fluid leakage. This preclinical trial aims to assess the feasibility of robotic and endoscopic cooperative colorectal surgery (RECS-CR).

METHODS

LECS-CR was performed in five female pigs and RECS-CR was also performed in five female pigs. With the animal under general anesthesia, pseudotumors were created on the colonic mucosa at a distance comprised between 20 and 25 cm from the anal verge. Desired resection margins were marked endoscopically and two stay sutures were placed either robotically or laparoscopically. A mucosa-to-submucosa dissection was performed endoscopically along the markings. Complete full-thickness dissection was performed cooperatively. The specimen was withdrawn endoscopically. The colon was closed using a self-fixating running suture. Abdominal contaminations, operating times, complications, and complete resections were evaluated and compared between LECS-CR and RECS-CR.

RESULTS

The mean number of colonies of Escherichia coli in the RECS group was significantly lower than in the LECS group (36.7 ± 30.2 vs. 142.2 ± 78.4, respectively, p < 0.05). Operating time was comparable (118 ± 11.2 vs. 98.6 ± 25.7, respectively, p = 0.22). Two stenoses occurred in the LECS group. R0 resection was achieved in all cases.

CONCLUSION

This study suggests that RECS-CR is feasible and has the potential to reduce intestinal content leakage, potentially preventing postoperative infections.

Automatic Recognition of Colon and Esophagogastric Cancer with Machine Learning and Hyperspectral Imaging

There are approximately 1.8 million diagnoses of colorectal cancer, 1 million diagnoses of stomach cancer, and 0.6 million diagnoses of esophageal cancer each year globally. An automatic computer-assisted diagnostic (CAD) tool to rapidly detect colorectal and esophagogastric cancer tissue in optical images would be hugely valuable to a surgeon during an intervention. Based on a colon dataset with 12 patients and an esophagogastric dataset of 10 patients, several state-of-the-art machine learning methods have been trained to detect cancer tissue using hyperspectral imaging (HSI), including Support Vector Machines (SVM) with radial basis function kernels, Multi-Layer Perceptrons (MLP) and 3D Convolutional Neural Networks (3DCNN). A leave-one-patient-out cross-validation (LOPOCV) with and without combining these sets was performed. The ROC-AUC score of the 3DCNN was slightly higher than the MLP and SVM with a difference of 0.04 AUC. The best performance was achieved with the 3DCNN for colon cancer and esophagogastric cancer detection with a high ROC-AUC of 0.93. The 3DCNN also achieved the best DICE scores of 0.49 and 0.41 on the colon and esophagogastric datasets, respectively. These scores were significantly improved using a patient-specific decision threshold to 0.58 and 0.51, respectively. This indicates that, in practical use, an HSI-based CAD system using an interactive decision threshold is likely to be valuable. Experiments were also performed to measure the benefits of combining the colorectal and esophagogastric datasets (22 patients), and this yielded significantly better results with the MLP and SVM models.

State of the Art in Robot-Assisted Eye Surgery

Despite the advantages that robot-assisted surgery can offer to patient care, its use in ophthalmic surgery has not yet progressed to the extent seen in other fields. As such, its use remains limited to research environments, both basic and clinical. The technical specifications for such ophthalmic surgical robots are highly challenging, but rapid progress has been made in recent years, and recent developments in this field ensure that the use of this technology in operating theatres will soon be a real possibility. Fully automated ocular microsurgery, carried out by a robot under the supervision of a surgeon, is likely to become our new reality. This review discusses the use of robot-assisted ophthalmic surgery, the recent progress in the field, and the necessary future developments which must occur before its use in operating theatres becomes routine.

Automatic Liver Viability Scoring with Deep Learning and Hyperspectral Imaging

Hyperspectral imaging (HSI) is a non-invasive imaging modality already applied to evaluate hepatic oxygenation and to discriminate different models of hepatic ischemia. Nevertheless, the ability of HSI to detect and predict the reperfusion damage intraoperatively was not yet assessed. Hypoxia caused by hepatic artery occlusion (HAO) in the liver brings about dreadful vascular complications known as ischemia-reperfusion injury (IRI). Here, we show the evaluation of liver viability in an HAO model with an artificial intelligence-based analysis of HSI. We have combined the potential of HSI to extract quantitative optical tissue properties with a deep learning-based model using convolutional neural networks. The artificial intelligence (AI) score of liver viability showed a significant correlation with capillary lactate from the liver surface (r = −0.78, p = 0.0320) and Suzuki’s score (r = −0.96, p = 0.0012). CD31 immunostaining confirmed the microvascular damage accordingly with the AI score. Our results ultimately show the potential of an HSI-AI-based analysis to predict liver viability, thereby prompting for intraoperative tool development to explore its application in a clinical setting.

Deep Learning Analysis of In Vivo Hyperspectral Images for Automated Intraoperative Nerve Detection

Nerves are critical structures that may be difficult to recognize during surgery. Inadvertent nerve injuries can have catastrophic consequences for the patient and lead to life-long pain and a reduced quality of life. Hyperspectral imaging (HSI) is a non-invasive technique combining photography with spectroscopy, allowing non-invasive intraoperative biological tissue property quantification. We show, for the first time, that HSI combined with deep learning allows nerves and other tissue types to be automatically recognized in in vivo hyperspectral images. An animal model was used, and eight anesthetized pigs underwent neck midline incisions, exposing several structures (nerve, artery, vein, muscle, fat, skin). State-of-the-art machine learning models were trained to recognize these tissue types in HSI data. The best model was a convolutional neural network (CNN), achieving an overall average sensitivity of 0.91 and a specificity of 1.0, validated with leave-one-patient-out cross-validation. For the nerve, the CNN achieved an average sensitivity of 0.76 and a specificity of 0.99. In conclusion, HSI combined with a CNN model is suitable for in vivo nerve recognition.

Intraoperative Time-Out to Promote the Implementation of the Critical View of Safety in Laparoscopic Cholecystectomy: A Video-Based Assessment of 343 Procedures

BACKGROUND

The critical view of safety (CVS) is poorly adopted in surgical practices although it is ubiquitously recommended to prevent major bile duct injuries during laparoscopic cholecystectomy (LC). This study aims to investigate whether performing a short intraoperative time out can improve CVS implementation.

STUDY DESIGN

In this before versus after study, surgeons performing LCs at an academic center were invited to use a 5-second long time out to verify CVS before dividing the cystic duct (5-second rule). The primary aim was to compare the rate of CVS achievement for LCs performed in the year before versus the year after implementation of the 5-second rule. The CVS achievement rate was computed after exclusion of bailout procedures using a mediated video-based assessment made by two independent reviewers. Clinical outcomes, LC workflows, and postoperative reports were also compared.

RESULTS

343 of the 381 LCs performed between December 2017 and November 2019 (171 before and 172 after implementation of the 5-second rule) were analyzed. The 5-second rule was associated with a significantly increased rate of CVS achievement (15.9 vs. 44.1% before vs. after the 5-second rule, respectively; P<0.001). Significant differences were also observed with respect to the rate of bailout procedures (8.2 vs. 15.7%; P=0.04), the median [IQR] time to clip the cystic duct or artery (00:17:26 [00:11:48, 00:28:35] vs. 00:23:12 [00:14:29, 00:31:45] duration; P=0.007), and the rate of postoperative CVS reporting (1.3 vs. 28.8%; P<0.001). Postoperative morbidity was comparable (1.8 vs. 2.3%; P=0.68).

CONCLUSION

Performing a short intraoperative time out was associated with an improved CVS achievement rate. Systematic intraoperative cognitive aids should be studied to sustain the uptake of guidelines.

A Computer Vision Platform to Automatically Locate Critical Events in Surgical Videos: Documenting Safety in Laparoscopic Cholecystectomy

OBJECTIVE

The aim of this study was to develop a computer vision platform to automatically locate critical events in surgical videos and provide short video clips documenting the critical view of safety (CVS) in laparoscopic cholecystectomy (LC).

BACKGROUND

Intraoperative events are typically documented through operator-dictated reports that do not always translate the operative reality. Surgical videos provide complete information on surgical procedures, but the burden associated with storing and manually analyzing full-length videos has so far limited their effective use.

METHODS

A computer vision platform named EndoDigest was developed and used to analyze LC videos. The mean absolute error (MAE) of the platform in automatically locating the manually annotated time of the cystic duct division in full-length videos was assessed. The relevance of the automatically extracted short video clips was evaluated by calculating the percentage of video clips in which the CVS was assessable by surgeons.

RESULTS

A total of 155 LC videos were analyzed: 55 of these videos were used to develop EndoDigest, whereas the remaining 100 were used to test it. The time of the cystic duct division was automatically located with a MAE of 62.8 ± 130.4 seconds (1.95% of full-length video duration). CVS was assessable in 91% of the 2.5 minutes long video clips automatically extracted from the considered test procedures.

CONCLUSIONS

Deep learning models for workflow analysis can be used to reliably locate critical events in surgical videos and document CVS in LC. Further studies are needed to assess the clinical impact of surgical data science solutions for safer laparoscopic cholecystectomy.

Multi-task temporal convolutional networks for joint recognition of surgical phases and steps in gastric bypass procedures

PURPOSE

Automatic segmentation and classification of surgical activity is crucial for providing advanced support in computer-assisted interventions and autonomous functionalities in robot-assisted surgeries. Prior works have focused on recognizing either coarse activities, such as phases, or fine-grained activities, such as gestures. This work aims at jointly recognizing two complementary levels of granularity directly from videos, namely phases and steps.

METHODS

We introduce two correlated surgical activities, phases and steps, for the laparoscopic gastric bypass procedure. We propose a multi-task multi-stage temporal convolutional network (MTMS-TCN) along with a multi-task convolutional neural network (CNN) training setup to jointly predict the phases and steps and benefit from their complementarity to better evaluate the execution of the procedure. We evaluate the proposed method on a large video dataset consisting of 40 surgical procedures (Bypass40).

RESULTS

We present experimental results from several baseline models for both phase and step recognition on the Bypass40. The proposed MTMS-TCN method outperforms single-task methods in both phase and step recognition by 1-2% in accuracy, precision and recall. Furthermore, for step recognition, MTMS-TCN achieves a superior performance of 3-6% compared to LSTM-based models on all metrics.

CONCLUSION

In this work, we present a multi-task multi-stage temporal convolutional network for surgical activity recognition, which shows improved results compared to single-task models on a gastric bypass dataset with multi-level annotations. The proposed method shows that the joint modeling of phases and steps is beneficial to improve the overall recognition of each type of activity.

Influence of intraoperative vasopressor use on indocyanine green fluorescence angiography: first evaluation in an experimental model

Intraoperative indocyanine green (ICG) fluorescence angiography has gained popularity and acceptance in many surgical fields for the real-time assessment of tissue perfusion. Although vasopressors have the potential to preclude an accurate assessment of tissue perfusion, there is a lack of literature with regards to its effect on ICG fluorescence angiography. An experimental porcine model was used to expose the small bowel for quantitative tissue perfusion assessment. Three increasing doses of norepinephrine infusion (0.1, 0.5, and 1.0 µg/kg/min) were administered intravenously over a 25-min interval. Time-to-peak fluorescence intensity (TTP) was the primary outcome. Secondary outcomes included absolute fluorescence intensity and local capillary lactate (LCL) levels. Five large pigs (mean weight: 40.3 ± 4.24 kg) were included. There was no significant difference in mean TTP (in seconds) at baseline (4.23) as compared to the second (3.90), third (4.41), fourth (4.60), and fifth ICG assessment (5.99). As a result of ICG accumulation, the mean and the maximum absolute fluorescence intensity were significantly different as compared to the baseline assessment. There was no significant difference in LCL levels (in mmol/L) at baseline (0.74) as compared to the second (0.82), third (0.64), fourth (0.60), and fifth assessment (0.62). Increasing doses of norepinephrine infusion have no significant influence on bowel perfusion using ICG fluorescence angiography.

Intraoperative and postoperative complications in colorectal procedures: the role of continuous updating in medicine

Accepting surgical complications, especially those related to the learning curve, as unavoidable events in colorectal procedures, is like accepting to fly onboard an aircraft with a 10 to 20% chance of not arriving at final destination. Under this condition, it is very likely that the aviation industry and the concurrent reshaping of the world and of our lives would have not been possible in the absence of high reliability and reproducibility of safe flights. It's hard to imagine surgery without any intraoperative and/or postoperative complications. Nevertheless, there is a plenty of room for improvement by simply adopting what has been explicitly and scientifically demonstrated; training outside of the OR, usage of modern information technologies and application of evidence-based perioperative care protocols. Additionally, the possibility to objectively measure and monitor the technical and even non-technical skills and competencies of individual surgeons and even of OR teams through the application of structured and validated assessment tools can finally put an end to the self-referential, purely hierarchical, and indeed extremely unreliable process of being authorized or not to perform operations on patients. Last but not least, a wide range of new technologies spanning from augmented imaging modalities, virtual reality for intraoperative guidance, improved robotic manipulators, artificial intelligence to assist in preoperative patient specific risk assessment, and intraoperative decision-making has the potential to tackle several hidden roots of surgical complications.

Endoscopic assessment of morphological and histopathological upper gastrointestinal changes after endoscopic sleeve gastroplasty

BACKGROUND

Endoscopic sleeve gastroplasty (ESG) is a promising bariatric endoluminal procedure. Restriction and shortening of the stomach are obtained by means of non-resorbable full-thickness sutures, thus inducing the formation of several endoluminal pouches in which food can stagnate. The effect of ESG on the upper gastrointestinal tract has never been investigated.

OBJECTIVES

This study objectively evaluates endoscopic macroscopic and histopathologic changes within 12-month follow-up (FU) in patients who underwent ESG.

SETTING

Retrospective study on a prospective database of patients who underwent ESG at our tertiary referral center between October 2016 and March 2019.

METHODS

All consecutive patients undergoing upper endoscopy (EGD) preoperatively and 6 and 12 months after ESG were included. The upper gastrointestinal tract was evaluated for mucosal abnormalities and biopsies were systematically taken.

RESULTS

Eighty-six patients were included. EGD results were as follows: esophagitis decreased from 14% preoperatively to 3.6% and 1.2% at 6- and 12-month FU, respectively (P = .001); 19.8% of patients presented preoperatively a type I hiatal hernia <4 cm and showed no size increment or de novo hiatal hernia at 6- and 12-months. The rate of preoperative hyperemic (23.2%) and erosive (3.5%) gastropathy decreased to 9.5% and 1.2% at 6 months and 17.4% and 1.2% at 12 months, respectively. Gastric ulcer (4.7%), duodenal hyperemic mucosa (1.2%) and duodenal micro-ulcerations (2.3%) detected preoperatively were not present at 6- and 12-month EGD. The rate of histopathological disease, which was 68.1% preoperatively, dropped to 29.2% at 12 months, chronic gastritis decreased from 40.3% to 26.4%, acute gastritis from 9.7% to 0%, and acute inflammation on chronic gastritis from 18% to 2.8% (P < .001).

CONCLUSION

ESG is a safe procedure that does not promote the new onset of macroscopic and histopathologic abnormalities within 1-year follow-up.

Super-Selective Intra-Arterial Indocyanine Green Administration for Near-Infrared Fluorescence-Based Positive Staining of Hepatic Segmentation: A Feasibility Study

BACKGROUND

Despite the increasing number of laparoscopic hepatic procedures for the resection of hepatocellular carcinoma (HCC), intraoperative tumor localization and demarcation remains challenging in comparison to open surgery. In this study, we evaluated the feasibility of positive liver segment staining through the super-selective intra-arterial indocyanine green (ICG) administration.

METHODS

Eight patients presenting with a single HCC underwent an interventional vascular procedure followed by laparoscopic surgery. A microcatheter was advanced into the hepatic artery branches perfusing the HCC followed by digital subtraction angiography and angiography computed tomography (angio-CT). Patients were then transferred to the operating room, and a laparoscopic hepatectomy was performed under ultrasound guidance. A 5 mL bolus of ICG with a concentration of .125 mg/mL was injected through the microcatheter, and a near-infrared laparoscope was used to detect the fluorescence signal to assess the correspondence between the fluorescence-based demarcation and the intraoperative ultrasound-based demarcation.

RESULTS

The duration for the angiography procedure was 32.7 +/- 5.3 min, and it took 242 +/- 118 min from the end of angiography procedure until the start of the surgical procedure. In all cases, the fluorescent liver segment was corresponding to the angio-CT findings. In 6/8 cases, fluorescence imaging was considered helpful in the identification of the resection line. In 3 patients, the resection line was changed according to the positively stained liver segment.

CONCLUSION

We successfully demonstrated the feasibility of the super-selective intra-arterial ICG administration for fluorescence-based positive staining of hepatic segmentation during laparoscopic surgery for HCC (NCT04266548).

A Standard Set of Value-Based Patient-Centered Outcomes for Pancreatic Carcinoma: An International Delphi Survey

BACKGROUND

Global health systems are shifting toward value-based health care to improve patient outcomes in the face of rising health care costs. The challenge is to identify standardized outcome measurements that allow optimal quality-of-care monitoring and comparison to optimize medical practices and patient pathways. A common outcomes definition is required, including medical results (Clinical Reported Outcomes Measurements [CROMs]) and quality-of-life components that matter most to patients (Patient-Reported Outcomes Measurements [PROMs]), which are particularly important for severe pathologies with short life expectancy such as pancreatic cancer. This study aimed to create standardized metrics that could be used for outcomes analysis of pancreatic cancer care.

METHODS

A multidisciplinary working group (WG) was assembled. A systematic review was performed to collect the most used outcomes in clinical studies of pancreatic cancers. The study reviewed 570 studies published in the last 10 years. From these studies, 3370 outcomes, including CROMs, and PROMs, were listed and prioritized. The WG reached a consensus on key outcomes, proposed groupings for CROMs and PROMs, identified existing questionnaires that could be used for PROMs collection, and set the timeline for data collection. To refine and validate the final outcomes set, an international external committee completed a Delphi process (two rounds for both CROMS and PROMs).

RESULTS

After the systematic literature review, the WG selected 102 outcomes (92 CROMs and 10 PROMs) for submission to the international Delphi vote committee. The committee retrained 89 outcomes (78 CROMs and 11 PROMs). For the PROMs, the WG and the international external committee chose a validated questionnaire, the Functional Assessment of Cancer Therapy-Hepatobiliary, which covers all of the 11 selected PROMs.

CONCLUSIONS

A standardized set of outcome measures that need to be validated through international health outcome comparisons and quality-of-care assessments was built. Pilot projects are underway to test and optimize the approach in real-life conditions.

Effects of Warmed and Humidified CO2 Surgical Site Insufflation in a Novel Experimental Model of Magnetic Compression Colonic Anastomosis

Background. Pneumoperitoneum insufflation with warmed and humidified carbon dioxide (WH-CO2) can prevent heat loss and increase tissue oxygenation. We evaluated the impact of localized WH-CO2 insufflation on the anastomotic healing process. Methods. Sixty male Wistar rats were randomized: Group 1 (control, n = 12), Group 2 (cold and dry CO2, CD-CO2, n = 24), and Group 3 (WH-CO2, n = 24). A magnetic compression side-to-side colonic anastomosis was performed under 60-minute local abdominal CO2 flow insufflation. Animal temperature was recorded. IL-1, IL-6, and CRP levels were assessed before and after insufflation and on postoperative day (POD) 7 and POD 10. Endoscopic follow-up was performed on POD 7 and POD 10. A burst pressure (BP) test of the specimen was performed on POD 10, and histopathological analysis was then performed. Metabolomics of the anastomotic site was determined. Results. Seven rats (5 CD-CO2 group, 1 WH-CO2 group, and 1 control group) died during the survival period. Necropsies revealed intestinal occlusions (n = 2). One additional rat from the CD-CO2 group was sacrificed on POD 7 due to intestinal perforation. The postoperative course was uneventful in the remaining cases. There was no difference in BP among the groups. Thermal monitoring confirmed that WH-CO2 insufflation was effective to reduce heat loss. IL-1 levels were statistically and significantly lower on POD 10 in the WH-CO2 group than the CD-CO2 group but not lower than the control group. CRP levels, histopathology, and metabolomics did not show any difference between the 3 groups. Conclusions. WH-CO2 was effective to preserve core temperature. However, it did not improve anastomotic healing.

Fluoroless intravascular ultrasound image-guided liver navigation in porcine models

Background

An intravascular ultrasound catheter (IVUSc) was developed for intracardiac ultrasound to assess interventions with compelling results. However, intrahepatic vascular exploration was rarely tested and was always associated with X-ray techniques. The aim of this study was to demonstrate the feasibility to navigate through the whole liver using an IVUSc, providing high-quality images and making it unnecessary to use ionizing radiation.

Methods

An ex vivo pig visceral block and an in vivo pig model were used in this study. The IVUS equipment was composed of an US system, and of an 8 French lateral firing IVUSc capable of producing 90-degree sector images in the longitudinal plane. After accessing the intravascular space with the IVUSc into the models, predetermined anatomical landmarks were visualized from the inferior vena cava and hepatic veins and corroborated.

Results

IVUS navigation was achieved in both models successfully. The entire navigation protocol took 87 and 48 min respectively, and 100% (21/21) and 96.15% (25/26) of the landmarks were correctly identified with the IVUSc alone in the ex vivo and in vivo models respectively. IVUS allowed to clearly visualize the vasculature beyond third-order branches of the hepatic and portal veins.

Conclusions

A complete IVUS liver navigation is feasible using the IVUSc alone, making it unnecessary to use ionizing radiation. This approach provides high-definition and real-time images of the complex liver structure and offers a great potential for future clinical applications during diagnostic and therapeutic interventions.

Dual Color Imaging from a Single BF2-Azadipyrromethene Fluorophore Demonstrated in vivo for Lymph Node Identification

Dual emissions at ~700 and 800 nm have been achieved from a single NIR-AZA fluorophore 1 by establishing parameters in which it can exist in either its isolated molecular or aggregated states. Dual near infrared (NIR) fluorescence color lymph node (LN) mapping with 1 was achieved in a large-animal porcine model, with injection site, channels and nodes all detectable at both 700 and 800 nm using a preclinical open camera system. The fluorophore was also compatible with imaging using two clinical instruments for fluorescence guided surgery. Methods: An NIR-AZA fluorophore with hydrophilic and phobic features was synthesised in a straightforward manner and its aggregation properties characterised spectroscopically and by TEM imaging. Toxicity was assessed in a rodent model and dual color fluorescence imaging evaluated by lymph node mapping in a large animal porcine models and in ex-vivo human tissue specimen. Results: Dual color fluorescence imaging has been achieved in the highly complex biomedical scenario of lymph node mapping. Emissions at 700 and 800 nm can be achieved from a single fluorophore by establishing molecular and aggregate forms. Fluorophore was compatible with clinical systems for fluorescence guided surgery and no toxicity was observed in high dosage testing. Conclusion: A new, biomedical compatible form of NIR-dual emission wavelength imaging has been established using a readily accessible fluorophore with significant scope for clinical translation.

Definitions of Computer-Assisted Surgery and Intervention, Image-Guided Surgery and Intervention, Hybrid Operating Room, and Guidance Systems: Strasbourg International Consensus Study

OBJECTIVE

To develop consensus definitions of image-guided surgery, computer-assisted surgery, hybrid operating room, and surgical navigation systems.

SUMMARY BACKGROUND DATA

The use of minimally invasive procedures has increased tremendously over the past 2 decades, but terminology related to image-guided minimally invasive procedures has not been standardized, which is a barrier to clear communication.

METHODS

Experts in image-guided techniques and specialized engineers were invited to engage in a systematic process to develop consensus definitions of the key terms listed above. The process was designed following review of common consensus-development methodologies and included participation in 4 online surveys and a post-surveys face-to-face panel meeting held in Strasbourg, France.

RESULTS

The experts settled on the terms computer-assisted surgery and intervention, image-guided surgery and intervention, hybrid operating room, and guidance systems and agreed-upon definitions of these terms, with rates of consensus of more than 80% for each term. The methodology used proved to be a compelling strategy to overcome the current difficulties related to data growth rates and technological convergence in this field.

CONCLUSIONS

Our multidisciplinary collaborative approach resulted in consensus definitions that may improve communication, knowledge transfer, collaboration, and research in the rapidly changing field of image-guided minimally invasive techniques.