Automated performance metrics and surgical gestures: two methods for assessment of technical skills in robotic surgery.

The objective of this study is to compare automated performance metrics (APM) and surgical gestures for technical skills assessment during simulated robot-assisted radical prostatectomy (RARP). Ten novices and six experienced RARP surgeons performed simulated RARPs on the RobotiX Mentor (Surgical Science, Sweden). Simulator APM were automatically recorded, and surgical videos were manually annotated with five types of surgical gestures. The consequences of the pass/fail levels, which were based on contrasting groups' methods, were compared for APM and surgical gestures. Intra-class correlation coefficient (ICC) analysis and a Bland-Altman plot were used to explore the correlation between APM and surgical gestures. Pass/fail levels for both APM and surgical gesture could fully distinguish between the skill levels of the surgeons with a specificity and sensitivity of 100%. The overall ICC (one-way, random) was 0.70 (95% CI: 0.34-0.88), showing moderate agreement between the methods. The Bland-Altman plot showed a high agreement between the two methods for assessing experienced surgeons but disagreed on the novice surgeons' skill level. APM and surgical gestures could both fully distinguish between novices and experienced surgeons in a simulated setting. Both methods of analyzing technical skills have their advantages and disadvantages and, as of now, those are only to a limited extent available in the clinical setting. The development of assessment methods in a simulated setting enables testing before implementing it in a clinical setting.

Computer-aided quality assessment of endoscopist competence during colonoscopy: a systematic review.

BACKGROUND AND AIMS: Endoscopists' competence can vary widely, as shown in the variation in the adenoma detection rate (ADR). Computer-aided quality assessment (CAQ) can automatically assess performance during individual procedures. In this review we identified and described different CAQ systems for colonoscopy. METHODS: A systematic review of the literature was done using MEDLINE, EMBASE, and Scopus based on 3 blocks of terms according to the inclusion criteria: colonoscopy, competence assessment, and automatic evaluation. Articles were systematically reviewed by 2 reviewers, first by abstract and then in full text. The methodological quality was assessed using the Medical Education Research Study Quality Instrument (MERSQI). RESULTS: Of 12,575 identified studies, 6831 remained after removal of duplicates and 6806 did not pass the eligibility criteria and were excluded, leaving 25 studies, of which 13 studies were included in the final analysis. Five categories of CAQ systems were identified: withdrawal speedometer (7 studies), endoscope movement analysis (3 studies), effective withdrawal time (1 study), fold examination quality (1 study), and visual gaze pattern (1 study). The withdrawal speedometer was the only CAQ system that tested its feedback by examining changes in ADR. Three studies observed an improvement in ADR, and 2 studies did not. The methodological quality of the studies was high (mean MERSQI, 15.2 points; maximum, 18 points). CONCLUSIONS: Thirteen studies developed or tested CAQ systems, most frequently by correlating it to the ADR. Only 5 studies tested feedback by implementing the CAQ system. A meta-analysis was impossible because of the heterogeneous study designs, and more studies are warranted.

Developing a phantom for simulating robotic-assisted complete mesocolic excision using 3D printing and medical imaging.

BACKGROUND: Robotic-assisted complete mesocolic excision is an advanced procedure mainly because of the great variability in anatomy. Phantoms can be used for simulation-based training and assessment of competency when learning new surgical procedures. However, no phantoms for robotic complete mesocolic excision have previously been described. This study aimed to develop an anatomically true-to-life phantom, which can be used for training with a robotic system situated in the clinical setting and can be used for the assessment of surgical competency. METHODS: Established pathology and surgical assessment tools for complete mesocolic excision and specimens were used for the phantom development. Each assessment item was translated into an engineering development task and evaluated for relevance. Anatomical realism was obtained by extracting relevant organs from preoperative patient scans and 3D printing casting moulds for each organ. Each element of the phantom was evaluated by two experienced complete mesocolic excision surgeons without influencing each other's answers and their feedback was used in an iterative process of prototype development and testing. RESULTS: It was possible to integrate 35 out of 48 procedure-specific items from the surgical assessment tool and all elements from the pathological evaluation tool. By adding fluorophores to the mesocolic tissue, we developed an easy way to assess the integrity of the mesocolon using ultraviolet light. The phantom was built using silicone, is easy to store, and can be used in robotic systems designated for patient procedures as it does not contain animal-derived parts. CONCLUSIONS: The newly developed phantom could be used for training and competency assessment for robotic-assisted complete mesocolic excision surgery in a simulated setting.

Surgical gestures can be used to assess surgical competence in robot-assisted surgery : A validity investigating study of simulated RARP.

To collect validity evidence for the assessment of surgical competence through the classification of general surgical gestures for a simulated robot-assisted radical prostatectomy (RARP). We used 165 video recordings of novice and experienced RARP surgeons performing three parts of the RARP procedure on the RobotiX Mentor. We annotated the surgical tasks with different surgical gestures: dissection, hemostatic control, application of clips, needle handling, and suturing. The gestures were analyzed using idle time (periods with minimal instrument movements) and active time (whenever a surgical gesture was annotated). The distribution of surgical gestures was described using a one-dimensional heat map, snail tracks. All surgeons had a similar percentage of idle time but novices had longer phases of idle time (mean time: 21 vs. 15 s, p < 0.001). Novices used a higher total number of surgical gestures (number of phases: 45 vs. 35, p < 0.001) and each phase was longer compared with those of the experienced surgeons (mean time: 10 vs. 8 s, p < 0.001). There was a different pattern of gestures between novices and experienced surgeons as seen by a different distribution of the phases. General surgical gestures can be used to assess surgical competence in simulated RARP and can be displayed as a visual tool to show how performance is improving. The established pass/fail level may be used to ensure the competence of the residents before proceeding with supervised real-life surgery. The next step is to investigate if the developed tool can optimize automated feedback during simulator training.

3D Ultrasound and MRI in Assessing Resection Margins during Tongue Cancer Surgery: A Research Protocol for a Clinical Diagnostic Accuracy Study.

Surgery is the primary treatment for tongue cancer. The goal is a complete resection of the tumor with an adequate margin of healthy tissue around the tumor.Inadequate margins lead to a high risk of local cancer recurrence and the need for adjuvant therapies. Ex vivo imaging of the resected surgical specimen has been suggested for margin assessment and improved surgical results. Therefore, we have developed a novel three-dimensional (3D) ultrasound imaging technique to improve the assessment of resection margins during surgery. In this research protocol, we describe a study comparing the accuracy of 3D ultrasound, magnetic resonance imaging (MRI), and clinical examination of the surgical specimen to assess the resection margins during cancer surgery. Tumor segmentation and margin measurement will be performed using 3D ultrasound and MRI of the ex vivo specimen. We will determine the accuracy of each method by comparing the margin measurements and the proportion of correctly classified margins (positive, close, and free) obtained by each technique with respect to the gold standard histopathology.

Comparing Simulator Metrics and Rater Assessment of Laparoscopic Suturing Skills.

BACKGROUND: Laparoscopic intracorporeal suturing is important to master and competence should be ensured using an optimal method in a simulated environment before proceeding to real operations. The objectives of this study were to gather validity evidence for two tools for assessing laparoscopic intracorporeal knot tying and compare the rater-based assessment of laparoscopic intracorporeal suturing with the assessment based on simulator metrics. METHODS: Twenty-eight novices and 19 experienced surgeons performed four laparoscopic sutures on a Simball Box simulator twice. Two surgeons used the Intracorporeal Suturing Assessment Tool (ISAT) for blinded video rating. RESULTS: Composite Simulator Score (CSS) had higher test-retest reliability than the ISAT. The correlation between the number performed procedures including suturing and ISAT score was 0.51, p<0.001, and 0.59 p<0.001 for CSS. We found an inter-rater reliability (0.72, p<0.001 for test 1 and 0.53 p<0.001 for test 2). The pass/fail rates for ISAT and CSS were similar. CONCLUSION: CSS and ISAT provide similar results for assessing laparoscopic suturing but assess different aspects of performance. Using simulator metrics and raters' assessments in combination should be considered for a more comprehensive evaluation of laparoscopic knot-tying competency.

Acquisition and usage of robotic surgical data for machine learning analysis.

BACKGROUND: The increasing use of robot-assisted surgery (RAS) has led to the need for new methods of assessing whether new surgeons are qualified to perform RAS, without the resource-demanding process of having expert surgeons do the assessment. Computer-based automation and artificial intelligence (AI) are seen as promising alternatives to expert-based surgical assessment. However, no standard protocols or methods for preparing data and implementing AI are available for clinicians. This may be among the reasons for the impediment to the use of AI in the clinical setting. METHOD: We tested our method on porcine models with both the da Vinci Si and the da Vinci Xi. We sought to capture raw video data from the surgical robots and 3D movement data from the surgeons and prepared the data for the use in AI by a structured guide to acquire and prepare video data using the following steps: 'Capturing image data from the surgical robot', 'Extracting event data', 'Capturing movement data of the surgeon', 'Annotation of image data'. RESULTS: 15 participant (11 novices and 4 experienced) performed 10 different intraabdominal RAS procedures. Using this method we captured 188 videos (94 from the surgical robot, and 94 corresponding movement videos of the surgeons' arms and hands). Event data, movement data, and labels were extracted from the raw material and prepared for use in AI. CONCLUSION: With our described methods, we could collect, prepare, and annotate images, events, and motion data from surgical robotic systems in preparation for its use in AI.

Learning insertion of a Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) catheter: Is clinical experience necessary? A prospective trial.

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an emerging and potentially life-saving procedure, necessitating qualified operators in an increasing number of centres. The procedure shares technical elements with other vascular access procedures using the Seldinger technique, which is mastered by doctors not only in endovascular specialties but also in trauma surgery, emergency medicine, and anaesthesiology. We hypothesised that doctors mastering the Seldinger technique (experienced anaesthesiologist) would learn the technical aspects of REBOA with limited training and remain technically superior to doctors unfamiliar with the Seldinger technique (novice residents) given similar training. METHODS: This was a prospective trial of an educational intervention. Three groups of doctors were enroled: novice residents, experienced anaesthesiologists, and endovascular experts. The novices and the anaesthesiologists completed 2.5 h of simulation-based REBOA training. Their skills were tested before and 8-12 weeks after training using a standardised simulated scenario. The endovascular experts, constituting a reference group, were equivalently tested. All performances were video recorded and rated by three blinded experts using a validated assessment tool for REBOA (REBOA-RATE). Performances were compared between groups and with a previously published pass/fail cutoff. RESULTS: Sixteen novices, 13 board-certified specialists in anaesthesiology, and 13 endovascular experts participated. Before training, the anaesthesiologists outperformed the novices by 30 percentage points of the maximum REBOA-RATE score (56% (SD 14.0) vs 26% (SD 17%), p<0.01). After training, there was no difference in skills between the two groups (78% (SD 11%) vs 78 (SD 14%), p = 0.93). Neither group reached the endovascular experts' skill level (89% (SD 7%), p<0.05). CONCLUSION: For doctors mastering the Seldinger technique, there was an initial inter-procedural transfer of skills advantage when performing REBOA. However, after identical simulation-based training, novices performed equally well to anaesthesiologists, indicating that vascular access experience is not a prerequisite to learning the technical aspects of REBOA. Both groups would need more training to reach technical proficiency.

Laser Speckle Contrast Imaging-based diagnosis of severe mesenteric traction syndrome: Hemodynamics and prostacyclin - A prospective cohort study.

BRIEF ABSTRACT: Today, the diagnosis and grading of mesenteric traction syndrome relies on a subjective assessment of facial flushing. However, this method has several limitations. In this study, Laser Speckle Contrast Imaging and a predefined cut-off value are assessed and validated for the objective identification of severe mesenteric traction syndrome. BACKGROUND: Severe mesenteric traction syndrome (MTS) is associated with increased postoperative morbidity. The diagnosis is based on an assessment of the developed facial flushing. Today this is performed subjectively, as no objective method exists. One possible objective method is Laser Speckle Contrast Imaging (LSCI), which has been used to show significantly higher facial skin blood flow in patients developing severe MTS. Using these data, a cut-off value has been identified. This study aimed to validate our predefined LSCI cut-off value for identifying severe MTS. METHODS: A prospective cohort study was performed on patients planned for open esophagectomy or pancreatic surgery from March 2021 to April 2022. All patients underwent continuous measurement of forehead skin blood flow using LSCI during the first hour of surgery. Using the predefined cut-off value, the severity of MTS was graded. In addition, blood samples for prostacyclin (PGI2) analysis and hemodynamics were collected at predefined time points to validate the cut-off value. MAIN RESULTS: Sixty patients were included in the study. Using our predefined LSCI cut-off value, 21 (35 %) patients were identified as developing severe MTS. These patients were found to have higher concentrations of 6-Keto-PGFaα (p = 0.002), lower SVR (p < 0.001), lower MAP (p = 0.004), and higher CO (p < 0.001) 15 min into surgery, as compared with patients not developing severe MTS. CONCLUSION: This study validated our LSCI cut-off value for the objective identification of severe MTS patients as this group developed increased concentrations of PGI2 and more pronounced hemodynamic alterations compared with patients not developing severe MTS.

Preparing for Reality: A Randomized Trial on Immersive Virtual Reality for Bronchoscopy Training.

BACKGROUND: Bronchoscopy is an essential procedure in the diagnosis and treatment of pulmonary diseases. However, the literature suggests that distractions affect the quality of bronchoscopy and affect inexperienced doctors more than experienced. OBJECTIVES: The objective of the study was as follows: does simulation-based bronchoscopy training with immersive virtual reality (iVR) improve the doctors' ability to handle distractions and thereby increase the quality, measured in procedure time, structured progression score, diagnostic completeness (%), and hand motor movements of a diagnostic bronchoscopy in a simulated scenario. Exploratory outcomes were heart rate variability and a cognitive load questionnaire (Surg-TLX). METHODS: Participants were randomized. The intervention group practiced in an iVR environment with a head-mounted display (HMD) while using the bronchoscopy simulator, while the control group trained without the HMD. Both groups were tested in the iVR environment using a scenario with distractions. RESULTS: 34 participants completed the trial. The intervention group scored significantly higher in diagnostic completeness (100 i.q.r. 100-100 vs. 94 i.q.r. 89-100, p value = 0.03) and structured progress (16 i.q.r. 15-18 vs. 12 i.q.r. 11-15, p value 0.03) but not in procedure time (367 s standard deviation [SD] 149 vs. 445 s SD 219, p value = 0.06) or hand motor movements (-1.02 i.q.r. -1.03-[-1.02] versus -0.98 i.q.r. -1.02-[-0.98], p value = 0.27). The control group had a tendency toward a lower heart rate variability (5.76 i.q.r. 3.77-9.06 vs. 4.12 i.q.r. 2.68-6.27, p = 0.25). There was no significant difference in total Surg-TLX points between the two groups. CONCLUSION: iVR simulation training increases the quality of diagnostic bronchoscopy in a simulated scenario with distractions compared with conventional simulation-based training.

Intraoperative near-infrared lymphography with indocyanine green may aid lymph node dissection during robot-assisted resection of gastroesophageal junction cancer.

BACKGROUND: Adequate lymphadenectomy during gastroesophageal junction (GEJ) cancer resection is essential, because lymph node (LN) metastasis correlates with increased recurrence risk. Fluorescence lymphography with indocyanine green (ICG) has been used for LN mapping in several surgical specialties; however, reports on GEJ cancer are lacking. Therefore, we investigated whether intraoperative ICG lymphography could facilitate LN harvest during robot-assisted resection of GEJ cancer. METHODS: Patients scheduled for robot-assisted resection of GEJ cancer were included, and outcomes were compared with historical controls. After intraoperative endoscopic submucosal ICG injection, standard D1 + LN dissection was performed under white light. Then, near-infrared (NIR) fluorescence imaging was activated, and each LN dissection area was re-examined. Any tissue within the D1 + field exhibiting distinctly increased ICG fluorescence compared with background tissue was dissected and sent for pathology review. RESULTS: We included 70 patients between June 2020 and October 2021. Three cases were aborted due to disseminated disease, and two were converted to open resection and excluded from the analysis. Additional tissue was dissected after NIR review in 34 of 65 (52%) patients. We dissected 43 fluorescent tissue samples, and after pathology review, 30 were confirmed LNs; none were metastatic. The median number of LNs harvested per patient (34, interquartile range [IQR] = 26-44) was not significantly different from that harvested from historical controls (32, IQR = 24-45; p = 0.92), nor were there any differences between these two groups in the duration of surgery, intraoperative blood loss, or comprehensive complication scores (p = 0.12, p = 0.46, and p = 0.41, respectively). CONCLUSIONS: Intraoperative NIR lymphography with ICG may aid LN detection during robot-assisted resection of GEJ cancer without increasing surgical risk. Although NIR lymphography may facilitate LN dissection, none of the LN removed after the NIR review was metastatic. Hence, it remains uncertain whether NIR lymphography will improve oncological outcomes.

Expertise in colonoscopy intubation does not predict diagnostic accuracy: a simulation-based study.

Background and study aims Studies have linked cecal intubation rate with adenoma detection rate; however, the direct association between technical performance during colonoscopy intubation and withdrawal has never been explored. Thus, it remains unclear whether gentle and efficient intubation predicts superior mucosal inspection. The aim of this study was to investigate the correlation between performance during intubation and withdrawal in a simulation-based setup. Methods Twenty-four physicians with various experience in colonoscopy performed twice on the Endoscopy Training System (ETS). Intubation skills were evaluated by assessing tasks on the ETS related to intubation (scope manipulation and loop management) and use of a computerized assessment tool called the 3D-Colonoscopy Progression Score (3D-CoPS). Diagnostic accuracy was defined by the number of polyps found during the ETS task of mucosal inspection. Pearson's correlations were calculated to explore associations between intubation skill and diagnostic accuracy. Results The correlation analysis between 3D-CoPS and number of polyps found during mucosal inspection revealed a weak and insignificant correlation (0.157, P  = 0.3). Likewise, an insignificant correlation was seen between ETS intubation and number of polyps found (0.149, P  = 0.32). Conclusions We found no evidence to support that technical performance during intubation is correlated with mucosal inspection performance in a simulation-based setting.

Colonoscope retraction technique and predicting adenoma detection rate: a multicenter study.

BACKGROUND AND AIMS: The success of preventing colorectal cancer relies on the expertise of the colonoscopists. Studies suggest that the retraction technique is a powerful indicator of expertise in distinguishing endoscopists with various adenoma detection rates (ADRs). We aimed to develop a retraction technique score and explore the correlation between endoscopists' retraction technique and their ADRs. METHODS: In a prospective, multicenter study, 8 colonoscopist nurses and physicians with various ADRs were included. Data from patients admitted for a colonoscopy, as part of the Danish nationwide screening program, were gathered directly from the Olympus ScopeGuide system (UPD-3; Olympus Optical, Tokyo, Japan) providing XYZ-coordinates from the coils along the length of the colonoscope. Motor skill measures were developed based on tip retraction, retraction efficiency, and retraction distance. The principal component analysis was used to study the association among the 3 measures and the historical ADR to create a combined score, the colonoscopy retraction score (CoRS). RESULTS: Three hundred thirty-three recordings were analyzed. We demonstrated a significant and strong correlation between CoRS and ADR (.90, P < .01). Conversely, withdrawal time did not correlate significantly with ADR (.33, P = .42). In procedures without polypectomies or biopsy sampling, a significant and strong correlation was found between CoRS and ADR (.88, P < .01) and between withdrawal time and ADR (.75, P = .03). CONCLUSIONS: This study presents a novel, real-time computerized and unbiased assessment tool for colonoscopy withdrawal. CoRS strongly correlated with ADR with and without therapeutic interventions during withdrawal and could be used to ensure quality instead of minimal withdrawal time. (Clinical trial registration number: NCT03587935.).

Intestinal perfusion assessed by quantitative fluorescence angiography in piglets with necrotizing enterocolitis.

BACKGROUND: Reduced intestinal perfusion is thought to be a part of the pathogenesis in necrotizing enterocolitis (NEC). This study aims to evaluate the intestinal perfusion assessment in NEC-lesions by quantitative fluorescence angiography with indocyanine green (q-ICG) during laparoscopy and open surgery. METHODS: Thirty-four premature piglets were delivered by cesarean section and fed with parenteral nutrition and increasing infant formula volumes to induce NEC. During surgery, macroscopic NEC-lesions were evaluated using a validated macroscopic scoring system (1-6 for increasing NEC severity). The intestinal perfusion was assessed by q-ICG and quantified with a validated pixel intensity computer algorithm. RESULTS: Significantly higher perfusion values were found in healthy areas of the colon (score 1) compared to those with NEC scores of 4, 5, and 6 (p < 0.05). Similarly, in the small intestine, perfusion was higher in the intestine with areas scored 1 compared to scores of 3 and 4 (p < 0.05). A cut-off value was found between NEC score of 1-2 vs. 3-4 for the small intestine at 117 and for colon at 107 between NEC scores 12 vs. scores of 36 with an area less than the curve value at 0.9 (p < 0.05). CONCLUSIONS: q-ICG seems to be a feasible and valuable technique to evaluate the perfusion of tissue with NEC-lesions. We found a cut-off between intestine with scores 1-2 and intestine with NEC scores 3-6 in colon, and NEC score 3-4 in the small intestine. LEVEL OF EVIDENCE: II.

Quantitative fluorescence angiography aids novice and experienced surgeons in performing intestinal resection in well-perfused tissue.

BACKGROUND: Anastomotic leakage (AL) after gastrointestinal resection is a devastating complication with huge consequences for the patient. As AL is associated with poor blood supply, tools for objective assessment of perfusion are in high demand. Indocyanine green angiography (ICG-FA) and quantitative analysis of ICG-FA (q-ICG) seem promising. This study aimed to investigate whether ICG-FA and q-ICG could improve perfusion assessment performed by surgeons of different experience levels. METHODS: Thirteen small bowel segments with a varying degree of devascularization, including two healthy sham segments, were constructed in a porcine model. We recruited students, residents, and surgeons to perform perfusion assessment of the segments in white light (WL), with ICG-FA, and after q-ICG, all blinded to the degree of devascularization. RESULTS: Forty-five participants fulfilled the study (18 novices, 12 intermediates, and 15 experienced). ICG and q-ICG helped the novices correctly detect the healthy bowel segments to experienced surgeons' level. ICG and q-ICG also helped novice surgeons to perform safer resections in healthy tissue compared with normal WL. The relative risk (RR) of leaving ischemic tissue in WL and ICG compared with q-ICG, even for experienced surgeons was substantial, intermediates (RR = 8.9, CI95% [4.0;20] and RR = 6.2, CI95% [2.7;14.1]), and experienced (RR = 4.7, CI95% [2.6;8.7] and RR = 4.0, CI95% [2.1;7.5]). CONCLUSION: Q-ICG seems to guide surgeons, regardless of experience level, to safely perform resection in healthy tissue, compared with standard WL. Future research should focus on this novel tool's clinical impact.

Reliable and valid assessment of procedural skills in resuscitative endovascular balloon occlusion of the aorta.

BACKGROUND: Valid and reliable assessment of skills is essential for improved and evidence-based training concepts. In a recent study, we presented a novel tool to assess procedural skills in resuscitative endovascular balloon occlusion of the aorta (REBOA), REBOA-RATE, based on international expert consensus. Although expert consensus is a strong foundation, the performance of REBOA-RATE has not been explored. The study aimed to examine the reliability and validity of REBOA-RATE. METHODS: This was an experimental simulation-based study. We enrolled doctors with three levels of expertise to perform two REBOA procedures in a simulated scenario of out-of-hospital cardiac arrest. Procedures were video-recorded, and videos were blinded and randomized. Three clinical experts independently rated all procedures using REBOA-RATE. Data were analyzed using Messick's framework for validity evidence, including generalizability analysis of reliability and determination of a pass/fail standard. RESULTS: Forty-two doctors were enrolled: 16 novices, 13 anesthesiologists, and 13 endovascular experts. They all performed two procedures, yielding 84 procedures and 252 ratings. The REBOA-RATE assessment tool showed high internal consistency (Cronbach's α = 0.95) and excellent interrater reliability (intraclass correlation coefficient, 0.97). Assessment using one rater and three procedures could ensure overall reliability suitable for high-stakes testing (G-coefficient >0.80). Mean scores (SD) for the three groups in the second procedure were as follows: novices, 32% (24%); anesthesiologists, 55% (29%); endovascular experts, 93% (4%) (p < 0.001). The pass/fail standard was set at 81%, which all experts but no novices passed. CONCLUSION: Data strongly support the reliability and validity of REBOA-RATE, which successfully discriminated between all experience levels. The REBOA-RATE assessment tool requires minimal instruction, and one rater is sufficient for reliable assessment. Together, these are strong arguments for the use of REBOA-RATE to assess REBOA skills, allowing for competency-based training and certification concepts. LEVEL OF EVIDENCE: Diagnostic test, no or poor gold standard, level V.

Time to maximum indocyanine green fluorescence of gastric sentinel lymph nodes and feasibility of combined indocyanine green/sodium fluorescein gastric lymphography.

PURPOSE: Indocyanine green (ICG) and sodium fluorescein (SF) are fluorescent dyes used for sentinel lymph node mapping. In oncological gastric surgery, ICG lymphography has increased the number of resected lymph nodes. However, the optimal time to administer ICG is unclear, and both preoperative and intraoperative injections have been practised. As dye spillage will diminish lymphogram visibility, a second dye with different excitation and emission spectra may present a clinical alternative. We measured the time until maximum ICG fluorescence of gastric sentinel lymph nodes and investigated the feasibility of combined lymphography with two fluorescent dyes: ICG and SF. METHODS: Ten Danish Landrace/Yorkshire pigs were used in this study. After completion of the laparoscopic setup, ICG and then SF were endoscopically injected into the gastric submucosa. Lymphograms for both dyes were recorded, and the time until maximum ICG sentinel lymph node fluorescence was determined. RESULTS: The mean time until maximum ICG fluorescence of gastric sentinel lymph nodes was 50 s (± 12.5), and the fluorescent signal then remained stable until the end of the recorded period (45 min). A lymphogram showing both ICG and SF was acquired for eight of the ten pigs. CONCLUSIONS: Because of the short time until maximum ICG fluorescence of sentinel lymph nodes, intraoperative injections could be a sufficient alternative to preoperative injections for oncological gastric surgery. Combined ICG and SF lymphography was feasible and resulted in clear lymphograms with no interference between the two dyes. The ability to use multiple dyes during a surgical procedure offers the exciting prospect of simultaneously assessing perfusion and performing fluorescence lymphography.

Automatic and Objective Assessment of Motor Skills Performance in Flexible Bronchoscopy.

BACKGROUND: Motor skills have been identified as a useful measure to evaluate competency in bronchoscopy. However, no automatic assessment system of motor skills with a clear pass/fail criterion in flexible bronchoscopy exists. OBJECTIVES: The objective of the study was to develop an objective and automatic measure of motor skills in bronchoscopy and set a pass/fail criterion. METHODS: Participants conducted 3 bronchoscopies each in a simulated setting. They were equipped with a Myo Armband that measured lower arm movements through an inertial measurement unit, and hand and finger motions through electromyography sensors. These measures were composed into an objective and automatic composite score of motor skills, the motor bronchoscopy skills score (MoBSS). RESULTS: Twelve novices, eleven intermediates, and ten expert bronchoscopy operators participated, resulting in 99 procedures available for assessment. MoBSS was correlated with a higher diagnostic completeness (Pearson's correlation, r = 0.43, p < 0.001) and a lower procedure time (Pearson's correlation, r = -0.90, p < 0.001). MoBSS was able to differentiate operator performance based on the experience level (one-way ANOVA, p < 0.001). Using the contrasting groups' method, a passing score of -0.08 MoBSS was defined that failed 30/36 (83%) novice, 5/33 (15%) intermediate, and 1/30 (3%) expert procedures. CONCLUSIONS: MoBSS can be used as an automatic and unbiased assessment tool for motor skills performance in flexible bronchoscopy. MoBSS has the potential to generate automatic feedback to help guide trainees toward expert performance.

Characterization of Lung Tumors that the Pulmonologist can Biopsy from the Esophagus with Endosonography (EUS-B-FNA).

BACKGROUND: According to guidelines, it is possible to biopsy lung tumors "immediately adjacent to the esophagus" with EUS-B-FNA. However, it is unknown what "immediately adjacent" exactly means. OBJECTIVE: to investigate the possibility of achieving EUS-B-FNA biopsies from a lung tumor depending on the distance from the esophagus and to establish the maximal allowable distance between the tumor and the esophagus. METHODS: In a prospective observational study, we included patients with a lung tumor located maximum 6 cm from the esophagus and indication of EUS-B-FNA from the tumor. The tumors were of different sizes. In a plot presenting the tumor size-distance relationship in cases with (biopsy) versus without (non-biopsy) successful EUS-B-FNA, a separation line representing the threshold between the groups were identified and a biopsy-index equation established. The maximal tumor-size corrected distance (TSCD) was calculated using the residuals to the separation line. RESULTS: In total, 70 patients were included. EUS-B-FNA from the lung tumor was possible in 46 patients. All tumors with a distance from the esophagus below 19 mm could be biopsied. The maximal allowable esophagus-tumor distance depended on tumor size. From the separation line, a biopsy-index equation was established with the sensitivity of 93.5%, a specificity of 100%, and total accuracy of 95.7%. The TSCD was 31 mm (sensitivity: 95.7%, specificity 75.0%, and accuracy: 88.6%). CONCLUSION: We established a biopsy-index equation to predict the achievability of a lung tumor using EUS-B-FNA depending on distance to esophagus and tumor size. A general maximal TSCD was 31 mm.