The relationship between perioperative central venous oxygen saturation and postoperative complications in highly invasive gastroenterological surgery.

Purpose: Operations for malignant diseases of the bile duct, pancreas, and esophagus are the most invasive gastroenterological surgeries. The frequency of complications after these surgeries is high, which affects the postoperative course and mortality. In patients who undergo these types of surgeries, continuous monitoring of the perioperative central venous oxygen saturation (ScvO2) is possible via a central venous catheter. We aimed to investigate the relationship between continuously monitored perioperative ScvO2 values and postoperative complications. Methods: The medical records of 115 patients who underwent highly invasive gastroenterological surgeries and ScvO2 monitoring from April 2012 to March 2014 were analyzed. Sixty patients met the inclusion criteria, and their ScvO2 levels were continuously monitored perioperatively. The relationship between ScvO2 levels and major postoperative complications, defined as Clavien-Dindo grade ≥ III, was examined using uni- and multivariate analysis. Results: Thirty patients developed major postoperative complications. The adequate cut-off value derived from receiver operating curves of the postoperative average ScvO2 levels for predicting major complications was 75%. Multivariate analysis revealed that low average postoperative ScvO2 levels (p = 0.016) and blood loss ≥ 1000 mL (p = 0.039) were significant predictors of major postoperative complications. Conclusions: Low perioperative ScvO2 values were associated with an increased risk of major postoperative complications. Continuous ScvO2 monitoring will help prevent postoperative complications.

A surgical instrument motion measurement system for skill evaluation in practical laparoscopic surgery training.

This study developed and validated a surgical instrument motion measurement system for skill evaluation during practical laparoscopic surgery training. Owing to the various advantages of laparoscopic surgery including minimal invasiveness, this technique has been widely used. However, expert surgeons have insufficient time for providing training to beginners due to the shortage of surgeons and limited working hours. Skill transfer efficiency has to be improved for which there is an urgent need to develop objective surgical skill evaluation methods. Therefore, a simple motion capture-based surgical instrument motion measurement system that could be easily installed in an operating room for skill assessment during practical surgical training was developed. The tip positions and orientations of the instruments were calculated based on the marker positions attached to the root of the instrument. Because the patterns of these markers are individual, this system can track multiple instruments simultaneously and detect exchanges. However due to the many obstacles in the operating room, the measurement data included noise and outliers. In this study, the effect of this decrease in measurement accuracy on feature calculation was determined. Accuracy verification experiments were conducted during wet-lab training to demonstrate the capability of this system to measure the motion of surgical instruments with practical accuracy. A surgical training experiment on a cadaver was conducted, and the motions of six surgical instruments were measured in 36 cases of laparoscopic radical nephrectomy. Outlier removal and smoothing methods were also developed and applied to remove the noise and outliers in the obtained data. The questionnaire survey conducted during the experiment confirmed that the measurement system did not interfere with the surgical operation. Thus, the proposed system was capable of making reliable measurements with minimal impact on surgery. The system will facilitate surgical education by enabling the evaluation of skill transfer of surgical skills.

Robotic spleen­preserving suprapancreatic and splenic hilar lymph node dissection using the preemptive retropancreatic approach in total gastrectomy for gastric cancer.

Advanced gastric cancer that has not invaded the greater curvature is a good indication for total gastrectomy (TG) with spleen-preserving suprapancreatic and splenic hilar lymph node dissection (LND). However, the suprapancreatic and splenic hilar LND increases the area of dissection of the pancreas, and prolonged pressure drainage of the pancreas is required to maintain a clear operative view. This can lead to an increased risk of postoperative pancreatic complications. To report the efficacy of our novel preemptive retropancreatic approach (PRA) for the suprapancreatic and splenic hilar LND in robotic TG (RTG). We report our experience with nine patients with gastric cancer who underwent spleen-preserving splenic hilar LND using PRA during RTG at Hokkaido University from October 2018 to November 2021. The PRA involves initial dissection of the left side of the retropancreatic space, followed by the release of the adherence between the retroperitoneum surface and the pancreas (fusion fascia), which provides a good operative field and prevents contact with the pancreas during the suprapancreatic and splenic hilar LND in RTG. The median operating time was 488 min (254-564 min). The median intraoperative bleeding was 55 mL (0-115 mL). One patient had postoperative complications (above grade II of the Clavien-Dindo classification), but there were no postoperative pancreatic complications. The spleen-preserving suprapancreatic and splenic hilar LND using PRA could help to reduce the postoperative pancreatic complications associated with RTG.Trial registration number and date of registration The Hokkaido University Hospital institutional review board approved the data collection and analysis. The trial registration number and date of registration are No. 021-0022 and July 26, retrospectively registered.

Incidence of atrial fibrillation after esophageal cancer surgery with L-carnitine use: a preliminary single-group interventional study.

PURPOSE: We aimed to investigate the POAF rate and blood FABP4 levels after perioperative L-carnitine administration in patients with esophageal cancer. METHODS: L-carnitine (3 g in three divided doses) was administered to 15 patients 2 days before and 3 days after surgery. POAF during the study period and blood FABP4 levels (ELISA) before and after L-carnitine administration were evaluated. Accurate 95% confidence intervals (CI) for POAF incidence and changes in blood FABP4 levels were calculated. The preoperative predicted POAF rate was calculated using an application for esophageal cancer. The correlation between FABP4 levels and the predicted POAF rate was analyzed using Pearson's coefficient (r). RESULTS: Thirteen patients completed this study. The predicted POAF rate was 24% (17%, 34%) (median; interquartile range). The actual incidence of POAF was 7.7% (95% CI: 0.2-36%). Blood FABP4 levels changed from 10.3 to 7.0 ng/mL; the average change was - 3.3 (95% CI: - 6.6 to - 0.1). A positive correlation was found between preoperative FABP4 levels and the predicted POAF rates (r = 0.564). CONCLUSIONS: The POAF rate after esophageal surgery was 7.7% for L-carnitine. L-carnitine may reduce blood FABP4 levels. This preliminary study will contribute to the planning of sample sizes in future randomized trials.

Tele-robotic distal gastrectomy with lymph node dissection on a cadaver.

The purpose of this study is to evaluate the performance of tele-robotic distal gastrectomy (tele-RDG) with lymph node dissection (LND) using a novel Japanese-made surgical robot hinotori™ (Medicaroid, Kobe, Japan) in a cadaver with a presumptive gastric cancer. The Cadaveric Anatomy and Surgical Training Laboratory (CAST-Lab.) at Hokkaido University and Kushiro City General Hospital (KCGH) are connected by a guaranteed type line (1 Gbps), and the distance between the two facilities is 250 km. A patient cart was installed at CAST-Lab, and a surgeon cockpit was installed at KCGH. Tele-RDG with D2 LND was performed on an adult human cadaver. In all surgical processes, the communication environment was stable without image degradation, and the mean round trip time was 40 milliseconds (36.5-55 milliseconds). For tele-RDG with D2 LND, the operation time was 199 minutes without any technical problems. Tele-RDG using hinotori™ was feasible and similar to local robotic RDG.

Impact of Neutrophil Extracellular Traps Identified by Citrullinated Histone H3 Immunohistochemistry for Postoperative Prognosis in Patients with Extrahepatic Cholangiocarcinomas.

BACKGROUND: Neutrophil extracellular traps (NETs) are extracellular chromatin structures composed of cytoplasmic, granular, and nuclear components of neutrophils. Recently, NETs have received much attention for their role in tumor biology; however, their impact on the postoperative prognosis of patients with extrahepatic cholangiocarcinomas (EHCCs) remains unclear. The purpose of this study was to clarify the impact of NETs identified by immunohistochemical citrullinated histone H3 (Cit-H3) staining on postoperative overall survival (OS) in patients with perihilar cholangiocarcinoma (PHCC) and distal cholangiocarcinoma (DCC). METHODS: This study included 318 patients with EHCC (PHCC, n = 192; DCC, n = 126) who underwent surgical resection with curative intent. Neutrophils and NETs were identified by immunohistochemistry using antibodies against CD15 and Cit-H3, respectively. Based on the distribution of CD15 and Cit-H3 expression in the tumor bed, the patients were classified into four groups: one negative group and three subgroups of the positive group (diffuse, intermediate, and focal subgroups). RESULTS: No significant difference was found in the postoperative OS rate depending on the distribution of CD15 expression in patients with PHCC or DCC. However, the three subgroups with positive Cit-H3 expression had significantly poorer OS than the negative group for both PHCC and DCC. Moreover, positive Cit-H3 was an independent OS factor in the multivariable analyses of PHCC (hazard ratio [HR] 1.69, 95% confidence interval [CI] 1.11-2.59, P = 0.0115) and DCC (HR 2.03; 95% CI 1.21-3.42, P = 0.0057). CONCLUSIONS: The presence of NETs in the tumor microenvironment may have adverse prognostic effects in patients with EHCCs.

How many cases do instructor class pediatric surgeons need to experience to be an independent operator in performing advanced endoscopic surgery? A nationwide survey to establish an ideal curriculum for pediatric endoscopic surgery in Japan.

PURPOSE: To ensure the safe spread of pediatric endoscopic surgery, it is essential to build a training curriculum, and a survey of the current situation in Japan is necessary. The present study assessed an efficient training curriculum by clarifying instructor class pediatric surgeons' experiences, including autonomy when performing advanced endoscopic surgeries. METHODS: An online nationwide questionnaire survey was conducted among pediatric surgeons who had Endoscopic Surgical Skill Qualification (ESSQ) and board-certified instructors who had skills comparable to ESSQ. We assessed participants' training experience, opinions concerning the ideal training curriculum, and the correlation between surgical experience and the level of autonomy. The Zwisch scale was used to assess autonomy. RESULTS: Fifty-two participants responded to the survey (response rate: 86.7%). Only 57.7% of the respondents felt that they had received sufficient endoscopic surgery training. Most respondents considered an educational curriculum for endoscopic surgery including off-the-job training essential during the training period. Autonomy had been acquired after experiencing two to three cases for most advanced endoscopic surgeries. CONCLUSION: This first nationwide survey in Japan showed that instructor class pediatric surgeons acquired autonomy after experiencing two to three for most advanced endoscopic surgeries. Our findings suggest that training, especially off-the-job training, has been insufficient.

Robot-assisted laparoscopic total gastrectomy for gastric cancer with common hepatic artery passed behind the portal vein: A case report.

INTRODUCTION: It is essential to identify variations of celiac artery (CA) and common hepatic artery (CHA), using preoperative computed tomography (CT) imaging, for safe gastrectomy and lymph node dissection in gastric cancer (GC) surgery. We report a relatively rare case with the CHA passing behind the portal vein (PV), in which we performed robot-assisted total gastrectomy (RTG) after chemotherapy as conversion surgery. CASE PRESENTATION: A 78-year-old man with GC was referred for conversion surgery. Three-dimensional CT angiography revealed an anomalous CHA passing behind the PV. The anomaly corresponded to type I according to Adachi's classification, and the patient underwent robot-assisted laparoscopic total gastrectomy D2 lymphadenectomy (RTG D2) with Roux-en-Y reconstruction. The operation time was 543 min, blood loss was 115 ml, and no intraoperative complications occurred. The postoperative course was uneventful. CLINICAL DISCUSSION: A word of caution during the surgical procedure entails the manipulation of the suprapancreatic lymph node dissection. Initially, it is crucial to identify the anterior surface of the portal vein (PV) and the nerve plexus surrounding the common hepatic artery (CHA). After completely dissecting the entire circumference, the PV is secured using vascular tape. By gently pulling the vascular tape towards the ventral aspect, a safe execution of lymph node dissection no.8 and 12 on the dorsal side of the PV can be accomplished. Meticulous handling of the anatomical abnormalities observed in the preoperative images may prevent unintended hemorrhage. CONCLUSION: We report a case with vascular anomalies in which RTG D2 was performed successfully as a conversion surgery.

The degree of satisfaction and level of learning in male and female surgical residents: a nationwide questionnaire survey of graduating residents in Japan.

PURPOSE: Since 2002, the Japan Surgical Society has established a board certification system for surgeons to be certified for a specialty. Surgery remains a male-dominated field in Japan. This study aimed to clarify if the Japanese surgical residency training system is equally suitable for female and male residents. METHODS: The Japan Surgical Society conducted the first questionnaire survey regarding the system of surgical training for the residents in 2016. The questionnaire included the degree of satisfaction with 7 aspects of the training system, including the number and variety of cases experienced and duration and quality of instruction, and the learning level for 31 procedures. The degree of satisfaction and level of learning were compared between female and male residents. RESULTS: The degree of satisfaction was similar for all items between female and male residents. Female residents chose breast surgery as their subspecialty more frequently than male residents and were more confident in breast surgery procedures than male residents. Conversely, fewer female residents chose gastrointestinal surgery and were less confident in gastrointestinal surgery procedures than male residents. CONCLUSION: Female residents were as satisfied with the current surgical training system as male residents. However, there may be room for improvement in the surgical system, considering that fewer applications for gastrointestinal surgery come from female residents than from males.

Surgical skills assessment of pancreaticojejunostomy using a simulator may predict patient outcomes: A multicenter prospective observational study.

BACKGROUND: Pancreatoduodenectomy, an advanced surgical procedure with a high complication rate, requires surgical skill in performing pancreaticojejunostomy, which correlates with operative outcomes. We aimed to analyze the correlation between pancreaticojejunostomy assessment conducted in a simulator environment and the operating room and patient clinical outcomes. METHODS: We recruited 30 surgeons (with different experience levels in pancreatoduodenectomy) from 11 institutes. Three trained blinded raters assessed the videos of the pancreaticojejunostomy procedure performed in the operating room using a simulator according to an objective structured assessment of technical skill and a newly developed pancreaticojejunostomy assessment scale. The correlations between the assessment score of the pancreaticojejunostomy performed in the operating room and using the simulator and between each assessment score and patient outcomes were calculated. The participants were also surveyed regarding various aspects of the simulator as a training tool. RESULTS: There was no correlation between the average score of the pancreaticojejunostomy performed in the operating room and that in the simulator environment (r = 0.047). Pancreaticojejunostomy scores using the simulator were significantly lower in patients with postoperative pancreatic fistula than in those without postoperative pancreatic fistula (P = .05). Multivariate analysis showed that pancreaticojejunostomy assessment scores were independent factors in postoperative pancreatic fistula (P = .09). The participants highly rated the simulator and considered that it had the potential to be used for training. CONCLUSION: There was no correlation between pancreaticojejunostomy surgical performance in the operating room and the simulation environment. Surgical skills evaluated in the simulation setting could predict patient surgical outcomes.

Comprehension of fundamental knowledge about pediatric endoscopic surgery: a cross-sectional study in Japan.

BACKGROUND: Pediatric endoscopic surgery has become an alternative to conventional techniques with the development of medical equipment. However, there is no formal, standardized curriculum for pediatric endoscopic surgery, and its requirement remains elusive. The purpose of this study is to determine the baseline knowledge of pediatric surgeons that is considered essential for pediatric laparoscopic and thoracoscopic surgery. METHODS: Sixteen web-based multiple-choice questions based on the fundamental cognitive knowledge of pediatric endoscopic surgery were administered. The questions were created based on the fields covered by the Fundamentals of Laparoscopic Surgery ™ (FLS) certification examination blueprints and eight specific diseases of pediatric surgery. Pediatric surgeons and pediatric surgical trainees participated in this study voluntarily. RESULTS: A total of 122 surgeons participated through the Japanese Society of Pediatric Surgeons. The response rate was 95% (122/128). The total mean examination score of all participants was 79.4% (77.3-81.4%). There were no significant differences in total scores between the board-certified pediatric surgeons without an endoscopic surgical skill qualification and the non-board-certified pediatric surgeons (80.4% vs. 77.1%, p = 0.12). The endoscopic surgical skill-qualified surgeons had significantly higher percentages of correct responses in specific subjects than board-certified pediatric surgeons and surgeons without pediatric board certification (94.3% vs. 82.9%, p = 0.02; 94.3% vs. 77.5%, p = 0.0002). The FLS original subjects' scores were not significantly different among them. The mean score of surgeons who had experienced more than 200 cases of endoscopic surgery, including adult cases, was 83.2% (80.4-85.9%). CONCLUSIONS: A knowledge gap exists between surgeons, board-certified pediatric surgeons, and endoscopic surgical skill-qualified surgeons in Japan. In the field of pediatric surgery, an effective formal curriculum, such as FLS, is required to help address this vast knowledge gap for the safe conduct of endoscopic surgeries.

Automatic assessment of laparoscopic surgical skill competence based on motion metrics.

The purpose of this study was to characterize the motion features of surgical devices associated with laparoscopic surgical competency and build an automatic skill-credential system in porcine cadaver organ simulation training. Participants performed tissue dissection around the aorta, dividing vascular pedicles after applying Hem-o-lok (tissue dissection task) and parenchymal closure of the kidney (suturing task). Movements of surgical devices were tracked by a motion capture (Mocap) system, and Mocap-metrics were compared according to the level of surgical experience (experts: ≥50 laparoscopic surgeries, intermediates: 10-49, novices: 0-9), using the Kruskal-Wallis test and principal component analysis (PCA). Three machine-learning algorithms: support vector machine (SVM), PCA-SVM, and gradient boosting decision tree (GBDT), were utilized for discrimination of the surgical experience level. The accuracy of each model was evaluated by nested and repeated k-fold cross-validation. A total of 32 experts, 18 intermediates, and 20 novices participated in the present study. PCA revealed that efficiency-related metrics (e.g., path length) significantly contributed to PC 1 in both tasks. Regarding PC 2, speed-related metrics (e.g., velocity, acceleration, jerk) of right-hand devices largely contributed to the tissue dissection task, while those of left-hand devices did in the suturing task. Regarding the three-group discrimination, in the tissue dissection task, the GBDT method was superior to the other methods (median accuracy: 68.6%). In the suturing task, SVM and PCA-SVM methods were superior to the GBDT method (57.4 and 58.4%, respectively). Regarding the two-group discrimination (experts vs. intermediates/novices), the GBDT method resulted in a median accuracy of 72.9% in the tissue dissection task, and, in the suturing task, the PCA-SVM method resulted in a median accuracy of 69.2%. Overall, the mocap-based credential system using machine-learning classifiers provides a correct judgment rate of around 70% (two-group discrimination). Together with motion analysis and wet-lab training, simulation training could be a practical method for objectively assessing the surgical competence of trainees.

Robotic real-time vessel navigation using indocyanine green fluorescence for lymph node dissection along the left gastroepiploic vessels during robotic distal gastrectomy - First experience.

Splenic infarction (SI) following gastrectomy is common; severe complications related to SI, such as splenic haemorrhage, abscess formation or rupture, can be fatal. To overcome these problems, we performed real-time vessel navigation using indocyanine green (ICG) fluorescence during robotic distal gastrectomy (RDG). The aim of study is to report the efficacy of robotic real-time vessel navigation for lymph node dissection (LND) along left gastroepiploic vessels (LGEVs). We treated seven patients with gastric cancer who underwent LND along the LGEVs using robotic real-time vessel navigation during RDG at our institution from January 2021 to July 2021. There were no complications (Clavien-Dindo classification II). There were no cases of post-operative SI or spleen-related complications. Robotic real-time vessel navigation using ICG for LND along LGEVs during RDG could help to reduce post-operative spleen-related complications associated with RDG.

Validation study of a skill assessment tool for education and outcome prediction of laparoscopic distal gastrectomy.

BACKGROUND: The Japanese operative-rating scale for laparoscopic distal gastrectomy (JORS-LDG) was developed through cognitive task analysis together with the Delphi method to measure intraoperative performance during laparoscopic distal gastrectomy. This study aimed to investigate the value of this rating scale as an educational tool and a surgical outcome predictor in laparoscopic distal gastrectomy. METHODS: The surgical performance of laparoscopic distal gastrectomy was assessed by the first assistant, through self-evaluation in the operating room and by video raters blind to the case. We evaluated inter-rater reliability, internal consistency, and correlations between the JORS-LDG scores and the evaluation methods, patient characteristics, and surgical outcomes. RESULTS: Fifty-four laparoscopic distal gastrectomy procedures performed by 40 surgeons at 16 institutions were evaluated in the operating room and with video recordings using the proposed rating scale. The video inter-rater reliability was > 0.8. Participating surgeons were divided into the low, intermediate, and high groups based on their total scores. The number of laparoscopic surgeries and laparoscopic gastrectomy procedures performed differed significantly among the groups according to laparoscopic distal gastrectomy skill levels. The low, intermediate, and high groups also differed in terms of median operating times (311, 266, and 229 min, respectively, P < 0.001), intraoperative complication rates (27.8, 11.8, and 0%, respectively, P = 0.01), and postoperative complication rates (22.2, 0, and 0%, respectively, P = 0.002). CONCLUSIONS: The JORS-LDG is a reliable and valid measure for laparoscopic distal gastrectomy training and could be useful in predicting surgical outcomes.

Objective evaluation of laparoscopic surgical skills in wet lab training based on motion analysis and machine learning.

BACKGROUND: Our aim was to build a skill assessment system, providing objective feedback to trainees based on the motion metrics of laparoscopic surgical instruments. METHODS: Participants performed tissue dissection around the aorta (tissue dissection task) and renal parenchymal closure (parenchymal-suturing task), using swine organs in a box trainer under a motion capture (Mocap) system. Two experts assessed the recorded movies, according to the formula of global operative assessment of laparoscopic skills (GOALS: score range, 5-25), and the mean scores were utilized as objective variables in the regression analyses. The correlations between mean GOALS scores and Mocap metrics were evaluated, and potential Mocap metrics with a Spearman's rank correlation coefficient value exceeding 0.4 were selected for each GOALS item estimation. Four regression algorithms, support vector regression (SVR), principal component analysis (PCA)-SVR, ridge regression, and partial least squares regression, were utilized for automatic GOALS estimation. Model validation was conducted by nested and repeated k-fold cross validation, and the mean absolute error (MAE) was calculated to evaluate the accuracy of each regression model. RESULTS: Forty-five urologic, 9 gastroenterological, and 3 gynecologic surgeons, 4 junior residents, and 9 medical students participated in the training. In both tasks, a positive correlation was observed between the speed-related parameters (e.g., velocity, velocity range, acceleration, jerk) and mean GOALS scores, with a negative correlation between the efficiency-related parameters (e.g., task time, path length, number of opening/closing operations) and mean GOALS scores. Among the 4 algorithms, SVR showed the highest accuracy in the tissue dissection task ([Formula: see text]), and PCA-SVR in the parenchymal-suturing task ([Formula: see text]), based on 100 iterations of the validation process of automatic GOALS estimation. CONCLUSION: We developed a machine learning-based GOALS scoring system in wet lab training, with an error of approximately 1-2 points for the total score, and motion metrics that were explainable to trainees. Our future challenges are the further improvement of onsite GOALS feedback, exploring the educational benefit of our model and building an efficient training program.

Predictors of Long-Term Survival in Pancreatic Ductal Adenocarcinoma after Pancreatectomy: TP53 and SMAD4 Mutation Scoring in Combination with CA19-9.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDA) is a fatal cancer for which even unfavorable clinicopathological factors occasionally fail to preclude long-term survival. We sought to establish a scoring system that utilizes measurable pre-intervention factors for predicting survival following surgical resection. METHODS: We retrospectively analyzed 34 patients who died from short-term recurrences and 32 long-term survivors among 310 consecutively resected patients with PDA. A logistic regression model was used to define factors related to clinical parameters, molecular profiles of 18 pancreatic cancer-associated genes, and aberrant expression of major tumor suppressors. RESULTS: Carbohydrate antigen 19-9 (CA19-9) had the best ability to classify patients with short-term recurrence and long-term survivors [odds ratio 21.04, 95% confidence interval (CI) 4.612-96.019], followed by SMAD4 and TP53 mutation scoring (odds ratio 41.322, 95% CI 3.156-541.035). Missense TP53 mutations were strongly associated with the nuclear expression of p53, whereas truncating mutations were associated with the absence of nuclear p53. The former subset was associated with a worse prognosis. The combination of aberrant SMAD4 and mutation types of TP53 exhibited a better resolution for distinguishing patients with short-term recurrences from long-term survivors (compared with the assessment of the number of mutated KRAS, CDKN2A, TP53, and SMAD4 genes). Calibration of mutation scores combined with CA19-9 in a logistic regression model setting demonstrated a practical effect in classifying long survivors and patients with early recurrence (c-statistic = 0.876). CONCLUSIONS: Genetic information, i.e., TP53 mutation types and SMAD4 abnormalities, combined with CA19-9, will be a valuable tool for improving surgical strategies for pancreatic cancer.

A novel laparoscopic near-infrared fluorescence spectrum system with indocyanine green fluorescence overcomes limitations of near-infrared fluorescence image-guided surgery.

BACKGROUND: Near-infrared (NIR) fluorescence image-guided surgery (FIGS) introduces a revolutionary new approach to address this basic challenge in minimally invasive surgery. However, current FIGS systems have some limitations - the infrared rays cannot detect and visualise thick tissues with low concentrations of the fluorescent agent. We established a novel laparoscopic fluorescence spectrum (LFS) system using indocyanine green (ICG) fluorescence to overcome these limitations. MATERIALS AND METHODS: Bovine serum albumin (BSA) was conjugated to ICG, and the mixtures were serially diluted at 5 × 10-8-5 × 10-1 mg/mL. We used the LFS system and a NIR camera system (NLS; SHINKO OPTICAL CO., LTD Tokyo, Japan) to determine the optical dilution for the fluorescence detection. BSA was conjugated to ICG (5.0 × 10-2 mg/mL) and used to coat the clips. We attempted to identify the fluorescence-coated clip from the serosal side of the cadaveric porcine stomach tissues using the LFS system and the NIR camera system. We measured the depth of the cadaveric porcine stomach wall at the thickest part that could be confirmed. RESULTS: We could not visualise fluorescence concentrations <2.5 × 10-3 mg/mL using the NIR camera system. The spectrum was detected at a concentration <2.5 × 10-3 mg/mL. We were able to identify the spectrum of ICG (829 nm) to a 13-mm depth of cadaveric porcine stomach wall by using the LFS system but could not identify the same with the NIR camera system regardless of wall thickness. CONCLUSIONS: The novel LFS system with NIR fluorescence imaging in this ex vivo and cadaveric porcine model was confirmed useful at deeper depths and lower concentrations. Based on these findings, we anticipate that the LFS system can be integrated and routinely used in minimally invasive surgery.

Outcomes of laparoscopic total gastrectomy in elderly patients: a propensity score matching analysis.

PURPOSE: This study evaluated the short-term outcomes and prognosis after laparoscopic total gastrectomy (LTG) in elderly patients aged ≥ 80 years in a multicenter retrospective cohort study using propensity score matching. METHODS: We retrospectively enrolled 440 patients who underwent curative LTG for gastric cancer at six institutions between January 2004 and December 2018. Patients were categorized into an elderly patient group (EG; age ≥ 80 years) and non-elderly patient group (non-EG; age < 80 years). Patients were matched using the following propensity score covariates: sex, body mass index, American Society of Anesthesiologists physical status, extent of lymph node dissection, and Japanese Classification of Gastric Carcinoma stage. Short-term outcomes and prognoses were compared. RESULTS: We identified 37 propensity score-matched pairs. The median operative time was significantly shorter, and postoperative stay was longer in the EG. In terms of postoperative outcomes, the rates of all complications were comparable. The median follow-up period of the EG and non-EG was 11.5 (1-106.4) months and 35.7 (1-110.0) months, respectively; there were significant differences in 5-year overall survival between the two groups (EG, 58.5% vs. non-EG, 91.5%; P = 0.031). However, there were no significant differences in 5-year disease-specific survival (EG, 62.1% vs. non-EG, 91.5%; P = 0.068) or 5-year disease-free survival (EG, 52.9% vs. non-EG, 60.8%; P = 0.132). CONCLUSIONS: LTG seems to be safe and feasible in elderly patients. LTG had a limited effect on morbidity, disease recurrence, and survival in elderly patients. Therefore, age should not prevent elderly patients from benefitting from LTG.

Targeted amplicon sequencing for primary tumors and matched lymph node metastases in patients with extrahepatic cholangiocarcinoma.

BACKGROUND: Lymph node metastasis (LNM) is one of the most adverse prognostic factors in extrahepatic cholangiocarcinoma (EHCC) cases. As next-generation sequencing technology has become more widely available, the genomic profile of biliary tract carcinoma has been clarified. However, whether LNMs have additional genomic alterations in patients with EHCC has not been investigated. Here, we aimed to compare the genomic alterations between primary tumors and matched LNMs in patients with EHCC. METHODS: Sixteen patients with node-positive EHCCs were included. Genomic DNA was extracted from tissue samples of primary tumors and matched LNMs. Targeted amplicon sequencing of 160 cancer-related genes was performed. RESULTS: Among the 32 tumor samples from 16 patients, 91 genomic mutations were identified. Genomic mutations were noted in 31 genes, including TP53, MAP3K1, SMAD4, APC, and ARID1A. TP53 mutations were most frequently observed (12/32; 37.5%). Genomic mutation profiles were highly concordant between primary tumors and matched LNMs (13/16; 81.3%), and an additional genomic mutation of CDK12 was observed in only one patient. CONCLUSION: Genomic mutations were highly concordant between primary tumors and matched LNMs, suggesting that genotyping of archived primary tumor samples may help predict genomic mutations of metastatic tumors in patients with EHCC.