To assess the concordance of CT-based radiological, surgical, and histopathological determination of vascular invasion in pancreatic ductal adenocarcinoma (PDAC). This retrospective single-center study included 103 treatment-naive PDAC patients (median age 68 years, male 61

Abstract Background Current imaging assessment for pancreatic cancer resectability demonstrates problematic inter-observer variability, with only fair-to-moderate agreement among experienced raters. Virtual reality technology offers stereoscopic three-dimensional visualization that may improve diagnostic accuracy and agreement. However, optimal visualization strategies for clinical adoption remain unclear. Methods Ten hepatopancreatobiliary surgeons from two high-volume centers were randomized 1:1 to assess twelve contrast-enhanced CT cases using either VR volumetric rendering or CSI. Primary outcomes included inter-rater agreement, diagnostic accuracy against expert reference standard, assessment time, and surgeon confidence. Statistical analysis employed Fleiss’ κ for inter-rater agreement and two-sided Mann–Whitney U tests on surgeon-level summary measures for between-group comparisons. Results CSI display on 2D screens achieved substantial inter-rater agreement for resectability assessment (κ = 0.609) while VR demonstrated only slight agreement (κ = 0.127). Diagnostic accuracy was superior with CSI (84.7% vs. 79.7%), with the most pronounced difference in resectability determination (83.3% vs. 58.3%, p = 0.033). VR users reported significantly lower confidence (4.85 ± 1.15 vs. 6.32 ± 0.77, p = 0.028). Assessment times were comparable between groups (median 313.5 s vs. 327.5 s, p = 1.00). Conclusions In this preliminary investigation, our VR visualization strategy demonstrated lower diagnostic accuracy and inter-rater agreement than CSI. However, prior studies suggest that VR systems employing alternative, hybrid visualization approaches may improve inter-rater agreement, indicating that visualization strategy, rather than VR technology per se, is the primary determinant of utility. Trial registration DRKS00033932 (German Clinical Trials Register), registered prospectively.

Background:Robotic-assisted liver surgery (RALSs) has numerous advantages over laparoscopic and open procedures. However, prior abdominal surgeries (PAS) are frequently considered as constraints for RALSs. Our study evaluated the impact of PAS on the intraoperative course and postoperative outcomes after RALSs. Materials and methods:For this retrospective cohort study, clinicopathological data were collected from all patients who underwent RALSs at the University Hospital Münster between December 2018 and March 2024. Patients were stratified based on whether they had undergone PAS or not (NPAS), the intraoperative course and postoperative outcomes after RALSs were analyzed. Results:In total, 116 patients were identified, 79 patients had undergone PAS, and 37 patients had not. The mean surgery time, conversion rate, intraoperative complications, postoperative intensive care unit (ICU) admissions and length of hospital stay (LOS) were comparable between the two groups. Forty-three patients had postoperative complications, without significant difference (PAS: 34 patients, NPAS: 9 patients). No deaths were observed within 30 days of surgery. One PAS patient died within 90 days of surgery. Discussion:Perioperative outcomes in patients undergoing RALSs were comparable in between PAS and NPAS patients and PAS was not associated with an increased risk of postoperative complications. PAS alone should not be considered as contraindication for RALSs.

INTRODUCTION AND OBJECTIVES:Liver resection is the standard treatment for resectable liver tumors and metastases. However, mortality and morbidity remain significant concerns, particularly for patients with chronically elevated central venous pressure (CVP), which increases perioperative complication risks. The optimal parenchymal transection technique for these patients remains unclear, necessitating further research. MATERIALS AND METHODS:This study established an innovative porcine model for high-CVP liver resection. Animals were divided into two groups: a control group (CVP ≤ 5 mmHg, low-CVP) and an intervention group (CVP ≥ 10 mmHg, high-CVP). A left lateral liver resection was performed using three parenchymal transection techniques: clamp-crush (CC), harmonic scalpel (HS), and stapler (ST). The primary endpoint was intraoperative blood loss, while secondary endpoints included transection time and bile leakage. RESULTS:No differences were found for blood loss or transection time among the low-CVP subgroups. In the high-CVP group, the HS and ST techniques were associated with significantly reduced blood loss and faster transection times than the CC technique. While transection times for the HS and ST were similar between the low- and high-CVP groups, they were significantly longer with the CC technique in the high-CVP group. The incidence of bile leakage was comparable across all three techniques. CONCLUSIONS:This pilot study demonstrates superior outcomes for HS and ST techniques in high-CVP liver resections. Insights from this large animal model provide a basis for investigating optimal transection techniques for chronically elevated CVP, bridging preclinical research and clinical practice.

Surgical training persists of intensive work, incessant practice, and, most importantly, experience. Owing to the changing surgical environment, increasing specialization, and rapid development of minimally invasive techniques, new innovative approaches in surgical training are necessary to achieve excellent postgraduate education. Here, we introduce a surgical skills lab that offers a multi-course program featuring a concise, modular curriculum comprising well-defined and simple-to-follow procedures, progressively moving surgical techniques from ex vivo to in vivo settings. The evaluation of the course was conducted by analyzing the participants’ self-assessment before and after the course. Over the time of ten years, we conducted one-day surgical training courses covering basic surgical techniques, gastrointestinal anastomosis, visceral resection techniques, and techniques in vascular surgery with a total of 348 participants. To assess differences in the self-evaluation of surgical skills before and after each course, a questionnaire (non-validated self-report 5-point Likert scale) was administered to each participant. Results were analyzed with t-test for paired samples. Before the course, most participants had no practical knowledge of most exercises, and major help was needed. However, after training, the majority of participants were able to perform the surgical techniques independently with little or no assistance. Moreover, a statistical analysis comparing pre- and post-course self-assessment scores for surgical skills revealed significant improvements (p < 0.05) after the course. During the one-day course, it was possible to teach and perform diverse surgical procedures under the guidance of experienced surgeons. The independent reproducibility of the learned material after the course is not yet known, therefore, further investigation is necessary to provide additional information to improve the program. However, with this step-by-step training, we were able to conduct a successful teaching program, shown by the fact that the participants showed significant improvement. Thus, the training presented in this study can serve as a guide for teaching surgical skills outside of the operating room.

Perivascular epithelioid cell tumors (PEComas) are rare mesenchymal neoplasms characterized by distinctive histological and immunohistochemical features. The tumor family originally included renal angiomyolipoma and pulmonary clear cell 'sugar' tumor. The present report describes a case of a hepatic PEComa in a 43-year-old man with no comorbidities and otherwise good health, who presented with abdominal discomfort and right upper quadrant tenderness. Laboratory findings were unremarkable. The patient underwent robotic-assisted left hemihepatectomy, and the results indicated negative margins. Histologically, the tumor consisted of epithelioid, polyhedral cells with central to eccentric nuclei and abundant eosinophilic cytoplasm, arranged in nests and separated by a delicate capillary network. Central necrosis was present, closely resembling hepatocellular carcinoma. Immunohistochemistry demonstrated strong expression of Melan-A and HMB-45, focal positivity for smooth muscle actin, and negativity for other lineage markers. The Ki-67 proliferation index was <5%. CD34 immunostaining demonstrated strong positivity in the endothelial cells, thereby highlighting the rich capillary network associated with the tumor. Molecular analysis supported the diagnosis. Next-generation sequencing identified pathogenic variants in TSC2 (exons 10 and 27), while fluorescence in situ hybridization excluded a TFE3 gene rearrangement at Xp11.23, ruling out TFE3-associated PEComa. The current case illustrated the diagnostic challenges of hepatic PEComas, given their rarity and morphologic overlap with primary liver tumors. It emphasizes the necessity of integrating histopathology, immunohistochemistry and molecular testing for accurate diagnosis, thereby guiding appropriate clinical management and avoiding misclassification.

The coronavirus disease (COVID-19) has significantly changed healthcare systems and medical education. Universities were required to develop innovative curricula based on remote and distance education to continue medical education. This prospective questionnaire-based study aimed to investigate the impact of COVID-19-associated remote learning on the surgical training of medical students. A 16-item questionnaire-based survey was distributed to medical students at the University Hospital of Münster before and after a surgical skills laboratory (SSL). Two cohorts were included: summer semester 2021 (COV-19), with rigorous social-distancing restrictions requiered SSL to be remotely, and winter semester 2021 (postCOV-19), in which the SSL was provided as a face-to-face, hands-on course. Both, cohorts showed a significant improvement in self-assessment of pre- and post-course confidence. While no significant difference in the average gain in self-confidence for sterile working was observed between the two cohorts, improvement in self-confidence was significantly higher in the COV-19 cohort regarding skin suturing and knot tying (p < 0.0001). However the average improvement regarding history and physical was significantly higher in the postCOV-19 cohort (p < 0.0001). In subgroup analysis, gender-associated differences varied in the two cohorts and were not related to specific subtasks, while age-stratified analysis revealed superior results for younger students. The results of our study underline the usability, feasibility, and adequacy of remote learning for the surgical training of medical students. The on-site distance education version, presented in the study, allows the continuing of hands-on experience in a safe environment in compliance with governmental social-distancing restrictions.

Lebermetastasen von G1- und G2-GEP-NET sollen reseziert werden, wenn ihre Entfernung im Gesunden möglich erscheint (sog. R0-Resektion). Entscheidend hierfür sind die Tumorgröße, die Anzahl der Metastasen und das Verteilungsmuster. Minimalinvasive Resektionen sollten den Standard bei GEP-NET-Lebermetastasen darstellen, da Patienten nach minimalinvasiven Resektionen weniger postoperative Komplikationen erleiden und vermutlich auch ein besseres Langzeitoutcome haben. Im Falle von hormonaktiven Metastasen kann nach dem Ausschöpfen der konservativen und interventionellen Therapieverfahren eine Debulking-OP indiziert sein, wenn mindestens ca. 80–90 % der Tumormasse entfernt werden können. Indikationen zur Lebertransplantation stellen die Ausnahme bei hoch-selektionierten Patienten dar. Obwohl Patienten nach kurativ intendierter Leberresektion häufig Rezidive erleiden, beträgt das 5-Jahres-Überleben der resezierten Patienten ca. 85 %.

Background Since autologous veins are unavailable when needed in more than 20% of cases in vascular surgery, the production of personalized biological vascular grafts for implantation has become crucial. Surface modification of decellularized xenogeneic grafts with vascular cells to achieve physiological luminal coverage and eventually thromboresistance is an important prerequisite for implantation. However, ex vivo thrombogenicity testing remains a neglected area in the field of tissue engineering of vascular grafts due to a multifold of reasons. Methods After seeding decellularized bovine carotid arteries with human endothelial progenitor cells and umbilical cord-derived mesenchymal stem cells, luminal endothelial cell coverage (LECC) was correlated with glucose and lactate levels on the cell supernatant. Then a closed loop whole blood perfusion system was designed. Recellularized grafts with a LECC > 50% and decellularized vascular grafts were perfused with human whole blood for 2 h. Hemolysis and complete blood count evaluation was performed on an hourly basis, followed by histological and immunohistochemical analysis. Results While whole blood perfusion of decellularized grafts significantly reduced platelet counts, platelet depletion from blood resulting from binding to re-endothelialized grafts was insignificant ( p = 0.7284). Moreover, macroscopic evaluation revealed thrombus formation only in the lumen of unseeded grafts and histological characterization revealed lack of CD41 positive platelets in recellularized grafts, thus confirming their thromboresistance. Conclusion In the present study we were able to demonstrate the effect of surface modification of vascular grafts in their thromboresistance in an ex vivo whole blood perfusion system. To our knowledge, this is the first study to expose engineered vascular grafts to human whole blood, recirculating at high flow rates, immediately after seeding.

The aim of this study was to investigate the dynamic changes of circulating tumor cells (CTCs) in patients with hepatocellular carcinoma (HCC) before and immediately after conducting a microwave ablation (MWA) and conventional transarterial chemoembolization (C-TACE). Additionally, the CTCs short-term dynamics were compared with the clinical course of the HCC-patients. Blood samples from 17 patients with HCC who underwent MWA (n = 10) or C-TACE (n = 7) were analyzed. Venous blood was taken before and immediately after the radiological interventions to isolate and quantify CTCs using flow cytometry. CTCs were identified as CD45- and positive for the markers ASGPR, CD146 and CD274 (PD-L1). Patients were followed of up to 2.2 years after the radiological intervention. CTCs were detected in 13 HCC patients (76%) prior to the radiological interventions. The rate of CTCs was significantly decreased after the intervention in patients treated with MWA (0.4 CTCs/mL of blood, p = 0.031). However, no significant differences were observed in patients who received C-TACE (0.3 CTCs/mL of blood, p = 0.300). Overall, no correlation was found between the CTCs rate before and after the radiological intervention and recurrence rate of HCC. This preliminary data could confirm the tumoricidal effects of MWA in patients with HCC by significantly decreasing CTCs rate. In our study, we were able to detect CTCs in HCC patients using 3 different tumor markers. This preliminary data shows significant lower CTCs detected in response to MWA. However, large-scale randomized clinical trials are needed to determine the future role and the prognostic relevance of CTCs following this treatment.

Islet-based recellularization of decellularized, repurposed rat livers may form a transplantable Neo-Pancreas. The aim of this study is the establishment of the necessary protocols, the evaluation of the organ structure and the analysis of the islet functionality ex vivo. After perfusion-based decellularization of rat livers, matrices were repopulated with endothelial cells and mesenchymal stromal cells, incubated for 8 days in a perfusion chamber, and finally repopulated on day 9 with intact rodent islets. Integrity and quality of re-endothelialization was assessed by histology and FITC-dextran perfusion assay. Functionality of the islets of Langerhans was determined on day 10 and day 12 via glucose stimulated insulin secretion. Blood gas analysis variables confirmed the stability of the perfusion cultivation. Histological staining showed that cells formed a monolayer inside the intact vascular structure. These findings were confirmed by electron microscopy. Islets infused via the bile duct could histologically be found in the parenchymal space. Adequate insulin secretion after glucose stimulation after 1-day and 3-day cultivation verified islet viability and functionality after the repopulation process. We provide the first proof-of-concept for the functionality of islets of Langerhans engrafted in a decellularized rat liver. Furthermore, a re-endothelialization step was implemented to provide implantability. This technique can serve as a bioengineered platform to generate implantable and functional endocrine Neo-Pancreases.

BACKGROUND Potential benefits of laparoscopic liver resections (LLRs) over open liver resections (OLRs) such as the clinical outcome and health-related quality of life (HRQoL) have not convincingly been investigated, yet. PATIENTS AND METHODS All patients who had undergone LLR and OLR at our department between 1 June 2014 and 10 October 2016 were identified. HRQoL was assessed using the short form 36 (SF-36). All patients who returned the surveys were then retrospectively analysed with regards to the perioperative outcome. RESULTS We received 66 eligible questionnaires (50%). The number of major liver resections did not significantly differ between both groups (LLR: 11 [33%], OLR: 16 [48%], P = 0.211).The proportion of patients with two or more co-morbidities (P = 0.044) and liver cirrhosis (P = 0.016), respectively, was significantly higher in the LLR group, when compared to the OLR group (LLR: 11 [33%] vs. 3 of 33 patients [9%], P = 0.016). HRQoL scores were good with no significant differences between both groups. Among these patients, there were significantly more pulmonary complications in the OLR group, and length of hospital stay was longer when compared to the LLR group. CONCLUSIONS Laparoscopic liver surgery can be performed safely even in multimorbid elderly patients resulting in high HRQoL scores.