AR visualizations in laparoscopy: surgeon preferences and depth assessment of vascular anatomy.

Introduction: This study compares five augmented reality (AR) vasculature visualization techniques in a mixed-reality laparoscopy simulator with 50 medical professionals and analyzes their impact on the surgeon. Material and methods: ​​The different visualization techniques' abilities to convey depth were measured using the participant's accuracy in an objective depth sorting task. Demographic data and subjective measures, such as the preference of each AR visualization technique and potential application areas, were collected with questionnaires. Results: Despite measuring differences in objective measurements across the visualization techniques, they were not statistically significant. In the subjective measures, however, 55% of the participants rated visualization technique II, 'Opaque with single-color Fresnel highlights', as their favorite. Participants felt that AR could be useful for various surgeries, especially complex surgeries (100%). Almost all participants agreed that AR could potentially improve surgical parameters, such as patient safety (88%), complication rate (84%), and identifying risk structures (96%). Conclusions: More studies are needed on the effect of different visualizations on task performance, as well as more sophisticated and effective visualization techniques for the operating room. With the findings of this study, we encourage the development of new study setups to advance surgical AR.

Regional transplant rates depend more on physician-dependent variables than on proximity to transplant center.

PURPOSE: The objective of this work was to uncover inequalities in access to liver transplantation in Bavaria, Germany. METHODS: For this purpose, the annual transplantation rate per 1 million inhabitants for the respective districts was determined from the aggregated postal codes of the place of residence of transplanted patients. The variables examined were proximity and travel time to the nearest transplant center, as well as the care category of the regional hospital. In addition, we assessed whether the head of gastroenterology at the regional hospital through which liver transplant candidates are referred was trained at a liver transplant center. RESULTS: We could not demonstrate a direct relationship between proximity or travel time to the nearest transplant center and access to liver transplantation. Multivariate regression analysis shows that liver transplant training (p < 0.0001) of the chief physician (gastroenterologist) of the regional hospital was the most decisive independent factor for access to liver transplantation within a district. CONCLUSION: We show that the transplant training experience of the head of gastroenterology at a regional hospital is an independent factor for the regional transplantation rate. Therefore, it appears important to maintain some liver transplant expertise outside the transplant centers in order to properly identify and assign potential transplant candidates for transplantation.

Textbook outcome in hepato-pancreato-biliary surgery: systematic review.

BACKGROUND: Textbook outcome (TO) is a multidimensional measure reflecting the ideal outcome after surgery. As a benchmarking tool, it provides an objective overview of quality of care. Uniform definitions of TO in hepato-pancreato-biliary (HPB) surgery are missing. This study aimed to provide a definition of TO in HPB surgery and identify obstacles and predictors for achieving it. METHODS: A systematic literature search was conducted using PubMed, Embase, and Cochrane Database according to PRISMA guidelines. Studies published between 1993 and 2021 were retrieved. After selection, two independent reviewers extracted descriptive statistics and derived summary estimates of the occurrence of TO criteria and obstacles for achieving TO using co-occurrence maps. RESULTS: Overall, 30 studies were included. TO rates ranged between 16-69 per cent. Commonly chosen co-occurring criteria to define TO included 'no prolonged length of stay (LOS)', 'no complications', 'no readmission', and 'no deaths'. Major obstacles for achieving TO in HPB surgery were prolonged LOS, complications, and readmission. On multivariable analysis, TO predicted better overall and disease-free survival in patients with cancer. Achievement of TO was more likely in dedicated centres and associated with procedural and structural indicators, including high case-mix index and surgical volume. CONCLUSION: TO is a useful quality measure to benchmark surgical outcome. Future definitions of TO in HPB surgery should include 'no prolonged LOS', 'no complications', 'no readmission', and 'no deaths'.

Stent-graft placement for hepatic arterial bleeding: assessment of technical efficacy and clinical outcome in a tertiary care center.

BACKGROUND: To evaluate technical and clinical results of stent-graft (SG) placement for bleeding from the hepatic artery (HA). METHODS: All patients intended and treated with SG deployment for bleeding from the HA at single center from January 2012 to May 2020 were retrospectively identified, and procedural details, risk factors for rebleeding, SG occlusion and mortality were analyzed. RESULTS: Twenty-seven patients (mean age 68.8 ± 10.1) were identified, and 25 patients underwent 26 SG procedures. Twenty-four patients had recent surgery. The technical success rate was 92.8%. Three patients (3/25) had rebleeding (88% clinical success). Intensive-care need before the procedure (p = 0.013) and smaller stent-graft size (≤4 mm, p = 0.032) were related to clinical failure. Twenty-two patients had follow-up imaging. The SG maintained patency in 10 (45.4%) patients at the most recent imaging. Only placement of SG distal to the HA bifurcation (p = 0.012) was related to occlusion. The 30-day and in-hospital mortality rate after SG was 8% and 24%. In-hospital mortality was associated with the intraabdominal septic source (p = 0.010) and revision surgery (p = 0.001). CONCLUSION: Stent-grafts are effective in the emergent treatment of HA bleeding. Mortality is mainly related to the general condition of the patient, and stent-grafts offer time to treat underlying medical problems sufficiently.

[Novel Examination Procedures for the Assessment of Retinal Artery Occlusion by OCT Angiography]. / Neue Untersuchungsmöglichkeiten in der Beurteilung retinaler Arterienverschlüsse mittels OCT-Angiografie.

Background Retinal artery occlusion (RAO) is the most common primary angiopathy of the retina. With an incidence of 0.01 - 0.15%, this it is a rather rare disease, but is associated with irreversible damage to the retina and a poor prognosis for visual acuity. Since the 1960s - when fluorescence angiography (FA) was developed -, there has been little change in diagnostic investigations. FA is still the standard procedure for the assessment of retinal artery occlusions. With the development of OCT angiography (OCT-A), new multimodal imaging procedures have become possible. Patients/Methods We used Zeiss AngioPlex®-OCT-A technology in combination with the CIRRUS™ HD-OCT 5000 (Carl Zeiss Meditec, Inc., Dublin, USA) to create 6 × 6 mm and 3 × 3 mm volume scans of the area of non-perfusion in patients with RAO. Qualitative OCT-A analysis was performed on retinal images segmented into the superficial and deep retinal capillary plexus. In addition to this, volumetric scans can be segmented to any specific depth of the retina. On the basis of 4 cases, we demonstrate that OCT-A can be used to evaluate RAO. We present typical OCT-A findings. Results OCT-A images allow the detection of non-perfused areas in patients with acute and chronic RAO. The zones of reduced vascular perfusion are differently distributed in the superficial and deep retinal capillary plexus. In both acute and chronic cases of RAO, OCT-A offers important information on retinal vascular perfusion. Conclusion OCT-A can be used in the diagnosis and monitoring of acute and chronic cases of RAO. The advantages of OCT-A are that this technique is non-invasive and allows three dimensional microvascular visualisation within seconds. Although artefacts and the currently limited field of view can make it difficult to interpret OCT-A images reliably, these findings suggest that OCT-A may in future replace FA in the assessment of RAO in most patients.

[ISO 9001:2015 Certification in Quality Management]. / Zertifizierung des Qualitätsmanagements nach DIN EN ISO 9001:2015.

Quality management improves the structures, processes and results of organizations of all kinds. Many practices and clinics have their existing quality management system certified according to ISO 9001, (e.g., to check their own quality management system or to obtain a testimonial against third parties). The latest version ISO 9001:2015 contains some changes, both structurally and in terms of content. These changes can be met with reasonable efforts. An ISO 9001:2015 certification represents a value for your organization, but these advantages are often not directly measurable.

Quality assessment of the guidelines on cystic neoplasms of the pancreas.

BACKGROUND: Though cystic pancreatic neoplasms (CPNs) are being increasingly detected, their evaluation and management are still debated and have lead to publication of multiple guidelines for diagnostic work-up, indications for resection, and non-operative management with follow-up strategies of CPNs. AIMS: To analyze available guidelines in order to evaluate their overall quality and clinical applicability, indications for surgical resection and its extent, modalities and timing of follow-up when non-operative management is indicated. METHODS: After a systematic search of the English literature, we selected eight guidelines for assessment according to the Appraisal of Guidelines, Research and Evaluation in Europe (AGREE) II instrument. RESULTS: One guideline received the lower AGREE score regarding the "scope and purpose", "rigor of development" and "clarity and presentation" domains, whereas one received the best score for "stakeholder involvement" domain. No differences were found among different guidelines regarding the "applicability". The overall quality assessment score showed that only two guidelines were significantly lower than the others. According to the practical utilization recommendation score, four guidelines were considered as having full applicability in clinical practice. CONCLUSION: Existing guidelines provide adequate guidance, at least with the present knowledge, for the management of cystic pancreatic lesions; however, not any one was satisfactory to all aspects related to the management of CPN. An update of the existing guidelines should be considered if and when more evidence-based data are available.

Clinical impact of perioperative myocardial infarction after pancreatic surgery.

BACKGROUND: The aim of this study was to evaluate the incidence, clinical impact and outcome of perioperative myocardial infarction (PMI) in patients undergoing pancreatic surgery. METHODS: A data of 1,625 patients undergoing pancreatic resection were prospectively collected and analysed with regard to PMI. Demographic aspects, co-morbidities and clinical course were evaluated. Cardiac risk factors (ASA and NYHA), postoperative complications and mortality were compared in a match-pair analysis (1:3) with patients without PMI. RESULTS: Twenty-nine patients with PMI after pancreatic surgery were identified. PMI occurred after all types of pancreatic operations and was observed most frequently (72.2%) within the first postoperative week. In a total of 90%, PMI fulfilled the criteria of non-STEMI. Nearly half of the patients (48%) were clinically asymptomatic. Both ASA III and heart failure were more frequent in patients with PMI. The in-hospital mortality was significantly increased after PMI (p < 0.002), with post-pancreatectomy haemorrhage (PPH) as the most relevant underlying risk factor. CONCLUSION: PMI is a rare but severe complication after pancreatic operations, contributing significantly to in-hospital mortality. Clinical management mainly includes an anti-coagulant approach. This may be related with an increased risk for PPH. Therefore, the use of anti-coagulant drugs in the early postoperative period-especially in asymptomatic patients-should be critically evaluated.

Irreversible electroporation of the pig kidney with involvement of the renal pelvis: technical aspects, clinical outcome, and three-dimensional CT rendering for assessment of the treatment zone.

PURPOSE: To analyze irreversible electroporation (IRE) of the pig kidney with involvement of the renal pelvis. MATERIALS AND METHODS: IRE of renal tissue including the pelvis was performed in 10 kidneys in five pigs. Three study groups were defined: group I (two applicators with parallel configuration; n = 11), group II (three applicators with triangular configuration; n = 2), and group III (six applicators with complex configuration; n = 3). After IRE and before euthanasia, pigs underwent contrast-enhanced computed tomography (CT). Technical aspects (radial distance of applicators, resulting mean current), clinical outcome (complications, blood samples), and three-dimensional CT rendering for assessment of the treatment zone (short axis, circularity) were assessed. RESULTS: Radial distances of applicators were 14.3 mm ± 2.8 in group I, 12.3 mm ± 1.9 in group II, and 16.4 mm ± 3.5 in group III. Resulting mean currents were 25.7 A ± 6.5 in group I, 27.0 A ± 7.1 in group II, and 39.4 A ± 8.9 in group III. In group III, two perirenal hematomas were identified. There was no damage to the renal pelvis. During IRE, clinical blood parameters and cardiovascular markers did not change significantly. Short axis measurements were 20.6 mm ± 3.6 in group I, 31.9 mm ± 8.2 in group II, and 39.3 mm ± 2.4 in group III (P < .01 between groups). Circularity scores were 0.8 ± 0.2 in group I, 0.7 ± 0.1 in group II, and 0.7 ± 0.1 in group III, with a score of 1 indicating perfect roundness (P value not significant). CONCLUSIONS: IRE of the pig kidney with involvement of the renal pelvis is feasible and safe. Size but not shape of the treatment zone is significantly affected by applicator configuration.

Design of a prospective clinical study on the agreement between the Continuous GlucoseMonitor, a novel device for CONTinuous ASSessment of blood GLUcose levels, and the RAPIDLab® 1265 blood gas analyser: The CONTASSGLU study.

BACKGROUND: Although a device is needed to continuously measure blood glucose levels within an intensive care setting, and several large-scale prospective studies have shown that patients might benefit from intensive insulin, potassium, or glucose therapy during intensive care, no devices are currently available to continuously assess blood glucose levels in critically ill patients. We conceived the study described here to evaluate the clinical use of the Continuous Glucose Monitor (CGM) performed via a central vein, and to determine the impact of phenomena, such as drift and shift, on the agreement between the CGM and a RAPIDLab® 1265 blood gas analyser (BGA). METHODS/DESIGN: In the CONTinuous ASSessment of blood GLUcose (CONTASSGLU) study, up to 130 patients under intensive care will be fitted with the CGM, an ex vivo device that continuously measures blood glucose and lactate levels. Readings from the device taken 8 h after initial placement and calibration will be compared with values measured by a BGA. For this study, we chose the BGA as it is an established standard point-of-care device, instead of the devices used in certified central laboratories. Nevertheless, we will also independently compare the results from the point-of-care BGA with those determined by a central laboratory-based device. Blood samples will be collected from each patient from the same site in which the CGM will measure blood glucose. Consequently, each participant will serve as their own control, and no randomisation is necessary. The 95% limits of agreement and the corresponding confidence intervals will be calculated and compared with a prespecified clinically acceptable relative difference of 20%. DISCUSSION: Several attempts have been made to develop a device to continuously measure blood glucose levels within an intensive care setting or to use the devices that were originally designed for diabetes management, as several of these devices are already available. However, none of these devices were successful in intensive care settings. CONTASSGLU may well bridge this gap by confirming the ability of the CGM to continuously measure blood glucose levels in intensive care settings. TRIAL REGISTRATION: ClinicalTrials.gov NCT01580176.

Decrease in clinically relevant pancreatic fistula by coverage of the pancreatic remnant after distal pancreatectomy.

BACKGROUND: Pancreatic fistulas after distal pancreatectomy occur in up to 60% of patients with distal pancreatectomy. Several techniques for closure of the pancreatic stump have been advocated, but the best management of stump closure remains controversial. Our aim was to evaluate the clinical benefits of coverage of the pancreatic resection margin by autologous tissue. METHODS: One hundred seventeen consecutive patients underwent distal pancreatectomy at the university hospital in Heidelberg between May 2009 and September 2010. A coverage procedure was performed in 73 of these patients. All patients were recorded prospectively, and the clinical course was evaluated focusing on the occurrence of pancreatic fistula as defined by the International Study Group on Pancreatic Fistula. A treatment cost analysis was performed. RESULTS: The rate of clinically relevant pancreatic fistulas (types B and C) was decreased in patients with coverage compared to the standard controls (type B, 7% vs 9%; type C, 7% vs 25%; P < .002). Patients with a coverage procedure had a shorter duration of stay in the hospital (P < .02), and treatment costs were lower (P < .001) compared to patients without coverage. CONCLUSION: Coverage of the pancreatic remnant after distal pancreatectomy decreases the rate of clinically relevant pancreatic fistulas, duration of stay, and treatment costs. A randomized trial is needed to verify these results.

The need for extended intensive care after pancreaticoduodenectomy for pancreatic ductal adenocarcinoma.

PURPOSE: Pancreaticoduodenectomy (PD) is standard for patients with resectable pancreatic ductal adenocarcinoma (PDAC) in the pancreatic head, neck, and uncinate process, but it is associated with a relatively high morbidity. This study aimed to identify risk factors for extended postoperative intensive care unit (ICU) admission and assess the impact of ICU treatment on patient survival. METHODS: Between October 2001 and June 2008, patients that underwent PD for PDAC in the pancreatic head were identified from a prospective database. Patients admitted to the ICU after an initial recovery period were compared to those not admitted regarding comorbidities, intraoperative parameters, resection size, and tumor biology. RESULTS: Five hundred and forty patients were included. Of these, 17.8% required extended postoperative ICU admission (immediate, 9.3%; delayed, 7.6%). Immediate ICU admission was most frequently required for increased intraoperative blood loss and fluid management. Delayed ICU treatment was most frequently required for hemorrhage, respiratory insufficiency, or pancreatic fistula. Morbidity and 30-day mortality rates were 54.2% and 2.6%, respectively. ICU admission correlated with significantly lower survival rates compared to no ICU admission (P = 0.0155). Multivariate risk factors for ICU admission included a history of diabetes mellitus and heart failure (NYHA I-III), an intraoperative blood transfusion, and a longer operating time. CONCLUSIONS: The need for extended ICU admission is associated with higher in-hospital mortality and reduced long-term outcome. The highest mortality was observed after delayed ICU admission. Preoperative diabetes, heart failure and long operations, and intraoperative blood transfusions substantially increased the risk for ICU requirement.