Single chest drain is not inferior to double chest drain after robotic esophagectomy: a propensity score-matched analysis.

Background: Chest drain management has a significant influence on postoperative recovery after robot-assisted minimally invasive esophagectomy (RAMIE). The use of chest drains increases postoperative pain by irritating intercostal nerves and hinders patients from early postoperative mobilization and recovery. To our knowledge, no study has investigated the use of two vs. one intercostal chest drains after RAMIE. Methods: This retrospective cohort study evaluated patients undergoing elective RAMIE with gastric conduit pull-up and intrathoracic anastomosis. Patients were divided into two groups according to placement of one (11/2020-08/2022) or two (08/2018-11/2020) chest drains. Propensity score matching was performed in a 1:1 ratio, and the incidences of overall and pulmonary complications, drainage-associated re-interventions, radiological diagnostics, analgesic use, and length of hospital stay were compared between single drain and double drain groups. Results: During the study period, 194 patients underwent RAMIE. Twenty-two patients were included after propensity score matching in the single and double chest drain group, respectively. Time until removal of the last chest drain [postoperative day (POD) 6.7 ± 4.4 vs. POD 9.4 ± 2.7, p = 0.004] and intensive care unit stay (4.2 ± 5.1 days vs. 5.3 ± 3.5 days, p = 0.01) were significantly shorter in the single drain group. Overall and pulmonary complications, drainage-associated events, re-interventions, number of diagnostic imaging, analgesic use, and length of hospital stay were comparable between both groups. Conclusion: This study is the first to demonstrate the safety of single intercostal chest drain use and, at least, non-inferiority to double chest drains in terms of perioperative complications after RAMIE.

Ensuring privacy protection in the era of big laparoscopic video data: development and validation of an inside outside discrimination algorithm (IODA).

BACKGROUND: Laparoscopic videos are increasingly being used for surgical artificial intelligence (AI) and big data analysis. The purpose of this study was to ensure data privacy in video recordings of laparoscopic surgery by censoring extraabdominal parts. An inside-outside-discrimination algorithm (IODA) was developed to ensure privacy protection while maximizing the remaining video data. METHODS: IODAs neural network architecture was based on a pretrained AlexNet augmented with a long-short-term-memory. The data set for algorithm training and testing contained a total of 100 laparoscopic surgery videos of 23 different operations with a total video length of 207 h (124 min ± 100 min per video) resulting in 18,507,217 frames (185,965 ± 149,718 frames per video). Each video frame was tagged either as abdominal cavity, trocar, operation site, outside for cleaning, or translucent trocar. For algorithm testing, a stratified fivefold cross-validation was used. RESULTS: The distribution of annotated classes were abdominal cavity 81.39%, trocar 1.39%, outside operation site 16.07%, outside for cleaning 1.08%, and translucent trocar 0.07%. Algorithm training on binary or all five classes showed similar excellent results for classifying outside frames with a mean F1-score of 0.96 ± 0.01 and 0.97 ± 0.01, sensitivity of 0.97 ± 0.02 and 0.0.97 ± 0.01, and a false positive rate of 0.99 ± 0.01 and 0.99 ± 0.01, respectively. CONCLUSION: IODA is able to discriminate between inside and outside with a high certainty. In particular, only a few outside frames are misclassified as inside and therefore at risk for privacy breach. The anonymized videos can be used for multi-centric development of surgical AI, quality management or educational purposes. In contrast to expensive commercial solutions, IODA is made open source and can be improved by the scientific community.

Measurement of the α-Particle Monopole Transition Form Factor Challenges Theory: A Low-Energy Puzzle for Nuclear Forces?

We perform a systematic study of the α-particle excitation from its ground state 0_{1}^{+} to the 0_{2}^{+} resonance. The so-called monopole transition form factor is investigated via an electron scattering experiment in a broad Q^{2} range (from 0.5 to 5.0 fm^{-2}). The precision of the new data dramatically supersedes that of older sets of data, each covering only a portion of the Q^{2} range. The new data allow the determination of two coefficients in a low-momentum expansion, leading to a new puzzle. By confronting experiment to state-of-the-art theoretical calculations, we observe that modern nuclear forces, including those derived within chiral effective field theory that are well tested on a variety of observables, fail to reproduce the excitation of the α particle.

How we do it-the use of peritoneal patches for reconstruction of vena cava inferior and portal vein in hepatopancreatobiliary surgery.

PURPOSE: Extended resections in hepatopancreatobiliary (HPB) surgery frequently require vascular resection to obtain tumor clearance. The use of alloplastic grafts may increase postoperative morbidity due to septic or thrombotic complications. The use of suitable autologous venous interponates (internal jugular vein, great saphenous vein) is frequently associated with additional incisions. The aim of this study was to report on our experience with venous reconstruction using the introperative easily available parietal peritoneum, focusing on key technical aspects. METHODS: All patients who underwent HPB resections with venous reconstruction using peritoneal patches at our department between January 2017 and November 2021 were included in this retrospective analysis with median follow-up of 2 months (IQR: 1-8 months). We focused on technical aspects of the procedure and evaluated vascular patency and perioperative morbidity. RESULTS: Parietal peritoneum patches (PPPs) were applied for reconstruction of the inferior vena cava (IVC) (13 patients) and portal vein (PV) (4 patients) during major hepatic (n = 14) or pancreatic (n = 2) resections. There were no cases of postoperative bleeding due to anastomotic leakage. Following PV reconstruction, two patients showed postoperative vascular stenosis after severe pancreatitis with postoperative pancreatic fistula and bile leakage, respectively. In patients with reconstruction of the IVC, no relevant perioperative vascular complications occurred. CONCLUSIONS: The use of a peritoneal patch for reconstruction of the IVC in HPB surgery is a feasible, effective, and low-cost alternative to alloplastic, xenogenous, or venous grafts. The graft can be easily harvested and tailored to the required size. More evidence is still needed to confirm the safety of this procedure for the portal vein regarding long-term results.

Does speed equal quality? Time pressure impairs minimally invasive surgical skills in a prospective crossover trial.

BACKGROUND: Time pressure can cause stress, subsequently influencing surgeons during minimally invasive procedures. This trial aimed to investigate the effect of time pressure on surgical quality, as assessed by force application and errors during minimally invasive surgical tasks. METHODS: Sixty-three participants (43 surgical novices trained to proficiency and 20 surgeons) performed four laparoscopic tasks (PEG transfer, precise Cutting, balloon resection, surgical knot) both with and without time pressure. The primary endpoint was the mean and maximal force exertion during each task. Secondary endpoints were the occurrence of predefined errors and the self-assessed stress level. RESULTS: Time pressure led to a significant shortening of the task time in all four tasks. However, significantly more errors were noticed under time pressure in one task (suture precision P < 0.001). Moreover, time pressure led to a significant increase in mean force in all tasks (PEG: P < 0.001; precision cutting: P = 0.001; surgical knot: P < 0.001; balloon: P = 0.004). In three tasks the maximal force application (PEG: P < 0.001; precision cutting: P < 0.001; surgical knot: P = 0.006) increased significantly. Performing the tasks under time pressure significantly increased the stress level. Cohort analysis revealed that time pressure impaired the performance of both, surgical novices and surgeons but novices were more strongly affected compared to surgeons. CONCLUSION: Time pressure during minimally invasive surgery may improve procedural time but impair the quality of surgical performance in terms of the incidence of errors and force exertion. Experience may only partially compensate for the negative influence of time pressure.

[Highlights of pancreatic surgery: extended indications in pancreatic neuroendocrine tumors]. / Highlights der Pankreaschirurgie: erweiterte Indikationen bei neuroendokrinen Tumoren des Pankreas.

Advanced pancreatic neuroendocrine tumors (paNET) are mostly characterized by infiltration of vascular structures and/or neighboring organs. The indications for resection in these cases should be measured based on the possibility of an R0 resection. Although the data situation for this rare entity is limited, small case series have shown a significant survival advantage in patients who underwent a radical resection in locally advanced stages of paNET. Both vascular reconstruction and multivisceral resection, when performed at experienced centers, should be considered as curative treatment options. The very special biological behavior of the paNET and the often young patient age justify a much more aggressive approach compared to the pancreatic ductal adenocarcinoma.

Short-term preoperative drainage is associated with improved postoperative outcomes compared to that of long-term biliary drainage in pancreatic surgery.

PURPOSE: The treatment of choice for patients presenting with obstructive cholestasis due to periampullary carcinoma is oncologic resection without preoperative biliary drainage (PBD). However, resection without PBD becomes virtually impossible in patients with obstructive cholangitis or severely impaired liver cell function. The appropriate duration of drainage by PBD has not yet been defined for these patients. METHODS: A retrospective analysis was conducted on 170 patients scheduled for pancreatic resection following biliary drainage between January 2012 and June 2018 at the University Hospital Dresden in Germany. All patients were deemed eligible for inclusion, regardless of the underlying disease entity. The primary endpoint analysis was defined as the overall morbidity (according to the Clavien-Dindo classification). Secondary endpoints were the in-hospital mortality and malignancy adjusted overall and recurrence-free survival rates. RESULTS: A total of 170 patients were included, of which 45 (26.5%) and 125 (73.5%) were assigned to the short-term (< 4 weeks) and long-term (≥ 4 weeks) preoperative drainage groups, respectively. Surgical complications (Clavien-Dindo classification > 2) occurred in 80 (47.1%) patients, with significantly fewer complications observed in the short-term drainage group (31.1% vs. 52%; p = 0.02). We found that long-term preoperative drainage (unadjusted OR, 3.386; 95% CI, 1.507-7.606; p < 0.01) and periampullary carcinoma (unadjusted OR, 5.519; 95% CI, 1.722-17.685; p-value < 0.01) were independent risk factors for postoperative morbidity, based on the results of a multivariate regression model. The adjusted overall and recurrence-free survival did not differ between the groups (p = 0.12). CONCLUSION: PBD in patients scheduled for pancreatic surgery is associated with substantial perioperative morbidity. Our results indicate that patients who have undergone PBD should be operated on within 4 weeks after drainage.

Perioperative Blood Management of Preoperative Anemia Determines Long-Term Outcome in Patients with Pancreatic Surgery.

BACKGROUND/PURPOSE: Anemia affects the postoperative course of patients undergoing a major surgical procedure. However, it remains unclear whether anemia has a different impact on the long-term outcome of patients with malignant or benign pancreatic disease. METHODS: A retrospective analysis of patients undergoing pancreatic surgery for pancreatic malignancies or chronic pancreatitis was conducted between January 2012 and June 2018 at the University Hospital Dresden, Germany. The occurrence of preoperative anemia and the administration of pre-, intra-, and postoperative blood transfusions were correlated with postoperative complications and survival data by uni- and multivariate analysis. RESULTS: A total of 682 patients were included with 482 (70.7%) undergoing surgical procedures for pancreatic malignancies. Univariate regression analysis confirmed preoperative anemia as a risk factor for postoperative complications > grade 2 according to the Clavien-Dindo classification. Multivariate regression analyses indicated postoperative blood transfusion as an independent risk factor for postoperative complications in patients with a benign (OR 20.5; p value < 0.001) and a malignant pancreatic lesion (OR 4.7; p value < 0.01). Univariate and multivariate analysis revealed preoperative anemia and pre-, intra-, and postoperative blood transfusions as independent prognostic factors for shorter overall survival in benign and malignant patients (p value < 0.001-0.01). CONCLUSION: Preoperative anemia is a prevalent, independent, and adjustable factor in pancreatic surgery, which poses a significant risk for postoperative complications irrespective of the entity of the underlying disease. It should therefore be understood as an adjustable factor rather than an indicator of underlying disease severity.

New Insight in the Q

Virtual Compton scattering on the proton has been investigated at three yet unexplored values of the four-momentum transfer Q^{2}: 0.10, 0.20, and 0.45 GeV^{2}, at the Mainz Microtron. Fits performed using either the low-energy theorem or dispersion relations allowed the extraction of the structure functions P_{LL}-P_{TT}/ε and P_{LT}, as well as the electric and magnetic generalized polarizabilities α_{E1}(Q^{2}) and ß_{M1}(Q^{2}). These new results show a smooth and rapid falloff of α_{E1}(Q^{2}), in contrast to previous measurements at Q^{2}=0.33 GeV^{2}, and provide for the first time a precise mapping of ß_{M1}(Q^{2}) in the low-Q^{2} region.

First Measurement of the Q

We report on the first Q^{2}-dependent measurement of the beam-normal single spin asymmetry A_{n} in the elastic scattering of 570 MeV vertically polarized electrons off ^{12}C. We cover the Q^{2} range between 0.02 and 0.05 GeV^{2}/c^{2} and determine A_{n} at four different Q^{2} values. The experimental results are compared to a theoretical calculation that relates A_{n} to the imaginary part of the two-photon exchange amplitude. The result emphasizes that the Q^{2} behavior of A_{n} given by the ratio of the Compton to charge form factors cannot be treated independently of the target nucleus.

[Early stage pancreatic cancer]. / Pankreasfrühkarzinom.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) represents the fourth most common cause of cancer mortality and it is expected to become the second most common cause of cancer mortality by 2020 in the USA. OBJECTIVE: Which strategies for the detection and treatment of an early stage pancreatic adenocarcinoma and its precursor lesions are to be applied? RESULTS: Currently, there is no effective general screening program for pancreatic cancer due to the low incidence and the lack of an accurate and inexpensive diagnostic method; however, in patients with a positive history of hereditary pancreatic cancer or in patients with a known sporadic germline mutation that is associated with an increased risk of pancreatic cancer, frequent screening is highly recommended to detect and to treat early stage PDAC. Moreover, patients with a precursor lesion for pancreatic cancer (namely a mucinous pancreatic neoplasm) should undergo an oncological pancreatic resection to prevent the development of late stage pancreatic cancer. In future, additional biomarkers from a liquid biopsy, such as circulating tumor cells, exosomes or circulating tumor DNA may improve the early detection of pancreatic cancer. CONCLUSION: The early detection and treatment of pancreatic cancer and its precursor lesions can help to improve the dismal prognosis of this aggressive tumor type.

[Minimally invasive and robot-assisted surgery for pancreatic cystic tumors]. / Minimalinvasive und roboterassistierte Chirurgie bei zystischen Pankreastumoren.

BACKGROUND: The indications for resection of pancreatic cystic lesions (PCL) are often complex and the operative risk has to be balanced against the risk of malignant transformation. The aim of the study was to provide a synopsis of the current treatment results of minimally invasive surgery for PCL. METHODS: A systematic literature search was performed using the Medline database (PubMed). Subsequently, the retrieved literature was selectively reviewed. RESULTS: No published prospective randomized controlled trials have yet addressed the comparison of open and minimally invasive surgery of PCL; however, retrospective case studies have demonstrated the feasibility, safety and a comparable morbidity after minimally invasive distal pancreatectomy (DP), pancreatoduodenectomy (PD), central (CP) or total pancreatectomy and enucleation. Whereas most DPs are performed laparoscopically, the experience of minimally invasive PD has been consolidated for the robot-assisted approach but is concentrated in only a few centers. The number of published reports on minimally invasive organ-sparing pancreas procedures (e. g. CP or enucleation) for PCL is scarce; however, the available (selected) results are promising. CONCLUSION: Minimally invasive surgery for PCL has the potential to reduce the operative trauma to the patients, while at the same time causing comparable or less morbidity. This requires an increasing specialization of complex minimally invasive resections. The clinical use of robotic systems will grow for the latter cases. A prospective registry of the results should be mandatory for quality management.

Beam-Recoil Polarization Measurement of π

The helicity-dependent recoil proton polarizations P_{x}^{'} and P_{z}^{'} as well as the helicity-independent component P_{y} have been measured in the p(e[over →],e^{'}p[over →])π^{0} reaction at four-momentum transfer Q^{2}≃0.1 GeV^{2}, center-of-mass proton emission angle θ_{p}^{*}≃90°, and invariant mass W≃1440 MeV. This first precise measurement of double-polarization observables in the energy domain of the Roper resonance P_{11}(1440) by exploiting recoil polarimetry has allowed for the extraction of its scalar electroexcitation amplitude at an unprecedentedly low value of Q^{2}, establishing a powerful instrument for probing the interplay of quark and meson degrees of freedom in the nucleon.

Management of patients with pancreatic cystic lesions: A case-based survey.

BACKGROUND: Pancreatic cystic lesions (PCL), including intraductal papillary mucinous neoplasia (IPMN), harbor different malignant potential and the optimal management is often challenging. The present study aims to depict the compliance of experts with current consensus guidelines and the accuracy of treatment recommendations stratified by the medical specialty and hospital volume. METHODS: An international survey was conducted using a set of 10 selected cases of PCL that were presented to a cohort of international experts on pancreatology. All presented cases were surgically resected between 2004 and 2015 and histopathological examination was available. Accuracy of the treatment recommendations was based on the European and international consensus guideline algorithms, and the histopathological result. RESULTS: The response rate of the survey was 26% (46 of 177 contacted experts), consisting of 70% surgeons and 30% gastroenterologists/oncologists (GI/Onc). In the case of main-duct IPMN (MD-IPMN), surgeons preferred more often the surgical approach in comparison with the GI/Onc (55 versus 44%). The mean accuracy rate based on the European and international consensus guidelines, and the histopathological result, were 71/76/38% (surgeons), and 70/73/34% (GI/Onc), respectively. High-volume centers achieved insignificantly higher accuracy scores with regard to the histopathology. Small branch-duct IPMN with cysts <2 cm and malignant potential were not identified by the guideline algorithms. CONCLUSION: The survey underlines the complexity of treatment decisions for patients with PCL; less than 40% of the recommendations were in line with the final histopathology in this selected case panel. Experts and consensus guidelines may fail to predict malignant potential in small PCL.

[Robot-assisted pancreatic resection]. / Roboterassistierte Pankreasresektion.

Although robot-assisted pancreatic surgery has been considered critically in the past, it is nowadays an established standard technique in some centers, for distal pancreatectomy and pancreatic head resection. Compared with the laparoscopic approach, the use of robot-assisted surgery seems to be advantageous for acquiring the skills for pancreatic, bile duct and vascular anastomoses during pancreatic head resection and total pancreatectomy. On the other hand, the use of the robot is associated with increased costs and only highly effective and professional robotic programs in centers for pancreatic surgery will achieve top surgical and oncological quality, acceptable operation times and a reduction in duration of hospital stay. Moreover, new technologies, such as intraoperative fluorescence guidance and augmented reality will define additional indications for robot-assisted pancreatic surgery.

Observation of Λ(4)H Hyperhydrogen by Decay-Pion Spectroscopy in Electron Scattering.

At the Mainz Microtron MAMI, the first high-resolution pion spectroscopy from decays of strange systems was performed by electron scattering off a (9)Be target in order to study the Λ binding energy of light hypernuclei. Positively charged kaons were detected by a short-orbit spectrometer with a broad momentum acceptance at 0° forward angles with respect to the beam, efficiently tagging the production of strangeness in the target nucleus. Coincidentally, negatively charged decay pions were detected by two independent high-resolution spectrometers. About 10(3) pionic weak decays of hyperfragments and hyperons were observed. The pion momentum distribution shows a monochromatic peak at pπ≈133 MeV/c, corresponding to the unique signature for the two-body decay of hyperhydrogen Λ(4)H→(4)He+π(-), stopped inside the target. Its Λ binding energy was determined to be BΛ=2.12±0.01 (stat)±0.09 (syst)MeV with respect to the (3)H+Λ mass.

[Appleby operation for locally advanced tumour of the pancreatic body and tail--a video demonstration]. / Appleby-Operation bei ausgedehntem Pankreaskorpus- und -schwanztumor - Video eines Falles.

INTRODUCTION: Patients with locally advanced pancreatic cancer and arterial infiltration of the coeliac artery are often classified as irresectable and therefore treated palliatively. For a highly selected group of patients, a complete resection (R0) of a pancreatic carcinoma including resection of the coeliac trunk without arterial reconstruction can mean a survival advantage. The expertise of the surgeon in vascular and pancreatic surgery as well as the proficiency of the entire surgical and anaesthesiological team and the appropriate infrastructure of the hospital are prerequisites for the success of such complex operations. Concerning the local finding of infiltration of the aorta, the gastroduodenal artery and the mesenteric superior artery should be excluded, to ensure R0 resection and perfusion of the liver via the gastroduodenal artery after resection. Moreover, the patient has to be fit for a large abdominal operation and extrapancreatic metastases have to be excluded, especially in ductal adenocarcinoma of the pancreas. In this video, the principles of the Appleby operation are shown in a case of locally advanced neuroendocrine carcinoma of the pancreas with infiltration of the coeliac artery. INDICATION: Locally advanced pancreatic neuroendocrine carcinoma with infiltration of the coeliac artery without distant metastasis after neoadjuvant therapy. PROCEDURE: Extended multiorgan pancreatic corpus and tail resection including resection of coeliac artery, portal vein resection, splenectomy, resection of left adrenal gland, subtotal gastrectomy and oversewing of the pancreatic head, end-to-end reconstruction of the portal vein and gastro-jejunostomy (Roux-Y) and duodeno-jejunostomy. CONCLUSION: Given the appropriate experience, the Appleby procedure is a technically demanding resection in pancreatic carcinomas involving the coeliac artery without arterial anastomosis. In selected cases this operation might have advantages compared to palliative treatment.

Search at the Mainz Microtron for light massive gauge bosons relevant for the muon g-2 anomaly.

A massive, but light, Abelian U(1) gauge boson is a well-motivated possible signature of physics beyond the standard model of particle physics. In this Letter, the search for the signal of such a U(1) gauge boson in electron-positron pair production at the spectrometer setup of the A1 Collaboration at the Mainz Microtron is described. Exclusion limits in the mass range of 40 MeV/c^{2} to 300 MeV/c^{2}, with a sensitivity in the squared mixing parameter of as little as ε^{2}=8×10^{-7} are presented. A large fraction of the parameter space has been excluded where the discrepancy of the measured anomalous magnetic moment of the muon with theory might be explained by an additional U(1) gauge boson.

[Arterial reconstruction in pancreatic carcinoma ­demonstration of surgical techniques]. / Arterielle Rekonstruktion beim duktalen Pankreaskarzinom­ Darstellung chirurgischer Techniken.

INTRODUCTION: For a highly selected group of patients, a complete resection (R0) of a pancreatic carcinoma including arterial resection and reconstruction can represent an advantage in survival. The expertise of the surgeon in vascular and pancreatic surgery as well as the proficiency of the entire surgical and anaesthesiological team and the appropriate infrastructure of the hospital are prerequisites for the success of such complex operations. Proximal and distal of the tumour, sufficient lengths of the vessels are needed for the vascular anastomoses. In this video, the principles of arterial resection and reconstruction are shown in two patients with advanced pancreatic carcinoma. INDICATION: This procedure is indicated for locally advanced pancreatic carcinoma with arterial infiltration without distant metastasis after neoadjuvant therapy. PROCEDURE: The procedure involves 2 steps: 1. pancreatic head resection with resection of the common hepatic artery and end-to-end anastomosis of the hepatic artery and portal vein resection; 2. left pancreatic resection including splenectomy; resection of the celiac trunk, the superior mesenteric artery; reinsertion of the superior mesenteric artery into the aorta; end-to-end anastomosis of the common hepatic artery with the stump of the celiac trunk. CONCLUSION: Given the appropriate experience, technically demanding arterial resections and reconstructions in pancreatic carcinoma are feasible and can provide superior survival for the patient compared to palliative therapy.

Precursor lesions for sporadic pancreatic cancer: PanIN, IPMN, and MCN.

Pancreatic cancer is still a dismal disease. The high mortality rate is mainly caused by the lack of highly sensitive and specific diagnostic tools, and most of the patients are diagnosed in an advanced and incurable stage. Knowledge about precursor lesions for pancreatic cancer has grown significantly over the last decade, and nowadays we know that mainly three lesions (PanIN, and IPMN, MCN) are responsible for the development of pancreatic cancer. The early detection of these lesions is still challenging but provides the chance to cure patients before they might get an invasive pancreatic carcinoma. This paper focuses on PanIN, IPMN, and MCN lesions and reviews the current level of knowledge and clinical measures.