A surgical activity model of laparoscopic cholecystectomy for co-operation with collaborative robots.

BACKGROUND: Laparoscopic cholecystectomy is a very frequent surgical procedure. However, in an ageing society, less surgical staff will need to perform surgery on patients. Collaborative surgical robots (cobots) could address surgical staff shortages and workload. To achieve context-awareness for surgeon-robot collaboration, the intraoperative action workflow recognition is a key challenge. METHODS: A surgical process model was developed for intraoperative surgical activities including actor, instrument, action and target in laparoscopic cholecystectomy (excluding camera guidance). These activities, as well as instrument presence and surgical phases were annotated in videos of laparoscopic cholecystectomy performed on human patients (n = 10) and on explanted porcine livers (n = 10). The machine learning algorithm Distilled-Swin was trained on our own annotated dataset and the CholecT45 dataset. The validation of the model was conducted using a fivefold cross-validation approach. RESULTS: In total, 22,351 activities were annotated with a cumulative duration of 24.9 h of video segments. The machine learning algorithm trained and validated on our own dataset scored a mean average precision (mAP) of 25.7% and a top K = 5 accuracy of 85.3%. With training and validation on our dataset and CholecT45, the algorithm scored a mAP of 37.9%. CONCLUSIONS: An activity model was developed and applied for the fine-granular annotation of laparoscopic cholecystectomies in two surgical settings. A machine recognition algorithm trained on our own annotated dataset and CholecT45 achieved a higher performance than training only on CholecT45 and can recognize frequently occurring activities well, but not infrequent activities. The analysis of an annotated dataset allowed for the quantification of the potential of collaborative surgical robots to address the workload of surgical staff. If collaborative surgical robots could grasp and hold tissue, up to 83.5% of the assistant's tissue interacting tasks (i.e. excluding camera guidance) could be performed by robots.

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.

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.

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.

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.

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.

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.

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.

[Intraductal papillary mucinous neoplasm of the pancreas (IPMN)--standards and new aspects]. / Intraduktale papillär-muzinöse Neoplasien (IPMN) des Pankreas--Standards und neue Aspekte.

Intraductal papillary mucinous neoplasms (IPMN) of the pancreas belong to the heterogeneous group of cystic pancreatic lesions and have been diagnosed more frequently in recent years. Diagnosis and differentiation from other cystic lesions (pseudocysts, serous-cystic neoplasias [SCN], mucinous-cystic neoplasias [MCN], intraductal papillary-mucinous neoplasias [IPMN] and solid pseudopapillary neoplasias [SPN]) is often challenging. IPMN of the pancreas are considered as precursor lesions for the development of invasive pancreatic cancer. However, depending on the morphological (MD-IPMN, BD-IPMN) and histological subtype (intestinal, pancreatobiliary, oncocytic or gastric) the malignant potential of IPMNs varies significantly. Hence, early diagnosis and selection of the appropriate therapeutic strategy is necessary for optimal outcome and cure. There is a strong consensus for the resection of all MD-IPMN. Small BD-IPMN without signs of malignancy can be followed by observation. The increasing understanding of the histopathology and tumour biology of IPMN has led to an amendment of the 2006 International Association of Pancreatology (IAP) guidelines for the treatment of cystic pancreatic tumours. In consideration of recent data, recommendations for observation and/or follow-up of IPMN cannot be given definitely.

[Recurrent colorectal liver metastases: who benefits from a second hepatic resection?]. / Rezidivlebermetastasen kolorektaler Karzinome: Wer profitiert von einer zweiten Leberresektion?

BACKGROUND: Hepatic recurrence is seen in approximately 40 % of patients undergoing hepatectomy for colorectal metastases. The authors assessed the benefit and the main prognostic factors for a second liver resection of recurrent colorectal metastases. METHODS: This study reports the experience with second liver resections for recurrent liver metastases at a German University Hospital. A total of 39 parameters from 60 patients were identified from a prospective database and analysed as to their influence on recurrence-free survival and overall survival. RESULTS: At a median follow-up of 26 months (range: 2-173 months) after second hepatic resection, recurrence-free survival at 3 and 5 years were 50 % and 37 %, respectively. The overall survival at three and five years were 61 % and 52 %, respectively. Recurrence was identified in 58.3 % of the patients. Recurrences involved exclusively the liver in 19 patients (31.6 %). By multivariate analysis (Cox proportional hazard model), a time interval between diagnosis of the liver metastases of less than 24 months after operation for colorectal primary carcinoma (HR: 6.47, p = 0.002), a CEA level of 4.0 ng/mL or more (HR: 3.48, p = 0.004) at the time of first liver metastases and a size of second liver metastases of 80 mm or more (HR: 4.73, p = 0.007) were independent prognostic factors for a reduced recurrence-free survival. A repeat recurrence of liver metastases without the option of curative resection was the only risk factor for overall survival after second hepatic resection (p = 0.009). In these cases, mortality risk was 4.51-fold, however, when the second liver recurrence was resectable, the mortality risk increased only 1.4-fold. CONCLUSIONS: Technically resectable recurrent colorectal hepatic metastases should be resected the same as the first metastases. Characteristics of the primary metastasis as well as parameters of the hepatic recurrence are shown to influence the prognosis of patients after resection of recurrent liver metastases. Repeat resection of colorectal liver metastases allows for improved survival in patients even after two previous liver operations.

Measurement of the neutron electric to magnetic form factor ratio at Q2=1.58 GeV2 using the reaction 3He[over →](e[over →],e'n)pp.

A measurement of beam helicity asymmetries in the reaction 3He[over →](e[over →],e'n)pp is performed at the Mainz Microtron in quasielastic kinematics to determine the electric to magnetic form factor ratio of the neutron GEn/GMn at a four-momentum transfer Q2=1.58 GeV2. Longitudinally polarized electrons are scattered on a highly polarized 3He gas target. The scattered electrons are detected with a high-resolution magnetic spectrometer, and the ejected neutrons are detected with a dedicated neutron detector composed of scintillator bars. To reduce systematic errors, data are taken for four different target polarization orientations allowing the determination of GEn/GMn from a double ratio. We find µnGEn/GMn=0.250±0.058(stat)±0.017(syst).

[Pancreatic anastomosis -- a video comparison of different techniques]. / Die Pankreasanastomose - ein Videovergleich unterschiedlicher Anastomosentechniken.

INTRODUCTION: The pancreatic anastomosis seems to be the most difficult and dangerous anastomosis in general surgery, especially in a soft pancreas. Many techniques have been described. The techniques most often used are: anastomosis of the pancreas to the jejunum as a pancreatico-jejunostomy (duct-to-mucosa anastomosis) or as a pancreato-jejunostomy (invaginating anastomosis). Another widely used anastomosis for reconstruction after pancreatic head resection is from the stomach to the pancreas, i.e., pancreato-gastrostomy. In literature the data concerning postoperative complications (pancreatic fistula, postoperative bleeding and others) are not consistent. INDICATIONS: Reconstruction after pancreatic head resection. PROCEDURE: Anastomosis between small intestine or stomach and the pancreas. CONCLUSION: There is no gold standard for pancreatic anastomosis. Thus, of the different commonly used techniques, in our opinion, the best technique for each surgeon seems to be the one that he/she is most familiar with.

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.

[New aspects of surgery for pancreatic cancer. Principles, results and evidence]. / Neue Aspekte in der Chirurgie des Pankreaskarzinoms. Prinzipien - Ergebnisse - Evidenz.

Ductal adenocarcinoma is the most frequent malignant tumor of the pancreas and total resection of the pancreatic tumor is still the only curative treatment option. Most tumors are located in the pancreatic head, therefore, pylorus-preserving pancreaticoduodenectomy (Whipple PPPD) is the oncological standard procedure. By concentrating pancreatic resections in specialized centers for pancreatic surgery perioperative mortality and morbidity has decreased in recent years. However, pancreatic resections remain complex and difficult operations and pancreatic anastomosis is particular challenging. To achieve complete resection (R0) resection and reconstruction of large venous vessels is often necessary. Resection of arterial vessels is rarely performed and usually does not lead to an R0 resection of the tumor. Currently adjuvant chemotherapy after total tumor resection is standard of care for all tumor stages but neoadjuvant regimes have recently been reported increasingly more often. Advances in translational research has led to a better understanding of tumor biology and new diagnostic options and therapies are expected in the near future.

[Transduodenal resection of ampullary tumors]. / Transduodenale Papillenresektion.

OBJECTIVE: Whether the treatment of benign ampullary tumors should be performed as transduodenal surgical excision or endoscopic ampullectomy depends on the size and spread of the tumor. In this videopaper we report technical hints on the surgical resection. INDICATIONS: Surgical resection is indicated for benign ampullary lesions if endoscopic resection is not possible. In addition, local resection can be performed in cases with high risk of malignancy or in a palliative intention. PROCEDURE: The duodenum is mobilized by the Kocher maneuver. It is recommendable to perform a cholecystectomy to introduce a flexible catheter antegrade into the common bile duct through the cystic duct for identification of the papilla of Vater by digital palpation. An anterolateral oblique duodenotomy is made and thereby the tumor of the papilla is exposed, followed by a submucosal injection of epinephrine to elevate the tumor. Afterwards a 5-10 mm margin is scored circumferentially in the mucosa around the adenoma. The extent of the excision is based on the preoperative and intraoperative assessment; a submucosal or full thickness (for transmural lesions) excision can be performed. After submucosal excision the mucosa of the ampulla is approximated to the mucosa of the duodenum. In cases with full thickness ampullectomy the borders of the pancreatic and bile duct are approximated and then the entire complex is sutured to the full wall of the duodenum. Furthermore in some cases with extensive resection a separate reconstruction of the pancreatic and bile duct may be required. A terminal assessment of the ductal patency is imperative. The duodenectomy is closed and a paraduodenal drain is placed. CONCLUSION: Transduodenal resection of periampullary tumors can be technically demanding, but provides a stage-adapted treatment modality for benign and premalignant lesions of the papilla of Vater.