[Anesthesia in gastrointestinal endoscopy: peroral endoscopic myotomy]. / Anästhesie in der gastrointestinalen Endoskopie: perorale endoskopische Myotomie.

Idiopathic achalasia is a motility disorder of the esophagus characterized by a dysfunction of the lower esophageal sphincter, which typically manifests as dysphagia. Peroral endoscopic myotomy (POEM) is an interventional endoscopic procedure for achalasia, which was introduced in 2010. Although results from randomized studies comparing short-term and long-term safety and efficacy are yet to be published, POEM is regarded to be less invasive than the standard treatment of achalasia (laparoscopic Heller myotomy). POEM is the first endoscopic procedure routinely performed with the patient under general anesthesia. During the preoperative assessment particular attention must be paid to the specific fasting intervals and the risk of aspiration during induction of anesthesia. For the purpose of temporary surgical access, the integrity of the esophageal wall is deliberately interrupted to create a long submucosal tunnel. As a result, unwanted fistulas can arise between the esophageal lumen, the mediastinum, the pleura or the intraperitoneal cavity. Endoscopically insufflated CO2 may escape into these surrounding compartments with subsequent systemic CO2 accumulation, capnomediastinum, tension capnoperitoneum or pneumothorax. As a result substantial cardiorespiratory instability can arise. Thus, the attending anesthesiologist must be familiar with these typical complications and with specific emergency measures, such as compensatory hyperventilation, percutaneous needle decompression and thoracic drainage. The POEM procedure is a therapeutic innovation and interdisciplinary challenge. However, anesthesia standards of care have not yet been specified. The aim of this review is therefore to outline some clinical recommendations for the daily clinical practice based on existing evidence.

A novel approach to electron data background treatment in an online wide-angle spectrometer for laser-accelerated ion and electron bunches.

Laser-based ion acceleration is driven by electrical fields emerging when target electrons absorb laser energy and consecutively leave the target material. A direct correlation between these electrons and the accelerated ions is thus to be expected and predicted by theoretical models. We report on a modified wide-angle spectrometer, allowing the simultaneous characterization of angularly resolved energy distributions of both ions and electrons. Equipped with online pixel detectors, the RadEye1 detectors, the investigation of this correlation gets attainable on a single shot basis. In addition to first insights, we present a novel approach for reliably extracting the primary electron energy distribution from the interfering secondary radiation background. This proves vitally important for quantitative extraction of average electron energies (temperatures) and emitted total charge.

Isolated proton bunch acceleration by a petawatt laser pulse.

Often, the interpretation of experiments concerning the manipulation of the energy distribution of laser-accelerated ion bunches is complicated by the multitude of competing dynamic processes simultaneously contributing to recorded ion signals. Here we demonstrate experimentally the acceleration of a clean proton bunch. This was achieved with a microscopic and three-dimensionally confined near critical density plasma, which evolves from a 1 µm diameter plastic sphere, which is levitated and positioned with micrometer precision in the focus of a Petawatt laser pulse. The emitted proton bunch is reproducibly observed with central energies between 20 and 40 MeV and narrow energy spread (down to 25%) showing almost no low-energetic background. Together with three-dimensional particle-in-cell simulations we track the complete acceleration process, evidencing the transition from organized acceleration to Coulomb repulsion. This reveals limitations of current high power lasers and viable paths to optimize laser-driven ion sources.

Proton acceleration by irradiation of isolated spheres with an intense laser pulse.

We report on experiments irradiating isolated plastic spheres with a peak laser intensity of 2-3×10^{20}Wcm^{-2}. With a laser focal spot size of 10 µm full width half maximum (FWHM) the sphere diameter was varied between 520 nm and 19.3 µm. Maximum proton energies of ∼25 MeV are achieved for targets matching the focal spot size of 10 µm in diameter or being slightly smaller. For smaller spheres the kinetic energy distributions of protons become nonmonotonic, indicating a change in the accelerating mechanism from ambipolar expansion towards a regime dominated by effects caused by Coulomb repulsion of ions. The energy conversion efficiency from laser energy to proton kinetic energy is optimized when the target diameter matches the laser focal spot size with efficiencies reaching the percent level. The change of proton acceleration efficiency with target size can be attributed to the reduced cross-sectional overlap of subfocus targets with the laser. Reported experimental observations are in line with 3D3V particle in cell simulations. They make use of well-defined targets and point out pathways for future applications and experiments.

Endoscopic ultrasound-guided drainage of abdominal fluid collections after pancreatic surgery: Efficacy and long-term follow-up.

BACKGROUND/PURPOSE: Endoscopic ultrasound-guided drainage (EUS-GD) of postoperative abdominal fluid collections (POFC) following pancreatic surgery is used as an alternative or complement to percutaneous drainage (PD) procedure. The present single-center retrospective study evaluates its efficacy and safety. METHOD: We included consecutive cases with POFC treated by EUS-GD between September 2009 and November 2014 in our department. Technical success, long-term clinical success, recurrence rate and need for surgery were analyzed. RESULTS: 24 procedures in 20 patients (95 % after pancreatic resection) were assessed. Indications for surgery included tumors/lesions located in the pancreas (15/20), chronic pancreatitis (3/20) and duodenal adenoma not completely resectable endoscopically (2/20). EUS-GD was performed within a median of 30 days (IQR: 8.25) for a median fluid collection size of 72.5 mm (IQR: 46.25), requiring a mean of 1.2 sessions with placement of a mean of 2.1 plastic stents (7 Fr/10 Fr) per patient for a mean of 89 days (IQR: 127). Microbiology of aspirated fluid revealed positive cultures in 13 patients, mostly polymicrobial, isolated positive for fungal and 3 multidrug-resistant gram negative (MRGN) in 4 cases. An additional transpapillary drainage was inserted in 1/20 patients. 4/20 patients received PD, mostly before EUS-GD. Technical and clinical success was achieved in 20/20 (100 %) and 18/20 (90 %) patients, respectively, while 2 patients required re-operation. During follow-up (median 630 days after stent removal, range: 45 - 2160), recurrence occurred in 1/18 (5.5 %) patient that was referred for surgery. No death or severe adverse events were noted. CONCLUSION: EUS-GD is an effective, minimally invasive and safe method for therapy of POFC after pancreatic surgery offering long-term remission in about 95 % of cases.

Feasibility of a colon capsule overnight procedure followed by colonoscopy.

BACKGROUND AND AIM: Due to limited acceptance of colonoscopy as diagnostic and screening test alternatives are warranted. Colon capsule endoscopy (CCE) has been shown to be a possible filter test, but because of logistical issues a second bowel preparation is usually required, if consecutive colonoscopy is needed. We therefore evaluated the feasibility of a single bowel preparation for both overnight CCE and (therapeutical) colonoscopy thereafter. METHODS: Patients from two university hospitals referred to undergo colonoscopy were prospectively included in a dual centre feasibility study. A polyethylene glycol (PEG) based bowel preparation-schedule with ingestion of a colon capsule endoscopy (CCE) at 10pm and subsequent colonoscopy at about 12am on the next day was investigated. The first generation PillCam colon capsule was used with 4 different preparation protocols containing several prokinetics in different compositions (i. e. metoclopramide, erythromycin, sennosoides). The main endpoint was the proportion of patients who completed both CCE and colonoscopy; secondary endpoints were capsule transit times, amount of colon seen on CCE, bowel cleanliness, sensitivity and specifity of CCE and patients' acceptance. RESULTS: 50 patients between 18 and 75 years were included. The sequence of overnight colon capsule endoscopy and colonoscopy was successfully completed in all but one (one refused colonoscopy). The capsule was excreted during recording time in 86 % of examinations, visualization of the complete colon was possible in 60 %, but adequate colon preparation was achieved in only 45 % irrespective of the regimen used. The preparation regimen consisting of a PEG-solution, erythromycin as prokinetic drug followed by PEG-solution as boost showed the largest proportion of adequate preparations. Overall sensitivity and specificity of CCE for polyps of any size were 65 % and 76 %, respectively. 26 of 30 patients (86.7 %) returned the subjective assessment questionnaire. 23 patients (88 %) reported mild to no discomfort or embarrassment during CCE, whereas 15 patients (58 %) did during the preparation procedure. Drinking the purgative solution was the most inconvenient step in 84 % of cases, drinking the boosts during CCE the second inconvenient step (60 %). CONCLUSION: Overnight CCE-procedure followed by direct capsule-reading is feasible and safe and might avoid repetitive bowel preparation for subsequent colonoscopy. The bowel preparation needs to be improved.

[Implementing an Organised Colorectal Cancer Screening Programme in Germany: Opportunities and Challenges]. / Einführung eines organisierten Darmkrebs-Screenings in Deutschland: Chancen und Herausforderungen.

BACKGROUND: Each year in Germany, about 65,000 people are diagnosed with colorectal cancer (CRC) and more than 25,000 people die of the disease. The majority of these cases could be avoided by a more effective screening programme. Recently, a law came into force that offers a great opportunity in this regard. It calls for introducing an organised CRC screening programme in Germany, which includes an invitation system as well as further measures for quality assurance and programme evaluation. To realise this opportunity, challenges of implementation need to be considered. The aim of this review article is to elaborate the challenges of an organised CRC screening in Germany in order to derive the need for action regarding successful implementation. METHODS: This review article is based on a selective literature search, including current guidelines and recommendations. RESULTS AND CONCLUSION: In the context of CRC screening, but also by colonoscopies performed for other indications (e.g., due to symptoms), precancerous lesions (adenomas) are detected and removed in a relevant proportion of the target population, which requires a surveillance examination after 3 or 5 years according to current recommendations. Therefore, an efficient invitation system for CRC screening should be designed to allow for a flexible interval depending on previous findings, which differs from mammography screening with its fixed interval. A prerequisite would be the standardised documentation of all colonoscopies irrespective of the indication, given that a substantial proportion of colonoscopies in Germany are performed outside of the screening program. Still, the work load regarding documentation could be less than for mammography screening. Another challenge in terms of organisation results from the parallel offer of 2 different screening tools (colonoscopy and faecal occult blood test). To realise the potential of an organised CRC screening, it seems important to devote sufficient time and resources for developing an efficient and feasible concept, while there might be interim options to avoid further delay regarding the initial invitation of the target population. Given that expertise from, amongst others, gastroenterology, epidemiology, clinical chemistry and health communication is required, an interdisciplinary approach appears essential.

Peroral endoscopic myotomy for achalasia.

BACKGROUND: Treatment of achalasia is complicated by symptom recurrence and a significant risk for severe complications. Endoscopic myotomy was developed in the search for a highly efficacious treatment with lower risks. Since its introduction in 2010, several centers have adopted the technique and published excellent short-term results of open label series. Randomized trials with long-term endpoint comparing per-oral endoscopic myotomy (POEM) with the established treatments such as balloon dilation and surgical myotomy are now warranted, before POEM can be regarded as the routine clinical care for achalasia patients. PURPOSE: This review describes the development, technical aspects, efficacy, and complications of POEM.

Long-term follow-up in patients with indeterminate Barrett esophagus.

BACKGROUND: Barrett esophagus (BE) is a major risk factor for adenocarcinoma of the distal esophagus. Reliable detection of BE during upper endoscopy is therefore mandatory. According to most guidelines, diagnosis of BE requires both endoscopy and histology for confirmation. However, since adenocarcinomas were also described in patients with indeterminate BE, i.e. endoscopic visible columnar metaplasia but no histological confirmation of goblet cells or vice versa, debate has risen on the risk of malignancy and the need for endoscopic surveillance in such patients. PATIENTS AND METHODS: The study was aimed to assess long-term follow-up data on 209 patients with indeterminate BE (on histopathology or endoscopy) initially examined between 1999 and 2000. Patients or referring physicians were contacted concerning the most recent endoscopic and histopathological results. RESULTS: Follow-up data could be assessed in 149/209 patients (65.1%) after a mean follow-up period of 9.4 years (SD ±2.4 years). Neoplasia was not reported for any patient. The previous endoscopic-histopathological diagnoses could be confirmed in 3 patients only. In the group with endoscopic diagnosis of BE but no histopathological confirmation, BE was described histopathologically in 1 patient during follow-up. CONCLUSION: Persistence of indeterminate BE is poor during long-term follow up. The risk of cancer appears to be negligible. Hence, surveillance of these patients appears equivocal.

[A 44-year-old woman with hereditary nonpolyposis colon carcinoma: screening examinations for non-colonic tumors]. / 44-jährige Patientin mit hereditärem nichtpolypösem Kolonkarzinom: Vorsorgeuntersuchungen nichtkolonischer Tumoren.

A 44-year-old woman presented in March 2010 for surveillance esophagogastroduodenoscopy (EGD). In October 2004, rectal cancer had been diagnosed and treated by resection of the rectum with adjuvant chemotherapy. A diagnosis of hereditary nonpolyposis colon carcinoma (HNPCC) was established on the basis of the Amsterdam II criteria. Due to a lack of clear guidelines we decided to perform annual systematic surveillance examinations of the stomach and the most frequent tumor manifestations. Until 2009, extracolonic tumors were not observed in the patient. In March 2010, EGD showed a discrete erosive lesion in the gastric antrum, which was biopsied. Most notably, the histopathological examination revealed a poorly differentiated mucinous adenocarcinoma. Due to the poor differentiation, we decided against technically possible, endoscopic resection. The patient underwent subtotal gastrectomy and is still doing fine 28 months after surgery. This case prompted us to evaluate our surveillance approach in HNPCC patients and to review the literature.

Progress in endoscopy: areas of current interest and topics to watch out for.

The past few years have seen a shift in focus for endoscopy research. For example, there has been a halt in the apparent revolution of natural orifice transluminal surgery (NOTES), which was long considered the most important innovation in flexible endoscopy. Other trends such as endoscopic histology are slowing down and not progressing into clinical practice. In general, the quality of endoscopic research needs to be improved, particularly in the field of diagnostics and imaging 1. Nevertheless, progress in some areas continues, albeit at a slower pace than we might like. In this review the areas of current interest are reviewed with reference to the most relevant areas of progress in recent years.

Endoscopic ultrasound for differential diagnosis of duodenal lesions.

PURPOSE: Duodenal tumors are rare and require a different management from that of esophagogastric neoplasia. The present study retrospectively analyses the endoscopic ultrasound (EUS) features of duodenal tumors of both epithelial and subepithelial origin. MATERIALS AND METHODS: During a 12 year period, all duodenal tumors with histologic confirmation by surgery or biopsy were collected including endoscopic and endosonographic images. EUS images were analyzed for specific features (echogenicity, wall layer structure and relation, outer margins) to possibly distinguish epithelial (polyps and carcinoma versus lymphoma) and subepithelial (tumor type) tumors. RESULTS: 53/80 cases had histologic confirmation (mean age 53.1 ±â€Š11.4 years, m:f = 33:20), 31 were epithelial (13 adenomas, 12 carcinomas, 6 lymphomas) and 22 subepithelial (11 GISTs, 7 Brunneromas, 1 lipoma, 3 NETs). EUS did not recognize carcinomas in 2/13 adenomas. EUS features suggesting carcinoma were loss of wall layers and irregular margins. 5/6 lymphomas showed inhomogeneous thickening with layers partially recognizable. Tumor type of subepithelial lesions correlated with echogenicity: GIST tumors were mostly (62.5 %) hypocheoic with the 3 malignant cases being characterized by heterogeneous echopattern with irregular outer margins. Of the hyperechoic lesions, lipomas had a homogeneous whitish appearance, while NET and Brunneromas were less hyperechoic. In the latter, the endoscopic aspect was also helpful for differential diagnosis. Accuracy of combined endoscopic/EUS imaging for all duodenal lesions was 84.9 % (45/53). No procedural complications occurred among all patients that received EUS examinations. CONCLUSION: EUS contributes to the differential diagnosis of epithelial lesions known to be malignant; in subepithelial tumors, tissue confirmation is still required.

Staging and outcome depending on surgical treatment in adenocarcinomas of the oesophagogastric junction.

BACKGROUND: Owing to controversial staging and classification of adenocarcinoma of the oesophago-gastric junction (AOG) before surgery, the choice of appropriate surgical approach remains problematic. In a retrospective study, preoperative staging of AOG and the impact of preoperative misclassification on outcome were analysed. METHODS: Data from patients with AOG were analysed from a prospectively collected database with regard to surgical treatment, preoperative and postoperative staging, and outcome. RESULTS: One-hundred and thirty patients with Siewert types I and II AOG who did not have neoadjuvant treatment were included in the study: 41 patients with an AOG type I who underwent oesophagectomy, 51 patients with an AOG staged before surgery as type I who underwent oesophagectomy but in whom the final histology showed a type II tumour, and 38 patients whose tumours were staged as AOG type II before and after operation who underwent gastrectomy. Among patients who had an oesophagectomy, lymph node metastases (P = 0.022), tumour relapse (P = 0.009) and recurrent distant metastases (P = 0.028) were significantly more frequent in patients with AOG type II; those with AOG type II had shorter overall survival than those with type I tumours (P = 0.024). Among those with AOG type II, recurrence-free survival was significantly shorter after oesophagectomy compared with extended gastrectomy (P = 0.019). Thoracoabdominal oesophagectomy had a favourable influence on outcome compared with the transhiatal approach. CONCLUSION: Accurate preoperative staging of AOG and appropriate surgical therapy are crucial for outcome. AOG type II is a more aggressive tumour with higher recurrence rates than AOG type I. These patients therefore benefit from more radical surgical treatment.

CO2 versus air insufflation for private practice routine colonoscopy: results of a randomized double blind trial.

BACKGROUND: Pain and bloating following colonoscopy are an underestimated problem, with 30 - 60 % of patients complaining of such symptoms. The use of CO2 has been shown to significantly decrease pain after colonoscopy in academic hospital-based studies. The aim of the present study was to evaluate whether such an effect can also be seen during private practice routine colonoscopy. PATIENTS AND METHODS: In a prospective double-blind randomized trial, one experienced colonoscopist (> 12,000 examinations) used either air or CO2 insufflation for diagnostic or screening colonoscopy in consecutive patients presenting for diagnostic and screening colonoscopy in private practice. Outcome parameters were occurrence and duration of pain and bloating after colonoscopy based on a patient questionnaire. RESULTS: Of 180 randomized patients, 156 replies were analyzed (43.3 % male, mean age 61.7 ± 9.7 years). There were no significant differences between the two groups with respect to age and sex distribution, indication, sedation, examination times and polypectomy rates. Both pain and abdominal bloating were significantly lower in the CO2 group. Abdominal pain and bloating in the CO2 vs. air group were absent in 84.4 vs. 64.6 % (p = 0.005) and 66.2 vs. 32.9 % (p < 0.001). Moderate/strong symptoms were also significantly lower with CO2. CONCLUSIONS: The use of CO2 appears to be as effective in daily routine in private practice colonoscopy as reported in previous hospital-based studies.