Virtual Hall sensor triggered multi-MHz endoscopic OCT imaging for stable real-time visualization.

Circumferential scanning in endoscopic imaging is crucial across various disciplines, and optical coherence tomography (OCT) is often the preferred choice due to its high-speed, high-resolution, and micron-scale imaging capabilities. Moreover, real-time and high-speed 3D endoscopy is a pivotal technology for medical screening and precise surgical guidance, among other applications. However, challenges such as image jitter and non-uniform rotational distortion (NURD) are persistent obstacles that hinder real-time visualization during high-speed OCT procedures. To address this issue, we developed an innovative, low-cost endoscope that employs a brushless DC motor for scanning, and a sensorless technique for triggering and synchronizing OCT imaging with the scanning motor. This sensorless approach uses the motor's electrical feedback (back electromotive force, BEMF) as a virtual Hall sensor to initiate OCT image acquisition and synchronize it with a Fourier Domain Mode-Locked (FDML)-based Megahertz OCT system. Notably, the implementation of BEMF-triggered OCT has led to a substantial reduction in image jitter and NURD (<4 mrad), thereby opening up a new window for real-time visualization capabilities. This approach suggests potential benefits across various applications, aiming to provide a more accurate, deployable, and cost-effective solution. Subsequent studies can explore the adaptability of this system to specific clinical scenarios and its performance under practical endoscopic conditions.

Liver transplantation for HCC in cirrhosis: Are Milan criteria outdated?

In Germany, organ allocation is based on the MELD-system and lab-MELD is usually low in patients with hepatocellular carcinoma (HCC) in cirrhosis. Higher medical urgency can be achieved by standard exception for HCC (SE-HCC), if Milan criteria (MC) are met. Noteworthy, UNOS T2 reflects MC, but excludes singular lesions < 2 cm. Thus, SE-HCC is awarded to patients with one lesion between 2 and 5 cm or 2 to 3 lesions between 1 and 3 cm. These criteria are static and do not reflect biological properties of HCC.We present a retrospective cohort of 111 patients, who underwent liver transplantation at UKSH, Campus Kiel between 2007 and 2017. No difference was found in overall survival for patient cohorts using Milan, UCSF, up-to-seven, and French-AFP criteria. However, there was a significantly reduced survival, if microvascular invasion was detected in the explanted organ and in patients with HCC-recurrence. The exclusive use of static selection criteria including MC appear to limit the access to liver transplantation.

Endoluminal Vacuum Therapy Using a New "Fistula Sponge" in Treating Defects of the Upper Gastrointestinal Tract-A Comparative, Retrospective Cohort Study.

Background and Objectives: Anastomotic insufficiencies (AI) and perforations of the upper gastrointestinal tract (uGIT) result in high morbidity and mortality. Endoscopic stent placement and endoluminal vacuum therapy (EVT) have been established as surgical revision treatment options. The Eso-Sponge® is the only licensed EVT system with limitations in treating small defects (<10 mm). Therefore, a fistula sponge (FS) was developed for the treatment of such defects as a new therapeutic approach. The aim of this study was to evaluate both EVT options' indications, success rates, and complications in a retrospective, comparative approach. Materials and Methods: Between 01/2018 and 01/2021, the clinical data of patients undergoing FS-EVT or conventional EVT (cEVT; Eso-Sponge®, Braun Melsungen, Melsungen, Germany) due to AI/perforation of the uGIT were recorded. Indication, diameter of leakage, therapeutic success, and complications during the procedure were assessed. FSs were prepared using a nasogastric tube and a porous drainage film (Suprasorb® CNP, Lohmann & Rauscher, Rengsdorf, Germany) sutured to the distal tip. Results: A total of 72 patients were included (20 FS-EVT; 52 cEVT). FS-EVT was performed in 60% suffering from AI (cEVT = 68%) and 40% from perforation (cEVT = 32%; p > 0.05). FS-EVT's duration was significantly shorter than cEVT (7.6 ± 12.0 d vs. 15.1 ± 14.3 d; p = 0.014). The mean diameter of the defect was 9 mm in the FS-EVT group compared to 24 mm in cEVT (p < 0.001). Therapeutic success was achieved in 90% (FS-EVT) and 91% (cEVT; p > 0.05). Conclusions: EVT comprises an efficient treatment option for transmural defects of the uGIT. In daily clinical practice, fistulas < 10 mm with large abscess formations poses a special challenge since intraluminal cEVT usually is ineffective. In these cases, the concept of extraluminal FS placement is safe and effective.

The role of pancreatoscopy in the diagnostic work-up of intraductal papillary mucinous neoplasms: a systematic review and meta-analysis.

BACKGROUND: Confirming the diagnosis, invasiveness, and disease extent of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas is challenging. The aim of this study was to summarize the literature on the efficacy and safety of peroral pancreatoscopy (POP) in the diagnosis of IPMN, including the impact of pre- and intraoperative POP on the management of IPMN. METHODS: The EMBASE, Medline Ovid, Web of Science, Cochrane CENTRAL, and Google Scholar databases were systematically searched for articles. Eligible articles investigated cohorts of patients who underwent POP for (suspected) IPMN. RESULTS: 25 articles were identified and included in this review; with 22 of these reporting on the diagnostic yield of POP in IPMN and 11 reporting on the effect of pre- or intraoperative POP on clinical decision-making. Cannulation and observation rates, and overall diagnostic accuracy were high across all studies. Frequently reported visual characteristics of IPMN were intraductal fish-egg-like lesions, hypervascularity, and granular mucosa. Overall, the adverse event rate was 12 %, primarily consisting of post-endoscopic retrograde cholangiopancreatography pancreatitis, with a pooled rate of 10 %, mostly of mild severity. Regarding the impact of POP on clinical decision-making, POP findings altered the surgical approach in 13 %-62 % of patients. CONCLUSION: POP is technically successful in the vast majority of patients with (suspected) IPMN, has a consistently high diagnostic accuracy, but an adverse event rate of 12 %. Data on intraoperative pancreatoscopy are scarce, but small studies suggest its use can alter surgical management. Future studies are needed to better define the role of POP in the diagnostic work-up of IPMN.

Digital single-operator pancreatoscopy for the treatment of symptomatic pancreatic duct stones: a prospective multicenter cohort trial.

BACKGROUND: Digital single-operator pancreatoscopy (DSOP)-guided lithotripsy is a novel treatment modality for pancreatic endotherapy, with demonstrated technical success in retrospective series of between 88 % and 100 %. The aim of this prospective multicenter trial was to systematically evaluate DSOP in patients with chronic pancreatitis and symptomatic pancreatic duct stones. METHODS: Patients with symptomatic chronic pancreatitis and three or fewer stones ≥ 5mm in the main pancreatic duct (MPD) of the pancreatic head or body were included. The primary end point was complete stone clearance (CSC) in three or fewer treatment sessions with DSOP. Current guidelines recommend extracorporeal shock wave lithotripsy (ESWL) for MPD stones > 5 mm. A performance goal was developed to show that the CSC rate of MPD stones using DSOP was above what has been previously reported for ESWL. Secondary end points were pain relief measured with the Izbicki pain score (IPS), number of interventions, and serious adverse events (SAEs). RESULTS: 40 chronic pancreatitis patients were included. CSC was achieved in 90 % of patients (36/40) on intention-to-treat analysis, after a mean (SD) of 1.36 (0.64) interventions (53 procedures in total). The mean (SD) baseline IPS decreased from 55.3 (46.2) to 10.9 (18.3). Overall pain relief was achieved in 82.4 % (28/34) after 6 months of follow-up, with complete pain relief in 61.8 % (21/34) and partial pain relief in 20.6 % (7/34). SAEs occurred in 12.5 % of patients (5/40), with all treated conservatively. CONCLUSION: DSOP-guided endotherapy is effective and safe for the treatment of symptomatic MPD stones in highly selected patients with chronic pancreatitis. It significantly reduces pain and could be considered as an alternative to standard ERCP techniques for MPD stone treatment in these patients.

PERcutaneous transhepatic CHOLangioscopy using a new single-operator short cholangioscope (PERCHOL): European feasibility study.

OBJECTIVES: A new short device for percutaneous endoscopic cholangioscopy was recently developed. However, feasibility and safety has not yet been evaluated. The aim of this study was to assess clinical success, technical success, and adverse events (AEs). METHODS: This observational multicenter retrospective study included all patients who underwent percutaneous cholangioscopy using a short cholangioscope between 2020 and 2022. The clinical success, defined as the complete duct clearance or obtaining at least one cholangioscopy-guided biopsy, was assessed. The histopathological accuracy, technical success, and the AE rate were also evaluated. RESULTS: Fifty-one patients (60 ± 15 years, 45.1% male) were included. The majority of patients had altered anatomy (n = 40, 78.4%), and biliary stones (n = 34, 66.7%) was the commonest indication. The technique was predominantly wire-guided (n = 44, 86.3%) through a percutaneous sheath (n = 36, 70.6%) following a median interval of 8.5 days from percutaneous drainage. Cholangioscopy-guided electrohydraulic lithotripsy was performed in 29 cases (56.9%), combined with a retrieval basket in eight cases (27.6%). The clinical success was 96.6%, requiring a median of one session (range 1-3). Seventeen patients (33.3%) underwent cholangioscopy-guided biopsies. There were four (7.8%) cholangioscopy-related AEs (cholangitis and peritonitis). Overall, the technical success and AE rates were 100% and 19.6%, respectively, in a median follow-up of 7 months. CONCLUSION: Percutaneous endoscopic cholangioscopy with a new short device is effective and safe, requiring a low number of sessions to achieve duct clearance or accurate histopathological diagnosis.

Prospective, double-blind diagnostic multicentre study of confocal laser endomicroscopy for wheat sensitivity in patients with irritable bowel syndrome.

OBJECTIVE: A considerable proportion of patients with irritable bowel syndrome (IBS) may be wheat-sensitive and respond to a gluten-free diet (GFD) although they do not have coeliac disease. However, a diagnostic test for wheat sensitivity (WS) is missing. Our study evaluated the diagnostic accuracy (sensitivity and specificity) of confocal laser endomicroscopy (CLE) for the identification of WS as primary outcome. DESIGN: In this prospective, double-blind diagnostic study 147 non-coeliac patients fulfilling the Rome III criteria for IBS were tested by CLE for duodenal changes after wheat (index test), soy, yeast or milk exposure. Patients with IBS responding to 2 months of GFD were classified as having WS (reference test) using response criteria recommended by regulatory bodies for pharmaceutical trials of patients with IBS. After 2 months, CLE results were unblinded and patients were advised to exclude those food components that had led to a positive CLE reaction. The clinical response was assessed at follow-up after 6 and 12 months. RESULTS: Of 130 patients who completed the study per protocol, 74 (56.9%) responded to GFD and were classified as WS after 2 months, and 38 of these 74 patients were correctly identified by CLE (sensitivity 51.4%; 97.5% CI: 38.7% to 63.9%). A total of 38 of 56 patients without WS were correctly identified by CLE (specificity 67.9%; 97.5% CI: 52.9% to 79.9%). At 6 months follow-up, CLE correctly identified 49 of 59 food-sensitive patients (sensitivity 83.1%; 97.5% CI: 69.9% to 91.3%) but specificity was only 32% (97.5% CI: 15.7% to 54.3%). CONCLUSION: In light of the high proportion of patients with IBS responding to GFD, the diagnostic accuracy of CLE is too low to recommend widespread use of this invasive procedure. TRAIL REGISTRATION NUMBER: This study was registered as clinical trial in the German Registry for Clinical Studies (DRKS00010123).

Endoscopic ultrasound-guided drainage of pancreatic walled-off necrosis using 20-mm versus 15-mm lumen-apposing metal stents: an international, multicenter, case-matched study.

BACKGROUNDS: Endoscopic ultrasound (EUS)-guided placement of lumen-apposing metal stents (LAMSs) has gained popularity for the treatment of pancreatic walled-off necrosis (WON). We compared the 20-mm and 15-mm LAMSs for the treatment of symptomatic WON in terms of clinical success and adverse events. METHODS: We conducted a retrospective, case-matched study of 306 adults at 22 tertiary centers from 04/2014 to 10/2018. A total of 102 patients with symptomatic WON who underwent drainage with 20-mm LAMS (cases) and 204 patients who underwent drainage with 15-mm LAMS (controls) were matched by age, sex, and drainage approach. Conditional logistic regression analysis was performed to compare clinical success (resolution of WON on follow-up imaging without reintervention) and adverse events (according to American Society for Gastrointestinal Endoscopy criteria). RESULTS: Clinical success was achieved in 92.2 % of patients with 20-mm LAMS and 91.7 % of patients with 15-mm LAMS (odds ratio 0.92; P = 0.91). Patients with 20-mm LAMS underwent fewer direct endoscopic necrosectomy (DEN) sessions (mean 1.3 vs. 2.1; P < 0.001), despite having larger WON collections (transverse axis 118.2 vs. 101.9 mm, P = 0.003; anteroposterior axis 95.9 vs. 80.1 mm, P = 0.01). There was no difference in overall adverse events (21.6 % vs. 15.2 %; P = 0.72) and bleeding events (4.9 % vs. 3.4 %; P = 0.54) between the 20-mm and 15-mm LAMS groups, respectively. CONCLUSIONS: The 20-mm LAMS showed comparable clinical success and safety profile to the 15-mm LAMS, with the need for fewer DEN sessions for WON resolution.

Vedolizumab is associated with changes in innate rather than adaptive immunity in patients with inflammatory bowel disease.

OBJECTIVE: Vedolizumab, a monoclonal antibody directed against the integrin heterodimer α4ß7, is approved for the treatment of Crohn's disease and ulcerative colitis. The efficacy of vedolizumab has been suggested to result from inhibition of intestinal T cell trafficking although human data to support this conclusion are scarce. We therefore performed a comprehensive analysis of vedolizumab-induced alterations in mucosal and systemic immunity in patients with inflammatory bowel disease (IBD), using anti-inflammatory therapy with the TNFα antibody infliximab as control. DESIGN: Immunophenotyping, immunohistochemistry, T cell receptor profiling and RNA sequencing were performed using blood and colonic biopsies from patients with IBD before and during treatment with vedolizumab (n=18) or, as control, the anti-TNFα antibody infliximab (n=20). Leucocyte trafficking in vivo was assessed using single photon emission computed tomography and endomicroscopy. RESULTS: Vedolizumab was not associated with alterations in the abundance or phenotype of lamina propria T cells and did not affect the mucosal T cell repertoire or leucocyte trafficking in vivo. Surprisingly, however, α4ß7 antibody treatment was associated with substantial effects on innate immunity including changes in macrophage populations and pronounced alterations in the expression of molecules involved in microbial sensing, chemoattraction and regulation of the innate effector response. These effects were specific to vedolizumab, not observed in response to the TNFα antibody infliximab, and associated with inhibition of intestinal inflammation. CONCLUSION: Our findings suggest that modulation of innate immunity contributes to the therapeutic efficacy of vedolizumab in IBD. TRIAL REGISTRATION NUMBER: NCT02694588.

Acute sedation-associated complications in GI endoscopy (ProSed 2 Study): results from the prospective multicentre electronic registry of sedation-associated complications.

OBJECTIVES: Sedation has been established for GI endoscopic procedures in most countries, but it is also associated with an added risk of complications. Reported complication rates are variable due to different study methodologies and often limited sample size. DESIGNS: Acute sedation-associated complications were prospectively recorded in an electronic endoscopy documentation in 39 study centres between December 2011 and August 2014 (median inclusion period 24 months). The sedation regimen was decided by each study centre. RESULTS: A total of 368 206 endoscopies was recorded; 11% without sedation. Propofol was the dominant drug used (62% only, 22.5% in combination with midazolam). Of the sedated patients, 38 (0.01%) suffered a major complication, and overall mortality was 0.005% (n=15); minor complications occurred in 0.3%. Multivariate analysis showed the following independent risk factors for all complications: American Society of Anesthesiologists class >2 (OR 2.29) and type and duration of endoscopy. Of the sedation regimens, propofol monosedation had the lowest rate (OR 0.75) compared with midazolam (reference) and combinations (OR 1.0-1.5). Compared with primary care hospitals, tertiary referral centres had higher complication rates (OR 1.61). Notably, compared with sedation by a two-person endoscopy team (endoscopist/assistant; 53.5% of all procedures), adding another person for sedation (nurse, physician) was associated with higher complication rates (ORs 1.40-4.46), probably due to higher complexity of procedures not evident in the multivariate analysis. CONCLUSIONS: This large multicentre registry study confirmed that severe acute sedation-related complications are rare during GI endoscopy with a very low mortality. The data are useful for planning risk factor-adapted sedation management to further prevent sedation-associated complications in selected patients. TRIAL REGISTRATION NUMBER: DRKS00007768; Pre-results.

EUS-guided drainage in the management of postoperative pancreatic leaks and fistulas (with video).

BACKGROUND AND AIMS: Postoperative pancreatic leakage and fistulae (POPF) are a leading adverse event after partial pancreatic resection. Treatment algorithms are currently not standardized. Evidence regarding the role of endoscopy is scarce. METHODS: One hundred ninety-six POPF patients with (n = 132) and without (n = 64) concomitant pancreatic fluid collections (PFCs) from centers in Berlin, Kiel, and Dresden were analyzed retrospectively. Clinical resolution was used as the primary endpoint of analysis. RESULTS: Analysis was stratified by the presence or absence of a PFC because these patients differed in treatment pathway and the presence of systemic inflammation with a median C-reactive protein of 30.7 mg/dL in patients without a PFC versus 131.0 mg/dL in patients with a PFC (P = 3.4 × 10-4). In patients with PFCs, EUS-guided intervention led to resolution in a median of 8 days as compared with 25 days for percutaneous drainage and 248 days for surgery (P = 3.75 × 10-14). There was a trend toward a higher success rate of EUS-guided intervention as a primary treatment modality with 85% (P = .034), followed by percutaneous drainage (64%) and surgery (41%). When applied as a rescue intervention (n = 24), EUS led to clinical resolution in 96% of cases. In patients without PFCs, EUS-guided internalization in a novel endoscopic technique led to resolution after a median of 4 days as compared with 51 days for a remaining surgical drainage (P = 9.3 × 10-9). CONCLUSIONS: In this retrospective analysis, EUS-guided drainage of POPF led to a more rapid resolution. EUS may be considered as a viable option in the management of PFCs and POPF and should be evaluated in prospective studies.

Magnetic bead-assisted endoscopic submucosal dissection: a gravity-based traction method for treating large superficial colorectal tumors.

BACKGROUND: Colorectal endoscopic submucosal dissection (ESD) has always been challenging for endoscopists, but the procedure can be facilitated after adequate exposure of submucosal layer and cutting line. We developed a traction method based on gravity for facilitating colorectal ESD, referred as magnetic bead-assisted ESD (MBA-ESD). This study aimed to compare the safety and effectiveness of MBA-ESD and conventional ESD for treating large superficial colorectal tumors. METHODS: This retrospective study included consecutive patients with large (≥ 20 mm in their maximal diameter) superficial colorectal tumors who underwent MBA-ESD or conventional ESD at our endoscopy center between June 2017 to January 2018. Each patient in the MBA-ESD group was matched to a patient in the conventional ESD group using propensity scores. RESULTS: Thirteen patients in each group were matched for the analyses. The baseline characteristics were balanced after propensity matching. The incidence of overall complications was significantly lower in the matched MBA-ESD group (0% vs. 38.5%, P = 0.039), while similar rates of en bloc resection, R0 resection, curative resection, and tumor recurrence were noted. Although without statistic difference, dissection time and speed were improved when using MBA-ESD (33 min vs. 40 min, P = 0.111; and 21 mm2/min vs. 16 mm2/min, P = 0.143, respectively). CONCLUSIONS: MBA-ESD is a feasible, safe, and effective method for treating large superficial colorectal tumors. Further large, prospective and controlled studies are needed to fully assess this method.

Risk of infection after iatrogenic perforation of the gut wall? Evaluation of preventive strategies in a randomized controlled animal trial.

BACKGROUND: Interventional endoscopies entail a risk of infection secondary to perforation of the luminal wall. Thereby, bacteria may be introduced into the sterile environment of the peritoneal cavity (PC). Limited data are available regarding the efficacy of prophylactic anti-infective treatments. The aim of the study was to examine the efficacy/safety of anti-infective means in the prevention of infection by interventional endoscopies in a randomized controlled animal trial. METHODS: Forty pigs were randomized to: 1: control; 2: oral lavage; 3: gastric lavage; 4: oral/gastric lavage; 5: i.m. antibiotics. Lavage was performed with Octenisept prior to the operation. After gastric wall perforation, peritoneoscopy was performed. Before the procedure, after closure and prior to autopsy, intraabdominal lavage for bacterial culture was taken using mini-laparoscopy. At autopsy, macroscopic appearance of the PC was scored. Lavage fluids were grown to identify/quantify bacterial load. Concentration of intraperitoneal bacteria at autopsy was defined as main outcome parameter. RESULTS: No major complications occurred in any of the procedures. Bacterial load of the PC at autopsy was significantly reduced with antibiotics compared to all other groups, whereas it did not differ between the lavage groups and control. Macroscopic scoring of the PC showed significant lower rate of intraabdominal abscesses in the antibiotic group compared to the lavage groups and control (p < 0.01). CONCLUSION: Only antibiotic prophylaxis is effective for the prevention of infection after iatrogenic perforation of the gastrointestinal wall. There was no difference between any form of lavage and the control group. Further studies in humans are required to prove these animal data.

Confocal endomicroscopy shows food-associated changes in the intestinal mucosa of patients with irritable bowel syndrome.

BACKGROUND & AIMS: We investigated suspected food intolerances in patients with irritable bowel syndrome (IBS) using confocal laser endomicroscopy (CLE) for real-time visualization of structural/functional changes in the intestinal mucosa after food challenge. Patients with functional changes after food challenge (CLE+) were placed on personalized exclusion diets and followed up for long-term symptom relief. METHODS: Thirty-six IBS patients with suspected food intolerance and 10 patients with Barrett's esophagus (controls) without IBS symptoms were examined by CLE at University Hospital Schleswig-Holstein (Kiel, Germany). Diluted food antigens were administered directly to the duodenal mucosa through the working channel of the endoscope. Epithelial breaks, intervillous spaces, and the number of intraepithelial lymphocytes (IEL) were measured before and after the food challenge. CLE+ patients were placed on exclusion diets, given symptom score questionnaires, and followed up for 1 year; controls resumed their previous diet. RESULTS: CLE showed a real-time response to food antigens in 22 of 36 patients; no responses were observed in 14 of 36 patients (CLE-) or any of the controls. Baseline IELs were significantly higher in CLE+ than CLE- subjects (P = .004); numbers increased significantly after food challenge (P = .0008). Within 5 minutes of exposure of CLE+ patients to food antigens, IELs increased, epithelial leaks/gaps formed, and intervillous spaces widened. Epithelial leaks and intervillous spaces also increased significantly in CLE+ vs baseline (both P < .001). The concordance of IELs measured by CLE and conventional histology was 70.6%; they did not correlate (P = .89; r(2) = 0.027). Symptom scores improved more than 50% in CLE+ patients after a 4-week exclusion diet and increased to 74% at 12 months; symptoms continued in CLE- patients. CONCLUSIONS: Based on CLE analysis of IBS patients with a suspected food intolerance, exposure to candidate food antigens caused immediate breaks, increased intervillous spaces, and increased IELs in the intestinal mucosa. These changes are associated with patient responses to exclusion diets. Registered at clinicaltrials.gov (registration number: NCT01692613).

The "Iceberg Phenomenon": As Soon as One Technological Problem in NOTES Is Solved, the Next One Appears!

PURPOSE: Though already proclaimed about 7 years ago, natural orifice transluminal endoscopic surgery (NOTES) is still in its early stages. A multidisciplinary working team tried to analyze the technical obstacles and identify potential solutions. METHODS: After a comprehensive review of the literature, a group of 3 surgeons, 1 gastroenterologist, 10 engineers, and 1 representative of biomedical industry defined the most important deficiencies within the system and then compiled as well as evaluated innovative technologies that could be used to help overcome these problems. These technologies were classified with regard to the time needed for their implementation and associated hindrances, where priority is based on the level of impact and significance that it would make. RESULTS: Both visualization and actuation require significant improvement. Advanced illumination, mist elimination, image stabilization, view extension, 3-dimensional stereoscopy, and augmented reality are feasible options and could optimize visual information. Advanced mechatronic platforms with miniaturized, powerful actuators, and intuitive human-machine interfaces could optimize dexterity, as long as enabling technologies are used. The latter include depth maps in real time, precise navigation, fast pattern recognition, partial autonomy, and cognition systems. CONCLUSION: The majority of functional deficiencies that still exist in NOTES platforms could be overcome by a broad range of already existing or emerging enabling technologies. To combine them in an optimal manner, a permanent dialogue between researchers and clinicians is mandatory.

Endoscopic ultrasound-guided lymph node ablation with a novel radiofrequency ablation probe: feasibility study in an acute porcine model.

BACKGROUND AND STUDY AIMS: Radiofrequency ablation (RFA) is an accepted method of tissue destruction for solid organ tumors. Endoscopic ultrasound (EUS)-guided RFA has been used for lesions in the pancreas and liver, but there is limited experience of lymph node ablation using EUS-guided RFA. The aim of this study was to determine feasibility and safety of prototype EUS-guided RFA of mediastinal lymph nodes. METHODS: This was an endoscopic experimental feasibility study in a porcine model. After EUS-guided puncture of targeted lymph nodes, the stylet of a 19-G needle was replaced by a prototype RFA probe. RFA was performed by ERBE generator (bipolar settings: 10 watts, effect 2, 2 minutes). The animals were euthanized, and the targeted lymph nodes were identified and removed for histology and measurement of the effect achieved. RESULTS: A total of 18 mediastinal lymph nodes were ablated (mean size 20.8 ±â€Š6.6  mm in the long axis). The average length of exposed probe was 10.0 ± 3.0 mm. The mean length and diameter of necrosis was 9.8 ±â€Š3.6  mm and 5.5 ±â€Š1.6  mm, respectively. Linear regression comparing needle length with necrosis diameter revealed a coefficient gradient of r = 0.92 (P = 0.0001). With EUS-RFA a mean of 17.6 ±â€Š10.3 % (range 8.0 % - 53.2 %) of the respective lymph node area was ablated. No complications (i. e. hemodynamic instability, local bleeding, tissue damage) occurred during the procedure. Technical problems included stripping of the probe by the EUS needle and bending of the tip of the probe. CONCLUSIONS: EUS-RFA of lymph nodes was performed safely and successfully using a prototype EUS-compatible probe. This method may have the potential for future use in patient care.