A nomogram for prediction of ERCP success in patients with bile duct leaks: a multicenter study.

BACKGROUND: Bile duct leaks (BDLs) are serious complications that occurs after hepatobiliary surgery and trauma, leading to rapid clinical deterioration. Endoscopic retrograde cholangiopancreatography (ERCP) is the first-line treatment for BDLs, but it is not clear which patients will respond to this therapy and which patients will require additional surgical intervention. The aim of our study was to explore the predictors of successful ERCP for BDLs. METHODS: A retrospective analysis was conducted using data from six centers' databases. All consecutive patients who were clinically confirmed as BDLs were included in the study. Collected data were demographics, disease severity, and ERCP procedure characteristics. Univariate and multivariate analysis were used to select independent predictive factors that affect the outcome of ERCP for BDLs, and a nomogram was established. Calibration and ROC curves were used to evaluate the models. RESULTS: Four hundred and forty-eight consecutive patients were clinically confirmed as BDLs and 347 were excluded. In the 101 patients included patients, clinical success was achieved in 78 patients (77.2%). In logistic multivariable regression, two independent factors were negatively associated with the success of ERCP: SIRS (OR, 0.183; 95% CI 0.039-0.864; P = 0.032) and high-grade leak (OR 0.073; 95% CI 0.010-0.539; P = 0.010). Two independent factors were positively associated with the success of ERCP: leak-bridging drainage (OR 4.792; 95% CI 1.08-21.21; P = 0.039) and cystic duct leak (OR 6.193; 95% CI 1.03-37.17; P = 0.046). The prediction model with these four factors was evaluated using a receiver-operating characteristic (ROC) curve, which demonstrated an area under the curve of 0.9351. The calibration curve showed that the model had good predictive accuracy. CONCLUSION: Leak-bridging drainage and cystic duct leak are positive predictors for the success of ERCP, while SIRS and high-grade leak are negative predictors. This prediction model with nomogram has good predictive ability and practical clinical value, and may be helpful in clinical decision-making and prognostication.

Potential Added Value of 18F-FDG PET Metabolic Parameters in Predicting Disease Relapse in Type 1 Autoimmune Pancreatitis.

BACKGROUND: The predictive value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) metabolic parameters for predicting AIP relapse is currently unknown. This study firstly explored the value of 18F-FDG PET/CT parameters as predictors of type 1 AIP relapse. METHODS: This multicenter retrospective cohort study analyzed 51 patients who received 18F-FDG PET/CT prior to treatment and did not receive maintenance therapy after remission. The study collected baseline characteristics and clinical data and conducted qualitative and semi-quantitative analysis of pancreatic lesions and extrapancreatic organs. The study used three thresholds to select the boundaries of pancreatic lesions to evaluate metabolic parameters, including the maximum standard uptake value (SUVmax), mean standard uptake value (SUVmean), total lesion glycolysis (TLG), metabolic tumor volume (MTV), and tumor-to-normal liver standard uptake value ratio (SUVR). Univariate and multivariate analyses were performed to identify independent predictors and build a recurrence prediction model. The model was internally validated using the bootstrap method and a nomogram was created for clinical application. RESULTS: In the univariable analysis, the relapsed group showed higher levels of SUVmax (6.0 ± 1.6 vs. 5.2 ± 1.1; P = 0.047), SUVR (2.3 [2.0-3.0] vs. 2.0 [1.6-2.4]; P = 0.026), and TLG2.5 (234.5 ± 149.1 vs. 139.6 ± 102.5; P = 0.020) among the 18F-FDG PET metabolic parameters compared to the non-relapsed group. In the multivariable analysis, serum IgG4 (OR, 1.001; 95% CI, 1.000-1.002; P = 0.014) and TLG2.5 (OR, 1.007; 95% CI, 1.002-1.013; P = 0.012) were independent predictors associated with relapse of type 1 AIP. A receiver-operating characteristic curve of the predictive model with these two predictors demonstrated an area under the curve of 0.806. CONCLUSION: 18F-FDG PET/CT metabolic parameters, particularly TLG2.5, are potential predictors for relapse in patients with type 1 AIP. A multiparameter model that includes IgG4 and TLG2.5 can enhance the ability to predict AIP relapse.

Risk factors for complications in elderly patients aged 85 years and over undergoing endoscopic biliary stone removal.

Background and aim: The number of elderly patients with biliary stones is increasing. Endoscopic retrograde cholangiography (ERCP) is considered to be an effective treatment for biliary stones. Having a sound knowledge of the risk factors can help reduce the incidence and severity of complications for ERCP. Furthermore, limited research has been published on patients aged over 85 years undergoing endoscopic biliary stone removal. This study aims to determine the risk factors that lead to complications of ERCP in patients over 85 years of age. Methods: This was a single-center retrospective study. We analyzed 156 patients aged ≥ 85 years with biliary stones who underwent their first ERCP at Chinese PLA General Hospital from February 2002 to March 2021. Logistic regression models were employed to identify the independent risk factors for complications. Results: A total of 13 patients (8.3%) had complications. Thereinto, pancreatitis, cholangitis, bleeding, and other complications occurred in 4 cases (2.6%), 1 cases (0.6%), 4 cases (2.6%), and 4 cases (2.6%), respectively. There was no perforation or death related to ERCP. Independent risk factors for complications were acute biliary pancreatitis (ABP) (P = 0.017) and Charlson Comorbidity Index (CCI) (P = 0.019). Significantly, reasons for incomplete stone removal at once were large stone (>10 mm) (P < 0.001) and higher acute physiology and chronic health evaluation scoring system (APACHE-II) (P = 0.005). Conclusions: ERCP was recommended with caution in patients ≥ 85 years of age with ABP or higher CCI undergoing endoscopic biliary stone removal. In patients with ABP without cholangitis or biliary obstruction we recommend against urgent (within 48 h) ERCP. Patients with higher CCI who can tolerate ERCP can undergo rapid ERCP biliary stenting or nasobiliary implantation with later treatment of stones, and patients who cannot tolerate ERCP are treated promptly with PTCD and aggressive conservative treatment.

Prospective single-center feasible study of innovative autorelease bile duct supporter to delay adverse events after endoscopic papillectomy.

BACKGROUND: Conventional endoscopic papillectomy (EP) is safe and effective for the treatment of small papilla adenoma to even large laterally spreading tumors of duodenum lesions. As reported by some existing studies, temporarily placing a prophylactic stent in the pancreatic and bile duct can lower the risk of this perioperative complication. AIM: To evaluate the usefulness, convenience, safety, and short-term results of a novel autorelease bile duct supporter after EP procedure, especially the effectiveness in preventing EP. METHODS: A single-center comparison study was conducted to verify the feasibility of the novel method. After EP, a metallic endoclip and human fibrin sealant kit were applied for protection. The autorelease bile duct supporter fell into the duct segment and the intestinal segment. Specifically, the intestinal segment was extended by nearly 5 cm as a bent coil. The bile was isolated from the pancreatic juice using an autorelease bile duct supporter, which protected the wound surface. The autorelease bile duct supporter fell off naturally and arrived in colon nearly 10 d after the operation. RESULTS: En bloc endoscopic resection was performed in 6/8 patients (75%), and piecemeal resection was performed in 2/8 of patients (25%). None of the above patients were positive for neoplastic lymph nodes or distant metastasis. No cases of mortality, hemorrhage, delayed perforation, pancreatitis, cholangitis or duct stenosis with the conventional medical treatment were reported. The autorelease bile duct supporter in 7 of 8 patients fell off naturally and arrived in colon 10 d after the operation. One autorelease bile duct supporter was successfully removed using forceps or snare under endoscopy. No recurrence was identified during the 8-mo (ranging from 6-9 mo) follow-up period. CONCLUSION: In brief, it was found that the autorelease bile duct supporter could decrease the frequency of procedure-associated complications without second endoscopic retraction. Secure closure of the resection wound with clips and fibrin glue were indicated to be promising and important for the use of autorelease bile duct supporters. Well-designed larger-scale comparative studies are required to confirm the findings of this study.

Predicting success of direct endoscopic necrosectomy with lumen-apposing metal stents for pancreatic walled-off necrosis.

BACKGROUND AND AIMS: Direct endoscopic necrosectomy (DEN) with lumen-apposing metal stents (LAMSs) is increasingly used in the management of pancreatic walled-off necrosis (WON). However, it still remains unknown which patients will fail to respond to DEN with LAMSs and require additional surgical intervention. Therefore, the aim of our study was to explore predictors of successful DEN with LAMSs for pancreatic WON. METHODS: This is a retrospective analysis of a prospectively collected database. All consecutive patients who underwent DEN with LAMSs for pancreatic WON were included. Collected data were demographics, disease severity, morphologic features, and procedure characteristics. Potential factors affecting DEN outcome were predefined and analyzed. RESULTS: One hundred one consecutive patients undergoing DEN with LAMSs for WON were identified, among whom 4 patients were excluded for technical failure (n = 1) and previous debridement without LAMSs (n = 3). In the 97 included patients, clinical success was achieved in 79 patients (81.4%). In logistic multivariable regression, 3 independent factors were negatively associated with success of DEN with LAMSs: increasing Acute Physiology and Chronic Health Evaluation II score (odds ratio [OR], .70; 95% confidence interval [CI], .55-.90; P = .005), >50% pancreatic necrosis (OR, .16; 95% CI, .03-.77; P = .022), and paracolic gutter extension (OR, .08; 95% CI, .02-.42; P = .003). A receiver-operating characteristic curve of the prediction model with these 3 factors demonstrated an area under the curve of .926. CONCLUSIONS: Paracolic gutter extension, increasing Acute Physiology and Chronic Health Evaluation II score, and >50% gland necrosis are negative predictors for success of DEN with LAMSs in WON. This prediction model with nomogram may be helpful in clinical decision-making and prognostication.

Safety and efficacy of therapeutic endoscopic retrograde cholangiopancreatography for patients over 90 years of age.

AIMS: This study aimed to explore the safety and efficacy of endoscopic retrograde cholangiopancreatography (ERCP) in patients over 90 years of age. METHODS: The study included 176 patients aged over 85 years who received their ERCP from February 2002 to January 2021. In the case group (super-elderly group), 44 patients were 90 years old or above. In the control group (younger group), there were 132 patients aged 85-89 years. The control group was matched according to patient gender and the same indications of ERCP at a 1:3 ratio. Logistic regression models were employed to evaluate all complications. RESULTS: The case group had higher acute physiology and chronic health evaluation scoring system (APACHE-II) scores and rate of hypoalbuminemia. APACHE-II scores (≥6 or 7) were significantly more common in the case group. The rates of technical success and complete success in the case group were 100% and 100% respectively, which were similar to the rates in the control group, namely a technical success rate of 98.5% and a complete success rate of 98.5%. The rate of complication in the case group was 9.1%, which was slightly lower than that of the control group (15.2%, P > 0.05). ERCP-related death occurred in one patient in the control group, who had malignant biliary obstruction and died from cholangitis. There was no significant difference in the incidence of complications such as pancreatitis, hemorrhage, and infection between the two groups. In the multivariate analysis, the independent risk factor was Charlson Comorbidity Index (CCI) for overall complication. CONCLUSIONS: ERCP can be performed safely and successfully in patients aged ≥90 years. Geriatr Gerontol Int 2022; 22: 50-55.

Multiple hidden vessels in walled-off necrosis with high-risk bleeding: Report of two cases.

BACKGROUND: Walled-off necrosis (WON), as a local complication of acute necrotizing pancreatitis, is difficult to differentiate from pancreatic pseudocysts (PPC). Imaging modalities such as computed tomography show a lower accuracy than endoscopic ultrasound (EUS) in confirming the diagnosis. EUS-guided cystogastrostomy following direct endoscopic necrosectomy has achieved excellent results and has been regarded as a preferred alternative to traditional surgery. However, high-risk bleeding is one of the greatest concerns. CASE SUMMARY: Two patients with symptomatic pancreatic fluid collections (PFCs) were admitted to our hospital for EUS-guided lumen-apposing metal stent therapy. The female patient suffered from intermittent abdominal pain and underwent two perioperative CT examinations. The male patient had recurrent pancreatitis and showed a growing PFC. The initial diagnosis was a PPC according to contrast-enhanced CT. However, the evidence of solid contents on EUS prompted revision of the diagnosis to WON. An endoscope was inserted into the cavity, and some necrotic debris and multiple hidden vascular structures were observed. Owing to conservative treatment by irrigation with sterile water instead of direct necrosectomy, we successfully avoided damaging hidden vessels and reduced the risk of intraoperative bleeding. CONCLUSION: The application of EUS is helpful for the identification of PFCs. Careful intervention should be conducted for WON with multiple vessels to prevent bleeding.

Hybrid endoscopic submucosal dissection: An alternative resection modality for large laterally spreading tumors in the cecum?

BACKGROUND: Endoscopic resection for large, laterally spreading tumors (LSTs) in the cecum is challenging. Here we report on the clinical outcomes of hybrid endoscopic submucosal dissection (ESD) in large cecal LSTs. METHODS: We retrospectively reviewed data from patients with cecal LSTs ≥ 2 cm who underwent ESD or hybrid ESD procedures between January of 2008 and June of 2019. We compared the baseline characteristics and clinical outcomes, including procedure time, the en bloc and complete resection rates, and adverse events. RESULTS: A total of 62 patients were enrolled in the study. There were 27 patients in the ESD group and 35 patients in the hybrid ESD group, respectively. Hybrid ESD was more used for lesions with submucosal fibrosis. No other significant differences were found in patient characteristics between the two groups. The hybrid ESD group had a significantly shorter procedure time compared with the ESD group (27.60 ± 17.21 vs. 52.63 ± 44.202 min, P = 0.001). The en bloc resection rate (77.1% vs. 81.5%, P = 0.677) and complete resection rate (71.4% vs. 81.5%, P = 0.359) of hybrid ESD were relatively lower than that of the ESD group in despite of no significant difference was found. The perforation and post-procedure bleeding rate (2.9% vs. 3.7%, P = 0.684) were similar between the two groups. One patient perforated during the ESD procedure, which was surgically treated. One patient in the hybrid ESD group experienced post-procedure bleeding, which was successfully treated with endoscopic hemostasis. Post-procedural fever and abdominal pain occurred in six patients in the ESD group and five patients in the hybrid ESD group. One patient in the ESD group experienced recurrence, which was endoscopically resected. CONCLUSION: The results of this study indicate that hybrid ESD may be an alternative resection strategy for large cecal LSTs with submucosal fibrosis.

Endoscopic versus surgical resection in the management of gastric schwannomas.

BACKGROUND AND AIMS: Gastric schwannoma (GS) is not well clinically recognized and surgical resection (SR) remains the mainstay of treatment. Recently, endoscopic resection (ER) appears to be a safe and effective alternative. However, its comparative outcomes with SR is lacking. Our aim was to first compare clinical outcomes and costs between ER and SR in the management of GSs. METHODS: A total of 46 consecutive patients with GSs who underwent ER (n = 16) or SR (n = 30) in our large tertiary center between July 2007 and Oct 2018 were included. Clinicopathologic features, clinical outcomes, medical costs and follow-up were retrospectively reviewed and compared between two groups. RESULTS: Baseline characteristics are comparable except for a smaller tumor size in ER group (22.9 vs 41.0 mm, p = 0.002). Complete resection was achieved in 87.5% of patients with ER and 100% of patients with SR (p = 0.116). The ER group had a significant shorter operative time (91.6 vs 128.2 min), less blood loss (16.9 vs 62.7 mL) and lower operation cost (21,054.4 vs 30,843.4 RMB) than SR group (all p < 0.05). There was no significant difference in adverse events (12.5% vs 10%, p = 0.812) and length of postoperative hospital stay (8.3 vs 8.2 days, p = 0.945). During a long-term follow-up of mean 37.4 months (range 6-140 months), no residue, recurrence or metastasis was observed in both groups. CONCLUSIONS: Compared with SR, ER has the similar safety and efficacy in the management of GSs, but contributes to a shorter operation time and lower medical costs. ER may be considered as the first-line treatment, especially for patients with GSs smaller than 30 mm.

Efficacy and safety of hybrid endoscopic submucosal dissection compared with endoscopic submucosal dissection for rectal neuroendocrine tumors and risk factors associated with incomplete endoscopic resection.

BACKGROUND: Neuroendocrine tumors (NETs) are rising in prevalence, particularly with the rectal area. This study evaluated and compared the safety and effectiveness of hybrid endoscopic submucosal dissection (ESD) with those of ESD for rectal NETs and risk factors associated with incomplete endoscopic resection. METHODS: A total of 272 consecutive patients who underwent ESD or hybrid ESD for rectal NETs at the Chinese PLA General Hospital in the period from February 2011 to September 2018 were involved in this study. Data were collected from clinical and endoscopic databases. The procedure time, en bloc resection, complete resection, complication, and recurrence rates were evaluated. RESULTS: In the hybrid ESD group were 111 patients (who had 119 lesions between them), with a further 161 patients (164 lesions) in the ESD group. No significance was found in baseline characteristics between the two groups. Hybrid ESD had a significantly shorter mean procedure time than ESD (13.2±8.3 vs. 18.1±9.7 min, P=0.000). Hybrid ESD showed similar en bloc resection (99.2% vs. 98.2%; P=0.373), complete resection (94.1% vs. 90.9%, P=0.641), and postprocedural bleeding (2.5% vs. 0.6%, P=0.313) rates to ESD. Univariate and multivariate analysis showed that higher histopathological grade was associated with incomplete resection. CONCLUSIONS: For rectal NET, both ESD and hybrid ESD are effective and safe forms of treatment. Hybrid ESD provides an alternative option in the treatment of rectal NETs. Further developments are needed to improve the complete resection rate, especially concerning tumors with higher histopathological grade.

Endoscopic submucosal excavation and endoscopic full-thickness resection for gastric schwannoma: five-year experience from a large tertiary center in China.

BACKGROUND AND AIMS: Endoscopic resection (ER) is an effective and safe method for gastric submucosal tumors, mostly composed of gastrointestinal stromal tumors and leiomyomas. The role of ER in gastric schwannoma (GS) has rarely been described. Our aim was to evaluate the efficacy and safety of ER for GS. METHODS: This is a retrospective study in consecutive patients who underwent ER for GS from March 2013 to October 2018 at our center. Clinicopathological, endoscopic, and follow-up data were collected and analyzed. RESULTS: A total of 16 consecutive patients (9 females, 56.3%) were included, with a mean age of 50.4 years (range 25-75 years). The mean tumor size was 22.9 ± 15.1 mm (range 10-55 mm). Thirteen tumors (81.3%) were located in the middle third of the stomach and 12 tumors (75%) grew with intraluminal pattern. Endoscopic submucosal excavation (ESE) was performed in 7 patients while endoscopic full-thickness resection (EFTR) was done in 9 patients. R0 resection was achieved in 14 patients (87.5%). The mean operative time was 91.6 ± 52.8 min (range 36-203 min) and the mean postoperative length of hospital stays was 8.3 ± 2.7 days (range 6-13 days). No adverse events were encountered except for fevers in 2 patients. No patients required surgical resection or intervention. During long-term follow-up of mean 21.8 months (range 6-62 months), no residue, recurrence, or metastasis was observed. CONCLUSIONS: ER is effective and safe for patients with GS with favorable long-term outcomes.

Consensus on the digestive endoscopic tunnel technique.

With the digestive endoscopic tunnel technique (DETT), many diseases that previously would have been treated by surgery are now endoscopically curable by establishing a submucosal tunnel between the mucosa and muscularis propria (MP). Through the tunnel, endoscopic diagnosis or treatment is performed for lesions in the mucosa, in the MP, and even outside the gastrointestinal (GI) tract. At present, the tunnel technique application range covers the following: (1) Treatment of lesions originating from the mucosal layer, e.g., endoscopic submucosal tunnel dissection for oesophageal large or circular early-stage cancer or precancerosis; (2) treatment of lesions from the MP layer, per-oral endoscopic myotomy, submucosal tunnelling endoscopic resection, etc.; and (3) diagnosis and treatment of lesions outside the GI tract, such as resection of lymph nodes and benign tumour excision in the mediastinum or abdominal cavity. With the increasing number of DETTs performed worldwide, endoscopic tunnel therapeutics, which is based on DETT, has been gradually developed and optimized. However, there is not yet an expert consensus on DETT to regulate its indications, contraindications, surgical procedure, and postoperative treatment. The International DETT Alliance signed up this consensus to standardize the procedures of DETT. In this consensus, we describe the definition, mechanism, and significance of DETT, prevention of infection and concepts of DETT-associated complications, methods to establish a submucosal tunnel, and application of DETT for lesions in the mucosa, in the MP and outside the GI tract (indications and contraindications, procedures, pre- and postoperative treatments, effectiveness, complications and treatments, and a comparison between DETT and other operations).

[Factors affecting the safety and efficacy of peroral endoscopic myotomy for achalasia].

OBJECTIVE: To identify the factors that affect the safety and efficacy of peroral endoscopic myotomy (POEM) for treatment of achalasia. METHODS: Data of consecutive patients undergoing POEM for confirmed achalasia between December, 2010 and December, 2015 were collected, including the procedure time, approach of tunnel entry incision, approach of myotomy, complications and follow-up data. RESULTS: Among the total of 439 patients enrolled, the overall complication rate was 28.7% (126/439). Treatment success (Eckardt score≤3) was achieved in 94.5% of 364 patients followed up for a median of 6 months (1-48 months), and the mean score was reduced significantly from 6.7∓1.5 before treatment to 1.2∓1.1 after the treatment (P<0.05). Logistic regression revealed that the year when POEM was performed and the approach of entry incision were two significant factors contributing to complications: with the year 2015 as the reference, the odds ratio (OR) was 9.454 (95% CI: 2.499-35.76) for the years before 2011, 2.177 (95% CI: 0.794-5.974) for 2012, 3.975 (95% CI: 1.904-8.298) for 2013, and 1.079 (95% CI: 0.601-1.940) for 2014; with the longitudinal entry incision as the reference, the OR was 0.369 (95% CI: 0.165-0.824) for inverted T entry incision and 0.456 (95% CI: 0.242-0.859) for transverse entry incision. The approach of myotomy was the significantly associated with symptomatic relapse: with full-thickness myotomy combined with indwelling an anti-reflux belt as the reference, the OR was 0.363 (95% CI: 0.059-2.250) for gradual full-thickness myotomy, 2.137 (95% CI: 0.440-10.378) for circular muscle myotomy, and 4.385 (95% CI: 0.820-23.438) for circular muscle myotomy in combination with balloon shaping; the recurrence rate was 0 with a full-thickness myotomy. CONCLUSION: The complication rates of POEM appears to decrease over time, and an inverted T entry incision is the best choice for controlling the complications. Gradual full-thickness myotomy is an excellent approach for treatment of achalasia in terms of the relapse rate, procedure time and the incidence of reflux esophagitis.

Endoscopic submucosal tunnel dissection for large superficial esophageal squamous cell neoplasms.

Endoscopic submucosal dissection (ESD) is a well-established treatment for superficial esophageal squamous cell neoplasms (SESCNs) with no risk of lymphatic metastasis. However, for large SESCNs, especially when exceeding two-thirds of the esophageal circumference, conventional ESD is time-consuming and has an increased risk of adverse events. Based on the submucosal tunnel conception, endoscopic submucosal tunnel dissection (ESTD) was first introduced by us to remove large SESCNs, with excellent results. Studies from different centers also reported favorable results. Compared with conventional ESD, ESTD has a more rapid dissection speed and R0 resection rate. Currently in China, ESTD for large SESCNs is an important part of the digestive endoscopic tunnel technique, as is peroral endoscopic myotomy for achalasia and submucosal tunnel endoscopic resection for submucosal tumors of the muscularis propria. However, not all patients with SESCNs are candidates for ESTD, and postoperative esophageal strictures should also be taken into consideration, especially for lesions with a circumference greater than three-quarters. In this article, we describe our experience, review the literature of ESTD, and provide detailed information on indications, standard procedures, outcomes, and complications of ESTD.

Endoscopic transesophageal biopsy in the posterior mediastinum using submucosal tunneling technology and novel homemade instruments.

BACKGROUND/AIMS: This animal study was performed to evaluate the feasibility and safety of endoscopic transesophageal biopsy by using submucosal tunneling technology novel homemade instruments in the posterior mediastinum. METHODOLOGY: In six survival pigs, a mid-esophageal mucosal incision and a 10-cm submucosal tunnel was created. The endoscope attached to homemade decompression tube was passed through the muscular layers into the posterior mediastinal space. The mediastinal compartment, lung, descending thoracic aorta, vertebra, and exterior surface of the esophagus will be identified, and mediastinal living tissue as lymph node biopsy will also be accomplished. During two survival weeks, blood test and temperature monitoring and chest radiograph and endoscopic examination were performed. RESULTS: The procedure was successfully completed in all six pigs. Mediastinal structures could be identified without difficulty by the transesophageal tunneling approach. Tissue as lymph nodes and pleural biopsy under direct visualization were easily accomplished. One pig died after operation due to an unexplained pneumothorax. At necropsy, apparent atelectasis was noted in the right lobe. After applying homemade drainage tube attached to the syringe, one pig with pneumothorax soon had restoration. There were no apparent ill effects in the survival pigs. CONCLUSIONS: Endoscopic transesophageal biopsy in the posterior mediastinum using a novel tunneling technology can provide excellent visualization of mediastinal structures. These procedures could be performed safely in pigs with short-term survival. Further study about immediate complications will be needed with a larger sample size and longer survival time.