Learning curve for esophageal peroral endoscopic myotomy: a systematic review and meta-analysis.

BACKGROUND AND STUDY AIMS : Peroral endoscopic myotomy (POEM) is a minimally invasive endoscopic procedure for the treatment of achalasia and certain spastic esophageal motility disorders, delivering excellent results in experienced hands. However, this complex and technically challenging procedure requires advanced endoscopic skills. The aim of this study was to conduct a systematic review and meta-analysis of current data to evaluate the learning curve for POEM in new adopters of this technique. METHODS : Electronic databases (PubMed, Embase, and Cochrane Library) from inception to November 2021 were searched for publications addressing the learning curve in POEM. Pooling was conducted by both fixed- and random-effects models. Secondary outcomes reviewed were clinical success defined by Eckardt score ≤ 3 when available and adverse events. RESULTS : Eight studies involving 1904 patients met the inclusion criteria. In the pooled analysis, new adopters of POEM attained proficiency at a mean of 24.67 procedures (95 %CI 23.93 to 25.41). Once proficiency was achieved, the pooled total procedure time plateaued at a mean of 85.38 minutes (95 %CI 81.48 to 89.28), the pooled mean procedure time per centimeter of myotomy was 6.25 minutes (95 %CI 5.69 to 6.82), and the pooled mean length of myotomy was 11.49 cm (95 %CI 10.90 to 12.08). CONCLUSIONS : Our analysis showed that new adopters of POEM with previous advanced endoscopy experience required about 25 procedures to attain proficiency. The average time for each procedure once proficiency was attained was about 85 minutes.

Surgical vs Endoscopic Management of T1 Esophageal Adenocarcinoma: A Modeling Decision Analysis.

BACKGROUND & AIMS: Although treatment of T1a esophageal adenocarcinoma (EAC) is shifting from esophagectomy to endoscopic therapy, T1b EACs are considered too high risk to be treated endoscopically. We investigated the effectiveness and cost effectiveness of esophagectomy vs endoscopic therapy for T1a and T1b EACs, and the effects of age and comorbidities, using a decision analytic Markov model. METHODS: We developed a model to simulate a hypothetical cohort of men 75 years old with Charlson comorbidity index scores of 0 and either T1aN0M0 or T1bN0M0 EAC, as a base case. We used the model to compare the effects of esophagectomy vs serial endoscopic therapy. We performed sensitivity analyses based on age at diagnosis of 60-85 years, comorbidity indices of 0-2, and utilities. Post-procedure cancer-specific mortality was derived from the Surveillance, Epidemiology, and End Results Medicare database. RESULTS: In the T1a base case, esophagectomy yielded more unadjusted life years than endoscopic therapy (6.97 vs 6.81), but fewer quality-adjusted life years (QALYs, 4.95 for esophagectomy vs 5.22 for endoscopic therapy). In the T1b base case, esophagectomy yielded more unadjusted life years than endoscopic therapy (5.73 vs 5.01) and QALYs (4.07 vs 3.85 for endoscopic therapy), but was not cost effective (incremental cost-effectiveness ratio $156,981). Sensitivity analyses showed endoscopic therapy optimized QALYs for patients more than 80 years old with a comorbidity index of 1 or 2, or if the ratio of post-esophagectomy to post-endoscopic therapy utilities was below 0.875. CONCLUSION: In a Markov model, we showed that endoscopic therapy of T1a EAC yields more QALYs and is more cost effective than esophagectomy for patients of all ages and comorbidity indices tested. In contrast, selection of therapy for T1b EAC depends on age and comorbidities, due to surgical mortality and the competing risk of non-cancer death.

Feasibility and safety of microforceps biopsy in the diagnosis of pancreatic cysts.

BACKGROUND AND AIMS: The tissue acquisition and diagnostic yield of cyst fluid cytology is low-to-moderate and rarely provides a specific diagnosis. The aim of this study was to compare the tissue acquisition and diagnostic tissue yield of microforceps biopsy (MFB) with cyst fluid cytology. METHODS: In this multicenter study, data of 42 patients who had cysts both aspirated by EUS-guided FNA (EUS-FNA) and biopsy specimens were then obtained with an MFB device, were collected. Cytology analysis of cyst fluid and histologic analysis of biopsy specimens were done. Acquisition yield was defined as percentage of patients with tissue present in the aspirate or biopsy. Diagnostic tissue yield was evaluated at 3 levels: the ability of differentiation between mucinous and/or nonmucinous cysts, detection of high risk for malignancy, and specific cyst type diagnosis. RESULTS: The mean patient age was 69 years. Sixteen pancreatic cysts (38.1%) were located in the head, 17 (40.5%) in the body, and 9 (21.4%) in the tail. The mean cyst size was 28.2 mm (12-60 mm); 25 of 42 (60%) were septated. The EUS-FNA tissue (fluid) acquisition yield was 88.1% (37/42). The MFB tissue acquisition yield was 90.4% (38/42). The diagnostic cytology yield to differentiate between mucinous and/or nonmucinous cysts was 47.6% (20/42), and the MFB histologic yield to differentiate between mucinous and/or nonmucinous cysts was 61.9% (26/42) (P = .188). The percentage of cysts at high risk for malignancy by cytology was 54.7% (23/42), and MFB was 71.5% (30/42) (P = .113). However, the ability of MFB to provide a specific cyst type diagnosis was 35.7% (15/42), and that for cytology was 4.8% (2/42) (P = .001). Surgical histology was concordant with that of MFB in 6 of 7 patients (85%), and with that of cytology in 1 of 7 patients (15%). CONCLUSION: The cyst tissue acquisition yield for MFBs was 90%. Although cytology of cyst fluid and MFB were comparable in distinguishing mucinous and nonmucinous cysts and detecting cysts at high risk for malignancy, MFB was far superior to cytology for providing a specific cyst diagnosis.

Needle-Based Confocal Laser Endomicroscopy for Evaluation of Cystic Neoplasms of the Pancreas.

BACKGROUND: The accurate diagnosis of cystic neoplasms of the pancreas (CNP) with current diagnostic methods is limited. Endoscopic ultrasound (EUS)-guided needle-based confocal laser endomicroscopy (nCLE) is a new technique which can obtain images from the cyst wall during EUS-fine needle aspiration (EUS-FNA). The aim of this study was to assess the safety, feasibility, and diagnostic value of nCLE for CNP. METHODS: Patients who underwent EUS-FNA to evaluate a CNP larger than 2 cm were enrolled. The cyst was punctured with 19-G FNA needle preloaded with an nCLE probe. The images from different areas of the cyst wall were recorded. Using the final diagnosis defined by surgery or EUS-FNA cyst fluid analysis, the accuracy of the confocal images was defined. RESULTS: The procedure and image acquisition was successful in 18 of the 20 patients. Predefined typical structures for mucinous cysts were visualized in 8 of 12 (66%) cysts but none of the non-mucinous cysts. The superficial vascular network which is a typical finding of serous cysts was observed in 2 of 3 patients. The sensitivity, specificity, and diagnostic accuracy of the findings of epithelial structures by nCLE were 66, 100, and 80%, respectively, for a mucinous cyst diagnosis. All patients tolerated the procedure well, and no adverse effects were determined. CONCLUSION: nCLE was found to be safe and feasible with high technical success, in this pilot study. With an overall accuracy of 80%, it has the potential to contribute to the diagnosis of CNP with specific imaging.

Value of adding GNAS testing to pancreatic cyst fluid KRAS and carcinoembryonic antigen analysis for the diagnosis of intraductal papillary mucinous neoplasms.

BACKGROUND AND AIM: Molecular analysis of pancreatic cyst fluid (PCF) has been proposed as a novel method for differentiating pancreatic cystic lesions (PCL). The present study aimed to investigate the value of GNAS testing when added to KRAS and carcinoembryonic antigen (CEA) testing of PCF for the diagnosis of intraductal papillary mucinous neoplasms (IPMN). METHODS: Prospectively collected endoscopic ultrasonography fine-needle aspiration (EUS-FNA) data were analyzed retrospectively for GNAS and KRAS mutations and CEA results. IPMN were histologically confirmed or supported by imaging and EUS-FNA findings (KRAS, CEA, cytology). Performance characteristics of GNAS added to KRAS and CEA for the diagnosis of IPMN were calculated. RESULTS: The study population consisted of 197 patients with cyst fluid test results. Cysts were histologically classified in 33 patients and by clinical criteria in 164 patients. The IPMN group included 108 patients and the non-IPMN group included 89 patients. GNAS was positive in 51 patients (47.2%) with IPMN. Forty-two of these patients (82.3%) also had a KRAS mutation. Adding GNAS to KRAS increased the diagnostic accuracy from 76.6% to 79.1% (P > 0.05). Adding GNAS to CEA increased the diagnostic accuracy from 66.4% to 80.7 % (P < 0.05), but did not achieve a diagnostic superiority to KRAS testing alone (80.7% vs 76.6%, P > 0.05). The diagnostic accuracy of the triple combination was significantly better than all single tests (P < 0.05). CONCLUSION: GNAS mutation is a highly specific test for IPMN. When GNAS testing is added to CEA and KRAS, a significantly greater overall accuracy (86.2%) is achieved.

Endoscopic Therapy With Lumen-apposing Metal Stents Is Safe and Effective for Patients With Pancreatic Walled-off Necrosis.

BACKGROUND & AIMS: Endoscopic ultrasound-guided transmural drainage and necrosectomy have become the standard treatment for patients with pancreatic walled-off necrosis (WON). Lumen-apposing metal stents (LAMS) have shown success in the management of pancreatic fluid collections. However, there are few data on their specific roles in management of WON. We investigated the efficacy and safety of LAMS in treatment of WON. METHODS: We performed a retrospective multicenter case series of 124 patients with WON who underwent endoscopic transmural drainage by using LAMS at 17 tertiary care centers from January 2014 through May 2015. Patients underwent endoscopic ultrasound-guided cystogastrostomy or cystoenterostomy with placement of an LAMS into the WON collection. At the discretion of the endoscopist, we performed direct endoscopic necrosectomy, irrigation with hydrogen peroxide, and/or nasocystic drain placement. We performed endoscopic retrograde cholangiopancreatography with pancreatic duct stent placement when indicated. Concomitant therapies included direct endoscopic debridement (n = 78), pancreatic duct stent placement for leak (n = 19), hydrogen peroxide-assisted necrosectomy (n = 38), and nasocystic irrigation (n = 22). We collected data for a median time of 4 months (range, 1-34 months) after the LAMS placement. The primary outcomes were rates of technical success (successful placement of the LAMS), clinical success (resolution of WON, on the basis of image analysis, without need for further intervention via surgery or interventional radiology), and adverse events. RESULTS: The median size of the WON was 9.5 cm (range, 4-30 cm). Eight patients had 2 LAMS placed for multiport access, all with technical success (100%). Clinical success was achieved in 107 patients (86.3%) after 3 months of follow-up. Thirteen patients required a percutaneous drain, and 3 required a surgical intervention to manage their WON. The stents remained patent in 94% of patients (117 of 124) and migrated in 5.6% of patients (7 of 124). The median number of endoscopic interventions was 2 (range, 1-9 interventions). CONCLUSIONS: On the basis of a retrospective analysis of 124 patients, endoscopic therapy of WON by using LAMS is safe and effective. Creation of a large and sustained cystogastrostomy or cystoenterostomy tract is effective in the drainage and treatment of WON.

Combined endoscopic trangastric drainage and video assisted retroperitoneal pancreatic debridement - The best of both worlds for extensive pancreatic necrosis with enteric fistulae.

Enteric fistula is a serious complication of necrotizing pancreatitis. Endoscopic transluminal drainage and necrosectomy can significantly reduce the incidence of enterocutaneous fistula after pancreatic debridement. However, endoscopic necrosectomy may not be well-suited to debridement of necrosis that tracks laterally to the paracolic gutters, which is often more efficiently addressed by video-assisted retroperitoneal debridement (VARD). We report the combined use of endoscopic transgastric drainage and VARD for treatment of a 76 year old man with severe necrotizing acute pancreatitis complicated by infected, walled-off pancreatic necrosis. Computed tomography showed laterally tracking pancreatic necrosis and flouroscopic drain injection after percutaneous drainage demonstrated with fistulas to the stomach, duodenum, and colon. The infection and fistulas resolved completely. This approach combined the major advantage of VARD with the major advantage of endoscopic transluminal drainage. We are not aware of any reports of combining these techniques and believe the combination offers a minimally invasive approach for patients with extensive necrosis and a high likelihood of enteric or pancreatic fistulas.

Radiofrequency ablation for the management of occluded biliary metal stents.

Background and study aim: Obstruction of biliary self-expandable metal stents (SEMSs) is seen frequently. Radiofrequency ablation (RFA) causes tissue necrosis. This study aimed to assess the efficacy of RFA for management of occluded SEMS. Patients and methods: Patients with biliary malignancy and treated for an occluded SEMS were retrospectively reviewed. The study group comprised patients treated with RFA using an Habib endoprobe inside the SEMS. The control group comprised patients treated only with insertion of a plastic stent into an occluded SEMS. The end points were; 90-day stent patency rate, time to stent reocclusion, 30-day mortality, and 3 - and 6-month survival rates. Results: During the 5-year study period 25 patients with an occluded SEMS underwent RFA and 25 patients underwent a plastic stent placement only. Both groups were matched for age and diagnosis. Immediate biliary drainage was restored in all patients. In the RFA group, the stenosis was ablated successfully in 14 patients (56 %); ablation failed in 11 and a plastic stent was then inserted into the SEMS for these. The control group had only placement of a plastic stent across the stenosis. Stent patency rate at 90 days was 56 % and 24 % in the RFA and control groups, respectively (P = 0.04). The mean stent patency time was significantly longer in the RFA group compared to the control group (119.5 vs. 65.3 days, P = 0.03). Conclusion: The application of RFA for occluded SEMS improves stent patency. RFA is an alternative treatment of tissue ingrowth in malignant biliary obstruction.

EUS-derived criteria for distinguishing benign from malignant metastatic solid hepatic masses.

BACKGROUND: Detection of hepatic metastases during EUS is an important component of tumor staging. OBJECTIVE: To describe our experience with EUS-guided FNA (EUS-FNA) of solid hepatic masses and derive and validate criteria to help distinguish between benign and malignant hepatic masses. DESIGN: Retrospective study, survey. SETTING: Single, tertiary-care referral center. PATIENTS: Medical records were reviewed for all patients undergoing EUS-FNA of solid hepatic masses over a 12-year period. INTERVENTIONS: EUS-FNA of solid hepatic masses. MAIN OUTCOME MEASUREMENTS: Masses were deemed benign or malignant according to predetermined criteria. EUS images from 200 patients were used to create derivation and validation cohorts of 100 cases each, matched by cytopathologic diagnosis. Ten expert endosonographers blindly rated 15 initial endosonographic features of each of the 100 images in the derivation cohort. These data were used to derive an EUS scoring system that was then validated by using the validation cohort by the expert endosonographer with the highest diagnostic accuracy. RESULTS: A total of 332 patients underwent EUS-FNA of a hepatic mass. Interobserver agreement regarding the initial endosonographic features among the expert endosonographers was fair to moderate, with a mean diagnostic accuracy of 73% (standard deviation 5.6). A scoring system incorporating 7 EUS features was developed to distinguish benign from malignant hepatic masses by using the derivation cohort with an area under the receiver operating curve (AUC) of 0.92; when applied to the validation cohort, performance was similar (AUC 0.86). The combined positive predictive value of both cohorts was 88%. LIMITATIONS: Single center, retrospective, only one expert endosonographer deriving and validating the EUS criteria. CONCLUSION: An EUS scoring system was developed that helps distinguish benign from malignant hepatic masses. Further study is required to determine the impact of these EUS criteria among endosonographers of all experience.

mAb Das-1 is specific for high-risk and malignant intraductal papillary mucinous neoplasm (IPMN).

OBJECTIVE: Intraductal papillary mucinous neoplasm (IPMN) consists of four epithelial subtypes that correlate with histological grades and risks for malignant transformation. mAb Das-1 is a monoclonal antibody against a colonic epithelial phenotype that is reactive to premalignant conditions of the upper GI tract. We sought to assess the ability of mAb Das-1 to identify IPMN with high risk of malignant transformation. DESIGN: mAb Das-1 reactivity was evaluated in 94 patients with IPMNs by immunohistochemistry. Lesional fluid from 38 separate patients with IPMN (n=27), low-grade non-mucinous cystic neoplasms (n=7) and pseudocysts (n=4) was analysed by ELISA and western blot. RESULTS: Immunohistochemistry-Normal pancreatic ducts were non-reactive and low-grade gastric-type IPMN (IPMN-G) (1/17) and intermediate-grade IPMN-G (1/23) were minimally reactive with mAb Das-1. In contrast, mAb Das-1 reactivity was significantly higher in high-risk/malignant lesions (p<0.0001) including: intestinal-type IPMN with intermediate-grade dysplasia (9/10); high-grade dysplasia of gastric (4/7), intestinal (12/12), oncocytic (2/2) and pancreatobiliary types (2/2); and invasive tubular (8/12), colloid (7/7) and oncocytic (2/2) carcinoma. The sensitivity and specificity of mAb Das-1 for high-risk/malignant IPMNs were 85% and 95%, respectively. Lesional fluid-Samples from low- and intermediate-grade IPMN-G (n=9), and other low-grade/benign non-mucinous lesions demonstrated little reactivity with mAb Das-1. Conversely, cyst fluid from high-risk/malignant IPMNs (n=18) expressed significantly higher reactivity (p<0.0001). The sensitivity and specificity of mAbDas-1 in detecting high-risk/malignant IPMNs were 89% and 100%, respectively. CONCLUSIONS: mAb Das-1 reacts with high specificity to tissue and cyst fluid from high-risk/malignant IPMNs and thus may help in preoperative clinical risk stratification.

Recurrences are common after endoscopic ampullectomy for adenoma in the familial adenomatous polyposis (FAP) syndrome.

BACKGROUND: Endoscopic ampullectomy is increasingly performed in patients with familial adenomatous polyposis (FAP)-associated ampullary adenomas. We sought to define the procedure-associated morbidities and long-term outcomes. METHODS: We performed a retrospective chart review of patients with FAP who underwent endoscopic ampullectomy at two tertiary institutions between 1999 and 2010. The severity of duodenal polyposis was classified according to Spigelman's classification. RESULTS: Of 26 FAP patients who underwent endoscopic ampullectomy, 21 arose in the setting of Spigelman's stage II duodenal polyposis. Adverse events associated with endoscopic ampullectomy included acute pancreatitis (19.2%), abdominal pain (7.6%), and bleeding (3.8%). The mean resected adenoma size was 0.99 ± 0.34 cm. Three adenomas (12.0%) contained foci of high-grade dysplasia. Follow-up data were available for 24 patients. The mean follow-up duration was 84.5 ± 36.2 months. Adenoma recurrence was observed in 14 patients (58.3%; 14/24) at a mean of 38.3 months after initial ampullectomy. Adenomas ≥10 mm recurred more frequently than smaller adenomas (76.9 vs. 36.4%; p = 0.002). Positive margins were not associated with higher recurrence rates. No cancers were observed during long-term follow-up. Three patients underwent a Whipple procedure, but none was performed for a recurrent ampullary adenoma. CONCLUSIONS: Endoscopic ampullectomy in FAP can be performed safely. Because ampullary adenomas frequently recur after endoscopic ampullectomy, close surveillance is essential. Smaller tumors are less likely to recur, suggesting a benefit for early recognition of these lesions.

Endoscopic ultrasound-guided gastroenterostomy versus enteral stenting for gastric outlet obstruction: a systematic review and meta-analysis.

Background: The symptoms of gastric outlet obstruction have traditionally been managed surgically or endoscopically. Enteral stenting (ES) is a less invasive endoscopic treatment strategy for this condition. Endoscopic ultrasound-guided gastroenterostomy (EUS-GE) has recently become a potential alternative technique. Objectives: We conducted a systematic review and meta-analysis of the effectiveness and safety profile of EUS-GE compared with ES. Design: Meta-analysis and systematic review. Data sources and methods: We searched multiple databases from inception to August 2023 to identify studies that reported the effectiveness and safety of EUS-GE compared with ES. The outcomes of technical success, clinical success, and adverse events (AEs) were evaluated. Pooled proportions were calculated using both fixed and random effects models. Results: We included 13 studies with 1762 patients in our final analysis. The pooled rates of technical success for EUS-GE were 95.59% [95% confidence interval (CI), 94.01-97.44, I 2 = 32] and 97.96% (95% CI, 96.06-99.25, I 2 = 63) for ES. The pooled rate of clinical success for EUS-GE was 93.62% (95% CI, 90.76-95.98, I 2 = 54) while for ES it was lower at 85.57% (95% CI, 79.63-90.63, I 2 = 81). The pooled odds ratio (OR) of clinical success was higher for EUS-GE compared to ES at 2.71 (95% CI, 1.87-3.93). The pooled OR of clinical success for EUS-GE was higher compared to ES at 2.72 (95% CI, 1.86-3.97, I 2 = 0). The pooled rates of re-intervention for EUS-GE were lower at 3.77% (95% CI, 1.77-6.46, I 2 = 44) compared with ES, which was 25.13% (95% CI, 18.96-31.85, I 2 = 69). The pooled OR of the rate of re-intervention in the ES group was higher at 7.96 (95% CI, 4.41-14.38, I 2 = 13). Overall, the pooled rate for AEs for EUS-GE was 8.97% (95% CI, 6.88-11.30, I 2 = 15), whereas that for ES was 19.63% (95% CI, 11.75-28.94, I 2 = 89). Conclusion: EUS-GE and ES are comparable in terms of their technical effectiveness. However, EUS-GE has demonstrated improved clinical effectiveness, a lower need for re-intervention, and a better safety profile compared to ES for palliation of gastric outlet obstruction.

Successful Endoscopic Retrograde Appendicitis Therapy Following a Recent ST-Elevation Myocardial Infarction.

Acute appendicitis is one of the most common abdominal surgical emergencies. A laparoscopic or open appendectomy has traditionally been the gold standard. Antibiotic therapy has recently been found to be noninferior. The treatment of acute uncomplicated appendicitis remains a challenge, especially in the presence of an appendicolith. We present a case of a 59-year-old man with recent ST-elevation myocardial infarction who underwent successful endoscopic retrograde appendicitis therapy.

Correction to: Successful Endoscopic Retrograde Appendicitis Therapy Following a Recent ST-Elevation Myocardial Infarction.

[This corrects the article DOI: 10.14309/crj.0000000000001324.].

Interobserver agreement for the detection of Barrett's esophagus with optical frequency domain imaging.

BACKGROUND: Optical frequency domain imaging (OFDI) is a second-generation form of optical coherence tomography (OCT) providing comprehensive cross-sectional views of the distal esophagus at a resolution of ~7 µm. AIM: Using validated OCT criteria for squamous mucosa, gastric cardia mucosa, and Barrett's esophagus (BE), the objective of this study was to determine the inter- and intra-observer agreements by a large number of OFDI readers for differentiating these tissues. METHODS: OFDI images were obtained from nine subjects undergoing screening and surveillance for BE. Sixty-four OFDI image regions of interest were randomly selected for review. A training set of 19 images was compiled distinguishing squamous mucosa from gastric cardia and BE using previously validated OCT criteria. The ten readers then interpreted images in a test set of 45 different images of squamous mucosa (n = 15), gastric cardia (n = 15), or BE (n = 15). Interobserver agreement differentiating the three tissue types and BE versus non-BE mucosa was determined using multi-rater Fleiss's κ value. The images were later randomized again and four readers repeated the test 3 weeks later to assess intraobserver reliability. RESULTS: All ten readers showed excellent agreement for the differentiation of BE versus non-BE mucosa (κ = 0.811 p < 0.0001) and for differentiating BE versus gastric cardia versus squamous mucosa (κ = 0.866, p < 0.0001). For the four readers who repeated the test, the median intraobserver agreement (BE vs. non-BE) was high (κ = 0.975, IQR: 0.94, 1.0). CONCLUSIONS: Trained readers have a high interobserver agreement for differentiating BE, squamous, and gastric cardia mucosa using OFDI.

Efficacy and Safety of Peroral Endoscopic Myotomy (POEM) in Achalasia: An Updated Meta-analysis.

Background: Heller myotomy has been considered the standard surgical treatment for patients with achalasia. Since the initiation of peroral endoscopic myotomy (POEM), it has represented an alternative for treating patients with achalasia. Over the years, numerous prospective and retrospective studies with POEM use for achalasia have been published. We performed a systematic review and meta-analysis to evaluate the efficacy and safety of POEM in patients with achalasia. Methods: Publications investigating the safety and efficacy of POEM in patients with achalasia were searched in Medline, Ovid Journals, Medline non-indexed citations, and Cochrane Central Register of Controlled Trials and Database of Systematic Reviews. Pooling was conducted by both fixed and random effects models. Results: The initial search identified 328 reference articles; of these, 34 relevant articles were selected and reviewed. Data was extracted from 20 studies (n=1753) which met the inclusion criteria. In pooled analysis, the clinical success of POEM at 3 months was 94% (95% CI=93-95). The pooled clinical success of POEM at 12 months was 91% (95% CI=90-92). The pooled rate of gastroesophageal reflux disease (GERD) was 21% (95% CI=19-23), esophagitis was reported in 16% (95% CI=15-18), pneumomediastinum in 4% (95% CI=3-6), cervical emphysema in 12% (95% CI=10-13), pneumoperitoneum in 8% (95% CI=7-10), pneumothorax in 5% (95% CI=4 - 6), pleural effusion in 3% (95% CI=2-3), post-operative bleeding in 4.29% (95% CI=1.91 -7.61) and aspiration pneumonia in 3.08% (95% CI=1.13-5.97) of the patients after POEM. Conclusion: This meta-analysis suggests that POEM is a highly effective and safe endoscopic treatment for patients with achalasia and a reasonable alternative to Heller myotomy.

Consensus statement on the pathology of IgG4-related disease.

IgG4-related disease is a newly recognized fibro-inflammatory condition characterized by several features: a tendency to form tumefactive lesions in multiple sites; a characteristic histopathological appearance; and-often but not always-elevated serum IgG4 concentrations. An international symposium on IgG4-related disease was held in Boston, MA, on 4-7 October 2011. The organizing committee comprising 35 IgG4-related disease experts from Japan, Korea, Hong Kong, the United Kingdom, Germany, Italy, Holland, Canada, and the United States, including the clinicians, pathologists, radiologists, and basic scientists. This group represents broad subspecialty expertise in pathology, rheumatology, gastroenterology, allergy, immunology, nephrology, pulmonary medicine, oncology, ophthalmology, and surgery. The histopathology of IgG4-related disease was a specific focus of the international symposium. The primary purpose of this statement is to provide practicing pathologists with a set of guidelines for the diagnosis of IgG4-related disease. The diagnosis of IgG4-related disease rests on the combined presence of the characteristic histopathological appearance and increased numbers of IgG4⁺ plasma cells. The critical histopathological features are a dense lymphoplasmacytic infiltrate, a storiform pattern of fibrosis, and obliterative phlebitis. We propose a terminology scheme for the diagnosis of IgG4-related disease that is based primarily on the morphological appearance on biopsy. Tissue IgG4 counts and IgG4:IgG ratios are secondary in importance. The guidelines proposed in this statement do not supplant careful clinicopathological correlation and sound clinical judgment. As the spectrum of this disease continues to expand, we advocate the use of strict criteria for accepting newly proposed entities or sites as components of the IgG4-related disease spectrum.