Efficacy and safety of MC-003 solution for endoscopic mucosal or submucosal resection: a prospective, multicenter, randomized, triple-blinded, parallel-group, phase III study.

BACKGROUND AND AIMS: The safety and efficacy of solutions for submucosal injection are critical for endoscopic resection of gastric adenomas or early gastric cancers. Although several injectable solutions have been introduced for endoscopic resection, they have some limitations. We aimed to compare the efficacy of the new sodium alginate-based solution MC-003 with that of normal saline (NS; 0.9% sodium chloride). METHODS: In this randomized, triple-blind study, 70 patients were initially enrolled for EMR or endoscopic submucosal dissection (ESD). The main outcomes included the need for additional injections, completion of en bloc resection, and occurrence of adverse events. RESULTS: Each group ultimately included 34 patients. Complete en bloc resections were achieved in all patients (P = 1.000). The MC-003 group had more peri-neoplasm tissue fibrosis (P = .056) and needed fewer additional injections for lesions >15 mm (P = .037), located in the distal portion of the stomach (P = .007), and during ESD procedures (P = .001). The adverse event rate was comparable in both groups. CONCLUSIONS: MC-003 outperformed NS in reducing the need for additional injections during en bloc resection, particularly in larger lesions located in the distal portion of the stomach (where most lesions were found) during ESD procedures, without increasing the incidence of serious adverse events. MC-003 is a promising submucosal injectable solution in real-world clinical settings.

Comparative evaluation of endoscopic anti-reflux mucosectomy and stretta radiofrequency ablation in the management of gastroesophageal reflux disease: insights from a retrospective multicenter cohort study.

BACKGROUND: Treatment options for gastroesophageal reflux disease (GERD) that is unresponsive to proton pump inhibitors (PPIs) remain limited. Therefore, we compared the therapeutic effects of anti-reflux mucosectomy (ARMS) and Stretta radiofrequency (SRF) for intractable GERD in over 400 individuals who underwent either procedure. METHODS: We conducted a retrospective study between 2016 and 2023 to evaluate the effectiveness of SRF and ARMS treatments for refractory GERD. The primary measure of success was the change in the GERD questionnaire (GERDQ) score. The secondary outcomes were various GERD-related indicators, including endoscopic Los Angeles (LA) classification, Hill's type-based flap valve grade (FVG), EndoFLIP™ distensibility index (DI), rate of PPI discontinuation, resolution rate of Barrett's esophagus, and incidence of adverse events. RESULTS: The ARMS group included patients with high GERDQ scores, FVG, LA grade, and Barrett's esophagus. Both groups had similar rates of improvements in GERDQ score (P = 0.884) and PPI withdrawal (P = 0.866); however, the ARMS group had significantly more side effects and improvements in the median change in GERDQ score (P = 0.011), FVG (P < 0.001), LA grade (P < 0.001), EndoFLIP™ DI (P < 0.001), and resolution of Barrett's esophagus (P < 0.001). CONCLUSIONS: The ARMS group had a greater GERDQ score improvement than the SRF group but had symptom relief and PPI discontinuation rates similar to those of the SRF group. However, objective measures, including EndoFLIP™ DI and endoscopic evaluations, were better in the ARMS group than in the SRF group.

Endoscopic resection and laparoscopic lymph node dissection for early gastric cancer beyond conventional endoscopic treatment indications: a 10-year outcome study.

BACKGROUND: Endoscopic full-thickness gastric resection (EFTGR) with laparoscopic regional lymph node dissection (LLND) and endoscopic submucosal dissection (ESD) with LLND have been investigated as treatment options for early gastric cancer beyond the absolute indications for ESD. However, comparative studies on the long-term outcomes of these procedures are lacking. This study aimed to analyze and compare the 10-year outcomes of both procedures in a real clinical setting. METHODS: Between January 2009 and December 2013, 28 and 37 patients diagnosed with EGC beyond the absolute indications for ESD were treated with EFTGR with LLND and ESD with LLND, respectively. In both procedures, the dye was injected into the tumor. However, after injection and LLND, EFTGR was performed immediately in the EFTGR with LLND group, whereas LLND was followed by ESD in the ESD with LLND group. The primary endpoint was the 10-year survival rate. RESULTS: The EFTGR with LLND group had one case of local recurrence (3.6%) and mortality (3.6%) each, while the ESD with LLND group had none (0.0% for both); however, the differences were not statistically significant (P = 0.247 for each). Furthermore, there was no significant difference in complications such as ischemia and anastomosis leakage between the groups (P = 0.247). CONCLUSIONS: When the procedures were properly applied, EFTGR with LLND and ESD with LLND did not increase the 10-year mortality in patients with EGC beyond the absolute ESD indications compared with conventional radical gastrectomy.

Da Vinci robot-assisted endoscopic full-thickness gastric resection with regional lymph node dissection using a 3D near-infrared video system: a single-center 5-year clinical outcome.

BACKGROUND: Endoscopic full-thickness gastric resection (EFTGR) with regional lymph node dissection (LND) has been used for early gastric cancer (EGC) exceeding the indications for endoscopic submucosal dissection (ESD). The extent of the dissected lymph nodes is crucial. A 3D near-infrared (NIR) video robot system significantly enhances visualization of the lymphatic system. However, this system has not been used in EFTGR with LND. Thus, this study assessed the benefits of the 3D NIR video robot system in a clinical setting. METHODS: Between February 2015 and September 2018, 24 patients with EGC exceeding the indications for ESD were treated with EFTGR and LND using a 3D NIR video system with the da Vinci surgical robot. Indocyanine green (ICG) was injected endoscopically around the tumor, and basin node (BN) dissection around the nodes was examined using the 3D NIR video system of the da Vinci Si surgical robot. Subsequently, robot-assisted EFTGR was performed. The primary outcome was the 5-year survival rate. RESULT: During a 5-year follow-up of all 24 patients, an 80-year-old patient with an ulcer and T2 invasion was lost to follow-up. Among the remaining 23 patients, no mortality or recurrence was observed. CONCLUSION: No metastasis or mortality occurred using the da Vinci robot-assisted EFTGR with LLND and a 3D NIR video system for patients who required radical gastrectomy for EGC in over 5 years. Hence, this may be a safe and effective method for radical gastrectomy; further studies are required confirming its effectiveness.

Comparative clinical feasibility of antireflux mucosectomy and antireflux mucosal ablation in the management of gastroesophageal reflux disease: Retrospective cohort study.

OBJECTIVES: No definitive treatment has been established for refractory gastroesophageal reflux disease (GERD). Antireflux mucosectomy (ARMS) and antireflux mucosal ablation (ARMA) using argon plasma coagulation are promising methods. However, no study has compared these two. This study compared the efficacy and safety of the two procedures. METHODS: This multicenter, retrospective, observational study included 274 patients; 96 and 178 patients underwent ARMA and ARMS, respectively. The primary outcome was subjective symptom improvement based on GERD questionnaire (GERDQ) scores. The secondary outcomes included changes in the presence of Barrett's esophagus, Los Angeles grade for reflux esophagitis, flap valve grade, and proton pump inhibitor withdrawal rates. RESULTS: The ARMS group had higher baseline GERDQ scores (10.0 vs. 8.0, P < 0.001) and a greater median postprocedure improvement than the ARMA group (4.0 vs. 2.0, P = 0.002), and even after propensity score matching adjustment, these findings remained. ARMS significantly improved reflux esophagitis compared with ARMA, with notable changes in Los Angeles grade (P < 0.001) and flap valve grade scores (P < 0.001). Improvement in Barrett's esophagus was comparable between the groups (P = 0.337), with resolution rates of 94.7% and 77.8% in the ARMS and ARMA groups, respectively. Compared with the ARMA group, the ARMS group experienced higher bleeding rates (P = 0.034), comparable stricture rates (P = 0.957), and more proton pump inhibitor withdrawals (P = 0.008). CONCLUSIONS: Both ARMS and ARMA showed improvements in GERDQ scores, endoscopic esophagitis, flap valve grade, and the presence of Barrett's esophagus after the procedures. However, ARMS demonstrated better outcomes than ARMA in terms of both subjective and objective indicators.

Is it enough to observe less than 2 cm sized gastric SET?

BACKGROUND AND AIMS: The recent surge in demand for screening endoscopy has led to an increased detection of gastric subepithelial tumors (SETs). According to current guideline, SETs less than 2 cm in size are recommended for periodic surveillance. In light of recent advancement in therapeutic endoscopy in resection of small SET, we analyzed the histopathological features and the effectiveness of endoscopic resection for these small SETs. METHODS: Retrospectively study was performed on 74 patients who underwent endoscopic resection of gastric small (≤ 2 cm) upper gastrointestinal tract SETs. The outcomes including histopathology and en bloc resection were analyzed. RESULTS: The mean SET size was 11.69 ± 5.11 mm. The mean procedure time was 81.26 ± 42.53 min. Of the 74 patients, 28 patients had leiomyomas, 26 had gastrointestinal stromal tumors (GISTs), 14 had ectopic pancreas, 4 had lipomas, and 2 had neuroendocrine tumors. Among those with GIST, two patients exhibited high-risk histology. All patients underwent successful and uneventful endoscopy. CONCLUSIONS: Endoscopic resection can be recommended even for the small gastric SETs. In our study, we found that SETs with a size of less than 2 cm have significant proportion of GISTs which harbor malignant transformation potential.

Severe clinical outcomes of COVID-19 associated with proton pump inhibitors: a nationwide cohort study with propensity score matching.

OBJECTIVE: The adverse effects of proton pump inhibitors (PPIs) have been documented for pneumonia; however, there is no consensus regarding whether the use of PPIs might be harmful regarding the risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In this regard, we aimed to measure the potential associations of the current use of PPIs with the infection rates of COVID-19 among patients who underwent SARS-CoV-2 testing. DESIGN: Data were derived from a Korean nationwide cohort study with propensity score matching. We included 132 316 patients older than 18 years who tested for SARS-CoV-2 between 1 January and 15 May 2020. Endpoints were SARS-CoV-2 positivity (primary) and severe clinical outcomes of COVID-19 (secondary: admission to intensive care unit, administration of invasive ventilation or death). RESULTS: In the entire cohort, there were 111 911 non-users, 14 163 current PPI users and 6242 past PPI users. After propensity score matching, the SARS-CoV-2 test positivity rate was not associated with the current or past use of PPIs. Among patients with confirmed COVID-19, the current use of PPIs conferred a 79% greater risk of severe clinical outcomes of COVID-19, while the relationship with the past use of PPIs remained insignificant. Current PPI use starting within the previous 30 days was associated with a 90% increased risk of severe clinical outcomes of COVID-19. CONCLUSION: Patients taking PPIs are at increased risk for severe clinical outcomes of COVID-19 but not susceptible to SARS-CoV-2 infection. This suggests that physicians need to assess benefit-risk assessments in the management of acid-related diseases amid the COVID-19 pandemic.

Impedance planimetry values for predicting clinical response following peroral endoscopic myotomy.

BACKGROUND: There is growing interest in developing impedance planimetry as a tool to enhance the clinical outcomes for endoscopic and surgical management of achalasia. The primary aim of this study was to determine whether impedance planimetry measurements can predict clinical response and reflux following peroral endoscopic myotomy (POEM). METHODS: A multicenter cohort study of patients with achalasia undergoing POEM was established from prospective databases and retrospective chart reviews. Patients who underwent impedance planimetry before and after POEM were included. Clinical response was defined as an Eckardt score of ≤ 3. Tenfold cross-validated area under curve (AUC) values were established for the different impedance planimetry measurements associated with clinical response and reflux development. RESULTS: Of the 290 patients included, 91.7 % (266/290) had a clinical response and 39.4 % (108/274) developed reflux following POEM. The most predictive impedance planimetry measurements for a clinical response were: percent change in cross-sectional area (%ΔCSA) and percent change in distensibility index (%ΔDI), with AUCs of 0.75 and 0.73, respectively. Optimal cutoff values for %ΔCSA and %ΔDI to determine a clinical response were a change of 360 % and 272 %, respectively. Impedance planimetry values were much poorer at predicting post-POEM reflux, with AUCs ranging from 0.40 to 0.62. CONCLUSION: Percent change in CSA and distensibility index were the most predictive measures of a clinical response, with a moderate predictive ability. Impedance planimetry values for predicting reflux following POEM showed weak predictive capacity.

Management of patients after failed peroral endoscopic myotomy: a multicenter study.

BACKGROUND: Although peroral endoscopic myotomy (POEM) is highly effective for the management of achalasia, clinical failures may occur. The optimal management of patients who fail POEM is not well known. This study aimed to compare the outcomes of different management strategies in patients who had failed POEM. METHODS: This was an international multicenter retrospective study at 16 tertiary centers between January 2012 and November 2019. All patients who underwent POEM and experienced persistent or recurrent symptoms (Eckardt score > 3) were included. The primary outcome was to compare the rates of clinical success (Eckardt score ≤ 3) between different management strategies. RESULTS : 99 patients (50 men [50.5 %]; mean age 51.4 [standard deviation (SD) 16.2]) experienced clinical failure during the study period, with a mean (SD) Eckardt score of 5.4 (0.3). A total of 29 patients (32.2 %) were managed conservatively and 70 (71 %) underwent retreatment (repeat POEM 33 [33 %], pneumatic dilation 30 [30 %], and laparoscopic Heller myotomy (LHM) 7 [7.1 %]). During a median follow-up of 10 (interquartile range 3 - 20) months, clinical success was highest in patients who underwent repeat POEM (25 /33 [76 %]; mean [SD] Eckardt score 2.1 [2.1]), followed by pneumatic dilation (18/30 [60 %]; Eckardt score 2.8 [2.3]), and LHM (2/7 [29 %]; Eckardt score 4 [1.8]; P = 0.12). A total of 11 patients in the conservative group (37.9 %; mean Eckardt score 4 [1.8]) achieved clinical success. CONCLUSION : This study comprehensively assessed an international cohort of patients who underwent management of failed POEM. Repeat POEM and pneumatic dilation achieved acceptable clinical success, with excellent safety profiles.

A modified endoscopic full thickness resection for gastric subepithelial tumors from muscularis propria layer: Novel method.

BACKGROUND AND AIM: The removal of subepithelial tumors (SETs) is challenging, particularly in tumors originating from the muscularis propria (MP) in the upper gastrointestinal (GI) tract, owing to the high risk of perforation. We developed mechanical spray lumpectomy (MSL), which is a novel method to safely and easily remove the tumor. This study aimed to evaluate the feasibility and safety of MSL as a novel endoscopic treatment for gastric subepithelial lesions. METHODS: We performed MSL in a total of 13 patients with upper GI SETs originating from the MP layer. First, mucosectomy was performed using a conventional snare. Repeated injections were performed towards the subserosal layer. After injection, the lesion was mechanically pushed to separate the MP layer using an endoscopic cap. Finally, the mucosa, submucosa, and MP layer with SETs were completely dissected using the spray coagulation mode, and the remaining defect was closed with clipping. RESULTS: All tumors were completely resected. The mean procedure time was 84.38 ± 41.73 min. There were four leiomyomas, six GI stromal tumors, one mucosa-associated lymphoid tissue lymphoma, and two ectopic pancreases. Although small perforation occurred in only one case, the defect was successfully closed using hemostatic clipping. Moreover, no serious complications related to MSL were encountered during or after the procedure. No residual lesion or recurrence was observed during the follow-up period. CONCLUSIONS: Mechanical spray lumpectomy can be a novel method that provides a safe and minimally invasive endoscopic treatment for upper GI SETs originating from the MP layer.

Comparison of peroral endoscopic myotomy between de-novo achalasia and achalasia with prior treatment.

Peroral endoscopic myotomy has been recognized as an effective treatment for patients with achalasia. Prior treatment may affect the outcome of subsequent treatment. We aimed to compare the safety and efficacy of POEM in treatment-naive patients vs. those with prior treatment failure. We retrospectively analyzed the data of achalasia patients who underwent POEM from November 2011 to January 2018. A comparative analysis was performed between De-Novo (DN) and Prior Treatment Failure (PTF) cases. Technical and clinical success, adverse events, operative time for POEM, hospital stay were compared between the two groups Overall, 209 patients with achalasia underwent POEM during the studied period, including 113 patients (54%) in the DN group and 96 patients (45%) in the PTF group. The baseline characteristics of the DN and PTF groups were not significantly different except for duration of disease. The PTF group had longer disease duration than the DN group. (7.92 ± 9.28 vs 4.45 ± 5.67 years, respectively, p = 0.005). Both groups were technically successful. Operative time was longer in the PTF group than that in the de-novo group, but the difference was not significant. The occurrence rates of complications were similar in both groups. Changes in the Eckardt score were comparable in the DN and PTF cases. IRP and LES pressure decreased after POEM. After 6 months, more patients suffered from reflux symptoms in the PTF group, but DeMeester score and endoscopic evaluation were not significantly different POEM is safe and equally effective for patients with prior treatment failure as well as de-novo patients up to 6 months post treatment.

Practice of endoscopy during COVID-19 pandemic: position statements of the Asian Pacific Society for Digestive Endoscopy (APSDE-COVID statements).

Coronavirus-19 (COVID-19) caused by SARS-CoV-2 has become a global pandemic. Risk of transmission may occur during endoscopy and the goal is to prevent infection among healthcare professionals while providing essential services to patients. Asia was the first continent to have a COVID-19 outbreak, and this position statement of the Asian Pacific Society for Digestive Endoscopy shares our successful experience in maintaining safe and high-quality endoscopy practice at a time when resources are limited. Sixteen experts from key societies of digestive endoscopy in Asia were invited to develop position statements, including patient triage and risk assessment before endoscopy, resource prioritisation and allocation, regular monitoring of personal protective equipment, infection control measures, protective device training and implementation of a strategy for stepwise resumption of endoscopy services after control of the COVID-19 outbreak.

Utility of EUS elastography in the diagnosis of gastric subepithelial tumors: a pilot study (with video).

BACKGROUND AND AIMS: EUS elastography is a real-time imaging technique that analyzes tissue elasticity. The aim of this study was to investigate the applicability of quantitative EUS elastography in the differential diagnosis of gastric subepithelial tumors (SETs). METHODS: We prospectively registered 41 consecutive patients with gastric SETs and measured their strain ratios with EUS elastography. The strain ratios of gastric SETs were compared with the histopathologic diagnosis. RESULTS: Thirty-one patients (mean age, 51.4 ± 12.6 years) were included in the analysis. The mean size of the SETs was 2.3 ± 0.7 cm. Lipomas had the lowest strain ratio of 1.6 (1.1-2.0), followed by leiomyomas 6.0 (2.0-29.0), ectopic pancreas 11.8 (1.7-29.3), gastrointestinal stromal tumors (GISTs) 51.1 (29.0-67.0), and schwannomas 62.0. With a cut-off value of 22.7, EUS elastography could differentiate GISTs from leiomyomas with sensitivity and specificity of 100% and 94.1%, respectively (P = .001; 95% confidence interval, 0.979-1.000). CONCLUSIONS: EUS elastography could be a promising diagnostic adjunct for the assessment of gastric SETs, especially in differentiating GISTs from leiomyomas.

Anti-reflux mucosectomy using a cap-assisted endoscopic mucosal resection method for refractory gastroesophageal disease: a prospective feasibility study.

BACKGROUND AND AIMS: Endoscopic therapy of gastroesophageal reflux disease (GERD) overcomes the "treatment gap" for patients with refractory GERD, who are not willing to go into surgery. We propose an easy and efficient technique that is referred to as anti-reflux mucosectomy (ARMS) using cap-assisted endoscopic mucosal resection (EMR-C) which could be called ARMS-C. This study aimed to investigate the short-term outcomes of ARMS-C in GERD patients. METHODS: From December 2016 to February 2018, we performed ARMS-C in 33 patients with pathologic reflux disease and esophageal hypersensitivity. ARMS-C involved endoscopic mucosal resection at the circumference of the esophagogastric junction (EGJ), resulting in narrowing of the hiatal opening after healing. The GERD symptoms, 24-h pH monitoring results, manometry, endoscopy, and EGJ distensibility were compared before and after the procedure. RESULTS: Six months after ARMS-C, 63% of patients discontinued the use of pump inhibitors (PPIs), while 30% patients reduced their PPI dose. The GERD questionnaire scores significantly decreased after ARMS-C, from 11.0 to 6.0 (P < 0.001). The median DeMeester score and acid exposure time based on pH monitoring also improved after ARMS-C. Furthermore, the median flap valve grade and EGJ distensibility decreased from 3.0 to 1.0 (P < 0.001) and from 19.0 to 13.9 (P < 0.001), respectively. Two patients were treated with balloon dilation due to stricture, but no other serious adverse events were encountered. CONCLUSION: ARMS-C may be an effective and safe treatment method for GERD in terms of short-term outcomes.

Feasibility of intraperitoneal placental-derived mesenchymal stem cell injection in stomachs of diabetic mice.

BACKGROUND AND AIM: Diabetic gastropathy is associated with loss of interstitial cells of Cajal and autonomic neuropathy. Effective management for diabetic gastropathy is still unavailable. This study was aimed to confirm the pathogenetic changes in diabetic gastropathy and to examine the effect of treatment with placental-derived mesenchymal stem cells (PDMSCs) in stomachs of animal models. METHODS: Fourteen non-obese diabetic/ShiLtJ mice of 8 weeks were bled until week 30. Diabetes mellitus developed in 10 out of 14 mice, which all survived with insulin. The mice were grouped into three groups: nondiabetic group (n = 4), diabetic sham group (n = 5), and diabetic PDMSC group (n = 5) all of which were treated with intraperitoneal PDMSCs injection at week 30. All mice were killed at week 34, and the stomachs were examined by immunohistochemical stain with c-kit and neuronal nitric oxide synthase antibodies. RESULTS: The number of c-kit positive cells in stomach decreased significantly in the diabetic sham group compared with that in the nondiabetic group (21.2 ± 6.7 vs 88.0 ± 29.3, P = 0.006) but increased with PDMSC treatment (21.2 ± 6.7 vs 64.0 ± 15.1, P = 0.02). The positive rate of neuronal nitric oxide synthase in neural plexus was also significantly lower in the diabetic sham group than in the nondiabetic group (22.3% ± 18.5% vs 48.0% ± 22.7%, P = 0.003) but increased with PDMSC treatment (22.3% ± 18.5% vs 43.3% ± 20.5%, P = 0.03). CONCLUSIONS: Interstitial cells of Cajal and neural plexus decreased in stomachs of mice with diabetes mellitus but were significantly repaired with intraperitoneal injection of PDMSC.

Clinical outcomes of minimally invasive treatment for early gastric cancer in patients beyond the indications of endoscopic submucosal dissection.

BACKGROUND: Endoscopic submucosal dissection (ESD) with laparoscopic sentinel lymph node dissection (ESN) and endoscopic full-thickness gastric resection with laparoscopic sentinel lymph node dissection (Hybrid-natural orifice transluminal endoscopic surgery, Hybrid-NOTES) are minimally invasive treatment options for early gastric cancer (EGC) beyond the indications of ESD. This study aimed to evaluate the short- and long-term clinical outcomes of ESN and Hybrid-NOTES. METHODS: We retrospectively analyzed patients who had undergone ESN or Hybrid-NOTES for EGC from January 2009 to March 2013. A total of 48 patients, including 21 undergoing ESN and 27 undergoing Hybrid-NOTES, were enrolled. All patients had cancer stage T1N0M0, EGC less than 5 cm in size, and suspected submucosal invasion according to imaging or biopsy-proven diffuse-type histology. RESULTS: In ESN and Hybrid-NOTES, the curative resection rates were 76.5% and 90.9% of patients, respectively. In the ESN group, 5 patients underwent an additional gastrectomy (1 for lymph node metastasis (LNM), 3 for surgical complications, and 1 for noncurative resection). In the Hybrid-NOTES group, 6 patients underwent additional gastrectomy, (1 for LNM, 3 for surgical complications, and 2 for noncurative resection). Of the 37 patients who were followed up in the long-term (a median follow-up of 59.8 months), one was found to have liver metastasis after ESN and received palliative chemotherapy. CONCLUSIONS: ESN and Hybrid-NOTES have shown favorable long-term outcomes despite their technical limitations. These methods may be utilized as a bridge between ESD and gastrectomy in cases of EGC with a high risk of LNM beyond the ESD indications.

Experimental study on the friction effect of plastic stents for biliary stone fragmentation (with video).

BACKGROUND AND AIM: In patients with irretrievable or intractable bile duct stone, temporary insertion of a plastic stent (PS) followed by further endoscopic retrograde cholangiopancreatography (ERCP) or surgery has been recommended as a 'bridge' therapy. However, the exact mechanism of stone fragmentation has not been discovered. The aim of the present study was to evaluate whether PS shape can facilitate stone fragmentation. METHODS: Using a new in vitro bile flow phantom model, we compared the friction effect among three different PS groups (straight PS group, double pigtail-shaped PS group, and screw-shaped PS group) and a control group. Each group had 10 silicon tube blocks that separately contained one stone and two PS. The control group had 10 blocks each with only a stone and no PS. We carried out analysis of the friction effect by stone weight and volume changes among the groups, excluding fragmented stones. RESULTS: After 8 weeks, complete fragmentation was noted in one out of 34 cholesterol stones (2.9%) and in four out of six pigmented stones (66.7%). Fragmentation tended to be more prominent in the screw-shaped PS group than in the straight PS group, double pigtail-shaped group, and control group (volume change: -11.33%, 7.94%, 4.43%, and 2.05%, respectively, P = 0.1390; weight change: -9.30%, 0.71%, -0.10%, and -1.23%, respectively, P = 0.3553). CONCLUSION: Stone fragmentation may be induced by PS friction effect. Also, screw-shaped plastic stents may improve friction effect. These results may help guide future PS development and clinical decisions.

Gastroesophageal reflux after peroral endoscopic myotomy: a multicenter case-control study.

Background and study aims The variables associated with gastroesophageal reflux (GER) after peroral endoscopic myotomy (POEM) are largely unknown. This study aimed to: 1) identify the prevalence of reflux esophagitis and asymptomatic GER in patients who underwent POEM, and 2) evaluate patient and intraprocedural variables associated with post-POEM GER. Patients and methods All patients who underwent POEM and subsequent objective testing for GER (pH study with or without upper gastrointestinal [GI] endoscopy) at seven tertiary academic centers (one Asian, two US, four European) were included. Patients were divided into two groups: 1) DeMeester score ≥ 14.72 (cases) and 2) DeMeester score of < 14.72 (controls). Asymptomatic GER was defined as a patient with a DeMeester score ≥ 14.72 who was not consuming proton pump inhibitor (PPI). Results A total of 282 patients (female 48.2 %, Caucasian 84.8 %; mean body mass index 24.1 kg/m2) were included. Clinical success was achieved in 94.3 % of patients. GER evaluation was completed after a median follow-up of 12 months (interquartile range 10 - 24 months). A DeMeester score of ≥ 14.72 was seen in 57.8 % of patients. Multivariable analysis revealed female sex to be the only independent association (odds ratio 1.69, 95 % confidence interval 1.04 - 2.74) with post-POEM GER. No intraprocedural variables were associated with GER. Upper GI endoscopy was available in 233 patients, 54 (23.2 %) of whom were noted to have reflux esophagitis (majority Los Angeles Grade A or B). GER was asymptomatic in 60.1 %. Conclusion Post-POEM GER was seen in the majority of patients. No intraprocedural variables were identified to allow for potential alteration in procedural technique.

The Stent Patency and Migration Rate of Different Shaped Plastic Stents in Bile Flow Phantom Model and In Vivo Animal Bile Duct Dilation Model.

BACKGROUND/AIM: In research and development of biliary plastic stents (PS), continuous efforts have been made to overcome short patency time and high rate of migration. The aim of this study was to evaluate the patency and migration rate of different PS shapes for a given period of time. METHODS: Using an in vitro bile phantom model, we compared the patency among different shapes of PS (three straight PS, four double-pigtail PS, and a new screw-shaped PS). We performed an analysis of the degree of luminal narrowing by light microscopic examination. Using an in vivo swine model, we compared the patency and migration rate among the three different types of PS. RESULTS: Eight weeks after the bile exposure in the bile flow phantom model, 80 PS were retrieved and analyzed. The straight PS showed less biofilm formation and luminal narrowing than other types of PS (p < 0.05). Forty-nine PS were inserted into the dilated bile ducts of 10 swine models, and 39 PS were successfully retrieved 8 weeks later. The stent migration occurred less frequently in the double-pigtail PS and the screw-shaped PS than it did in the straight PS (11.1, 10, and 27.3%, respectively). However, there was no statistical difference in stent patency among the different shapes. CONCLUSIONS: Stent patency may not be significantly different depending on the shape of PS for 8 weeks. The screw-shaped PS showed similar patency and migration rate to the double-pigtail PS. These results may help guiding future PS development and clinical decisions.