This paper presents a novel approach for estimating the Gaussian kernel width widely employed in radial basis function (RBF) network, support vector machine (SVM), Kriging models, etc. As widely ...known, the Gaussian kernel width in these surrogate models is highly significant, and estimating the appropriate applicable width is usually an arduous task. Therefore, the need to develop a simple method to determine the kernel width becomes imperative. In this study, firstly, we examine the fundamental description of triple surrogate models, based on which a unified formulation to describe surrogate models is proposed. Thereafter, a novel unified estimate procedure based on local density of sampling points is developed. During this procedure, the calculations of numerous kernel widths are transformed into the calculation of a singular parameter, which is solved with the method of moment estimate. The proposed estimate is applicable to the wide range of surrogate models employing the Gaussian kernel. Validation of the novel method is carried out through examples in various domains, which showcases the efficacy of this proposed method.
The use of peroral endoscopic myotomy (POEM) for achalasia has a high incidence of post-procedural gastroesophageal reflux (GER). Transoral incisionless fundoplication (TIF) may be an ideal ...endoscopic treatment. We report our experience with the use of post-POEM TIF.
In this multicenter retrospective study, post-POEM patients with GER who underwent TIF were included. The study end points were: (i) technical success; (ii) safety; (iii) effectiveness (changes in symptoms, scores, proton pump inhibitor PPI use, pH studies).
12 patients underwent TIF after POEM, nine of whom had daily symptoms, with 91.7% requiring twice daily (BID) PPIs. Technical success was achieved in all patients. Two adverse events occurred. There were significant decreases in the percentage of patients on BID PPIs (
= 0.03), frequency of daily symptoms (
= 0.03), Reflux Severity Index questionnaire, and GERD Health-related Quality of Life scores (
= 0.03 and
= 0.003; n = 6). pH studies performed in seven of the patients showed a significant reduction in the mean DeMeester score (
= 0.05) and mean percentage acid exposure time (
= 0.04).
Our experience suggests that TIF may be effective and safe in treating GER after POEM. Larger prospective trials are needed.
The American Society for Gastrointestinal Endoscopy’s GIE Editorial Board reviewed original endoscopy-related articles published during 2019 in Gastrointestinal Endoscopy and 10 other leading medical ...and gastroenterology journals. Votes from each individual member were tallied to identify a consensus list of 10 topic areas of major advances in GI endoscopy. Individual board members summarized important findings published in these 10 areas of disinfection, artificial intelligence, bariatric endoscopy, adenoma detection, polypectomy, novel imaging, Barrett’s esophagus, third space endoscopy, interventional EUS, and training. This document summarizes these “top 10” endoscopic advances of 2019.
The American Society for Gastrointestinal Endoscopy’s Gastrointestinal Endoscopy Editorial Board reviewed original endoscopy-related articles published during 2018 in Gastrointestinal Endoscopy and ...10 other leading medical and gastroenterology journals. Votes from each individual member were tallied to identify a consensus list of 10 topic areas of major advances in GI endoscopy. Individual board members summarized important findings published in these 10 areas of adenoma detection, bariatric endoscopy, EMR/submucosal dissection/full-thickness resection, artificial intelligence, expandable metal stents for palliation of biliary obstruction, pancreatic therapy with lumen-apposing metal stents, endoscope reprocessing, Barrett’s esophagus, interventional EUS, and GI bleeding. This document summarizes these “Top 10” endoscopic advances of 2018.
In this paper, a general and efficient method for constructing LHDs possessing favorable characteristics of orthogonality and better computational efficiency is first proposed. Next, a sequentially ...enlarging strategy is derived based on the initial design. During the enlarging process, optimization of space-filling property is carried out, and a near-orthogonal space-filling augmented LHD is subsequently obtained. The enlarging process is repeated iteratively until the desired accuracy is achieved. Numerical examples and two mechanical applications are utilized in order to confirm and emphasize the effectiveness of this proposed method.
•A novel generation of LHDs is proposed, which possessed favorable characteristics and were computationally attractive.•A robust sequentially enlarging strategy is derived based on the initial design matrix.•During each repeated iteration, the augmented design set is guaranteed to be space-filling and near-orthogonal.
Background Single-balloon enteroscopy (SBE) and spiral enteroscopy (SE) are recently described device-assisted techniques in endoluminal evaluation of the small bowel. No studies comparing SBE and SE ...in patients with suspected small-bowel disorders have previously been reported. Objective The aims of this study were to compare SBE and SE in terms of diagnostic yield, procedure time, depth of maximal insertion, and complications. Design Retrospective cohort study. Setting Tertiary-care referral center. Patients A retrospective analysis was performed on all patients at our institution undergoing anterograde SBE or SE between 2007 and 2009. Patients with altered anatomy or prior small-bowel surgery were excluded. Intervention Deep enteroscopy. Main Outcome Measurement Diagnostic yield. Results During the study period, 92 patients underwent 105 procedures (52 SBE, 53 SE). The most common indication for small-bowel endoscopy was obscure GI bleeding (n = 42). The diagnostic yield was not statistically different between SBE and SE (59.6% and 43.4%, respectively, P = .12). The overall diagnostic yield in patients with obscure GI bleeding was 67%. There was no significant difference between mean SBE and SE procedure times (53 minutes range 15-99 minutes vs 47 minutes range 20-125 minutes, respectively; P = .2). The mean depth of maximal insertion beyond the ligament of Treitz for SE was significantly higher than that for SBE (301 cm range 175-400 cm vs 222 cm range 110-400 cm, respectively; P < .001). Perforation occurred in one SBE procedure. Limitations Retrospective design and nonstandardized gas insufflation. Conclusion This is the first report comparing SE and SBE. Although SE yielded greater depth of maximal insertion than SBE, both techniques had similar diagnostic yields and procedure times. In addition, both techniques were safe and were particularly useful in patients with obscure GI bleeding.
Background
Endoscopic retrograde cholangiopancreatography (ERCP) is often unsuccessful in patients with Roux-en-Y anatomy. Augmented enteroscopy allows deep insertion into the small bowel and can be ...useful in patients with Roux-en-Y anatomy. The aim of this study was to compare single balloon assisted ERCP (SBE-ERCP) and spiral assisted ERCP (SE-ERCP) in patients with Roux-en-Y anatomy in terms of diagnostic and therapeutic yield, procedure time, and complications.
Methods
This is a retrospective cohort study of consecutive patients with Roux-en-Y anatomy who underwent SBE-ERCP or SE-ERCP between October 2007 and March 2011. Diagnostic yield was defined as successful duct cannulation. Therapeutic yield was defined as the ability to successfully carry out endoscopic therapy in those cannulated. Procedure time and complications were assessed.
Results
Thirty-four consecutive patients with Roux-en-Y anatomy underwent 54 ERCP procedures. The overall diagnostic yield was 44.4% with no significant difference between the diagnostic yield of SBE-ERCP (48.3%) and SE-ERCP (40%). The diagnostic yield was lower in patients with gastric by-pass (38.9%) compared with other types of Roux-en-Y anatomy (47.2%) but this was not statistically significant (
P
= 0.772). The overall therapeutic yield was 93.8%, with a therapeutic yield of 100% for SBE-ERCP and 87.5% for SE-ERCP (
P
= 1.0). There was one perforation during SBE-ERCP, giving a complication rate of 3.5%. The mean procedure time did not differ between the two techniques.
Conclusion
Diagnostic and therapeutic yields are similar with SBE-ERCP and SE-ERCP in patients with Roux-en-Y anatomy with no significant difference in procedure time or complication rates.
Fully covered self-expandable metal stents (FCSEMSs) have increasingly been used in benign upper gastrointestinal (UGI) conditions; however, stent migration remains a major limitation. Endoscopic ...suture fixation (ESF) may prevent stent migration. The aims of this study were to compare the frequency of stent migration in patients who received endoscopic suturing for stent fixation (ESF group) compared with those who did not (NSF group) and to assess the impact of ESF on clinical outcome.
This was a retrospective study of patients who underwent FCSEMS placement for benign UGI diseases. Patients were divided into either the NSF or ESF group. Outcome variables, including stent migration, clinical success (resolution of underlying pathology), and adverse events, were compared.
A total of 125 patients (44 in ESF group, 81 in NSF group; 56 benign strictures, 69 leaks/fistulas/perforations) underwent 224 stenting procedures. Stent migration was significantly more common in the NSF group (33 % vs. 16 %; P = 0.03). Time to stent migration was longer in the ESF group (P = 0.02). ESF appeared to protect against stent migration in patients with a history of stent migration (adjusted odds ratio OR 0.09; P = 0.002). ESF was also significantly associated with a higher rate of clinical success (60 % vs. 38 %; P = 0.03). Rates of adverse events were similar between the two groups.
Endoscopic suturing for stent fixation is safe and associated with a decreased migration rate, particularly in patients with a prior history of stent migration. It may also improve clinical response, likely because of the reduction in stent migration.
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