Optimization of tracheoesophageal fistula model established with T-shaped magnet system based on magnetic compression technique.

BACKGROUND: The magnetic compression technique has been used to establish an animal model of tracheoesophageal fistula (TEF), but the commonly shaped magnets present limitations of poor homogeneity of TEF and poor model control. We designed a T-shaped magnet system to overcome these problems and verified its effectiveness via animal experiments. AIM: To investigate the effectiveness of a T-shaped magnet system for establishing a TEF model in beagle dogs. METHODS: Twelve beagles were randomly assigned to groups in which magnets of the T-shaped scheme (study group, n = 6) or normal magnets (control group, n = 6) were implanted into the trachea and esophagus separately under gastroscopy. Operation time, operation success rate, and accidental injury were recorded. After operation, the presence and timing of cough and the time of magnet shedding were observed. Dogs in the control group were euthanized after X-ray and gastroscopy to confirm establishment of TEFs after coughing, and gross specimens of TEFs were obtained. Dogs in the study group were euthanized after X-ray and gastroscopy 2 wk after surgery, and gross specimens were obtained. Fistula size was measured in all animals, and then harvested fistula specimens were examined by hematoxylin and eosin (HE) and Masson trichrome staining. RESULTS: The operation success rate was 100% for both groups. Operation time did not differ between the study group (5.25 min ± 1.29 min) and the control group (4.75 min ± 1.70 min; P = 0.331). No bleeding, perforation, or unplanned magnet attraction occurred in any animal during the operation. In the early postoperative period, all dogs ate freely and were generally in good condition. Dogs in the control group had severe cough after drinking water at 6-9 d after surgery. X-ray indicated that the magnets had entered the stomach, and gastroscopy showed TEF formation. Gross specimens of TEFs from the control group showed the formation of fistulas with a diameter of 4.94 mm ± 1.29 mm (range, 3.52-6.56 mm). HE and Masson trichrome staining showed scar tissue formation and hierarchical structural disorder at the fistulas. Dogs in the study group did not exhibit obvious coughing after surgery. X-ray examination 2 wk after surgery indicated fixed magnet positioning, and gastroscopy showed no change in magnet positioning. The magnets were removed using a snare under endoscopy, and TEF was observed. Gross specimens showed well-formed fistulas with a diameter of 6.11 mm ± 0.16 mm (range, 5.92-6.36 mm), which exceeded that in the control group (P < 0.001). Scar formation was observed on the internal surface of fistulas by HE and Masson trichrome staining, and the structure was more regular than that in the control group. CONCLUSION: Use of the modified T-shaped magnet scheme is safe and feasible for establishing TEF and can achieve a more stable and uniform fistula size compared with ordinary magnets. Most importantly, this model offers better controllability, which improves the flexibility of follow-up studies.

Fully automated magnetically controlled capsule endoscopy for examination of the stomach and small bowel: a prospective, feasibility, two-centre study.

BACKGROUND: The use of magnetically controlled capsules for gastroscopy is in the early stages of clinical adoption. We aimed to evaluate the safety and efficacy of a fully automated magnetically controlled capsule endoscopy (FAMCE) system in clinical practice for gastroscopy and small bowel examination. METHODS: We did a prospective, comparative study to evaluate the safety and efficacy of FAMCE. Patients from two hospitals in Chongqing, China were consecutively enrolled. Eligible participants were aged 18-80 years with suspected gastric pathology and no previous surgery. Participants underwent FAMCE for screening of gastric lesions, then conventional transoral gastroscopy 2 h later, and stomach examination results were compared. The primary outcome was the rate of complete detection of gastric anatomy landmarks (cardia, fundus, body, angulus, antrum, and pylorus) by FAMCE. Secondary outcomes were the time required for gastric completion by FAMCE, the rate of detection of gastric lesions by FAMCE compared with conventional transoral gastroscopy, and the rate of complete small bowel examination. Adverse events were also evaluated. The study was registered in the Chinese Clinical Trial Registry, ChiCTR2000040507. FINDINGS: Between May 12 and Aug 17, 2020, 114 patients (mean age 44·0 years [IQR 34·0-55·0]; 63 [55%] female) were enrolled. The rate of complete detection of gastric anatomical structures by FAMCE was 100% (95% CI 99·3-100·0). The concordance between FAMCE and conventional transoral gastroscopy was 99·61% (99·45-99·78). The mean completion time of a gastroscopy with FAMCE was 19·17 min (SD 1·43; median 19·00, IQR 19·00-20·00), compared with 5·21 min (2·00; 5·18, 3·68-6·45) for conventional transoral gastroscopy. In 114 enrolled patients, 214 lesions were detected by FAMCE and conventional transoral gastroscopy. Of those, 193 were detected by both modalities. FAMCE missed five pathologies (four cases of gastritis and one polyp), whereas conventional transoral gastroscopy missed 16 pathologies (12 cases of gastritis, one polyp, one fundal xanthoma, and two antral erosions). FAMCE was able to provide a complete small bowel examination for all 114 patients and detected intestinal lesions in 50 (44%) patients. During the study, two (2%) patients experienced adverse events. No serious adverse events were recorded, and there was no evidence of capsule retention. INTERPRETATION: The performance of FAMCE is similar to conventional transoral gastroscopy in completion of gastric examination and lesion detection. Furthermore, it can provide a complete small bowel examination. Therefore, FAMCE could be effective method for examination of the gastrointestinal tract. FUNDING: Chinese National Key Research and Development Program.

Miniature Flexible Instrument with Fibre Bragg Grating-Based Triaxial Force Sensing for Intraoperative Gastric Endomicroscopy.

Optical biopsy methods, such as probe-based endomicroscopy, can be used to identify early-stage gastric cancer in vivo. However, it is difficult to scan a large area of the gastric mucosa for mosaicking during endoscopy. In this work, we propose a miniaturised flexible instrument based on contact-aided compliant mechanisms and fibre Bragg grating (FBG) sensing for intraoperative gastric endomicroscopy. The instrument has a compact design with an outer diameter of 2.7 mm, incorporating a central channel with a diameter of 1.9 mm for the endomicroscopic probe to pass through. Experimental results show that the instrument can achieve raster trajectory scanning over a large tissue surface with a positioning accuracy of 0.5 mm. The tip force sensor provides a 4.6 mN resolution for the axial force and 2.8 mN for transverse forces. Validation with random samples shows that the force sensor can provide consistent and accurate three-axis force detection. Endomicroscopic imaging experiments were conducted, and the flexible instrument performed no gap scanning (mosaicking area more than 3 mm2) and contact force monitoring during scanning, demonstrating the potential of the system in clinical applications.

Colorectal stent placement assisted by a slim gastroscope: technique and outcomes.

BACKGROUND: The distorted anatomy in patients with obstruction renders colon stent placement difficult. Here, we propose two novel techniques for stent implantation. METHODS: Patients in whom there was difficulty placing the guidewire with the normal method were retrospectively included in our study. All of the patients underwent the technique of combining a slim gastroscope with a normal colonoscope. We assessed the technical success, clinical success, and adverse events associated with self-expanding metal stent placement. RESULTS: From June 2018 to June 2020, 30.5% of patients with difficult catheterization were included in this study. Finally, stents in 17 of 18 patients (3 rectum, 13 sigmoid colon, 1 descending colon, and 1 hepatic flexure) (94.4%) were placed successfully, assisted by a slim gastroscope with or without radiography, and the obstruction was relieved. Only one remaining patient experienced failure. No intraoperative or 30-day postoperative morbidity or mortality was observed. CONCLUSION: The present study showed that the stent implantation technique assisted by a slim gastroscope combined with a normal colonoscope was a relatively safe and effective method for abolishing difficult intestinal stenosis. More studies are needed to compare the advantages and disadvantages of this technique with normal endoscopic implantation.

Use of an Ultra-slim Gastroscope to Accomplish Endoscopist-Facilitated Rescue Intubation During ERCP: A Novel Approach to Enhance Patient and Staff Safety.

BACKGROUND: ERCP is often performed under monitored anesthesia care (MAC) rather than general anesthesia (GA), with patients positioned semi-prone on the fluoroscopy table. Rarely, a MAC ERCP must be converted to GA due to hypoxia or retained food in the stomach. In these circumstances, standard intubation is associated with a significant delay and potential for patient/staff injury during repositioning. We report a novel endoscopist-driven approach to intubation during ERCP using an ultra-slim, flexible gastroscope with an endotracheal tube backloaded onto it. MATERIALS AND METHODS: We identified patients who underwent ERCP from 2014 to 2019, and MAC to GA conversion events. Mode of intubation (standard vs. endoscopist-facilitated) and patient/procedure characteristics were evaluated. All endoscopist-facilitated intubations were performed under anesthesiologist supervision. RESULTS: A total of 3409 patients underwent ERCP; 1568 (46%) GA and 1841 (54%) MAC. Of these, 42 (2.3%) required intubation during ERCP and 16 underwent endoscopist-facilitated intubation due to retained food in the stomach and/or hypoxia. In 3 patients, aspirated material was suctioned from the trachea and bronchi using the ultra-slim gastroscope. Immediate post-procedure extubation was successful in all endoscopist-facilitated intubation patients and none exhibited radiographic evidence of aspiration pneumonia. CONCLUSIONS: Endoscopist-facilitated intubation using an ultra-slim flexible gastroscope is feasible and expeditious for MAC to GA conversion during ERCP. This technique is readily accomplished in the semi-prone position, while standard intubation requires patient transfer from fluoroscopy table to gurney, with associated delay/risks. These data suggest that further study of this approach is warranted, and this may be the most favorable approach for intubation during ERCP.

A Millimeter-Scale Crystal-Less MICS Transceiver for Insertable Smart Pills.

This paper presents a millimeter-scale crystal-less wireless transceiver for volume-constrained insertable pills. Operating in the 402-405 MHz medical implant communication service (MICS) band, the phase-tracking receiver-based over-the-air carrier recovery has a ±160 ppm coverage. A fully integrated adaptive antenna impedance matching solution is proposed to calibrate the antenna impedance variation inside the body. A tunable matching network (TMN) with single inductor performs impedance matching for both transmitter (TX) and receiver (RX) and TX/RX mode switching. To dynamically calibrate the antenna impedance variation over different locations and diet conditions, a loop-back power detector using self-mixing is adopted, which expands the power contour up to 4.8 VSWR. The transceiver is implemented in a 40-nm CMOS technology, occupying 2 mm2 die area. The transceiver chip and a miniature antenna are integrated in a 3.5 × 15 mm2 area prototype wireless module. It has a receiver sensitivity of -90 dBm at 200 kbps data rate and delivers up to - 25 dBm EIRP in the wireless measurement with a liquid phantom.

Successful endoscopic treatment of a large impacted gallstone in the duodenum using laser lithotripsy, Bouveret's syndrome: A case report.

BACKGROUND: Bouveret´s syndrome is defined as a gastric outlet obstruction after passage of a gallstone through a fistula into the duodenum. Due to its rarity, the diagnosis of Bouveret's syndrome is often delayed and causes a high morbidity and mortality rate. CASE SUMMARY: A 93-year-old female presented with worsening pain in the right upper abdomen and vomiting. A gastroscopy revealed fluid retention caused by a massive obstructive stone in the bulbus. Endoscopic laser lithotripsy of the impacted stone was planned after multidisciplinary consultation. A Dornier Medilas H Solvo lithotripsy 350 µm laser fiber (10 Hz, 2 Joules) was used to disintegrate the stone into smaller pieces. The patient recovered completely. CONCLUSION: A mechanical obstruction due to a gallstone that has entered the gastrointestinal tract is a complication that appears in 0.3%-0.5% of patients who have cholelithiasis. Stones larger than 2 cm can become impacted in the digestive tract, which occurs mostly in the terminal ileum. In approximately 1%-3% of cases, the stones cause obstruction in the duodenum. This phenomenon is called Bouveret's syndrome. As this condition is mostly observed in elderly individuals with multiple comorbidities, treatment by an open surgical approach is unsuitable. Endoscopic removal is the preferred technique. The benefit of using laser lithotripsy is the precise targeting of energy onto the stone with minimal tissue injury. Endoscopic laser lithotripsy is a safe and feasible treatment option for Bouveret's syndrome.

[Ingestion of magnetic foreign bodies during the paediatric age. Case report, location and endoscopic extraction aided by a magnet]. / Ingesta de cuerpos extraños magnéticos en la edad pediátrica. Caso clínico de localización y extracción endoscópica con ayuda de un imán.

The ingestion of more than one magnet can cause multiple complications. Current protocols recommend endoscopic extraction if possible. We report a patient who swallowed two magnets and the endoscopic extraction technique. An 11-yearold boy presented at the Emergency Room after ingesting two small magnets, being asymptomatic. In the abdominal x-ray two radiopaque bodies were identified at the gastric chamber, apparently together. A gastroscopy was done in the operating room under general anaesthesia. To enable the extraction, a neodymium magnet was placed externally at the abdominal wall. In the endoscopic image, the two magnets were fixed to the anterior gastric wall. Once located, the neodymium magnet was removed and the two magnets were retrieved with an endoscopic basket.

La ingesta accidental de más de un imán puede producir complicaciones graves. Los protocolos actuales recomiendan la extracción endoscópica de ser posible. El objetivo de este trabajo es presentar un caso clínico de una ingesta de dos imanes y la técnica endoscópica de extracción. Niño de 11 años que acudió a Urgencias tras la ingesta de dos imanes, asintomático. En la radiografía de abdomen, se identificaron dos cuerpos extraños radiopacos, aparentemente unidos, en la cámara gástrica. Se realizó una endoscopía bajo anestesia general en quirófano. Para facilitar la extracción, se colocó, encima de la pared abdominal, a nivel gástrico, un imán de neodimio. En la endoscopía, se observaron dos pequeños imanes localizados y fijados en la cara anterior del estómago. Una vez localizados, se retiró el imán externo y se procedió a su extracción con cesta.

A novel endoscopic visible full-thickness cryoablation device on stomach.

Cryoablation has been used for the treatment of various sorts of solid visceral tumors, but few are reported on gastric tumor via endoscope, in terms of accurate control of ablation site, freezing depth and effective temperature. Thus, we developed a novel device, which could perform accurate cryoablation on the stomach via endoscope. This study aimed to evaluate the efficacy and safety of the device on porcine stomach. Results showed that the novel device could provide direct view of the operation space, allowing accurate and safe ablation of the stomach. Three minutes cryoablation caused a transmural, 1 cm radius gastric lesion. On serosal side, the temperature dropped to -64.2 °C, -34.1 °C, 26.1 °C at the center, 1 cm and 2 cm from center, respectively. Histopathology revealed acute ruptured cells with damaged glands in mucosa, partial disruption in muscularis propria and serosal slight exudation. Three months later, scar formed with complete recovery of gastric structure. No active bleeding or perforation of stomach, nor injury or adhesion of adjacent organs was observed. This endoscopic cryoablation device allowed safe, full-thickness cryoablation with effective temperature, which may provide an alternative treatment for gastric tumor.

Mucosectomy device-assisted endoscopic resection of gastric subepithelial lesions.

OBJECTIVE: Some gastrointestinal subepithelial tumors (SETs) have malignant potential and complete resection may be required. However, endoscopic submucosal dissection (ESD) can be a tedious procedure and requires a long and extensive training to master. Devices for endoscopic full-thickness resection (EFTR) are limited and are not widely available. We report here a simpler endoscopic method to resect small SETs using a commercially available endoscopic mucosal resection (EMR) kit and enucleation technique. METHODS: All patients with SET who underwent device-assisted resection at our tertiary care hospital from April 2015 to November 2016 were enrolled in this retrospective study. All procedures were performed by a single expert endoscopist with an advanced endoscopy trainee. A mucosectomy and a limited dissection under mucosa were performed to preserve the mucosa before a device-assisted enucleation of the tumor to facilitate endoscopic closure of the defect closure in all cases. RESULTS: A total of 12 patients aged 38-70 y, of whom six were males, were included. Most of the tumors originated from the muscularis propria and were located at the proximal gastric body. The mean procedural duration was 53 minutes (range 23-91 min). The average size of the lesions was 13 mm (range 9-21 mm). The mean duration of hospitalization was 1.3 days. Bleeding and intentional perforation were all successfully managed during the procedure and did not result in any clinically significant adverse event. CONCLUSION: A device-assisted EFTR using a commercially available EMR kit is a safe and feasible method for the endoscopic resection of small gastric extrovert SETs.

Predictors of outcomes of endoscopic balloon dilatation in strictures after esophageal atresia repair: A retrospective study.

BACKGROUND: Endoscopic balloon dilatation (EBD) has become the first line of therapy for benign esophageal strictures (ESs); however, there are few publications about the predictive factors for the outcomes of this treatment. AIM: To assess the predictive factors for the outcomes of EBD treatment for strictures after esophageal atresia (EA) repair. METHODS: Children with anastomotic ES after thoracoscopic esophageal atresia repair treated by EBD from January 2012 to December 2016 were included. All procedures were performed under tracheal intubation and intravenous anesthesia using a three-grade controlled radial expansion balloon with gastroscopy. Outcomes were recorded and predictors of the outcomes were analyzed. RESULTS: A total of 64 patients were included in this analysis. The rates of response, complications, and recurrence were 96.77%, 8.06%, and 2.33%, respectively. The number of dilatation sessions and complications were significantly higher in patients with a smaller stricture diameter (P = 0.013 and 0.023, respectively) and with more than one stricture (P = 0.014 and 0.004, respectively). The length of the stricture was significantly associated with complications of EBD (P = 0.001). A longer interval between surgery and the first dilatation was related to more sessions and a poorer response (P = 0.017 and 0.024, respectively). CONCLUSION: The diameter, length, and number of strictures are the most important predictive factors for the clinical outcomes of endoscopic balloon dilatation in pediatric ES. The interval between surgery and the first EBD is another factor affecting response and the number of sessions of dilatation.

Can image-enhanced endoscopy improve the diagnosis of Kyoto classification of gastritis in the clinical setting?

Endoscopic diagnosis of Helicobacter pylori (H. pylori) infection, the most common cause of gastric cancer, is very important to clarify high-risk patients of gastric cancer for reducing morbidity and mortality of gastric cancer. Recently, the Kyoto classification of gastritis was developed based on the endoscopic characteristics of H. pylori infection-associated gastritis for clarifying H. pylori infection status and evaluating risk factors of gastric cancer. Recently, magnifying endoscopy with narrow-band imaging (NBI) has reported benefits of the accuracy and reproducibility of endoscopic diagnosis for H. pylori-related premalignant lesions. In addition to NBI, various types of image-enhanced endoscopies (IEEs) are available including autofluorescence imaging, blue laser imaging, and linked color imaging. This review focuses on understanding the clinical applications and the corresponding evidences shown to improve the diagnosis of gastritis based on Kyoto classification using currently available advanced technologies of IEEs.

Linked Color Imaging and the Kyoto Classification of Gastritis: Evaluation of Visibility and Inter-Rater Reliability.

BACKGROUND/AIMS: To compare white light imaging (WLI) with linked color imaging (LCI) and blue LASER imaging (BLI) in endoscopic findings of Helicobacter pylori presently infected, previously infected, and uninfected gastric mucosae for visibility and inter-rater reliability. METHODS: WLI, LCI and BLI bright mode (BLI-bright) were used to obtain 1,092 endoscopic images from 261 patients according to the Kyoto Classification of Gastritis. Images were evaluated retrospectively by 10 experts and 10 trainee endoscopists and included diffuse redness, spotty redness, map-like redness, patchy redness, red streaks, intestinal metaplasia, and an atrophic border (52 cases for each finding, respectively). Physicians assessed visibility as follows: 5 (improved), 4 (somewhat improved), 3 (equivalent), 2 (somewhat decreased), and 1 (decreased). Visibility was assessed from totaled scores. The inter-rater reliability (intraclass correlation coefficient) was also evaluated. RESULTS: Compared with WLI, all endoscopists reported improved visibility with LCI: 55.8% for diffuse redness; LCI: 38.5% for spotty redness; LCI: 57.7% for map-like redness; LCI: 40.4% for patchy redness; LCI: 53.8% for red streaks; LCI: 42.3% and BLI-bright: 80.8% for intestinal metaplasia; LCI: 46.2% for an atrophic border. For all endoscopists, the inter-rater reliabilities of LCI compared to WLI were 0.73-0.87. CONCLUSION: The visibility of each endoscopic finding was improved by LCI while that of intestinal metaplasia was improved by BLI-bright.

Accuracies of Endoscopic Diagnosis of Helicobacter pylori-Gastritis: Multicenter Prospective Study Using White Light Imaging and Linked Color Imaging.

INTRODUCTION: The diagnosis of Helicobacter pylori infection status with white light imaging (WLI) is difficult. We evaluated the accuracies of using WLI and linked color imaging (LCI) for diagnosing H. pylori-active gastritis in a multicenter prospective study setting. METHODS: Patients who underwent esophagogastroduodenoscopy were prospectively included. The image collection process was randomized and anonymous, and the image set included 4 images with WLI or 4 images with LCI in the corpus that 5 reviewers separately evaluated. Active gastritis was defined as positive when there was diffuse redness in WLI and crimson coloring in LCI. The H. pylori infection status was determined by the urea breath test and the serum antibody test. Cases in which both test results were negative but atrophy or intestinal metaplasia was histologically confirmed were defined as past infections. The primary endpoint was the diagnostic accuracies of WLI and LCI, and the secondary endpoint was inter-observer agreement. RESULTS: Data for 127 patients were analyzed. The endoscopic diagnostic accuracy for active gastritis was 79.5 (sensitivity of 84.4 and specificity of 74.6) with WLI and 86.6 (sensitivity of 84.4 and specificity of 88.9) with LCI (p = 0.029). LCI significantly improved the accuracy in patients with past infections over WLI (36.8 in WLI and 78.9 in LCI, p < 0.01). The κ values were 0.59 in WLI and 0.70 in LCI. CONCLUSIONS: LCI is useful for endoscopic diagnosis of H. pylori-active or inactive gastritis, and it is advantageous for patients with past infections of inactive gastritis.

Human gastric magnet-controlled capsule endoscopy conducted in a standing position: the phase 1 study.

BACKGROUND: Current magnet-controlled capsule endoscopy (MCE) for the stomach is not yet satisfactory with respect to navigation control, especially in the gastric fundus and cardia. A newly developed MCE system conducted in a standing rather than supine position may improve capsule maneuverability within the stomach. The aim of this phase 1 study was to assess the feasibility and safety of this system for examining the human stomach in healthy volunteers. METHODS: A cohort of 31 healthy volunteers were enrolled. Each swallowed a capsule after drinking water and gas producing agents intended to produce distention. Under the newly developed standing MCE system, subjects were examined endoscopically while standing with external guide magnets placed on the abdominal wall and left lower chest. Safety, gastric preparation, maneuverability, visualization of anatomical landmarks and the gastric mucosa, and examination time were the primary parameters assessed. The gastric preparation and examination procedures were well accepted by the subjects and there were no adverse events. RESULTS: Gastric examination took 27.8 ± 8.3 min (12-45 min). Gastric cleanliness was good in 24 participants (77.4%) and moderate in 7 participants (22.6%). Gastric distention was good in all of 31 participants (100%). Capsule maneuverability was also graded as good in all 31 subjects (100%), and manipulation in the fundus and cardia regions was as easy as that in the antrum and body. Visualization of the gastric cardia, fundus, body, angulus, antrum and pylorus was assessed subjectively as complete in all 31 subjects (100%). Visualization of the gastric mucosa was also good (> 75%) in all 31 subjects (100%). In areas where the mucosa could not be visualized, the low visibility was due to opaque fluid or foam. Polyps and erosive lesions were found in 25 subjects. CONCLUSION: MCE of the stomach conducted in a standing position is feasible and safe with satisfactory maneuverability.

Endobronchial foreign body removal using fiberoptic bronchoscope together with gastroscope biopsy forceps: A case report.

RATIONALE: There are many difficult cases in the clinic because of the diversity of foreign bodies. The removal of a syringe cap is not so easy because there is always no hole at the closed end. PATIENT CONCERNS: A 54-year-old man suddenly developed dyspnea during his treatment in the hospital. DIAGNOSES: Foreign body in the left main bronchus. INTERVENTIONS: The foreign body was removed using fiberoptic bronchoscope together with gastroscope biopsy forceps. OUTCOMES: A repeat CT showed well inflation of left lung. LESSONS: The combined use of gastroscope biopsy forceps in trachea is more conducive to remove a foreign body similar to a syringe cap.