Japanese guidelines for peroral endoscopic myotomy: 1st edition

Navigating the learning landscape: Comprehensive training in third space endoscopy - training, techniques, and practical recommendations

Third space endoscopy (TSE), including ESD, POEM, or STER are advanced procedures requiring precise endoscopic control and tissue recognition. Despite its increasing adoption, evidence-based curricula, and standardized training protocols for TSE are lacking. This review explores training methods, cognitive skills, and technical proficiency requirements for endoscopists performing TSE, with a primary emphasis on POEM. Generally, it seems wise to recommend a step-up approach to TSE training, starting with ex-vivo models or POEM simulators; mechanical and virtual reality (VR) simulators are commonly used during early training. Preclinical training involving ex-vivo and live animal models is suggested to prepare trainees for safe and effective procedures. Studies suggest varying numbers of procedures for training, with approximately 20-40 cases needed before a first plateau is achieved in terms of complications and speed. The duration of on-patient clinical training varies depending on prior experience. Mentorship programs, workshops, and case discussions may facilitate dynamic knowledge transfer. In addition, adverse event management is a crucial aspect of any TSE training program. Existing evidence supports the use of preclinical models and emphasizes the importance of specialized training programs for TSE in alignment with our proposed step-up training approach. This review outlines practical recommendations for the theoretical knowledge and technical skills required before commencing TSE training, covering clinical understanding, diagnostic and outcome assessment, procedural requirements, and the role of mentorship programs.

POEM from A to Z: current perspectives

The "third space endoscopy" or also called "submucosal endoscopy" is a reality we can transfer to our patients since 2010. Various modifications of the submucosal tunneling technique allow access to the submucosa or deeper layers of the gastrointestinal tract. In addition to peroral endoscopic myotomy for the treatment of achalasia, also called esophageal POEM, other variants have emerged that make it possible to treat different esophageal motility disorders, esophageal diverticula, subepithelial tumors of various locations, gastroparesis, reconnection of complete esophageal strictures or even thanks to exceptional endoscopists, pediatric disorders such as Hirschsprung's disease. Although some technical aspects are yet to be standardized, these procedures are becoming widespread worldwide and will likely become the standard treatment of these pathologies soon.

Gastroesophageal Reflux after Peroral Endoscopic Myotomy: Myth or Reality?

Peroral endoscopic myotomy (POEM) is an accepted treatment for achalasia cardia (AC), and results are comparable to those of laparoscopic Heller myotomy (LHM). In recent years, several reports have confirmed higher incidence of gastroesophageal reflux (GER) following POEM. This review evaluates the current evidence regarding post-POEM GER, critically examines the potential contributing factors responsible for GER, limitations of the current available functional testing, and precautions and preventive measures, and provides future directions for research. Factors conclusively contributing to increased post-POEM GER include injury to the sling fibers of the lower esophageal sphincter, length of gastric myotomy > 2 cm, and others. Historically, these same factors have been implicated for development of GER after surgical (laparoscopic) myotomy. Although less invasive, optimal technique of POEM may be important to control post-POEM GER. Most post-POEM GER occurs during the immediate post-POEM period, is mild, and is easily treatable using proton-pump inhibitors. GER incidence plateaus at 2 years and is comparable to that after LHM. Patients should therefore be prescribed proton-pump inhibitors for at least 2 years. Antireflux procedures (ARPs) are infrequently required in these patients as the incidence of refractory GER is low. Novel ARPs have been recently described and are currently under evaluation. Conclusive diagnosis of GER is a clinical challenge. Most patients are asymptomatic, and GER is diagnosed only on abnormal esophageal acid exposure (EAE). Studies have demonstrated that current measures to diagnose GER are inadequate, inaccurate, and cannot differentiate between true GER and abnormal EAE due to food fermentation in the distal esophagus. The Lyon Consensus criteria should be implemented for confirmation of diagnosis of GER. Finally, the review recommends an evidence-based clinical algorithm for evaluation and management of post-POEM GER and provides guidelines for future research in this field.

Detection of cytokine storm in patients with achalasia using ELISA

Esophageal achalasia is characterized by abnormal peristaltic movements of the esophageal body and impaired relaxation of the lower esophageal sphincter (LES). However, its etiology remains unknown. In our previous study, it was shown that in the LES of patients with achalasia, hsv1-miR-H1 was overexpressed, ATG16L1 expression was downregulated and interleukin (IL)-1β levels were upregulated. However, systemic features were not evaluated. Herein, the plasma cytokine levels in patients with achalasia were determined. Plasma was collected from patients at Nagasaki University Hospital between February 2013 and March 2016, both before and after peroral endoscopic myotomy (POEM). Cytokine analysis was performed using plasma collected from 10 healthy individuals (control group) and 12 patients with achalasia using the Bio-Plex Pro™ Human Cytokine 27-plex assay kit. The levels of IL-17, IL-1β, C-C motif chemokine ligand 2, IL-4, IL-5, IL-1ra, IL-7, IL-12, interferon-γ, IL-2, fibroblast growth factor-2, colony-stimulating factor (CSF)2 and CSF3 were significantly higher in patients with achalasia compared with the control subjects. However, the levels did not differ between plasma samples collected before and after POEM. Thus, the occurrence of a cytokine storm was confirmed in the patients with achalasia.

Autophagy-related 16-like 1 is influenced by human herpes virus 1-encoded microRNAs in biopsy samples from the lower esophageal sphincter muscle during per-oral endoscopic myotomy for esophageal achalasia

Esophageal achalasia is characterized by abnormal peristalsis of the esophageal body and impaired relaxation of the lower esophageal sphincter (LES); however, its etiology remains unknown. One of the potential causes of esophageal achalasia is herpes simplex virus type 1 (HSV-1). Following infection with HSV-1, a complex interaction between the autoimmune and inflammatory responses is initiated. Viral microRNAs (miRNAs/miRs) serve a crucial role in this interaction. In the present study, the expression of E3 ubiquitin-protein ligase component n-recognition 1 (UBR1) and autophagy-related 16-like 1 (ATG16L1) was assessed in patients with sporadic and classic achalasia as potential targets of the viral miRNAs. We assessed the mRNA levels of target transcripts using reverse transcription-quantitative PCR. UBR1 expression was slightly decreased, although the difference was not significant. However, ATG16L1 expression was significantly decreased in the LES. In conclusion, ATG16L1 expression was reduced in the LES of achalasia patients; therefore, ATG16L1 might be a target of HSV1-miR-H1, and its reduction could be related to the disease mechanism.

Third Space Endoscopy: Lessons Learnt From a Decade of Submucosal Endoscopy

The field of third space endoscopy (TSE), also called submucosal endoscopy using a mucosal flap valve, allows secure access to the submucosal and deeper layers of the gastrointestinal tract without the risk of a full-thickness perforation. Since the first description of per-oral endoscopic myotomy (POEM) for the treatment of achalasia cardia 10 years ago, this field has expanded rapidly. Several new procedures, submucosal tunneling endoscopic resection, gastric-POEM, Zenker POEM, per-rectal endoscopic myotomy, diverticular POEM, and recanalization for complete esophageal obstruction (per-oral endoscopic tunneling for restoration of the esophagus), have been performed. All TSE procedures employ a similar technique-after a mucosal incision, a submucosal tunnel is created, a myotomy is performed, or a subepithelial tumor is resected distal to the site of mucosal incision, after which the mucosal incision is closed. Potential indications for TSE include resection of subepithelial tumors in the esophagus, gastroesophageal junction, or stomach; refractory gastroparesis; Zenker diverticulum; Hirschsprung disease or other forms of megacolon; and recanalization for complete esophageal obstruction. Data are currently available for POEM, submucosal tunneling endoscopic resection, and gastric-POEM, although mainly in the form of retrospective studies, and randomized trials and long-term follow-up data are limited. Submucosal endoscopy has an excellent safety profile with very few intraoperative adverse events, the majority being related to insufflation, although bleeding, perforation, and sepsis have been reported. TSE procedures require special training and have demonstrated a learning curve.

Identification of human herpes virus 1 encoded microRNAs in biopsy samples of lower esophageal sphincter muscle during peroral endoscopic myotomy for esophageal achalasia

Esophageal achalasia is a rare chronic debilitating disorder characterized by incomplete lower esophageal sphincter (LES) relaxation and abnormal peristalsis as a result of myenteric plexus degeneration. Although complex interactions among immunity, viruses and inheritance have been proposed, its causes remain unknown. MicroRNAs (miRs) play crucial roles in the regulation of gene expression during pathophysiological processes. Certain viruses such as herpes simplex virus (HSV) encode miRs derived from their own genomes. To determine the underlying relationship of miRNAs to achalasia, we analyzed the expression profile of miRNAs using biopsy samples obtained from LES muscle during peroral endoscopic myotomy. Peroral LES muscle biopsy sampling was uneventfully carried out in our case series of achalasia. Control biopsy tissues were also obtained from LES muscle of patients without symptoms relating to abnormal esophageal motility whose esophagogastric junction was surgically excised. RNA was extracted from biopsy specimens and analyzed using a microarray. Differentially expressed miRNAs in achalasia patients compared to controls were identified and analyzed using reverse transcription quantitative polymerase chain reaction. HSV-1-derived hsv1-miR-H1 and -H18 was significantly overexpressed in achalasia cohorts compared to controls. Correlations between the expression levels of viral miR and the patients' clinical characteristics including achalasia morphological type, dilatation grading, and disease duration were not identified. Further studies with a larger sample size are needed to replicate the current heuristic identification of neurotropic viral miRs and unravel their functional significance in order to provide new insight linking neurodegenerative etiology in achalasia.