Analysis of a learning curve and predictors of intraoperative difficulty for peroral esophageal myotomy (POEM)

Curriculum for training in peroral endoscopic myotomy (POEM) in Europe (Part I): European Society of Gastrointestinal Endoscopy (ESGE) Position Statement

Peroral endoscopic myotomy (POEM) is an advanced endoscopic procedure that has become a first-line treatment for esophageal achalasia and other esophageal spastic disorders. Structured training is essential to optimize the outcomes of this technique. The European Society of Gastrointestinal Endoscopy (ESGE) has recognized the need to formalize and enhance training in POEM. This Position Statement presents the results of a systematic review of the literature and a formal Delphi process, providing recommendations for an optimal training program in POEM that aims to produce endoscopists competent in this procedure. In a separate document (POEM curriculum Part II), we provide technical guidance on how to perform the POEM procedure based on the best available evidence. 1: POEM trainees should acquire a comprehensive theoretical knowledge of achalasia and other esophageal motility disorders that encompasses pathophysiology, diagnostic tool proficiency, clinical outcome assessment, potential adverse events, and periprocedural management. 2: Experience in advanced endoscopic procedures (endoscopic mucosal resection and/or endoscopic submucosal dissection [ESD]) is encouraged as a beneficial prerequisite for POEM training. 3: ESGE suggests that POEM trainees without ESD experience should perform an indicative minimum number of 20 cases on ex vivo or animal models before advancing to human POEM cases with an experienced trainer. 4: ESGE recommends that the trainee should observe an indicative minimum number of 20 live cases at expert centers before starting to perform POEM in humans. 5: The trainee should undertake an indicative minimum number of 10 cases under expert supervision for the initial human POEM procedures, ensuring that trainees can complete all POEM steps independently. 6: ESGE recommends avoiding complex POEM cases during the early training phase. 7: POEM competence should reflect the technical success rate, both the short- and long-term clinical success rates, and the rate of true adverse events. 8: A POEM center should maintain a prospective registry of all procedures performed, including patient work-up and outcomes, procedural techniques, and adverse events.

Peroral endoscopic myotomy for complex achalasia and the POEM difficulty score: An update

Objectives

We present an update on the (peroral endoscopic myotomy (POEM) difficulty score [PDS] by introducing a novel knife with waterjet functionality.

Methods

This is a retrospective review of patients who underwent POEM between May 2018 and July 2023 at the Kingston Health Sciences Center. Demographic and procedural variables were compared using descriptive and inferential statistics.

Results

One hundred thirty-nine consecutive POEMs were included in the study. Seventy-four (56.7% male; aged 56.7 ± 16.5 years) complex achalasia (CA) and 65 (55.4% female; aged 47.3 ± 20.2 years) non-CA POEM procedures were performed. PDS correlates moderately with procedural efficiency with a correlation coefficient of 0.595 (Spearman's p < 0.001). The mean efficiency for non-CA was 3.3 ± 1.2 min/cm compared to CA as follows: type III 3.3 ± 1.3 min/cm; prior myotomy 5.3 ± 2.3 min/cm; ≧4 prior procedures 4.0 ± 1.7 min/cm; sigmoid type 5.2 ± 2.4 min/cm. The median PDS for non-CA was 1 (1-5). In comparison, the median PDS for CA is as follows: type III 3 (2-4); prior myotomy 4 (3-5); ≧4 prior procedures 3 (1.25-4); sigmoid type 3 (2-4). PDS excluding the presence of spastic contractions correlated better with procedural velocity, with a correlation coefficient of 0.645 (Spearman's p < 0.001).

Conclusions

PDS continues to moderately correlate with procedural efficiency using the novel knife. The presence of spastic contractions correlated poorly with procedural efficiency. Thus, it may be omitted in further studies.

Advances in Third Space Endoscopy

This article offers a detailed overview of recent advancements in third space endoscopy (TSE), highlighting key procedures and their clinical applications and outcomes. Clinical TSE started as a treatment for achalasia and was named peroral endoscopic myotomy (POEM). Outcome data and comparative data of POEM with other treatments were detailed and discussed. This article also explores the indications and outcomes of other TSE procedures, such as G-POEM, Z-POEM, D-POEM, per-rectal endoscopic myotomy, and STER/POET. This article serves as a valuable resource for endoscopists looking to enhance their understanding and stay updated on these advanced TSE procedures.

Complications related to third space endoscopic procedures

Third space endoscopy (TSE) encompasses a breadth of procedures for the treatment of a variety of GI disorders. The widespread use of per-oral endoscopic myotomy (POEM) and its diversification to include extended indications and at locations other than the oesophagus has provided an insight into the potential complications encountered. The most common adverse events associated with POEM, the epitome of TSE procedures, include insufflation related injuries, bleeding, failure of mucosal barrier, infections, pain, blown out myotomy and gastroesophageal reflux disease. The purpose of this review is to highlight the pitfalls and to identify the risk factors that may lead to adverse events, and to recommend appropriate salvage interventions in the scope of the current evidence.

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.

Hood-attached versus conventional triangular tip-jet knife in peroral endoscopic myotomy: a propensity score matching cohort study

BACKGROUND AND AIMS

Peroral endoscopic myotomy (POEM) is a safe and effective endoscopic treatment for achalasia and other esophageal motility disorders, and a versatile knife (TriangleTipKnife J [TTJ]; Olympus, Tokyo, Japan) is currently widely used in POEM. Recently, we reported a novel modification of TTJ, which was adjusted to a knife length of 2 mm by attaching a disposable clip (QuickClip Pro; Olympus) sheath to the tip as a hood attachment. This study compares the safety and effectiveness of TTJ and TTJ with a hood attachment (TTJ-H) in POEM.

METHODS

This 1:1 propensity score-matched retrospective cohort study compared the procedure time, myotomy efficiency, number of coagulation forceps usage, adverse events, length of hospital stay after POEM, procedural success, and clinical success between the TTJ and TTJ-H groups.

RESULTS

A total of 682 consecutive patients who underwent POEM between January 2021 and June 2023 were examined. We excluded 134 patients who had already undergone POEM or laparoscopic Heller myotomy as prior myotomy. Finally, 98 propensity score-matched pairs (n = 196) were identified. The mean procedure time was shortened from 93.5 minutes to 80.2 minutes (14% reduction, P = .012) when comparing the TTJ-H group versus the TTJ group. The mean myotomy efficiency was improved from 2.76 min/cm to 2.32 min/cm (16% improvement, P ≤ .001), and usage of coagulation forceps for hemostasis was decreased from 3.87 to .55 (86% reduction, P ≤ .001).

CONCLUSIONS

This study showed that use of TTJ-H could reduce total procedure time, improve myotomy efficiency, and reduce costs compared with TTJ.

Development and initial validation of a video-based peroral endoscopic myotomy assessment tool

BACKGROUND AND AIMS

Video analysis has emerged as a potential strategy for performance assessment and improvement. We aimed to develop a video-based skill assessment tool for peroral endoscopic myotomy (POEM).

METHODS

POEM was deconstructed into basic procedural components through video analysis by an expert panel. A modified Delphi approach and 2 validation exercises were conducted to refine the POEM assessment tool (POEMAT). Twelve assessors used the final POEMAT version to grade 10 videos. Fully crossed generalizability (G) studies investigated the contributions of assessors, endoscopists' performance, and technical elements to reliability. G coefficients below .5 were considered unreliable, between .5 and .7 as modestly reliable, and above .7 as indicative of satisfactory reliability.

RESULTS

After task deconstruction, discussions, and the modified Delphi process, the final POEMAT comprised 9 technical elements. G analysis showed low variance for endoscopist performance (.8%-24.9%) and high interrater variability (range, 63.2%-90.1%). The G score was moderately reliable (≥.60) for "submucosal tunneling" and "myotomy" and satisfactorily reliable (≥.70) for "active hemostasis" and "mucosal closure."

CONCLUSIONS

We developed and established initial content and response process validity evidence for the POEMAT. Future steps include appraisal of the tool using a wider range of POEM videos to establish and improve the discriminative validity of this tool.

Peroral Endoscopic Myotomy; Novice Surgeon Learning Curve

INTRODUCTION

Peroral endoscopic myotomy (POEM) is a novel endoscopic procedure used to treat achalasia and other spastic esophageal disorders that is an alternative to Heller myotomy. We seek to define the learning curve of POEM for a foregut surgeon with no formal endoscopic or POEM training by analyzing different intraoperative factors in a single series.

METHODS AND PROCEDURES

The first 38 consecutive patients undergoing POEM by a single foregut surgeon were included in this retrospective study. Inverse curve regression models were used to analyze total operative time (TOT) and total operative time per centimeter of myotomy (TOT-CM), in addition to other intraoperative variables. Clinical outcomes were reported as pre- and post-operative Eckardt Scores.

RESULTS

All patients had type II achalasia with no post-operative complications observed. Eckardt scores improved postoperatively (median (range): 1 (0-4)) compared with the preoperative scores (10 (8-12)) (P < .001). The total operative time (median 76 minutes, range 51-129) decreased significantly over the course of the series (R2 = .38, P < .001), with a learning plateau at 70 minutes and a learning rate of 12 cases. Total operative time per centimeter of myotomy (median 7.08 min/cm, range 4.25 to 15.38) decreased over time (R2 = .45, P < .001), with a learning plateau at 7 minutes/cm and a learning rate of 12 cases.

CONCLUSION

The number of cases for a foregut surgeon to become proficient in a POEM procedure was found to be 12-14 cases. The learning curve for a POEM in a formally trained foregut surgeon may be comparable to an endoscopically trained interventionist.

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.

Risk-scoring system for predicting challenging cases of peroral endoscopic myotomy

OBJECTIVES

Peroral endoscopic myotomy (POEM) is an effective treatment for esophageal motility disorders including achalasia and its variants. However, some surgeons have encountered challenging cases. This study aimed to develop a risk-scoring system to predict challenging cases of POEM.

METHODS

Consecutive patients who underwent POEM between April 2015 and March 2020 at our hospital were included in this single-center retrospective study. Challenging cases of POEM were defined as patients with any of the following: (i) procedure time ≥90 min; (ii) mucosal perforation; (iii) pneumothorax; and (iv) major bleeding. A risk-scoring system for predicting challenging cases was developed based on multivariate logistic regression and internal validation was performed using the bootstrap method. Clinical usefulness was evaluated using a decision curve analysis.

RESULTS

Of the 467 patients, 59 (12.6%) had challenging POEM. A risk-scoring system consisted of four variables: duration of symptoms ≥5 years (assigned score, 1 point), antithrombotics use (1 point), manometric diagnosis of achalasia variants (2 points), and dilation grade 3 (2 points). Our scoring system showed satisfactory discrimination (area under the receiver operating characteristic curve, 0.69; 95% confidence interval [CI] 0.61-0.77) and calibration (slope, 0.99; 95% CI 0.65-1.35). The decision curve analysis demonstrated its clinical usefulness.

CONCLUSIONS

We established a risk-scoring system to predict challenging cases of POEM. This scoring system may aid the selection of patients who require treatment from experienced surgeons.

Early outcomes following EndoFLIP-tailored peroral endoscopic myotomy (POEM): the establishment of POEM services in two UK centers

Peroral endoscopic myotomy (POEM) is a safe and effective minimally invasive treatment for achalasia. Postoperative reflux rates remain high. The functional luminal imaging probe (FLIP) allows intraoperative measurement of lower esophageal distensibility during POEM. In theory, this enables a tailoring of myotomies to ensure adequate distensibility while minimizing postoperative reflux risk. Two prospectively collected POEM databases were analyzed from two UK tertiary upper GI centers. The operators in each center used FLIP measurements to ensure adequate myotomy. Outcome measures included Eckardt score (where <3 indicated clinical success) and proton-pump inhibitor use (PPI), collected at the first postoperative appointment. Length of stay was recorded as were complications. In all, 142 patients underwent POEM between 2015 and 2019. Overall, 90% (128/142) had postoperative Eckardt scores of <3 at 6 weeks. Clinical success improved to 93% (66/71) in the latter half of each series with a significantly higher rate of complete symptom resolution (53 versus 26%, P = 0.003). In all, 79% of the poor responders had previous interventions compared with 55% of responders (P = 0.09). Median post-myotomy distensibility index was 4.0 mm2/mmHg in responders and 2.9 in nonresponders (P = 0.16). Myotomy length of <7 cm was associated with 93% clinical success and 40% post op PPI use compared with 60% PPI use with longer myotomies. There were two type IIIa, two type IIIb, and one IV Clavien-Dindo complications. This is the largest series of endoluminal functional lumen imaging probe (EndoFLIP)-tailored POEM in the UK to date. The shorter myotomies, allowed through EndoFLIP tailoring, remained clinically effective at 6 weeks. Complete symptom response rates improved in the latter half of each series. More data will be needed from high-volume collaborations to decipher optimal myotomy profiles based on EndoFLIP parameters.

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.

Learning curve for peroral endoscopic myotomy in therapeutic endoscopy experts and nonexperts: Large single-center experience

OBJECTIVES

Reports on learning curve for peroral endoscopic myotomy (POEM) in therapeutic endoscopy nonexperts are limited. We aimed to assess the number of cases required to achieve POEM proficiency for endoscopic submucosal dissection (ESD) experts and nonexperts.

METHODS

This is a retrospective study at the largest POEM referral center in Japan. POEM between April 2014 and December 2020 were included. Nonexperts and ESD experts were divided by training phases: A, 1-20; B, 21-40; C, 41-60; D, 61-80; and E, 81-100 cases. Primary outcome was operation time, and the phase to reach target time (83 min) was investigated. Secondary outcomes were clinical success rate, adverse events, and post-POEM gastroesophageal reflux disease (GERD).

RESULTS

Five hundred and sixty-six cases were performed by 14 nonexperts, and 555 cases by 15 ESD experts. As the primary outcome, operation time in nonexperts was: A, 95 (79-115.8); B, 86.5 (71-105); C, 80 (70-100); D, 73 (64.5-100.5); and E, 73.5 (57.8-88.8) min, while in ESD experts: A, 90 (74-128); B, 77 (70-92); and C, 77 (70-93.5) min (median [interquartile range]). Operation time decreased significantly as experience increased in both groups (P < 0.001), and nonexperts required 41-60 cases to achieve proficiency, while experts required 21-40 cases. As secondary outcomes, in nonexperts, clinical success was 96.9-100%, adverse events were 5.0-9.2%, symptomatic GERD was 11.8-26.5%, and proton pump inhibitor (PPI) intake was 11.5-18.7% in each phase. While in experts, clinical success was 96.2-100%, adverse events were 3.0-5.8%, symptomatic GERD was 14.6-22.0%, and PPI intake was 12.6-17.9%. There were no significant differences among training phases.

CONCLUSIONS

Non-ESD experts require more cases to achieve proficiency in POEM. These results are useful for establishing POEM training programs and institutional implementation of the procedure.

A prediction model and nomogram for technical difficulty of peroral endoscopic myotomy

BACKGROUND AND AIMS

Peroral endoscopic myotomy (POEM) is a promising endoscopic technique for achalasia. We aimed to establish a regression model and develop a simple nomogram to predict the technical difficulty of POEM in a single center with large volume cases.

METHODS

3385 achalasia patients treated with POEM were included, and the technical difficulty was systemically evaluated. All of them were randomized into the training cohort (n = 1693) or internal validation cohort (n = 1692). Then, the prediction model and nomogram were proposed based on multivariate logistic regression analysis in the training cohort and assessed in the validation cohort.

RESULTS

Of 3385 patients, technical difficulty happened in 417 (12.32%) cases. In the training stage, six factors were weighted based on the β coefficient from the regression model, including age, disease duration, sigmoid esophagus, mucosal edema, submucosal fibrosis, and tunnel length. The patients were categorized into low-risk (< 0.1), medium-risk (0.1-0.25), and high-risk (> = 0.25) groups. Our score model performed satisfying discrimination with the areas under the receiver-operating characteristic curve (AUC) of 0.743 (95% confidence interval (CI), 0.701-0.785) and calibration with goodness of fit in the Hosmer-Lemeshow test (P = 0.088) in internal validation.

CONCLUSIONS

The prediction model and nomogram demonstrated good performance in predicting the technical difficulty of POEM.

New Applications for Submucosal Tunneling in Third Space Endoscopy: A Comprehensive Review

Third space endoscopy (TSE), a type of natural orifice transluminal endoscopic surgery, was first introduced a decade ago, and since then, has revolutionized the field of therapeutic endoscopy. TSE involves tunneling into the submucosal space between the intestinal mucosa and the muscularis propria. By accessing this "third space," endoscopists can perform minimally invasive myotomies, resections, and dissections while maintaining the mucosa and preventing full-thickness perforation. TSE procedures can be used to treat motility disorders as well as neoplasms throughout the gastrointestinal tract, which were traditionally conditions that would require open or laparoscopic surgery. The main TSE procedures include peroral endoscopic myotomy, gastric peroral endoscopic myotomy, Zenker peroral endoscopic myotomy, submucosal tunneling for endoscopic resection, endoscopic submucosal tunnel dissection, peroral endoscopic tunneling for restoration of the esophagus, and per-rectal endoscopic myotomy. Some of those procedures have now been accepted as viable alternative to surgical techniques due to their limited invasiveness, safety and cost. This review will explore the different techniques recently added to our arsenal while describing their potential efficacy and limitations.

Adverse Events Associated With Peroral Endoscopic Myotomy Affecting Extended Hospital Stay: A Multi-center Retrospective Study in South Korea

Background/Aims

To analyze various adverse events (AEs) related to the peroral endoscopic myotomy (POEM) procedure and to analyze whether these AEs are related to an extended hospital stay.

Methods

Patients admitted for POEM for esophageal motility disorders from August 2012 to February 2020 at 5 centers were retrospectively collected. Length of hospital stay, AEs during or after the POEM procedure were analyzed.

Results

Of the 328 patients, 63.1% did not have any AEs, but 2.4% had major AEs, and 33.4% had minor AEs. Major AEs included mucosal injury, bleeding, and hemothorax, accounting for 1.5%, 0.6%, and 0.3%, respectively. Among the minor AEs, pneumoperitoneum was the most common gas-related AEs. Among non-gas-related minor AEs, pneumonia was the most common at 4.6%, followed by pain, fever, and pleural effusion. All major AEs had meaningful delayed discharge and significantly extended hospital stay compared to the no AEs group (median differences range 4.5-9.0 days). Among gas-related minor AEs, except for 4 cases of emphysema, the extended hospital stay was meaningless. All non-gas-related minor AEs was associated with a significant prolongation of hospital stay compared to that in the no AEs group (median differences range 2.0-4.0 days).

Conclusions

In conclusion, most gas-related minor AEs do not significantly affect the patient's clinical course. However, subcutaneous emphysema and minor non-gas related AEs such as pneumonia, pain, fever, and pleural effusion can prolong the hospital stay, therefore careful observation is required. Efforts will be made to reduce major AEs that significantly prolong hospitalization.

Gastric Peroral Endoscopic Myotomy: A Specific Learning Curve

INTRODUCTION

Gastric peroral endoscopic pyloromyotomy (G-POEM) is a novel option for patients with gastroparesis. It involves submucosal tunneling across the pylorus, followed by pyloromyotomy, and subsequent closure of the endoscopic tunnel. The aim of this study was to determine the learning curve for G-POEM.

METHODS

Consecutive patients undergoing G-POEM by a single operator were included from a prospective registry over 2 years. Demographics, procedure info, postprocedure follow-up data, and adverse events were collected. Nonlinear regression and cumulative sum control chart analyses were conducted for the learning curve. Clinical outcomes were improvement in Gastroparesis Cardinal Symptom Index score and gastric emptying scintigraphy.

RESULTS

Thirty-six patients were included (16.7% M, mean age 46 y). The majority had idiopathic gastroparesis (n=16, 44%), with the remaining having diabetes (n=5, 17%), postsurgical (n=10, 28%), or other (n=4, 11%). Technical success was achieved in 35 of 36 (97%). There was a significant reduction in the total Gastroparesis Cardinal Symptom Index score (2.09 units, P<0.00001) and a significant reduction in postoperative gastric emptying scintigraphy (82.44 mins, P<0.00001). Mean follow-up was 15 months (SD, 1.05). Median procedure time was 60.5 minutes (range, 35 to 136). Cumulative sum control chart shows 60-minute procedure was achieved at the 18th procedure. Procedure durations further reduced with consequent procedures with the last 3 being 45 minutes, thus demonstrating continued improvement with ongoing experience (nonlinear regression P<0.0001).

CONCLUSION

Endoscopists experienced in G-POEM are expected to achieve a reduction in procedure time over successive cases, with efficiency reached at 60.5 minutes and a learning rate of 18 cases with continuing improvement.

Per-oral Endoscopic Myotomy: State of the Art

For more than a decade, per-oral endoscopic myotomy (POEM) has been performed for the treatment of achalasia and other dysmotilities of the esophagus. POEM has become an accepted alternative to Heller myotomy, a salvation technique for patients not responding to Heller myotomy and the favorite intervention for diffuse esophageal spasm and jackhammer esophagus. POEM paved the way for endoscopic pyloromyotomy, Zenker's diverticulum myotomy, and submucosal tunneling with endoscopic resection. This review will cover the technique and the most current literature of this revolutionary third space technique.

Pilot prospective study on formal training in per-oral endoscopic myotomy (POEM) during advanced endoscopy fellowship

Background and study aims  Gastroenterology societies have recently proposed core curricula for training in per-oral endoscopic myotomy (POEM) based on expert opinion with limited data on its applicability for advanced endoscopy fellowship (AEF) trainees. We prospectively evaluated the feasibility of a structured POEM training curriculum during a dedicated AEF and the trainee's performance during independent practice. Methods  This was a single-center prospective study evaluating a trainee's performance of POEM using a structured assessment tool (POEMAT) to assess core cognitive and technical skills. The trainee's performance was then prospectively assessed during the first 12 months of independent practice. Results  The trainee, who had not prior background in submucosal endoscopy, first observed 22 POEM cases followed by 35 hands-on procedures during his advanced endoscopy fellowship. Based on the POEMAT, submucosal entry and mucosal incision closure were the most challenging technical aspects, while cognitive skills were uniformly attained early in training. Overall, the trainee was able to cross the threshold for competence in his POEMAT performance score in 15 of his last 18 cases (83.3 %). The trainee performed 16 POEMs (baseline mean Eckardt 7.2) in his first 12 months of independent practice. Mean procedural time was 79.8 minutes (interquartile range: 67-94 minutes minutes) with no adverse events. Clinical success (Eckardt score < 3) was achieved in 100 % of the cases at a median follow-up of 20 weeks. Conclusions  Results from this pilot study support the adoptability of the recently proposed core curricula for POEM training within the context of a dedicated AEF and provide a potential blueprint for future studies of performance in POEM among trainees.

Long-term Outcome of Per-oral Endoscopic Myotomy Performed in the Endoscopy Unit With Trainees

INTRODUCTION

Per-oral endoscopic myotomy (POEM) has been widely adopted for the treatment of achalasia as it provides a precise, tailored myotomy in a minimally invasive endoscopic procedure. Several short-term studies and a few long-term studies have confirmed that POEM is a safe and effective treatment for achalasia. However, the long-term outcome of POEM performed by trainees is unknown.

MATERIALS AND METHODS

We conducted a retrospective study of all patients who underwent POEM for achalasia at our tertiary care center during December 2012 and January 2019. All procedures performed with trainees were included. The primary outcome was the clinical response to POEM, defined as an Eckardt score of <3 after POEM. Trainees were trained in performing mucosotomy and submucosal dissection, creating a submucosal tunnel, identifying gastroesophageal junction, and performing myotomy and closure of mucosal incision in a step-by-step fashion. Trainees' performance was evaluated by the mentor based on several key points in each step.

RESULTS

A total of 153 consecutive patients with a median age of 57±18 years were analyzed in this study. Of the total patients, 69 (45%) were male. The median length of follow-up after POEM was 32 months (range: 7 to 77 mo). A clinically significant response to POEM was achieved in 95% of patients at year 1, 84% at year 2, 80% at year 3, 79% at year 4, 78% at year 5, and 78% at year 6 and above. All trainees obtained competence within 6 cases for each step and could perform the procedure alone after 20 supervised cases.

CONCLUSIONS

Overall, 78% of patients maintained positive clinical response at 6 years following POEM procedure. The recurrence rate of symptoms following POEM was 22% at a 6-year follow-up. This long-term outcome of POEM performed with trainees was comparable to those without trainees in other studies. To our knowledge, this is the longest follow-up and the largest number of patients after the POEM procedure performed with trainees.

The Learning Curve for Peroral Endoscopic Myotomy in Latin America: A Slide to the Right?

BACKGROUND/AIMS

Peroral endoscopic myotomy (POEM) has been increasingly used for achalasia in Latin America, where Chagas disease is prevalent, and this makes POEM more challenging. The aim of this study was to determine the learning curve for POEM in Latin America.

METHODS

Patients undergoing POEM in Latin America with a single operator were included from a prospective registry over 4 years. Non-linear regression and cumulative sum control chart (CUSUM) analyses were conducted for the learning curve.

RESULTS

A total of 125 patients were included (52% male; mean age, 59 years), of which 80 had type II achalasia (64%), and 38 had Chagas disease (30%). The average pre-procedure and post-procedure Eckardt scores were 6.79 and 1.87, respectively. Technical success was achieved in 93.5% of patients, and clinical success was achieved in 88.8%. Adverse events occurred in 27 patients (22%) and included bleeding (4 patients), pneumothorax (4 patients), mucosal perforation (13 patients), mediastinitis (2 patients), and leakage (4 patients).
The CUSUM chart showed a median procedure time of 97 min (range, 45-196 min), which was achieved at the 61st procedure. Procedure duration progressively decreased, with the last 10 procedures under 50 min approaching a plateau (p-value <0.01).

CONCLUSION

Mastering POEM in Latin America requires approximately 61 procedures for both POEM efficiency and to accomplish the procedure within 97 minutes.

Peroral endoscopic myotomy: techniques and outcomes

Achalasia is progressive neurodegenerative disorder of the esophagus, resulting in uncoordinated esophageal motility and failure of lower esophageal sphincter relaxation, leading to impaired swallowing. Surgical myotomy of the lower esophageal sphincter, either open or minimally invasive, has been a standard of care for the past several decades. Recently, new procedure-peroral endoscopic myotomy (POEM) has been introduced into clinical practice. This procedure accomplishes the same objective of controlled myotomy only via endoscopic approach. In the current chapter authors review the present state, clinical applications, outcomes and future directions of the POEM procedure.

Per-oral Endoscopic Myotomy and Other Applications of Third Space Endoscopy: Current Status and Future Perspectives

INTRODUCTION

The modification of NOTES (natural orifice transluminal endoscopic surgery) by mucosal safety flap has introduced us to the world of third space endoscopy (TSE). POEM (per-oral endoscopic myotomy) for achalasia cardia being its first vista, the realm expanded so that we can now remove en bloc a subepithelial/intramural tumor by POET (per-oral endoscopic tumor resection), perform G-POEM (gastric per-oral endoscopic myotomy) for refractory gastroparesis, restore esophageal continuity in complete obstruction by performing POETRE (per-oral endoscopic tunneling for the restoration of the esophagus), divide the septum in Zenker diverticulum completely with negligible risk of perforation by Z-POEM (Zenker per-oral endoscopic myotomy) and relieve constipation in Hirschsprung disease by PREM (per-rectal endoscopic myotomy). However, the real potential of TSE became evident with the introduction of POEM with fundoplication. TSE has opened the gates of the peritoneal cavity. Improved expertise and equipment will make the role of endoscopist complimentary to the surgeon with the dawn of a new field in therapeutic endoscopy.

AREAS COVERED

This review intends to comprehensively discuss the various aspects of POEM for achalasia studied so far followed by a brief discussion about other applications of TSE and the future perspectives in this exciting field.

Optimization of insufflation and pressure control in third-space endoscopy

BACKGROUND

Third-space endoscopy requires a delicate and accurate insufflation technique to secure the endoscopic visualization and maintain the working space. However, optimal third-space insufflation parameters have yet to be determined. The aim of this study was to assess: (1) the diversity of endoluminal third-space pressure by manual insufflation, and (2) the performance of the insufflation settings for third-space endoscopy.

METHODS

A submucosal tunnel was created in the upper posterior wall of the porcine stomach. Using two-channel esophagogastroduodenoscopy, one channel was used for insufflation and the other was used for pressure measurement. Experiment 1 Endoluminal submucosal tunnel pressure was measured in a 10-cm submucosal tunnel of a single porcine. Six board-certified endoscopists in turn maintained what they considered sufficient exposure under manual insufflation. Experiment 2 Endoluminal submucosal tunnel pressure and number of insufflations were measured using the pressure-regulated insufflation device; the differences in the submucosal tunnel length (long: 10-cm, short: 4-cm) and the insufflation route diameter (large: 3.8-mm, small: 2.2-mm) were compared.

RESULTS

Experiment 1 The endoluminal submucosal tunnel pressure profiles during third-space endoscopy varied between endoscopists. Experiment 2 Longer submucosal tunnels and larger insufflation route diameters lead to stable endoluminal submucosal tunnel pressure. The gap with the preset pressure of the insufflator and endoluminal pressure narrowed, and the required number of insufflations decreased with longer tunnel length and larger route diameter.

CONCLUSIONS

The pressure dynamics in third-space endoscopy differed among endoscopists. Longer submucosal tunnels and larger insufflation route diameters lead to stable endoluminal submucosal tunnel pressure.

Per-oral endoscopic myotomy (POEM) training and skills evaluation tool: a pilot study

Background and study aims  Hands-on training for per-oral endoscopic myotomy (POEM) in the United States is limited and without a structured curriculum or assessment tool. Training to competency in POEM is critical and POEM trainees must acquire multiple cognitive and technical skills to achieve proficiency. The aim of this study was to develop a POEM training and skills evaluation tool. Patients and methods  The training protocol included initial explant porcine models followed by live human cases, proctored by a single endoscopist experienced in POEM who prospectively graded trainees for each step ("skill") of the procedure on a 5-point scale. Procedural skills were divided into cognitive and technical skills. Acceptable passing level was considered a score ≥ 4 for each skill. Results  Three trainees completed a total of 18 cases (8 cases on animal explant models and 10 human cases). Overall, cognitive skills were acquired early in training with scores of ≥ 4 achieved by ≤ 3 cases. Technical skills required more cases and direction with scores ≥ 4 in technical skills achieved by three porcine and eight human cases. Entry of the endoscope into the submucosal space and submucosal tunneling were the most challenging steps followed by myotomy. Conclusion  This pilot study introduces a POEM training and skills evaluation tool for training to competency. Submucosal entry, tunneling, and myotomy were the most challenging to learn while cognitive skills were learned early in training. Evaluation of more trainees at multiple sites will be necessary to further validate the utility of this tool.

The status of training in new technologies in advanced endoscopy: from defining competence to credentialing and privileging

The landscape of advanced endoscopy continues to evolve as new technologies and techniques become available. Although postgraduate advanced endoscopy fellowships have traditionally centered on ERCP and diagnostic EUS, the breadth of training has increased over the years in response to the ever-growing demand for therapeutic endoscopy. The increasing diversity and complexity of emerging endoscopic techniques accompanied by the shift in focus toward competency-based medical education requires innovative changes to the curriculum that will ensure adequate training yet without compromising best patient practices. The purpose of this review is to highlight the expansive array of advanced endoscopic procedures and the challenges of both defining and measuring competence during training. All authors are interventional endoscopists at their respective institutions performing these complex procedures, as well as training fellows in these techniques. We share our perspectives based on our experience navigating through these issues at our institutions and discuss strategies to standardize training and how to potentially incorporate these measures in the process of credentialing and privileging in endoscopy.

Objectively Confirmed Gastroesophageal Reflux Disease Following Per Oral Endoscopic Myotomy Higher in Obese Patients (BMI>30)

INTRODUCTION

Per oral endoscopic myotomy (POEM) is a promising minimally invasive therapy in the treatment of achalasia and other esophageal motility disorders. A concern surrounding POEM is the development of gastroesophageal reflux disease (GERD) postoperatively. This study was designed to report outcomes and identify risk factors for the development of postoperative GERD.

METHODS

Patients who underwent POEM between January 1, 2015 and December 12, 2019 were prospectively followed in an Institutional Review Board approved database. All patients were invited for a full comprehensive workup 6 months post-POEM including symptom scores, pH testing, manometry and esophagogastroduodenoscopy. In a retrospective review of this database, those who developed postoperative GERD were compared with those who did not.

RESULTS

There were 82 patients that met study criteria (median age 59). Indications for POEM include 35 type I achalasia, 16 type II achalasia, 21 type III achalasia and other spastic esophageal motility disorders, and 10 esophagogastric junction outflow obstruction. Mean Eckardt scores post-POEM were 2.67 compared with 6.79 pre-POEM (P<0.05). Mean integrated relaxation pressure improvement decreased from 27 to 13.1 (P<0.05). The presence of postoperative GERD was defined as an abnormal DeMeester score (>14.7) with pH testing off-medications or the presence of Grade C/D esophagitis on endoscopy. Thirty-five percent (29/82) of patients developed postoperative GERD following POEM. Negative predictive factors for the development of postoperative GERD include myotomy length and normal body mass index (BMI). Obesity (BMI>30) was a positive predictive risk factor in the development of GERD (P=0.029).

CONCLUSIONS

POEM provides symptomatic relief and reduced Eckardt scores in patient with achalasia and other esophageal motility disorders. Patients who undergo POEM are at risk for developing gastroesophageal reflux disease especially in obese patients.

POEM for Esophageal Achalasia

Over the past decade, per-oral endoscopic myotomy has been shown to be a durable minimally invasive approach to the treatment of esophageal achalasia. Patients with suspected achalasia should undergo upper endoscopy, timed barium esophagram, and high-resolution manometry to confirm the diagnosis. The procedure includes several key steps including mucosotomy, submucosal tunneling, selective myotomy of the circular muscle layer, and mucosotomy closure. Specialized endoscopic dissection tools are used during the procedure to access the submucosal space. Common procedural challenges include minor bleeding and capnoperitoneum.

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.

Updated Systematic Review of Achalasia, with a Focus on POEM Therapy

AIM

To systematically review clinical presentation, diagnosis, and therapy of achalasia, focusing on recent developments in high-resolution esophageal manometry (HREM) for diagnosis and peroral endoscopic myotomy (POEM) for therapy.

METHODS

Systematic review of achalasia using computerized literature search via PubMed and Ovid of articles published since 2005 with keywords ("achalasia") AND ("high resolution" or "HREM" or "peroral endoscopic myotomy" or "POEM"). Two authors independently performed literature searches and incorporated articles into this review by consensus according to prospectively determined criteria.

RESULTS

Achalasia is an uncommon esophageal motility disorder, usually manifested by dysphagia to solids and liquids, and sometimes manifested by chest pain, regurgitation, and weight loss. Symptoms often suggest more common disorders, such as gastroesophageal reflux disease (GERD), thus often delaying diagnosis. Achalasia is a predominantly idiopathic chronic disease. Diagnosis is typically suggested by barium swallow showing esophageal dilation; absent distal esophageal peristalsis; smoothly tapered narrowing ("bird's beak") at esophagogastric junction; and delayed passage of contrast into stomach. Diagnostic findings at high-resolution esophageal manometry (HREM) include: distal esophageal aperistalsis and integrated relaxation pressure (trough LES pressure during 4 s) > 15 mmHg. Achalasia is classified by HREM into: type 1 classic; type 2 compartmentalized high pressure in esophageal body, and type 3 spastic. This classification impacts therapeutic decisions. Esophagogastroduodenoscopy is required before therapy to assess esophagus and esophagogastric junction and to exclude distal esophageal malignancy. POEM is a revolutionizing achalasia therapy. POEM creates a myotomy via interventional endoscopy. Numerous studies demonstrate that POEM produces comparable, if not superior, results compared to standard laparoscopic Heller myotomy (LHM), as determined by LES pressure, dysphagia frequency, Eckardt score, hospital length of stay, therapy durability, and incidence of GERD. Other therapies, including botulinum toxin injection and pneumatic dilation, have moderately less efficacy and much less durability than POEM.

CONCLUSION

This comprehensive review suggests that POEM is equivalent or perhaps superior to LHM for achalasia in terms of cost efficiency, hospital length of stay, and relief of dysphagia, with comparable side effects. The data are, however, not conclusive due to sparse long-term follow-up and lack of randomized comparative clinical trials. POEM therapy is currently limited by a shortage of trained endoscopists.

Difficult peroral endoscopic myotomy: definition and management strategies

Introduction: Peroral endoscopic myotomy (POEM) has been established as an alternative endoscopic method for the treatment of achalasia, and several studies have confirmed its relatively long-term efficacy. Although most of the POEM procedures can be smoothly completed, technical difficulties do arise during the treatment of some patients, which may lead to prolonged procedure duration, increased procedure-related complications, or even aborted POEM.Area covered: In the present review, we provide a comprehensive review of difficult POEM, focusing on its definition, risk factors, and intraoperative management strategies. The present review is expected to provide tips for not so experienced operators who perform POEM.Expert commentary: Submucosal fibrosis and sigmoid-type esophagus are associated with difficult POEM. Sometimes, the following may also be associated with difficult POEM: previous endoscopic or surgical treatments, spastic esophageal disorders (type III achalasia, distal esophageal spasm, and hypercontractile esophagus), achalasia with diverticulum or situs inversus. For operators who begin to perform POEM, I suggest an exclusion of patients with severe submucosal fibrosis or sigmoid-type esophagus, and begin to perform POEM for these patients when they have completed at least 50 cases of 'easy POEM' and the proposed management strategies may be helpful.

Clinical practice guidelines for peroral endoscopic myotomy

Peroral endoscopic myotomy (POEM) is a novel clinical technique developed in Japan used to treat esophageal achalasia and esophageal motility disorders. This technique has been rapidly accepted and widely disseminated throughout our clinical practice because of its low invasiveness, technical novelty, and high efficacy. Since the advent of POEM, there have been no clinical guidelines that clearly indicated its standard of care, and these guidelines have been anticipated both nationally and internationally by clinicians who engage in POEM practice. In 2017, to meet these needs, the Japan Gastroenterological Endoscopy Society (JGES) launched the guideline committee for POEM. Based on the guideline development process proposed by the Medical Information Network Distribution Service (MINDS), the guideline committee initially created research questions on POEM and conducted a systematic review and meta-analysis on each topic. The clinical research extracted from databases for these clinical questions and the systematic review mainly comprised a few retrospective studies with a small number of participants and short trial periods; hence, the strength of the evidence and recommendations derived from these results was low. Throughout this process, the guideline committee met thrice: once on May 13, 2017, and again on September 17, 2017, to formulate the draft. A consensus meeting was then held on January 14, 2018, in Tokyo to establish the guideline statements and finalize the recommendations using the modified Delphi method. This manuscript presents clinical guidelines regarding current standards of practice and recommendations in terms of the nine chief topics in POEM.

Comprehensive Evaluation of the Learning Curve for Peroral Endoscopic Myotomy

BACKGROUND & AIMS

Peroral endoscopic myotomy (POEM) is a minimally invasive endoscopic surgical procedure that is effective in treatment for spastic esophageal motility disorders. However, little is known about the learning curve for endoscopists. We aimed to evaluate the effects of various factors on the POEM learning curve.

METHODS

We performed a retrospective study of 1346 patients who underwent POEM for achalasia at Shanghai Zhongshan Hospital in China from August 2010 through July 2015. We used risk-adjusted cumulative sum and moving average methods to evaluate outcomes. The primary outcome was a composite of technical failure and adverse events. Secondary outcomes included procedure time and the composite outcome of technical failure, adverse events, and clinical failure of the first 192 cases performed by only the original, training surgeon.

RESULTS

The primary composite outcome occurred in 54 (4%) of the 1346 patients: 10 technical failures and 44 adverse events. This composite outcome was independently associated with the case number (P = .010), full-thickness myotomy (P = .002), and procedure time (P = .001). After we adjusted for these risk factors, cumulative sum analysis showed that the primary composite outcome decreased gradually after 100 cases. The procedure time was high during the first few cases and decreased after endoscopists performed 70 cases. The secondary composite outcome of technical failure, adverse events, and clinical failure for the 192 cases performed by only the original surgeon gradually decreased after 90-100 cases.

CONCLUSIONS

In a retrospective analysis of POEM procedures, we found that 100 cases were required to decrease the risk of technical failure, adverse events, and clinical failure (the learning curve). Seventy cases can be considered the threshold for decreasing procedure time.

The 2018 ISDE achalasia guidelines

Achalasia is a relatively rare primary motor esophageal disorder, characterized by absence of relaxations of the lower esophageal sphincter and of peristalsis along the esophageal body. As a result, patients typically present with dysphagia, regurgitation and occasionally chest pain, pulmonary complication and malnutrition. New diagnostic methodologies and therapeutic techniques have been recently added to the armamentarium for treating achalasia. With the aim to offer clinicians and patients an up-to-date framework for making informed decisions on the management of this disease, the International Society for Diseases of the Esophagus Guidelines proposed and endorsed the Esophageal Achalasia Guidelines (I-GOAL). The guidelines were prepared according the Appraisal of Guidelines for Research and Evaluation (AGREE-REX) tool, accredited for guideline production by NICE UK. A systematic literature search was performed and the quality of evidence and the strength of recommendations were graded according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE). Given the relative rarity of this disease and the paucity of high-level evidence in the literature, this process was integrated with a three-step process of anonymous voting on each statement (DELPHI). Only statements with an approval rate >80% were accepted in the guidelines. Fifty-one experts from 11 countries and 3 representatives from patient support associations participated to the preparations of the guidelines. These guidelines deal specifically with the following achalasia issues: Diagnostic workup, Definition of the disease, Severity of presentation, Medical treatment, Botulinum Toxin injection, Pneumatic dilatation, POEM, Other endoscopic treatments, Laparoscopic myotomy, Definition of recurrence, Follow up and risk of cancer, Management of end stage achalasia, Treatment options for failure, Achalasia in children, Achalasia secondary to Chagas' disease.

Treatment of Idiopathic Achalasia with Per-Oral Esophageal Myotomy

Achalasia is a rare esophageal motility disorder that necessitates the disruption of the lower esophageal sphincter. Patients with achalasia should be evaluated in a systematic, multidisciplinary fashion. Workup should include upper endoscopy, esophagography, and high-resolution manometry. The gold standard for surgical treatment is laparoscopic Heller myotomy with partial fundoplication. Per-oral esophageal myotomy is a novel endoscopic technique that has gained considerable traction over the past decade. The procedure includes the creation of a submucosal tunnel and a selective circular myotomy of the lower esophageal sphincter. Common intra-operative hazards include bleeding within the submucosal tunnel and capnoperitoneum. Significant complications are rare. Patients experience excellent dysphagia relief that is on par with laparoscopic Heller myotomy at moderate-term follow up. Post-operative gastroesophageal reflux disease occurs in greater than one-third of patients, and the vast majority of cases are readily controlled with an anti-secretory medication. Although data is sparse, there is a growing body of literature that supports the long-term durability of per-oral esophageal myotomy.

Muscle layer thickness affects the peroral endoscopic myotomy procedure complexity

Esophageal motility disorders can cause severe dysphagia, regurgitation, and/or noncardiac chest pain due to a lack of coordinated esophageal motility function. However, the clinical significance of esophageal muscle layer thickness remains unclear. The aims of this study are to elucidate the clinical significance of esophageal muscle layer thickness in patients with esophageal motility disorders who undergo peroral endoscopic myotomy (POEM), and to identify predictors of a longer POEM procedure time. Seventy-four consecutive patients with esophageal motility disorders who underwent POEM procedures at Kobe University Hospital from April 2015 to December 2016 were prospectively recruited into this study. First, we investigated the associations between the thickness of the esophageal muscular layer and clinical parameters. There were no significant differences, except in the POEM procedure time, between the patients with esophageal muscle layer thickness values of ≥1.5 mm (group A) and <1.5 mm (group B). However, the relative frequency of a longer POEM procedure time (≥78 min) was significantly higher in group A than in group B (66.7% vs. 19.5, P < 0.0001). Next, independent clinical factors that were related to longer POEM procedures were investigated. Multivariate logistic regression analysis with stepwise selection demonstrated that a thick esophageal muscle layer and the length of myotomy were an independent predictor of a longer POEM procedure (odds ratio: 13.9 and 12.0, respectively). Our results indicate that preoperative endoscopic ultrasonography evaluations can help to predict the technical complexity of POEM procedures.

Per oral endoscopic myotomy: early experience and safety of a multispecialty approach

BACKGROUND

Per oral endoscopic myotomy (POEM) has gained increasing popularity for treating achalasia. A multidisciplinary approach may allow safe and early adoption of POEM into clinical practice.

MATERIALS AND METHODS

We performed a retrospective review of our initial POEM cases. All procedures were performed by a team of interventional gastroenterologist and thoracic surgeon. We analyzed demographics, comorbidities, achalasia subtypes, length of hospital stay, duration of surgery, morbidity, mortality, length of myotomy, preoperative and postoperative Eckardt scores.

RESULTS

Thirty-one consecutive patients underwent POEM during the 24-month period from January 2014 to December 2015. Eighteen patients (58%) had prior non-operative interventions. Average duration of follow-up was 9.6 months. Seventeen patients (66.8%) had follow-up of 12 months and longer. Average preoperative Eckardt score was 6.3 (3-10), median 6. Average postoperative Eckardt score was 1.4 (0-8), median 1, in 1 month and an average 2.2, median 1, in 1 year. Patients with type III achalasia were most refractory to treatment, while patients with type II had the best results. Average LOS was 1.3 days (1-5), median 1 day. Average DOS was 106 min (60-148), median 106. Average LOM was 13 cm (10-15), with median of 13 cm. We had one 30-day mortality secondary to coronary artery disease. Four patients had prior Heller myotomies and underwent a posterior myotomy during POEM, with outcomes similar to patients with no prior myotomy.

CONCLUSIONS

We demonstrated safety and efficiency of a multispecialty approach for achalasia with POEM with a low rate of complications.

Submucosal surgery: novel interventions in the third space

Traditional surgeries involve accessing body cavities, such as the abdomen and thorax, via incisions that divide skin and muscle. These operations result in postoperative pain and convalescence, and a risk of complications such as wound infection and hernia. The development of flexible endoscopy allowed diseases as varied as gastrointestinal bleeding and colon adenomas to be treated without incisions, but this technique is restricted by its endoluminal nature. A novel category of surgical endoscopic procedures has recently been developed that uses flexible endoscopic techniques to enter and access the submucosa of the gastrointestinal tract. Through this approach, the advantages of incisionless endoscopy can be applied to areas of the body that previously could only be reached with surgery. This Review introduces this new class of interventions by describing two examples of such submucosal surgeries for the treatment of benign gastrointestinal disease: per-oral endoscopic myotomy and per-oral pyloromyotomy. The approach to pre-procedure patient evaluation, operative technique, and the published outcomes are discussed, as well as potential future applications of similar techniques and procedures in this so-called third space.

Adverse events during and after per-oral endoscopic myotomy: prevention, diagnosis, and management

Per-oral endoscopic myotomy (POEM) has surfaced as an effective endoscopic treatment modality for achalasia cardia (AC). Promising results in short- and mid-term follow-up studies have increased the use of POEM for the management of AC. POEM can be safely performed in an endoscopy suit, and major adverse events (AEs) are uncommon. AEs encountered during POEM or during the perioperative period principally include insufflation-related AEs, mucosal injuries, bleeding, pain, and aspiration pneumonia. Most insufflation-related AEs do not require an active intervention and therefore should not be considered as AEs in the true sense. When management of AEs is required, most intraoperative AEs can be managed at the same time without untoward consequences. Occurrences of AEs lessen after completion of the learning curve. However, experience alone does not ensure "zero" incidence of AEs, and early recognition remains essential. Postoperative AEs, like leaks, delayed bleeding, and delayed mucosal perforations, may pose special challenges for diagnosis and management. There is no standardized classification system for grading the severity of AEs associated with POEM, resulting in wide variation in their reported occurrences. Uniform reporting of AEs is not only crucial to comprehensively analyze the safety of POEM but also for comparison with other established treatment modalities like Heller's myotomy. GERD is an important long-term AE after POEM. Unlike the perioperative AEs, little is known regarding the intraoperative or patient-related factors that influence the occurrence of post-POEM GERD. Large prospective studies with long-term follow-up are required to determine the procedural factors associated with GERD after POEM.

Management of recurrent symptoms after per-oral endoscopic myotomy in achalasia

BACKGROUND AND AIMS

Per-oral endoscopic myotomy (POEM) has been rapidly gaining ground as a treatment for achalasia. Although POEM is a safe and effective treatment, a subset of patients has persistent or recurrent symptoms after POEM. This study aimed to examine the efficacy of different retreatments after failed POEM.

METHODS

POEM was performed on 441 patients with achalasia at 3 tertiary-care hospitals between 2010 and 2015. A review of prospectively collected data was conducted. All patients with achalasia with significant persistent or recurrent symptoms within 3 years after POEM, defined as an Eckardt symptom score >3, were included.

RESULTS

Forty-three of 441 patients (9.8%) had persistent or recurrent symptoms after POEM, of which 34 (8%) received 1 or more retreatments. Retreatment with laparoscopic Heller myotomy and retreatment with POEM showed a modest efficacy of 45% and 63%, respectively, whereas pneumatic dilatation showed a poor efficacy of only 0% to 20%, depending on the size of the balloon. Male patients were more likely to have retreatment failure than female patients (P = .038).

CONCLUSIONS

In patients with achalasia with persistent or recurrent symptoms after failed POEM, retreatment with laparoscopic Heller myotomy or retreatment with POEM has a higher efficacy than retreatment with pneumatic dilatations. Failure of retreatment occurred more often in male patients.

Per-oral endoscopic myotomy (POEM): mid-term efficacy and safety

BACKGROUND AND AIMS

Per-oral endoscopic myotomy (POEM) is becoming a standard treatment for achalasia. Long-term efficacy and the rate of post-POEM reflux should be further investigated. The main aim of this study was to analyze safety and mid-term (12 and 24 months) clinical outcomes of POEM.

METHODS

Data on single tertiary center procedures were collected prospectively. The primary outcome was treatment success defined as an Eckardt score < 3 at 12 and 24 months. A total of 155 consecutive patients with achalasia underwent POEM; 133 patients were included into the analysis (22 patients will be analyzed separately as part of a multicenter randomized clinical trial).

RESULTS

POEM was successfully completed in 132 (99.2%) patients, and the mean length of the procedure was 69.8 min (range 31-136). One patient underwent a drainage for pleural effusion; no other serious adverse events occurred. Treatment success at 3, 12, and 24 months was observed in 95.5% (CI 89.6-98.1), 93.4% (86.5-96.8), and 84.0% (71.4-91.4) of patients, respectively. A total of 11 patients (8.3%) reported initial treatment failure (n = 5) or later recurrence (n = 6). The majority of relapses occurred in patients with achalasia type I (16.7 vs. 1.1% achalasia type II vs. 0% achalasia type III; p<0.05). At 12 months, post-POEM reflux symptoms were present in 29.7% of patients. At 3 months, mild reflux esophagitis was diagnosed in 37.6% of patients, and pathological gastroesophageal reflux was detected in 41.5% of patients. A total of 37.8% of patients had been treated with a proton pump inhibitor.

CONCLUSION

POEM resulted in greater than 90% treatment success at 12 months which tends to decrease to 84% after 2 years. More than one-third of the patients had mild reflux symptoms and/or mild esophagitis.

Learning curve for laparoscopic Heller myotomy and Dor fundoplication for achalasia

Purpose

Although laparoscopic Heller myotomy and Dor fundoplication (LHD) is widely performed to address achalasia, little is known about the learning curve for this technique. We assessed the learning curve for performing LHD.

Methods

Of the 514 cases with LHD performed between August 1994 and March 2016, the surgical outcomes of 463 cases were evaluated after excluding 50 cases with reduced port surgery and one case with the simultaneous performance of laparoscopic distal partial gastrectomy. A receiver operating characteristic (ROC) curve analysis was used to identify the cut-off value for the number of surgical experiences necessary to become proficient with LHD, which was defined as the completion of the learning curve.

Results

We defined the completion of the learning curve when the following 3 conditions were satisfied. 1) The operation time was less than 165 minutes. 2) There was no blood loss. 3) There was no intraoperative complication. In order to establish the appropriate number of surgical experiences required to complete the learning curve, the cut-off value was evaluated by using a ROC curve (AUC 0.717, p < 0.001). Finally, we identified the cut-off value as 16 surgical cases (sensitivity 0.706, specificity 0.646).

Conclusion

Learning curve seems to complete after performing 16 cases.

Peroral endoscopic myotomy using FlushKnife BT: a single-center series

BACKGROUND AND STUDY AIMS

Peroral endoscopic myotomy (POEM) is an evolving new treatment strategy for achalasia. Although several kinds of electrosurgical knives have been used in performing POEM, the best device has yet to be determined. The FlushKnife BT is a waterjet-emitting short needle-knife with a small ball tip (BT) that offers the potential to perform all aspects of POEM with a single device. In this study, we evaluated the safety and efficiency of the FlushKnife BT for POEM.

PATIENTS AND METHODS

 A total of 54 consecutive patients with achalasia and other spastic esophageal motility disorders, such as jackhammer esophagus or distal esophageal spasm, who underwent POEM between January 2016 and August 2016, were included in this retrospective study.

RESULTS

 The median operation time was 73.0 minutes (range 39 - 184 minutes). All procedures were completed using only the FlushKnife BT without changing to any other electrosurgical instrument. The median number of additional submucosal injections with an injection needle was 0 (range 0 - 1). Endoscopic vessel sealing was performed a mean of 3 times (range 0 - 7). The median number of bleeding episodes requiring treatment with hemostatic forceps was 0 (range 0 - 5). There were no significant adverse events. Seven of 52 patients (13.5 %) reported symptoms of gastroesophageal reflux disease such as heartburn or acid reflux at 3 month follow-up.

CONCLUSIONS

 The FlushKnife BT enabled POEM to be performed with very few device exchanges, either for re-injection or to control intraoperative bleeding. In this uncontrolled case series, the ability of the FlushKnife BT to perform nearly all aspects of the POEM procedure seems to make it particularly well suited to this procedure.