Successful Peroral Endoscopic Myotomy Research Articles

Successful Design and Implementation of a POEM Program for Achalasia in an Integrated Healthcare System.

Per Oral Endoscopic Myotomy (POEM) is a minimally invasive treatment for achalasia with results comparable to laparoscopic Heller myotomy (LHM). Studies have described the development of proficiency for endoscopists learning to perform POEM, and societies have defined educational and technical objectives for advanced endoscopy fellows in training. However, there is limited guidance on the organizational strategy and educational plan necessary to develop an achalasia service with POEM expertise. We aim to outline the steps for design and implementation of a successful POEM program. We reported our experience developing a multi-disciplinary clinical program for POEM and the steps taken to achieve procedural proficiency. We also reported our technical success (successful tunneling into the gastric cardia and myotomy of LES muscle fibers) and clinical success (post-procedure Eckardt score ≤ 3) at 3-6months and 12months post-procedure. Adverse events were classified per the ASGE lexicon for endoscopic adverse events. After creating a multi-disciplinary clinical program for achalasia and completing procedural proficiency for POEM, our technical success rate was 100% and clinical success rate 90% for the first 41 patients. One adverse event (2.4%) occurred, moderate in severity per the American Society of Gastrointestinal Endoscopy (ASGE) lexicon for adverse endoscopic events. In this study, we outlined the steps involved to establish a POEM service in a large integrated healthcare system. Prior competency in interventional endoscopy, procedural training models, POEM observation and education, proctorship, and interdisciplinary patient care are recommended.

Diagnosis of congenital esophageal stenosis in adults and treatment with peroral endoscopic myotomy.

BackgroundCongenital esophageal stenosis (CES) in adults is a rare disorder that can present as achalasia, particularly in the distal esophagus. We describe the salient features of CES in adults and identify the feasibility and short-term outcomes of peroral endoscopic myotomy (POEM) for CES.MethodsIn this retrospective, single-center case series, we included 6 patients with a “misdiagnosis” of achalasia established elsewhere, ultimately diagnosed with CES and referred to our institution for POEM. Symptom improvement (clinical success rate), defined as an Eckardt Symptom Score (ESS) of <3 at 2-month follow up was assessed.ResultsSix patients (median age: 40 [range: 18-58] years; 4 males) were included. A long-standing history of dysphagia, ring-shaped stenosis on endoscopic examination, “lopsided hourglass” sign on barium esophagogram, and high-resolution manometry findings indicated by a compartmentalized intrabolus pressure pattern with distinction between the stenotic area and the lower esophageal sphincter were the salient features identified. POEM could not be completed in the first 2 cases due to technical challenges. All subsequent 4 patients who underwent successful POEM, exhibited improved ESS of ≤3 (clinical success rate 100%) at 2 months post-POEM.ConclusionsAlong with identification of salient features on several diagnostic modalities, a differential diagnosis of CES in adults must be considered in patients presenting with long-standing history of dysphagia arising from childhood and persisting into adulthood. Although favorable short-term outcomes of POEM were achieved, further evaluation is still warranted, and an inexperienced operator should not attempt POEM on CES patients due to its technical difficulties.

Same-day discharge is safe and feasible following POEM surgery for esophageal motility disorders.

Per-oral endoscopic myotomy (POEM) is an effective treatment for achalasia and other esophageal dysmotility disorders. Current practices surrounding post-operative care involve admission and routine esophagogram prior to discharge. This study aims to establish the safety and feasibility of same-day discharge following POEM. Retrospective analysis of prospectively collected data for patients who underwent POEM between November 2013 and June 2019 at a single institution in Ontario, Canada. Patients were discharged home on the same day with controlled pain, when tolerating clear fluids. Patients were admitted if clinically indicated. Esophagography was initially a systematic practice prior to discharge, but later only performed when clinically indicated. Emergency department visits and hospital admissions within 90days were assessed. In total, 90 patients underwent a successful POEM procedure. A total of 72 patients (79.1%) were discharged on the same day, 14 patients (15.4%) were discharged home the following day, and 5 patients (5.5%) experienced longer admissions to hospital. One POEM was unsuccessful. 22 (24.2%) patients had adverse events, leading to 8 (8.8%) unplanned admissions, with one patient requiring prolonged admission for esophageal leak, identified clinically. Fifty-three patients underwent routine esophagography while part of our protocol, with no identified leak, which prompted our change in practice to only perform esophagography when clinically indicated. In the 90-day post-procedure, ten patients visited the emergency department, of which seven were re-admitted, five for POEM-related issues. Our mean Eckhardt score at 2weeks was 2.1 from 7.2 preoperatively. This study establishes that same-day discharge is both safe and feasible following POEM and suggests that esophagography should be performed only when clinically indicated. This represents a shift from the routine practice of admission and imaging for patients undergoing POEM, encouraging the transition to outpatient POEM procedures.

Sa1251 PREDICTOR OF CLINICAL FAILURE OF PER-ORAL ENDOSCOPIC MYOTOMY: A LARGE SINGLE-CENTER EXPERIENCE

Per-oral endoscopic myotomy (POEM) is considered as an effective and safe minimally invasive endoscopic treatment for esophageal achalasia and achalasia related motility disorders, and more than 2000 cases have been performed at our institution. Although POEM is a highly efficacious treatment, there have been reports of clinical failure and the cause of these failure is unknown. This study aimed to identify the predictor of clinical failure of POEM. We conducted a retrospective analysis of a prospectively maintained database comprised of consecutive patients who underwent POEM for esophageal achalasia or achalasia related motility disorders at a tertiary-referral center between 2008 and 2019. Clinical failure of POEM was defined as primary failure with Eckardt score not decreasing to 3 or under during one-year follow-up. Patients were divided into two groups according to whether they had clinically successful POEM or failed POEM. Baseline characteristics (Age, sex, BMI, duration of symptoms, esophageal diameter, manometric diagnosis), anti-thrombotic agents, prior treatments, myotomy orientation, myotomy length were retrieved. Univariate and multivariate logistic regression analyses were performed to assess the predictive factors of clinical failure (Table 1, 2). A total of 2091 POEM were performed, 1770 of whom had available 3-12 months follow-up data. Of those, 75 cases (4.2%) were considered failed POEM in short term follow-up. Multivariate analysis revealed that younger age (odd ratio [OR] 0.98, 95% confidence interval [95% CI] 0.97-0.99, P=0.009) , prior Heller myotomy ([OR] 4.13, [95%CI] 1.88-9.09, P<0.001), prior endoscopic balloon dilatation ([OR] 1.90, [95%CI] 1.15-3.15, P=0.012) were independent factors associated with clinical failure of POEM. Younger age, prior Heller myotomy, and prior endoscopic balloon dilatation were identified as the independent predictors of clinical failure of POEM in this single center large cohort study.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Epiphrenic diverticula: An added source of complexity in achalasia management

Epiphrenic (pulsion) esophageal diverticula can occur in the setting of underlying esophageal motility disorders such as achalasia and present a unique management challenge to the gastroenterologist. Asymptomatic diverticula do not require treatment, but symptomatic diverticula require therapy targeted to the underlying esophageal motility disorder, or else the diverticula will recur. Generally, laparoscopic or combined laparoscopic/thoracoscopic myotomy, diverticulectomy, and anterior fundoplication are required. However, therapeutic options for epiphrenic diverticula are evolving as peroral endoscopic myotomy (POEM) becomes more commonplace. We review two cases of achalasia complicated by epiphrenic diverticula at our institution. In the first case, type II achalasia was identified and the patient underwent laparoscopic myotomy. In the second case, type III achalasia was present and the patient underwent successful POEM. We discuss the presentation, pathophysiology, and management of epiphrenic diverticula as well as the expanding role for POEM in diverticula.

424 POEM Training and Skills Evaluation Tool: A Pilot Study

INTRODUCTION: Hands-on training for Per-Oral Endoscopic Myotomy (POEM) in the United States is limited and without a structured curriculum and assessment tool. Training to competency in POEM is critical and POEM trainees must acquire multiple cognitive and technical skills to achieve proficiency. METHODS/METHODS AND AIM: The aim of this study was to develop a POEM training and skills evaluation tool. This pilot study was performed at a tertiary academic medical center in the US from 5/2018 – 11/2018. The training protocol included initial swine explant models followed by live human cases, proctored by a single endoscopist experienced in POEM who graded trainees for each task on a 5-point scale (1 = trainer had to take over, 2 = trainer provided technical assistance, 3 =trainer provided substantial verbal guidance, 4 =trainer provided minimal verbal guidance, and 5 =trainee performed completely independently). Three trainees were prospectively graded on specific cognitive (identification of GE junction, incision site selection, identification of esophageal wall layers, recognition of planes during tunneling, identifying structures at GEJ and cardia in the tunnel, and identification of circular and longitudinal muscles) and technical skills (entry into the submucosal space, submucosal tunneling, myotomy and hemostasis) essential for successful POEM completion. Competency was considered at skill level ≥ 4 for each skill. RESULTS: Three trainees (interventional endoscopy fellows) completed a total of 18 cases (8 cases on animal explant models and 10 human cases) and were evaluated by one expert supervisor. Cognitive skills were acquired early in training with trainee scores of ≥ 4 by the 3rd swine explant case and 3rd human case. Technical skills required more cases and direction. Level ≥ 4 in technical skills was achieved by the 8th human case. Entry of the endoscope into the submucosal space was the most difficult step. No adverse events occurred in the human cases. 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. The main limitations of this study include single site study with small number of trainees and procedures, and a single instructor. Evaluation of POEM procedures performed by more trainees at multiple sites will be necessary to further validate the utility of this tool.

Successful PerOral Endoscopic Myotomy (POEM) After Three Failed Heller in a 62-Years-Female with Sigmoid Type II Achalasia and Mega-esophagus

Successful PerOral Endoscopic Myotomy (POEM) After Three Failed Heller in a 62-Years-Female with Sigmoid Type II Achalasia and Mega-esophagus

Electrical Stimulation of the Lower Esophageal Sphincter to Treat Gastroesophageal Reflux After POEM

As per-oral endoscopic myotomy (POEM) is not followed by any anti-reflux procedure, a common concern is the risk of postoperative gastro-esophageal reflux disease (GERD). Electrical stimulation of the lower esophageal sphincter (LES-EST) could be an option for post-POEM GERD. A 68-year old male obese patient underwent successful POEM but developed GERD not responsive to proton pump inhibitors. Consecutively, the patient had implanted an electrical LES stimulation device, consisting of bipolar LES-electrodes connected to a subcutaneous pulse generator. POEM reduced the Eckardt score (9 vs. 0), the LES resting pressure (52.0 vs. 16.4 mmHg), and the Integrated Relaxation Pressure (62.0 vs. 10.0 mmHg). LES-EST substantially reduced post-POEM GERD symptoms. GERD-HRQL scores indicated the elimination of heartburn (26 vs. 7) and regurgitation (24 vs. 3) at three months. A reduced total number refluxes (82 vs. 14) was observed. The %-time of pH below 4 was only slightly reduced (8.6% to 6.2%).LES-EST appears to be a feasible option to symptomatically treat post-POEM GERD for patients not ideal for conventional anti-reflux surgery.

Peroral endoscopic myotomy: a literature review and the first UK case series

Peroral endoscopic myotomy (POEM) is an established treatment for primary achalasia. It has gained endorsement from the American Society for Gastrointestinal Endoscopy with increasing clinical acceptance since the first procedure, performed in Japan in 2008. The first successful POEM in the UK was performed in November 2013 at King's College Hospital and this article presents the first UK case series. Prospective data were collected at 3and 12-24 months for consecutive patients undergoing POEM. Post-POEM gastro-oesophageal reflux health-related quality of life scale (GORD-HRQoL) score was recorded. Statistical comparisons were made using paired non-parametric testing. In an initial series of 33 consecutive prospectively followed patients (12 female; 49.5±13 years; median follow-up 9 (3-28) months; 58% having had previous intervention), a 91% success rate has been achieved at 3 months. To date, 16 patients have reached the 12-month time point, with 13 (81%) sustaining response. This case series compares well with international cohorts and demonstrates excellent long-term safety and favourable efficacy.

Successful peroral endoscopic myotomy performed in Endoscopy Department as a radical, long-term treatment for esophageal achalasia - the Greek experience.

IntroductionPeroral endoscopic myotomy (POEM) has been considered as a minimal-invasive, innovative technique for long-term treatment of all types of esophageal achalasia and other esophageal motility disorders.Patients and methodsWe report on 20 consecutive Greek patients with manometrically proved esophageal achalasia (14 patients with type I, 4 with type II, 2 with type III, and 4 with sigmoid esophagus), with an age range of 32–92 years, mean age 59 years, 12 males, successfully treated by POEM from 2013 to 2015. The Eckardt score was 7–12 (type III). Seventeen (85%) POEM procedures were performed in the Endoscopy Department, according to a previous study. During POEM, CO2 insufflation was mandatory, while the Triangle Tip knife was the only knife used in all procedures. Eckardt score, esophagogram and manometry before and after performing POEM were used for evaluation of our results. The follow-up period was 6 months to 3 years.ResultsSelective circular myotomy, 10–13 cm in length, was successfully completed in all patients without severe acute or late complications. Three patients (15%) showed moderate pneumomediastinum and pneumoperitoneum, which was successfully managed by abdominal needle drainage during the procedure. One patient showed mild pleural collection, and in one patient the clip–endoloop technique was used to successfully close the mucosal entry after the completion of POEM. The outcome was uneventful without any further clinical consequences. No other short- or long-term serious complications were reported. Patients were discharged after 1–3 days of hospitalization. Six months to 3 years after the POEM procedure, all patients were alive; the majority (90%) had complete clinical improvement, while two patients with sigmoid-type achalasia showed moderate-to-significant clinical improvement. Erosive esophagitis was reported in 15%.ConclusionOur results are in accordance with international data, and proved the safety and efficacy of the POEM technique for radical long-term treatment of all types of achalasia, including end-stage sigmoid-type achalasia, in the Endoscopy Department. However, long-term follow-up is necessary and awaited.

Ling classification describes endoscopic progressive process of achalasia and successful peroral endoscopy myotomy prevents endoscopic progression of achalasia.

AIMTo verify the hypothesis that the Ling classification describes the endoscopic progressive process of achalasia and determine the ability of successful peroral endoscopic myotomy (POEM) to prevent endoscopic progression of achalasia.METHODSWe retrospectively reviewed the endoscopic findings, symptom duration, and manometric data in patients with achalasia. A total of 359 patients (197 women, 162 men) with a mean age of 42.1 years (range, 12-75 years) were evaluated. Symptom duration ranged from 2 to 360 mo, with a median of 36 mo. Patients were classified with Ling type I (n = 119), IIa (n = 106), IIb (n = 60), IIc (n = 60), or III (n = 14), according to the Ling classification. Of the 359 patients, 349 underwent POEM, among whom 21 had an endoscopic follow-up for more than 2 years. Pre-treatment and post-treatment Ling classifications of these 21 patients were compared.RESULTSSymptom duration increased significantly with increasing Ling classification (from I to III) (P < 0.05), whereas lower esophageal sphincter pressure decreased with increasing Ling type (from I to III) (P < 0.05). There was no difference in sex ratio or onset age among the Ling types, although the age at time of diagnosis was higher in Ling types IIc and III than in Ling types I, IIa, and IIb. Of the 21 patients, 19 underwent high-resolution manometry both before and after treatment. The mean preoperative and postoperative lower esophageal sphincter pressure were 34.6 mmHg (range, 15.3-59.4 mmHg) and 15.0 mmHg (range, 2.1-21.6 mmHg), respectively, indicating a statistically significant decrease after POEM. All of the 21 patients were treated successfully by POEM (postoperative Eckardt score ≤ 3) and still had the same Ling type during a mean follow-up period of 37.8 mo (range, 24-51 mo).CONCLUSIONThe Ling classification represents the endoscopic progressive process of achalasia and may be able to serve as an endoscopic assessment criterion for achalasia. Successful POEM (Eckardt score ≤ 3) seems to have the ability to prevent endoscopic evolvement of achalasia. However, studies with larger populations are warranted to confirm our findings.

Long-term outcome of peroral endoscopic myotomy for esophageal achalasia in patients with previous Heller myotomy.

Peroral endoscopic myotomy (POEM) is an emerging procedure in the treatment of esophageal achalasia, a primary motility disorder. However, the long-term outcome of POEM in patients, who have previously undergone a Heller myotomy, is unknown. Using a local database, we identified patients with esophageal achalasia, who underwent POEM. We compared patients with a previous Heller myotomy to those, who had received none or only non-surgical therapy prior to the POEM procedure. We conducted follow-up examinations at 3, 12, and 24months following the procedure. We included 66 consecutive patients undergoing POEM for achalasia, of which 14 (21.2%) had undergone a prior Heller myotomy. In both groups, the preoperative Eckardt score was 7. Postoperatively, the non-Heller group experienced a more pronounced symptom relief at both 3-, 12-, and 24-month follow-up compared with the Heller group, and there was a tendency for the effect of POEM to reduce over time. We suggest that there isa correlation between preoperative measurements of gastroesophageal sphincterpressures and the chance of a successful POEM. POEM has a place in the treatment of esophageal achalasia in patients with a prior Heller myotomy and persistent symptoms as it is a safe procedure with acceptable long-term results.

Tu1514 The Nuts and Bolts of Starting a Successful Per-Oral Endoscopic Myotomy (POEM) Program: a Practical Approach

Tu1514 The Nuts and Bolts of Starting a Successful Per-Oral Endoscopic Myotomy (POEM) Program: a Practical Approach

Tu1507 Creation of a Second Sub-Mucosal Tunnel Enabled Successful Per-Oral Endoscopic Myotomy (POEM) in a Patient With Previous Thoracocotomy and Heller's Myotomy

Per-Oral Endoscopic Myotomy (POEM) is an evolving treatment modality for Achalasia. Standard steps of POEM include a 2 cm mucosotomy in mid esophagus, creation of submucosal tunnel extending 2-4 cm onto gastric side, then dividing the inner circular muscle in distal 5-6 cm of esophagus and extending 2-4 cm on gastric side, and closure of mucosotomy with endoscopic clips. Prior treatments such as Botox injections, Pneumatic dilation or Heller's myotomy pose a technical challenge due to submucosal fibrosis adding complexity.

Long-term outcomes of peroral endoscopic myotomy for achalasia in pediatric patients: a prospective, single-center study

Peroral endoscopic myotomy (POEM) has been developed to provide a less-invasive myotomy for achalasia in adults but seldom has been used in pediatric patients. To evaluate the feasibility, safety, and efficacy of POEM for pediatric patients with achalasia. Single-center, prospective study. Academic medical center. A total of 27 pediatric patients (mean age 13.8 years, range 6-17 years) with achalasia. The primary outcome was symptom relief during follow-up, defined as an Eckardt score of≤3. Secondary outcomes were procedure-related adverse events, clinical reflux adverse events, and lower esophageal sphincter (LES) pressure on manometry before and after POEM. A total of 26 cases (96.3%) underwent successful POEM. A submucosal tunnelling attempt failed in 1 case because of serious inflammation and adhesion. No serious adverse events related to POEM were encountered. During a mean follow-up period of 24.6 months (range 15-38 months), treatment success was achieved in all patients (mean score before vs after treatment 8.3 vs 0.7; P< .001). Mean LES pressure also decreased from a mean of 31.6mm Hg to 12.9mm Hg after POEM (P< .001). Five patients developed clinical reflux adverse events (19.2%). Single center and lack of some objective evaluations. This relatively long-term follow-up study adds to the evidence that POEM seems to be a promising new treatment for pediatric patients with achalasia, resulting in long-term symptom relief in all cases and without serious adverse events.

Successful peroral endoscopic myotomy with use of a single instrument multipurpose knife

Successful peroral endoscopic myotomy with use of a single instrument multipurpose knife

Peroral endoscopic remyotomy for failed Heller myotomy: a prospective single-center study

Recurrence/persistence of symptoms occurs in approximately 20 % of patients after Heller myotomy for achalasia. Controversy exists regarding the therapy for patients in whom Heller myotomy has failed. The aim of the current study was to evaluate the efficacy and feasibility of peroral endoscopic myotomy (POEM), a new endoscopic myotomy technique, for patients with failed Heller myotomy. A total of 12 patients with recurrence/persistence of symptoms after Heller myotomy, as diagnosed by established methods and an Eckardt score of ≥ 4, were prospectively included. The primary outcome was symptom relief during follow-up, defined as an Eckardt score of ≤ 3. Secondary outcomes were procedure-related adverse events, lower esophageal sphincter (LES) pressure on manometry, reflux symptoms, and medication use before and after POEM. All 12 patients underwent successful POEM after a mean of 11.9 years (range 2 - 38 years) from the time of the primary Heller myotomy. No serious complications related to POEM were encountered. During a mean follow-up period of 10.4 months (range 5 - 14 months), treatment success was achieved in 11/12 patients (91.7 %; mean score pre- vs. post-treatment 9.2 vs. 1.3; P < 0.001). Mean LES pressure was 29.4 mmHg pre-treatment and 13.5 mmHg post-treatment (P < 0.001). One patient developed mild reflux symptoms and required intermittent medication with proton pump inhibitors. POEM seems to be a promising new treatment for failed Heller myotomy resulting in short-term symptom relief in > 90 % of cases. Previous Heller myotomy may make subsequent endoscopic remyotomy more challenging, but does not prevent successful POEM.

Peroral Endoscopic Myotomy in a Porcine Model: A Step to Achalasia Patients

See Peroral Endoscopic Myotomy for Treating Achalasia in an Animal Model: A Feasibility Study by Byoung Wook Bang, Young Chul Choi, Hyung Gil Kim, et al., on page 54-58 Achalasia is an idiopathic motility disorder that results from degeneration of the myenteric plexus in the wall of the esophagus and the lower esophageal sphincter (LES).1 In esophageal manometry, achalasia is characterized by impaired relaxation of LES and loss of peristalsis in the body of the esophagus. Achalasia results in severe dysphagia for solids and liquids. Additional symptoms can also develop such as chest pain, regurgitation, aspiration, weight loss, and irreversible dilatation of the esophageal body. The therapy for achalasia focuses on the forced relaxation of the LES by endoscopic method or surgery. The treatment modalities using endoscopy or surgery have mainly included endoscopic pneumatic dilation and laparoscopic Heller myotomy (LHM). Recently, peroral endoscopic myotomy (POEM) has been introduced as a novel endoscopic procedure for the treatment of achalasia. A submucosal esophageal myotomy was first described in a porcine model by Pasricha et al.,2 and POEM was first performed to achalasia patients by Inoue et al.3 Since 2010, several small-sized case series for POEM have shown safety and excellent short-term outcomes.4-6 The advantages of POEM are theoretically based on those of endoscopic operation such as no skin incisions, decreased pain, and less blood loss. Furthermore, POEM incorporates the advantage of LHM consisted of durable surgical myotomy and single procedure. A recent porcine study showed that the preservation of longitudinal muscle layer does not compromise the effectiveness of the myotomy.7 In a paper published in Clinical Endoscopy, Bang et al.8 reported a study that evaluated the feasibility of POEM in a porcine model. The authors showed successful POEM procedure and no definite perioperative complications in two mini pigs. After 2 weeks from POEM procedure, the histopathologic evaluation of the necropsy specimens revealed complete loss of the inner circular muscle and replaced fibrosis at the myotomy site. The authors concluded that POEM is a technically feasible treatment in the animal model. This study has several limitations. First, the authors used only two pigs in the study. Second, the observation period was short for follow-up after the procedure. Third, the authors did not perform esophageal manometry to analyze the difference of LES pressure before and after the procedure. However, this study seems to be a step for transition of the treatment method for achalasia in the near future. In addition, this study was the first animal study of POEM in Korea. The porcine model is the most useful animal model for training in POEM because of its anatomy being similar to that of humans, although the normal porcine esophagus is thinner than the human achalasia-affected esophagus. And the porcine esophageal submucosal space is softer and more easily dissected than in humans. However, ex vivo porcine explants are a useful model for training of POEM as well as in vivo training.9 Several clinical data for POEM in human have been recently published. They suggest that POEM may soon replace traditional esophageal myotomy as the surgical treatment of choice for achalasia. A major advantage of POEM is the ability to control myotomy length. In POEM, myotomy is usually performed more than 10 cm and may be as long as 25 cm in previous case series.10 In contrast, surgical myotomy can be performed only a maximum of 8 cm in the length. POEM also permits any myotomy length required and in any direction, without injury to surrounding structures. Therefore, POEM can be considered for surgically failed cases or previous POEM failure cases. These are very important and major advantages of POEM. In study of Bang et al.,8 the authors did not detect any evidences of complications in necropsy. However, previous human studies reported postoperative subcutaneous emphysema and pneumomediastinum on clinical grounds or computed tomography scan.9 Mild forms of pneumomediastinum or subcutaneous emphysema had no clinical consequences such as pneumomediastinum during thoracoscopic surgery. Other complications such as peritonitis, penumoperitoneum, and mucosal damage at the esophagogastric junction have been noted, too. However, most complications were ameliorated by conservative and medical treatment. Further long-term studies with a large number of patients from different centers are awaited. In Korea, few centers have performed POEM for achalasia patients since November 2011. The first Korean study of POEM in human will be published soon. However, further studies with a greater number of animals are still needed to evaluate other issues such as repeated sessions of myotomy, multiple myotomy at different sites, or training system using ex vivo or in vivo animal model.