This retrospective study aimed to compare treatment outcomes and postoperative courses, including the incidence of esophageal cancer (EC), according to disease types, in 450 achalasia patients who underwent peroral endoscopic myotomy (POEM).

Data from consecutive POEM procedures performed from September 2011 to January 2023 at a single institution were reviewed. Achalasia was classified into straight (St), sigmoid (S1), and advanced sigmoid (S2) types using esophagography findings. Regarding efficacy, POEM was considered successful if the Eckardt score was ≤3. A statistical examination of the incidence and trend of EC occurrence across the disease type of achalasia was conducted using propensity score matching.

Of the 450 patients, 349 were diagnosed with St, 80 with S1, and 21 with S2. POEM efficacy was 97.9% at 1 year and 94.2% at 2 years postprocedure, with no statistical difference between disease types. Using propensity score matching, the incidence of EC in each disease type was as follows: St, 1% (1/98); S1, 2.5% (2/77); S2, 10% (2/18). While no statistical significance was observed between St (1.0%: 1/98) and all sigmoid types (4.0%, 4/95; P = 0.3686). However, a trend test revealed a tendency for EC to occur more frequently in the order of S2, S1, and St type with a statistically significant difference (P = 0.0413).

Outcomes of POEM are favorable for all disease types. After POEM, it is important not only to monitor the improvement of achalasia symptoms but also to pay attention to the occurrence of EC, especially in patients with sigmoid-type achalasia.

Patients with sigmoid-type achalasia can be challenging to treat with peroral endoscopic myotomy (POEM). A short myotomy improves technical success; however, outcomes have not previously been evaluated.

This was a multicenter, international, retrospective study of patients who underwent POEM with short (≤4 cm) or standard esophageal myotomy. Outcomes included clinical and technical success, procedural adverse events, and reflux rates.

A total of 109 patients with sigmoid achalasia (sigmoid, n = 74; advanced sigmoid, n = 35) underwent POEM across 13 centers (short myotomy, n = 59; standard, n = 50). Technical success was 100% across both groups. Patients who underwent short myotomy had a significantly shorter mean procedure time (57.7 ± 27.8 vs 83.1 ± 44.7 minutes, P = .0005). A total of 6 adverse events were recorded in 6 patients (5.5%; 4 mild, 2 moderate); the adverse event rate was not significantly different between short and standard groups. Ninety-eight patients had follow-up data (median, 3.6 months; interquartile range, 1-14 months). Clinical success was 94% (short, 93%; standard, 95%; P = .70) and did not differ based on achalasia subtype or sigmoid achalasia severity. Twenty-one (22%) patients reported post-POEM reflux and 44% (16 of 36) had objective evidence of pathologic reflux. Rates of pathologic reflux were significantly increased in the standard versus short group (odds ratio, 18.0; 95% confidence interval, 2.0-159.0; P = .009).

POEM with short myotomy is effective and safe for the short-term treatment of sigmoid and advanced sigmoid achalasia. Short myotomy may lead to less reflux than standard myotomy.

To investigate the safety and short-term effectiveness of laparoscopic-assisted cardiectomy with side-overlap esophagogastric reconstruction for the treatment of terminal or end-stage achalasia, patients with end-stage achalasia treated with laparoscopic-assisted cardiectomy with side-overlap esophagogastric reconstruction were retrospectively enrolled. The clinical data, surgical data and follow-up were analyzed. Among twenty-five patients enrolled, the achalasia type St was present in 12 (48%) patients, type Sg in 9 (36%), and type aSg in 4 (16%). The surgical time ranged 60-180 min (median 100 min) with an intraoperative blood loss 20-200 ml (median 50 ml). Five (20%) patients experienced complications within a week after surgery, with fever (> 38.5 ℃) in two (40%) patients within 3 days after surgery, abdominal incision infection in one (20%), and anastomotic leak in two (40%). The postoperative hospitalization time ranged 8-44 (median 10) days. Follow-up was conducted 6-38 months (median 16) after surgery. Compared with the preoperative Eckardt score (7.64 ± 1.32), the Eckardt score was significantly (P < 0.01) decreased at one month (0.52 ± 0.87), 6 (0.84 ± 1.11) and 12 (1.23 ± 1.23) months after surgery in all patients. The Eckardt score in type St was significantly (P < 0.05) smaller than in type Sg or aSg at 6 and 12 months after surgery. Seven patients maintained an Eckardt score 0 with complete relief of their symptoms. The effective rate was 100% for type St, 88.8% for type Sg, and 75% for type aSg. The effective rates at 1 month, 6 and 12 months after surgery were 100% (95% CI: 100% -100%), 96% (95% CI: 87.7 -100%), and 92% (95% CI: 80.6 -100%). Two patients were diagnosed with gastroesophageal reflux disease (GERD) at the end of the follow-up. The cumulative incidence of GERD at 1 month, 6 and 12 months after surgery was 0, 4% (95% confidence interval or CI: 0-12.3%), and 8% (95% CI: 0-19.4%). In conclusion, the laparoscopic-assisted cardiectomy with side-overlap esophagogastric reconstruction is safe and effective for the treatment of end-stage achalasia, and the effect is significantly better for achalasia type St than for types Sg and aSg.

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

Peroral endoscopic myotomy (POEM) is an established treatment for achalasia, yet there is still a lack of technical standardization. No clear definition of 'long', 'standard', or 'short' POEM exists to date. We conducted a systematic review with meta-analysis to analyze current POEM length standards. We included studies reporting technical details of POEM, in which no definite or comparative myotomy length was intentionally adopted (standard myotomy). The primary outcome was the pooled mean total myotomy length. Sub-group analyses were performed to explore heterogeneity across studies. From the initial 7172 records, 31 studies with 3023 patients were included. Pooled mean of total myotomy length was 10.39 cm (95% CI 10.06-10.71; I2 99.3%). Pooled mean of esophageal and gastric myotomy length, provided by 17 studies, was 7.11 cm (95% CI 6.51-7.71; I2 99.8%) and 2.81 cm (95% CI 2.41-3-22; I2 99.8%), respectively. On subgroup analysis for achalasia subtypes, pooled mean length in non-spastic achalasia (type I and II) was 10.17 cm (95% CI 9.91-10.43; I2 94.2%), while in type III it was 14.02 cm (95% CI 10.59-17.44; I2 98.9%). Pooled mean myotomy length for studies conducted between 2014-2020 was 10.53 cm (95% CI, 10.22-10.84; I2 99.1%) and 9.74 cm (95% CI, 7.95-11.54; I2 99.7%) in 2021-2022. Myotomy length during a 'standard' POEM is 10.4 cm, remaining over 10 cm in non-spastic achalasia. The high heterogeneity across studies confirms that the POEM technique needs further standardization. We found no significant time trend towards adopting short POEM, despite recent evidence supporting its use.

Per oral endoscopic myotomy (POEM) has emerged as a preferred approach for the treatment of idiopathic achalasia and various esophageal motility disorders, offering a minimally invasive alternative to traditional laparoscopic Heller's myotomy. Over the past decade, POEM has solidified its status as the primary therapeutic choice in these conditions through constant improvements. Its evolution has been marked by continuous progress, driven by the integration of innovative technologies and sophisticated techniques. Notable advancements in the techniques include the advent of shorter myotomies and sling fiber-preserving gastric myotomies. The introduction of novel image-enhanced endoscopic techniques, such as red dichromatic imaging and much safer bipolar devices, promises to enhance safety and reduce the technical demands of the POEM procedure. Furthermore, significant strides have been made in understanding gastroesophageal reflux (GERD) following POEM, enabling the differentiation of "true reflux" from acidification resulting from fermentation through manual pH tracing assessment. This distinction aids in identifying cases necessitating treatment with proton pump inhibitors. Other treatment strategies of post-POEM GERD have expanded to the incorporation of NOTES fundoplication and device-assisted fundoplication if the necessity arises. This comprehensive review delves into recent developments in POEM, encompassing technical variations, the assessment and management of post-POEM reflux, outcomes in special populations, and future prospects. By exploring these facets, we aim to provide a comprehensive overview of the current state of POEM, shedding light on its evolution and the promising directions it is poised to take in the field of third-space endoscopy.

Per oral endoscopic myotomy (POEM) is a safe therapy for the treatment of achalasia. Long-term effects of untreated achalasia include worsening dysmotility and disruptions in esophageal anatomy, i.e., tortuosity and dilation. We hypothesize that long-standing achalasia prior to intervention will have worse outcomes following POEM than in patients with symptoms for shorter duration.

We retrospectively analyzed achalasia patients who underwent POEM at our institution from 2011 to 2023, categorizing them into symptom duration cohorts (< 1 year, 1-3 years, 4-10 years, > 10 years). Inclusion criteria comprised patients with documented achalasia diagnosis who received POEM treatment at our facility. Exclusion criteria encompassed individuals lacking data pertaining to achalasia diagnosis, the time frame before intervention, or those missing pre and postoperative Eckardt scores. POEM failure was defined as symptom recurrence, necessity for repeat intervention, or high postoperative Eckardt score. We compared demographic, preoperative, and postoperative outcomes across these cohorts, and employed multivariable logistic regression to explore the link between symptom duration and POEM response.

During the study period, in our increased cohort 234 patients met inclusion criteria. 75 patients had symptoms for < 1 year, 78 patients had symptoms from 1 to 3 years, 47 patients had symptoms from 4 to 10 years, and 34 patients had symptoms > 10 years. Patient demographics such as age, sex, BMI, Charleson-Deyo-Comorbidity-Index, and diabetes did not differ amongst cohorts. High-resolution manometry data, including achalasia type, Median IRP, LES residual pressure, and Basal LES pressure did not differ between groups. Preoperative Eckardt scores ranged from 4 to 5 across groups (p 0.24). Patients endorsed an average of three total preoperative symptoms across groups (p 0.13). Patients with symptoms greater than 4 years had significantly more endoscopic interventions prior to POEM (37% vs, 68% p .001). There was no significant difference in post-procedure mean Eckardt scores between cohorts. All cohorts experienced the same number of post-POEM symptoms. Post-POEM manometric measurements remained consistent across cohorts. Similarly, there were no significant differences in terms of symptom recurrence, requirement for repeat interventions, or repeat POEM among the cohorts. Multivariable logistic regression analysis determined achalasia symptoms greater than a decade did not result in increased odds of having a higher postoperative Eckardt score, worse dysphagia, regurgitation, or weight loss.

In this increased cohort, this data once again suggests that longer symptom duration is not associated with increased rates of POEM failure.

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.

Symptom scales for achalasia after per-oral endoscopic myotomy (POEM) are lacking. This study aimed to propose a new scale based on the conventional Eckardt score (c-ES) and evaluate persistent symptoms that impair patients' quality of life (QOL) post-POEM.

Dysphagia, regurgitation, and chest pain frequencies were assessed using a 6-point scale modified-ES (m-ES) after POEM, with "occasional" symptoms on the c-ES further subdivided into three-period categories on m-ES. Symptom severity was further evaluated using a 5-point scale ranging from 1 to 5 points, with a score ≥ 3 points defined as persistent symptoms impairing QOL. We analyzed the correlation between the m-ES and severity score, diagnostic performance of the m-ES for persistent symptoms, and overlaps between each residual symptom.

Overall, 536 patients (median follow-up period, 2.9 years) post-POEM were included in this multicenter study. Significant correlations were observed between the m-ES and severity scores for dysphagia (r = 0.67, p < 0.01), regurgitation (r = 0.73, p < 0.01), and chest pain (r = 0.85, p < 0.01). Twenty-six patients (4.9%) had persistent symptoms post-POEM, and 23 of them had m-ES-specific symptom frequency ≥ once a month, which was determined as the optimal frequency threshold for screening persistent symptoms. The total m-ES predicted persistent symptoms more accurately than the total c-ES (area under the curve: 0.95 vs. 0.79, p < 0.01). Furthermore, dysphagia and chest pain were the major residual symptoms post-POEM covering 91.4% of regurgitation.

The new post-POEM scale successfully evaluated the QOL-based patient symptom severities. Our study implied the possibility of a simpler scale using residual dysphagia and chest pain.

To explore the feasibility of peroral endoscopic myotomy (POEM) in patients with achalasia and hiatal hernia.

We performed a retrospective review of 2136 patients with achalasia between January 2016 and December 2022. Patients with achalasia and hiatal hernia were assigned into study group, and matched patients with achalasia but no hiatal hernia were assigned into control group. The preoperative baseline information, procedure-related adverse events (AEs) and follow-up data were compared between the two groups.

Hiatal hernia was identified in 56/1564 (3.6%) patients with achalasia. All of these patients underwent POEM with success. The preoperative baseline characteristics were similar between the study and control group. The study group presented with a similar rate of mucosal injury (12.5% vs 16.1, P = 0.589), pneumothorax (3.6% vs 1.8%, P = 1.000), pleural effusion (8.9% vs 12.5%, P = 0.541) and major AEs (1.8% vs 1.8%, P = 1.000) compared with the control group. As for the follow-up data, no significant differences were observed in clinical success (96.4% vs 92.9%, P = 0.679; 93.6% vs 94.0%, P = 1.000; 86.5% vs 91.4%, P = 0.711) clinical reflux (25.0% vs 19.6%, P = 0.496; 31.9% vs 26.0%, P = 0.521; 35.1% vs 31.4%, P = 0.739) and proton pump inhibitor usage (17.9% vs 16.1%, P = 0.801; 29.8% vs 24.0%, P = 0.520; 32.4% vs 25.7%, P = 0.531) between the study group and control group at 1-year, 2-year and 3-year follow-ups.

POEM is a safe and effective treatment for achalasia combined with hiatal hernia.

The concept of third space endoscopy first described in 2007, was adapted and performed in humans in 2010 by Inoue et al. in a group of patients with esophageal achalasia (EA). Since then, esophageal endoscopic myotomy (E-POEM), has been performed in more than 10,000 patients worldwide up to now. Safety and efficacy have been confirmed at early, mid and long-term evaluations, in different gastrointestinal diseases including achalasia, refractory gastroparesis, and other esophageal motility disorders (EMD). Nowadays, this treatment has shown to be not only an excellent option, but also with its excellent outcomes, the first option in certain clinical scenarios such as type III achalasia. Thus, the minimal invasive nature of POEM gives us multiple advantages compared with the classical treatments that includes pneumatic dilation (PD) and laparoscopic Heller myotomy (LHM), including not only clinical aspects but also economical. High resolution manometry (HRM) has substantially redefined the actual approach of esophageal motility disorders with the major changes in instrumental use, diagnostic algorithms, and therapeutics. The previous Chicago's classification V 3.0 clearly improved our knowledge about pathophysiology of spastic esophageal motor disorders, however, with its recent update (Chicago V 4.0), multiple changes in diagnosis and treatment are expected. In the present article, we aimed to review and analyze the most important aspects about the results of E-POEM in the management of EMD according to the view of the new Chicago's classification V 4.0.

Peroral endoscopic myotomy (POEM) achieves a satisfactory short-term clinical response in patients with achalasia. However, data on mid- and long-term clinical outcomes are limited. We aimed to assess the mid- and long-term efficacy and safety of POEM in achalasia patients.

Using the pre-designed search strategy, we identified relevant studies that evaluated the efficacy and safety of POEM with a minimum of 2-year follow-up in the Embase, Cochrane, and PubMed databases from inception to January 2021. Primary outcome was pooled mid- and long-term clinical success rate based on the Eckardt score. Secondary outcome was pooled long-term reflux-related adverse events.

A total of 21 studies involving 2,698 patients were included. Overall, the pooled clinical success rates with 2-, 3-, 4-, and 5-year follow-ups were 91.3% (95% confidence interval [CI] 88.4-93.6%), 90.4% (95% CI 88.1-92.2%), 89.8% (95% CI 83.6-93.9%), and 82.2% (95% CI 76.6-86.7%), respectively. Besides, the pooled long-term clinical success rates for type I, II, and III achalasia were 86.1% (95% CI 80.9-90.1%; I2 = 0%), 87.9% (95% CI 84.2-90.8%; I2 = 48.354%), and 83.9% (95% CI 72.5-91.2%; I2 = 0%), respectively. Moreover, the pooled incidence of symptomatic reflux and reflux esophagitis was 23.9% (95% CI 18.7-29.9%) and 16.7% (95% CI 11.9-23.1%), respectively.

POEM is associated with a long-term clinical success of 82.2% after 5 years of follow-up. Randomized control trials comparing POEM with laparoscopic Heller myotomy or pneumatic dilation with longer follow-up periods are needed to further demonstrate the long-term safety and efficacy of POEM.

Advanced achalasia cardia (AC) represents the end stage in the natural history of AC. Role of per oral endoscopic myotomy (POEM) in this technically difficult subset is emerging.

Retrospective review of the patients who had undergone POEM for advanced AC with sigmoid esophagus. We assessed the technical success, clinical success and adverse event rate. Pre and post POEM Eckardt score (ES), integrated relaxation pressure-4sec (IRP-4), lower oesophageal sphincter pressure (LESP) and height and width of barium column at 5 minutes were noted.

Of the 85 patients who underwent POEM for AC, 10 patients had advanced AC with sigmoid esophagus of which eight were sigmoid and two were advanced sigmoid. The clinical and technical success was 100% with significant reduction of ES, IRP-4, LESP and height and width of barium column at 5 minutes. One patient had a minor adverse event in the form of mucosal injury that was closed with hemoclips. At a median follow up of 17 months there was no recurrence.

Our study demonstrates POEM to be a safe and effective modality of treatment in this technically difficult subset of AC with sigmoid morphology.

To date, the ideal endoscopic knife for peroral endoscopic myotomy (POEM) with good performance and cost-effectiveness is still under investigation. The present study was aimed to evaluate the efficacy, safety, and cost-effectiveness of snare-assisted POEM, compared with the conventional endoscopic knife approach.

From May 2017 to December 2018, patients with achalasia presenting for POEM without previous endoscopic or surgical therapy were prospectively recruited in this randomized controlled trial. Patients were randomly allocated to receive POEM using either the snare (snare group) or HookKnife (conventional group). The primary outcome was clinical success (Eckardt score ≤ 3) at 12-month follow-up, powered for noninferiority with a margin of -15%. The secondary outcomes included adverse events (AEs), procedure-related parameters, clinical outcomes, and cost-effectiveness.

A total of 75 patients with similar baseline characteristics between the snare (N = 37) and conventional (N = 38) groups were included. Clinical success at 12-month follow-up was achieved in 94.6% of patients in the snare group and 92.1% of patients in the conventional group (difference, 2.5% [95% CI, -8.7% to 13.7%]; P < 0.001 for noninferiority). No severe AEs occurred in both groups. The use of snare is associated with comparable procedure time (40.6 minutes vs. 42.5 minutes, P = 0.337), a lower frequency of hemostatic forceps use (27.0% vs. 68.4%, P < 0.001), and lower hospital costs ($4271.1 vs. $5327.3, P < 0.001). The cost-effectiveness plane revealed that 96.9% of snare-assisted POEM procedures offered more cost-savings and health utility benefits.

The snare-assisted POEM was noninferior to the conventional endoscopic knife approach in terms of clinical efficacy, with comparable safety outcomes and cost-effective benefits.

Sigmoid esophagus and/or megaesophagus are considered as an advanced stage in the natural history of achalasia cardia. The role of peroral endoscopic myotomy (POEM) in these subset of patients is emerging. We performed a systematic review and metanalysis to study the efficacy of POEM in advanced achalasia cardia with sigmoid and megaesophagus.

A literature search in PubMed and Embase was done from inception till August 3, 2021 to look for studies reporting exclusively on the role of POEM in advanced achalasia cardia with sigmoid and/or megaesophagus. The random effect method with inverse variance approach was used for the computation of pooled prevalence. For 2 groups' analysis of continuous outcome standardized mean difference was used as the summary measure.

Eleven studies with 428 patients were included for analysis. The pooled technical and clinical success was 98.27% (95% CI, 96.19-99.22; I2 = 0%) and 89.38% (95% CI, 84.49-92.86; I2 = 26%) and on subgroup analysis into sigmoid and megaesophagus it was (98.06% [95% CI, 95.41-99.19; I2 = 0%], 98.47% [95% CI, 92.72-99.69; I2 = 0%] and 87.92% [95% CI, 80.68-92.70; I2 = 37%], 88.36% [95% CI, 62.62-97.17; I2 = 77%]) respectively. The clinical success at < 1 year and 1-3 year follow-up was 89.37% (95% CI, 82.82-93.61; I2 = 0%) and 88.66% (95% CI, 81.65-91.22; I2 = 46%) respectively. There was a significant reduction in the post-POEM scores with standardized mean difference for Eckardt score (4.81), for integrated relaxation pressure at 4 seconds (1.93), and for lower esophageal sphincter pressure (2.06).

POEM is an effective modality of treatment even in the subset of patients of advanced achalasia cardia with sigmoid and megaesophagus.

Achalasia, a rare primary esophageal motility disorder, is often misdiagnosed as refractory gastroesophageal reflux disease (GERD). This study is aimed to identify the clinical and histopathologic features that may help to differentiate these two entities. Patients with untreated achalasia and those with refractory reflux symptoms despite ≥8 weeks of proton-pump inhibitor treatment were enrolled prospectively. All patients underwent validated symptom questionnaires, esophagogastroduodenoscopy with biopsy, and high-resolution impedance manometry (HRIM). Histopathology of esophageal mucosa was compared based on four pre-determined histological criteria: basal cell hyperplasia or papillae elongation, eosinophilic infiltration, petechiae formation, and hypertrophy of the muscularis mucosae (MM). Compared with the GERD patients, patients with achalasia had similar reflux symptoms, but higher Eckardt scores, fewer erosive esophagitis and hiatal hernia, more esophageal food retention on endoscopy, and higher prevalence of hypertrophy of the MM and petechiae formation on histopathology. Multivariate logistic regression based on Eckardt score ≥4, normal esophagogastric junction morphology or esophageal food retention, and coexistence of petechiae formation and hypertrophy of the MM, established the best prediction model for achalasia. Therefore, combination of routinely accessible variables, including Eckardt score, endoscopic features, and histopathology obtained via esophageal mucosal biopsy, may provide an earlier identification of achalasia.

Peroral endoscopic myotomy (POEM) is an established therapy for achalasia, but outcome evaluation has often been limited to Eckardt score (ES). The present study was aimed to improve knowledge about outcome evaluation and predictive outcome factors by performing a comprehensive objective evaluation of achalasia patients treated by POEM.

This single centre prospective study reports outcome data 12 months after POEM in treatment-naive achalasia patients. A predefined follow-up protocol included ES, high resolution manometry, 24-h pH measurement, upper endoscopy and timed barium esophagogram (TBE). Univariate and multivariate regression analyses were performed to analyze association between post-POEM variables and identify predictive factors for objective outcome.

Fifty patients were included with a drop-out rate of <5%. ES, lower oesophageal sphincter pressures, TBE heights and maximal oesophageal diameter were all reduced after POEM (p < .001), and 28% (13/47) of the patients had a positive 24-h pH registration. An oesophageal diameter >3 cm after POEM was associated with treatment failure assessed by ES (p = .04) and TBE (p = .03). Advanced achalasia stage (p = .02) and long symptom duration (p = .04) were identified as independent predictive factors for poor outcome assessed by TBE.

The present study confirms that POEM is an efficient therapy for achalasia. The comprehensive objective evaluation after POEM demonstrates that long symptom duration and major changes in oesophageal anatomy at diagnosis imply poor treatment outcome, and a post-POEM dilated oesophagus is associated with treatment failure.Key messagesPeroral endoscopic myotomy (POEM) is established as a safe and effective therapy for achalasia.Timed barium esophagogram offers objective variables that are valuable in treatment response evaluation. Advanced achalasia stage and long symptom duration are predictive factors for poor objective treatment response after POEM.

The outcomes of peroral endoscopic myotomy for advanced achalasia are not well known. This study aimed to evaluate the outcomes of peroral endoscopic myotomy for achalasia with megaesophagus, which is one of the characteristics of advanced achalasia.

In total, 234 patients with achalasia who underwent peroral endoscopic myotomy in our hospital from April 2015 to March 2019 were included in this retrospective observational study. Megaesophagus was defined as a maximum esophageal diameter of 6 cm or more. Outcomes, including clinical success (Eckardt score ≤ 3 without retreatment) at the 1-year follow-up, technical success, and perioperative complications, were investigated and compared between patients with and without megaesophagus.

Eleven patients (4.7%) were diagnosed with megaesophagus. The clinical success rate achieved was 63.6% in patients with megaesophagus, with a significant decrease in the Eckardt score (6 vs. 2, p = 0.003) and integrated relaxation pressure (28 mmHg vs. 9 mmHg, p = 0.028). The technical success rate was 100%. However, patients with megaesophagus had a significantly lower clinical success rate than those without megaesophagus (63.6% vs. 96.0%, p = 0.002). Furthermore, patients with megaesophagus had significantly higher rates of major adverse events than those without megaesophagus (18.2% vs. 2.7%, p = 0.048).

Peroral endoscopic myotomy improved achalasia-related symptoms, and this was technically feasible in patients with megaesophagus. However, the clinical success rate was somewhat low, and the rate of major adverse events was high. Therefore, peroral endoscopic myotomy should be carefully performed for advanced achalasia with megaesophagus.

Although peroral endoscopic myotomy (POEM) is highly effective for the management of achalasia, clinical failures may occur. The optimal management of patients who fail POEM is not well known. This study aimed to compare the outcomes of different management strategies in patients who had failed POEM.

This was an international multicenter retrospective study at 16 tertiary centers between January 2012 and November 2019. All patients who underwent POEM and experienced persistent or recurrent symptoms (Eckardt score > 3) were included. The primary outcome was to compare the rates of clinical success (Eckardt score ≤ 3) between different management strategies. RESULTS : 99 patients (50 men [50.5 %]; mean age 51.4 [standard deviation (SD) 16.2]) experienced clinical failure during the study period, with a mean (SD) Eckardt score of 5.4 (0.3). A total of 29 patients (32.2 %) were managed conservatively and 70 (71 %) underwent retreatment (repeat POEM 33 [33 %], pneumatic dilation 30 [30 %], and laparoscopic Heller myotomy (LHM) 7 [7.1 %]). During a median follow-up of 10 (interquartile range 3 - 20) months, clinical success was highest in patients who underwent repeat POEM (25 /33 [76 %]; mean [SD] Eckardt score 2.1 [2.1]), followed by pneumatic dilation (18/30 [60 %]; Eckardt score 2.8 [2.3]), and LHM (2/7 [29 %]; Eckardt score 4 [1.8]; P = 0.12). A total of 11 patients in the conservative group (37.9 %; mean Eckardt score 4 [1.8]) achieved clinical success. CONCLUSION : This study comprehensively assessed an international cohort of patients who underwent management of failed POEM. Repeat POEM and pneumatic dilation achieved acceptable clinical success, with excellent safety profiles.

Background: The efficacy and safety of peroral endoscopic myotomy (POEM) in the treatment of sigmoid-type achalasia is unknown. This meta-analysis aims to explore the clinical outcomes of POEM for sigmoid-type achalasia. Method: We searched all relevant studies published up to September 2020 in PubMed, Embase, and Cochrane library databases. Meta-analyses for clinical success, Eckardt score, angle of esophageal tortuosity, diameter of esophagus, lower esophageal sphincter (LES) pressure, integrated relaxation pressure (IRP), adverse events, and gastroesophageal reflux diseases were performed based on random or fixed-effects models as needed. Results: We found a total of eight studies that provided data on 248 patients. Overall, the pooled clinical success was achieved in 211 sigmoid-type achalasia patients [90.4%; 95% confidence interval (CI), 85.5%-93.8%]. The pre- and post-POEM Eckardt scores, angle of esophageal tortuosity, diameter of esophageal, LES pressure, and IRP were significantly improved (All p < 0.05). The pooled adverse events rate was 13.0% (95% CI, 3.6%-37.4%). The pooled objective confirmation of reflux rate was 41.5% (95% CI, 26.5%-58.3%), and symptomatic reflux rate was 12.5% (95% CI, 8.3%-18.4%). Conclusions: Our current evidence indicated that POEM is an effective and safe therapeutic modality for the treatment of sigmoid-type achalasia.

Idiopathic achalasia is a primary motility disorder of the esophagus that results in dysphagia, weight loss, and impaired quality of life. Several treatment options are available to gastroenterologists, and insights on the long-term outcome of these modalities are discussed.

Peroral endoscopic myotomy (POEM) represents a novel endoscopic technique in the treatment of achalasia. Studies on long-term outcomes and comparison to other well-known treatment modalities such as laparoscopic Heller myotomy (LHM) and pneumodilation have recently been published. POEM and LHM both have excellent 2-year success rates for relieving achalasia symptoms, but reflux disease and erosive esophagitis are more prevalent following POEM.

Several treatment modalities with excellent long-term outcomes are available for the treatment of achalasia. The different options should be discussed with patients and treatments should be tailored to their individual needs.

In advanced achalasia patients with sigmoid esophagus, peroral endoscopic myotomy (POEM) might be technically challenging and its outcomes are not well known in western population. Hence, our study aims were to assess and compare the safety and efficacy of POEM in achalasia patients with and without sigmoid esophagus.

Medical records of achalasia patients who had POEM at our institution between April 2014 and December 2019 were reviewed. Patients who underwent work-up comprising timed barium esophagram (TBE) and high-resolution esophageal manometry (HREM) before POEM along with 2-month post-POEM esophageal pH study, TBE and HREM were included in the final analysis. Patients were categorized as either sigmoid or no sigmoid esophagus based on the morphology of esophagus on TBE as per Japan Esophageal Society guidelines. Treatment success was defined as reduction of post-POEM Eckardt score to ≤3.

A total of 168 patients (sigmoid esophagus=20; no sigmoid esophagus=148) were included. Esophageal width on TBE at 1 minute was significantly higher in sigmoid esophagus group compared with no sigmoid esophagus group (4.9 vs. 3.0 cm, P<0.001). Procedural outcomes and complications were similar in both groups. At 2-month follow-up, both groups had significant improvement in Eckardt scores, TBE, and HREM parameters. Treatment success was high and similar in both sigmoid and no sigmoid groups (94.4% vs. 93.2%, P=0.84). The rates of gastroesophageal reflux disease were also similar in both groups.

Our study findings suggest that POEM is safe and highly effective treatment for achalasia patients with sigmoid esophagus similar to those without sigmoid esophagus in western population. POEM should be considered as the treatment of choice in advanced achalasia with sigmoid esophagus.

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.

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.

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.

Peroral endoscopic myotomy (POEM) has been increasingly accepted as the first-line treatment of achalasia. However, laparoscopic Heller myotomy or esophagectomy still remains as the mainstay treatment for advanced achalasia featured with megaesophagus and/or sigmoid-shaped esophagus. Although the efficacy of POEM for advanced achalasia with sigmoid-shaped esophagus has been described, little is known about the role of POEM for patients with megaesophagus. The aim of our study is to evaluate the efficacy and safety of POEM for advanced achalasia with megaesophagus. Patients who received initial examinations and underwent POEM in our hospital from June 2013 to December 2018 were identified and data were retrospectively analyzed. The advanced achalasia was defined as megaesophagus with a diameter of ≥6 cm. The primary outcome was clinical success. The secondary outcomes were technical success and adverse events. A total of 112 patients (50 females, 44.6%) were included with a mean age of 44.8 years. The median symptom duration was 6.5 years (IQR:3.0-13.0 years). Modified POEM techniques were used in 27.7% (31/112) of patients. Technical success rate was 99.1% (112/113) per procedure. Clinical success was seen in 93.1% patients with median Eckardt score decreasing from 8.0 to 1.0 (P < 0.001) during a median 31.0 months of follow-up. The mean LES pressure decreased from 29.5 mmHg to 14.2 mmHg after POEM (P < 0.05). Procedure-related adverse events occurred in 8.9% patients. Reflux disease was observed postoperatively in 26.7% of patients. POEM is also indicated for patients with advanced achalasia with a favorable safety and efficacy.

Background and study aims  Since per-oral endoscopic myotomy (POEM) was introduced in 2010, it has become accepted as one of the standard treatments for esophageal achalasia worldwide. This study aimed to present long-term clinical results of POEM over 10 years and evaluate the technique and outcomes at the institution where it was first used in clinical settings. Patients and methods  Questionnaire-based surveys were sent to patients who received POEM in our institution from September 2008 to May 2010. Patient demographics and procedural outcomes and open-ended questions were posed about the postoperative courses, including symptom improvement and recurrence, additional treatments, and post-POEM gastroesophageal reflux disease (GERD) symptoms. Achalasia symptoms and post-POEM GERD symptoms were evaluated with Eckhardt scores and GerdQ systems, respectively. Results  Thirty-six consecutive POEMs were performed in that period and 10-year follow-up data were obtained from 15 patients (41.7 %). Although four cases (26.7 %) required additional pneumatic balloon dilatation (PBD), reduction in post-Eckardt scores were observed in 14 cases (93.3 %). GerdQ score was positive in one patient (6.7 %). Proton pump inhibitors (PPI) were taken by four patients (26.7 %) and their symptoms were well-controlled. Conclusions  Clinical results of POEM over 10 years were favorable regardless of various factors. Symptoms improved even in patients who required additional treatments, suggesting that POEM plays a significant role in treatment of achalasia.

Per-oral endoscopic myotomy (POEM) has gained widespread enthusiasm amongst foregut specialists since its introduction in the mid 2000s as an effective and less invasive treatment option for achalasia. As more than 6000 POEM procedures have been performed to date throughout the world, we aim to summarize the history and current state of POEM in the treatment of esophageal motility disorders.

We performed a comprehensive review of the published literature focusing on the history and development of the POEM procedure, and its most current applications and outcomes.

Multiple favorable long-term studies have been published advocating for the use of POEM as a valid and perhaps the most valid treatment option for achalasia. The procedure is also increasingly being applied to a wider spectrum of esophageal motility disorders including type III achalasia, spastic esophageal disease or isolated lower esophageal sphincter (LES) dysfunction, as well as new endoluminal procedures such as submucosal tumor endoscopic resection (STER), endoscopic fundoplications (POEM-F) and peroral pyloromyotomy (POP or G-POEM).

While POEM is a proved and valid procedure, its further adoption is being threatened by external factors: challenges related to teaching, institutional support (politics) and insurance reimbursement. While this technique has come an incredible distance in its relatively short lifespan, the future of POEM in the USA will depend on the support from surgical societies to validate it as a valuable tool in the esophageal specialist's armamentarium, and to encourage a commitment to training in endoluminal surgery.

Therapy for end-stage achalasia is debated, and data on long-term functional results of myotomy and esophagectomy are lacking. We compared quality of life and objective outcomes after pull-down Heller-Dor and esophagectomy.

The study included 32 patients, aged 57 years (interquartile range [IQR], 49-70 years), who underwent the Heller-Dor operation with verticalization of the distal esophagus in case of first instance treatment or failed surgery caused by insufficient myotomy, and 16 patients, aged 58 years (IQR, 49-67 years; P = .806), who underwent esophagectomy after failed surgery for other causes. Data were extracted from a database designed for prospective clinical research. Postoperative dysphagia, reflux symptoms, and endoscopic esophagitis were graded by semiquantitative scales. Quality of life was assessed with the 36-Item Short Form Health Survey questionnaire.

The median follow-up period was 68 months (IQR, 40.43-94.48 months) after pull-down Heller-Dor and 61 months (IQR 43.72-181.43 months) after esophagectomy (P = .598). No statistically significant differences were observed for dysphagia (P = .948), reflux symptoms (P = .186), or esophagitis (P = .253). No statistically significant differences were observed in the domains physical functioning (P = .092), bodily pain (P = .075) or general health (P = .453). Significant differences were observed in favor of pull-down Heller-Dor for the domains role physical (100 vs 100, P = .043), role emotional (100 vs 0, P = .002), vitality (90 vs 55, P< .001), mental health (92 vs 68, P = .002), and social functioning (100 v s75, P = .011).

The pull-down Heller-Dor achieved objective results similar to those of esophagectomy with a better quality of life. This technique may be the first choice for end-stage achalasia in patients with null or low risk for cancer or after recurrent dysphagia caused by insufficient myotomy.

Peroral endoscopic myotomy (POEM) is the first-line treatment of achalasia cardia (AC). However, the efficacy of POEM in treating patients with advanced AC remains to be determined. The aim of the present study was to evaluate the feasibility and clinical outcome of POEM in treating patients with advanced AC involving different esophageal morphologies. The study was a single-center, retrospective analysis of patients suffering from advanced AC. The primary endpoint was the Eckardt score at the follow-up examination. Secondary endpoints were procedural-related details, including the operation time and length of myotomy, adverse events (AEs) and hospital stay, as well as post-procedural gastroesophageal reflux disease. The technical success rate was 100%. All 50 patients enrolled underwent successful endoscopic myotomy (conventional POEM, n=20; modified POEM, n=30). AEs were observed in 10 patients. During a 6- to 50-month follow-up period, 41 patients achieved clinical success as evidenced by a decrease in the Eckardt score. Only 3 of 6 patients with a sigmoid-shaped megaesophagus obtained symptomatic relief. Symptomatic reflux occurred in 13 of 46 patients who completed their follow-up. In conclusion, POEM is safe, feasible and effective in treating advanced AC. Patients with a sigmoid-shaped megaesophagus are less likely to report palliation of symptoms.

Achalasia is a progressive neurodegenerative disorder characterized by failure of relaxation of the lower esophageal sphincter (LES) and altered motility of the esophagus. The traditional, highly effective, surgical approach to relieve obstruction at the LES includes cardiomyotomy. Fundoplication is added to decrease risk of postoperative reflux. Per oral endoscopic myotomy is a new endoscopic procedure that allows division of the LES via transoral route. It has several advantages including less invasiveness, cosmesis, and tailored approach to the length on the myotomy. However, it is associated with increased rate of post-procedural reflux. Various endoscopic interventions are used to address this problem.

Achalasia is a type of esophageal motility disorder, consisting of relaxation dysfunction of the lower esophagus and disturbed esophageal peristalsis. Related clinical symptoms include dysphagia, regurgitation, chest pain, and weight loss. Traditional treatment options include endoscopic botulinum toxin injection, endoscopic pneumatic dilation, and laparoscopic Heller's myotomy. These therapies mainly relieve symptoms by reducing the pressure on the lower esophageal sphincter and reducing blood flow resistance at the esophagogastric junction. Based on endoscopic submucosal dissection and natural orifice transluminal endoscopic surgery, peroral endoscopic myotomy (POEM) is a purely endoscopic method of myotomy with minimal invasiveness and a low rate of adverse events when performed by experienced operators. Since then, numerous studies have shown the significant clinical efficacy and safety of POEM. The purpose of this article is to introduce different modified POEMs, special indications for different POEMs, and their advantages as well as disadvantages.

Peroral endoscopic myotomy (POEM) has been recently considered as the first treatment option for achalasia. The standard POEM procedures are often successful in most patients, but sometimes technical challenges are encountered. We report a new technique that is divided between two tunneling sites in the esophagus for sigmoid-type achalasia. A 40-year-old male patient with dysphagia for 10 years was diagnosed with a sigmoid-shaped esophagus at our hospital. We devised a two-stage myotomy technique to treat sigmoidtype achalasia. The myotomy was first performed in the upper part of the greater flexion area and then in the lower part of the flexion. We termed this method "two-stage POEM", which was successfully performed without any complications. This new POEM method can also be used to improve symptoms in patients with achalasia who have a structural deformity that may result in a high change of treatment failure.

Achalasia is a chronic, progressive motility disorder of the esophagus. The sigmoid-type achalasia is an advanced stage of achalasia characterized by severe dilatation and tortuous angulation of the esophageal body. Peroral endoscopic myotomy (POEM) has been reported to provide excellent clinical outcomes for achalasia, including the sigmoid type, but the restoration of esophageal morphology and function remain poorly described. The aim of our study is to investigate esophageal restoration after POEM for sigmoid-type achalasia.

From 98 patients with achalasia who underwent POEM in the Yonsei University Health System from 2013 to 2018, we recruited 13 patients with sigmoid-type achalasia (7 male; mean age 53.3 years) and assessed morphological and manometric changes in the esophagus.

Clinical success (Eckardt score < 3) was achieved in all cases. After POEM, the average angle of esophageal tortuosity became more obtuse (91.5° vs 114.6°, P = 0.046), esophageal body diameter decreased (67.6 vs 49.8 mm, P = 0.002), and esophagogastric junction opening widened (6.4 vs 9.5 mm, P = 0.048). Patients whose esophageal tortuosity did not improve had longer durations of symptoms than patients with improvement (80.2 vs 636 months, P < 0.001). An absence of peristalsis was observed in all patients pre- and post-POEM.

POEM resulted in excellent clinical outcomes and morphologic improvement in sigmoid-type achalasia. These results suggest that the improvement of esophageal tortuosity through POEM reflects a reduced esophageal burden.

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.

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.

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.

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.

During peroral endoscopic myotomy (POEM), creation of the tunnel is highly technically demanding and mucosal injury is one of the most common potential complications. We explored a method without a submucosal tunnel, which we call open peroral endoscopic myotomy (O-POEM). This study aimed to assess the feasibility and safety of O-POEM. O-POEM was performed on 82 patients with achalasia. Treatment success was defined as an Eckardt score of less than or equal to 3 after the myotomy. Adverse events including operative and postoperative adverse events were recorded. Treatment success and procedure-related adverse events were analyzed. After a median follow-up of 18 months (range: 6-26 months), the treatment success (Eckhart score ≤3) was achieved in 96.3% of cases (mean score pre- vs. post-treatment (7.4 vs. 1.8); P < 0.001) with a recurrence of 3 cases. Ten patients (12.2%) had adverse events consisting of 2 cases of mediastinitis, 1 case of post-O-POEM bleeding, 1 case of subcutaneous emphysema, 6 cases of pleural effusion. Two cases of mediastinitis required intraprocedural drainage, and other patients were managed by endoscopy and conservative medical treatment. There were no deaths. No patients required surgical conversion. Clinical reflux occurred in 15.9% of patients (13/82). O-POEM was reliable and effective for the treatment of achalasia. In addition, O-POEM might be a better option for patients with severe submucosal fibrosis.

Background and aim  Accurate estimation of the distance to the gastroesophageal junction (GEJ) through a tunnel during per oral endoscopic myotomy (POEM) is technically challenging. The methods currently employed are often insufficient, and resultant errors may lead to incomplete myotomy and/or prolonged procedure times. Our hypothesis states that the additional distance while traversing the tunnel is directly proportional to the widest esophageal diameter; and is calculated by the formula X = Y + CZ (X = distance to the GEJ through the tunnel, Y = distance to the GEJ through the lumen, Z = widest esophageal diameter, C = arithmetic constant). This study evaluates the validity and accuracy of this hypothesis. Patients and methods  This was a prospective single-center study with 80 patients, 12 in the pilot group and 68 in the study group. In the pilot group, Y was recorded during esophagogastroduodenoscopy (EGD) before POEM, Z on barium swallow/contrast enhanced computed tomography (CECT), and X was measured during POEM. Using the formula, mean C (SD) was calculated. In the study group, 'C' was substituted in the equation to predict the GEJ distance through the tunnel (Xp) before POEM. The operator was blinded to Xp and recorded the true Xt during POEM. The correlation between Xp and Xt was calculated. Results  In the pilot group, the mean distances (cm, SD) for X, Y, and Z were 42.58 (3.33), 39.83 (3.08), and 4.39 (1.16), respectively. The calculated mean C was 0.63 (0.11). In the study group, the mean distances (cm, SD) for Y, Z, Xp, and Xt were 40.45 (2.58), 4.99 (1.43), 43.57 (2.68), and 43.54 (2.78), respectively. The Xp and Xt values demonstrated a high correlation (r = 0.97, P  = 0.000). Conclusions  Formula X = Y + CZ reliably predicts the GEJ distance through a tunnel during POEM. It is user friendly and requires no additional resources.

Per-oral endoscopic myotomy (POEM) is an endoscopic procedure whereby the esophageal muscle is incised in order to lower the lower esophageal sphincter (LES) pressure. Since the time it was first performed in 2008 and subsequently reported on in 2010 by Inoue et al., POEM has been shown to be safe and effective for straight type of achalasia. On the other hand, the efficacy of POEM had been controversial for patients with achalasia of the sigmoid type, in which a high LES pressure is accompanied by morphological changes, including dilation, acute angulation, and rotation. The aim of this study is to evaluate the safety and efficacy of POEM in patients with sigmoid type of achalasia.

Between May 2015 and December 2017, 16 patients with a sigmoid type of achalasia underwent POEM in our institute. The POEM procedure was the same as that for the straight type of achalasia. The double-scope technique was used to check the distal end of the submucosal tunnel from the gastric side. The primary endpoint was improvement of Eckardt score at 2 months after POEM. The secondary endpoints comprised operating time, change in the esophageal angulation, and adverse events.

All patients underwent POEM without severe adverse events. The respective parameters before and after POEM significantly differed in terms of mean (SD) Eckardt score [4.9 (2.0) vs. 0.4 (0.6), p < 0.01], LES pressure [19.4 (10.2) vs. 9.2 (6.4), p < 0.01], and integrated relaxation pressure [17.6 (9.2) vs. 7.9 (5.5), p < 0.01]. The average operation time was 94.7 ± 31.4 min. The average esophageal angulation was 88.4° ± 23.1° before POEM and 109.5° ± 16.7° after POEM (p < 0.01). Four patients had postoperative complications that were treated conservatively.

POEM can improve both LES pressure and esophageal angulation in patients with sigmoid achalasia.

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.