A Decade of Investigation: Peroral Endoscopic Myotomy Versus Laparoscopic Heller Myotomy for Achalasia

Abstract

Background:

Although laparoscopic Heller myotomy (LHM) with partial fundoplication has long been considered the gold standard for treatment of patients with achalasia, peroral endoscopic myotomy (POEM) has emerged in the last decade as a viable alternative.

Methods:

A collective review of literature concerning investigations that have reported patient outcomes and treatment success of LHM and POEM for all achalasia subtypes.

Results:

While POEM has shown excellent short-term safety and efficacy in the relief of symptoms, the long-term symptomatic outcomes after the intervention are yet to be concluded. Further evaluation of patients' interpretations and answers on subjective questionnaires is warranted before determining treatment success for POEM. Use of more reliable and disease-specific health-related quality-of-life questionnaires are better justified when comparing a new endoscopic procedure to an established gold standard. The need for objective parameters to measure reflux, longer follow-up studies, and randomized trials comparing POEM to LHM is particularly important when assessing the outcome of this new technique. High incidence of post-POEM pathologic reflux and indication for daily proton pump inhibitor use is of concern, and the lack of more long-term, objective evidence leaves the clinical value of the procedure in a state of uncertainty.

Conclusions:

The LHM combined with partial fundoplication is still considered to be the gold standard treatment modality for achalasia, but as the POEM procedure rapidly becomes common practice, this treatment may be performed in the majority of achalasia cases. Given the number of flaws overlooked in seminal investigations, careful consideration should be given to the patients being selected for this therapy.

Introduction

Idiopathic achalasia is the most common primary esophageal motor disorder, estimated to affect up to 1.6 per 100,000 in the population.¹ This motility disorder results in degeneration of the myenteric nerve plexus of the esophageal wall and is characterized manometrically by an absence of coordinated peristalsis and insufficient relaxation of the lower esophageal sphincter (LES) in response to swallowing.^1–6 Depending on the type, patients with achalasia may often present with symptoms of dysphagia to solids and liquids, regurgitation of undigested food, nocturnal cough, chest pain, and heartburn.^1–6 Other diagnostic tests, including upper gastrointestinal endoscopy and timed barium esophagram, classically reveal a proximal dilation of the esophagus, spastic LES, retained saliva, and food particles in the absence of mucosal stricture or tumor, and a narrowed gastroesophageal junction, demonstrating a “bird's beak” appearance.^3–5 High-resolution manometry (HRM) has been established as the gold standard diagnostic tool for achalasia of the esophagus, classifying the disease into three subtypes presenting with different manometric patterns: type I (classic achalasia), type II (with esophageal compression), and type III (spastic achalasia), as defined by the Chicago classification.⁷

There is currently no curative treatment for achalasia. Surgical procedures aim to relieve the high pressure resulting from the hypertonic LES by selectively incising the tight circular muscle fibers of the distal esophagus. Laparoscopic Heller myotomy (LHM) with or without fundoplication has been the longest practiced surgical approach, and the LHM with partial fundoplication remains the current gold standard treatment.⁸ However, we have witnessed a shift toward scarless approaches to achalasia management in the last decade. Peroral endoscopic myotomy (POEM), aimed to reduce the LES pressure and facilitate esophageal emptying, was first performed in 2008 as a novel natural orifice transluminal endoscopic surgery (NOTES) procedure for achalasia.⁹ It is now performed globally, demonstrating the propensity to become a day procedure with same-day or next-day discharge of the patient and quicker recovery times. Still, the experience among established centers has differed, and thus much debate persists regarding what is now the gold standard treatment of achalasia: LHM with partial fundoplication, or POEM.

Methods

Review of literature

Two reviewers (M.T.O. and S.S.) independently conducted a collective review of the literature through PubMed covering a period from January 2008 to April 2019 with language restricted to English, and using the search terms: “peroral endoscopic myotomy,” “laparoscopic Heller myotomy,” “POEM,” “LHM,” “achalasia,” and logical combinations of these terms using the Boolean operators “AND” and “OR.” Initial selection of studies for review was based on the title and abstract. An article was selected for further evaluation when the study concerned (1) adult human study participants undergoing LHM or POEM for achalasia, (2) the comparison between LHM and POEM for the treatment of achalasia, or (3) reported relevant patient outcomes after LHM or POEM, including pathologic reflux and treatment success. Reference lists of relevant publications were assessed for additional references. Included studies were categorized according to the studies' key findings and assessed with the Oxford Center for Evidence-based Medicine Levels of Evidence. A study was excluded from evaluation if it was a review, guidelines, did not concern adult human study participants, did not compare LHM and POEM for the treatment of achalasia, did not report relevant patient outcomes after LHM or POEM for achalasia, or the study was not in English.

Results

Existing levels of evidence

The initial reference search yielded 1063 potentially relevant articles. After evaluating the titles and abstracts of these articles, 951 articles were removed from consideration. The remaining 112 articles were suitable for review, and they were stratified according to their methodology and key findings in Figure 1. The articles critiqued below were chosen based on their importance to the field in establishing, and subsequently validating, a novel approach to achalasia treatment (POEM), or by their value in comparing the safety and efficacy of such an approach to the current standard of care (LHM).

FIG. 1.

Number of articles in literature (2008–2019) supporting key research findings, stratified by level of evidence.

Procedural Comparison

Surgical cardiomyotomy

The surgical cardiomyotomy was first introduced in 1913 by Ernst Heller as a thoracoscopic procedure to eliminate outflow obstruction and relieve tension by incising the circular muscle fibers of the distal esophagus. This operation has since evolved to be performed laparoscopically with reduced postoperative pain, less morbidity, greater symptom relief, and shorter length of hospital stays.^8,10,11 LHM has been accepted as the superior first-line therapeutic approach for achalasia, but is prone to precipitate the development of postoperative gastroesophageal reflux disease (GERD).^8,10,11 Pathologic gastroesophageal reflux at six postoperative months has been reported in up to 48% of patients who undergo LHM without antireflux surgery.¹² Therefore, a concomitant antireflux surgery has been recommended in literature and current surgical guidelines,¹³ and its addition is shown to significantly reduce the risk of postoperative abnormal reflux (8.5%–17%),^12,14–16 without impairing the food emptying of the esophagus.^17–19 Zaninotto et al.¹⁶ reported the outcomes of 407 patients who underwent LHM with an additional Dor fundoplication, and esophageal 24-hour pH monitoring revealed an abnormal acid exposure in 8.5% of patients, respectively, with a 10% (39/407) surgical failure rate. Most failures (64%) occurred within 12 months of the operation and resulted from an incomplete myotomy. The 5-year actuarial probability of being asymptomatic was 87%, with effective symptom control identified in 97% of patients.¹⁶ The Dor fundoplication accommodates one of the few weak points in the LHM, which is its postoperative incidence of acid reflux and generally elevated Eckardt score. When these procedures are combined, it is considered to be a clinically and objectively effective treatment modality for (Chicago) type I and type II achalasia.^16,20 To date, there are no specific randomized trials comparing other treatments to LHM in (Chicago) type III achalasia, but patients with end-stage achalasia may not benefit from the addition of a fundoplication. The results of recent meta-analyses have consistently concluded that LHM combined with an antireflux surgery has comparable, if not more efficacious outcomes in terms of long-term postoperative GERD, dysphagia, and relief of other symptoms, than other therapeutic modalities, including pneumatic dilation, endoscopic botulinum toxin injection, and endoscopic balloon dilation.^21,22 The LHM has long been regarded as the standard of care for achalasia, but the introduction of a novel endoscopic surgical method in the last decade has warranted greater investigation.

Peroral endoscopic myotomy

Pasricha et al.²³ were the first to introduce a novel experimental approach to a Heller-type cardiomyotomy using NOTES on porcine models in 2007. Thereafter, the technique was further developed in Japan, with the first clinical POEM on humans being performed by Inoue and colleagues in 2008.²⁴ Although several variations to the procedure have been reported, the original developers have recently described their standard technique in detail.²⁵ In short, the procedure involves performing a myotomy starting at a variable distance proximal to the esophagogastric junction (EGJ) and advancing to the distal end of the submucosal tunnel, ∼2 to 3 cm distal to the EGJ.²⁵ The inner muscular layer is cauterized to form the starting point for the anterograde esophageal myotomy, which is extended 2–3 cm distally onto the gastric cardia.²⁵ In contrast to the POEM, the extent of the myotomy on the esophagus is generally 6 cm in the LHM, while the extent on the stomach is comparable. POEM has subsequently drawn increased attention as a potential first-line therapy, given its excellent safety profile and promising short- and intermediate-term results after what is now thousands of successful cases performed in many high-volume esophageal centers. POEM has especially been successful in treating patients with (Chicago) type III achalasia who present with impaired EGJ relaxation and premature, spastic contractions of the distal esophagus. These patients require a longer myotomy, and the myotomy performed with the POEM procedure can be extended proximally.²⁶ Although POEM is now a validated therapeutic option for treating achalasia, it is important to address a few of the questions and controversies that surround the procedure and underlie its recent investigation.

Controversy over Eckardt Score

Clinical and objective evaluation of the surgical outcomes have been controversial in the comparison between the endoscopic and surgical myotomy. The most widely used and accepted questionnaire for diagnosing achalasia and measuring the severity of the disease before and after treatment is the four-item Eckardt symptom score, shown in Table 1.²⁷ Treatment outcomes are generally assessed using this symptom score, with an increasingly higher score greater than three representing a worsening disease. In the majority of observational studies, treatment success is solely measured as a total score of ≤3 (out of a total of 12). It should be noted that this threshold is an arbitrary hypothesis that is not extensively evaluated in the existing studies. The four-item Eckardt symptom score is a subjective questionnaire that relies on patients' reported symptoms, which may be difficult to distinguish. Chest pain is heterogeneous in achalasia and may be multifactorial in nature, potentially resulting from bolus flow obstruction, esophageal stasis, or spastic esophageal contractions.²⁸ Weight loss is the only objective measure in this questionnaire. However, it is less commonly experienced by achalasia patients compared with other symptoms, and its manifestation is not associated with worsening severity of disease, as it is significantly more common in (Chicago) type II than (Chicago) type III achalasia.²⁹ Furthermore, 50% of the items on the Eckardt symptom score are not related to standard physiological assessment of achalasia severity.²⁸ The results of patients' Eckardt symptom score require further evaluation in the form of patient interviews to truly understand a patient's interpretation and answer to each item. This evaluation will help refine current research protocols, standardize reporting of outcomes, and improve disease education with patients. A recently developed measure, the Northwestern Esophageal Quality of Life Scale,³⁰ has demonstrated higher internal consistency and split-half reliability than the Eckardt symptom score, and it effectively measures health-related quality of life (HRQOL) in chronic, esophageal conditions, such as achalasia.³⁰ This evaluation was established in lieu of current guidelines for patient-reported outcome measure development, unlike the Eckardt symptom score. The use of more reliable and disease-specific HRQOL questionnaires and objective measures of reporting, such as 24-hour pH monitoring and dynamic HRM, are better justified when comparing a new endoscopic surgical procedure to an established gold standard.

Table 1.

Eckardt Score²⁷

Score	Weight loss (kg)	Dysphagia	Retrosternal pain	Regurgitation
0	None	None	None	None
1	<5	Occasional	Occasional	Occasional
2	5–10	Daily	Daily	Daily
3	>10	Each meal	Each meal	Each meal

POEM for Achalasia Treatment

In 2013, Von Renteln et al.³¹ published a prospective, international, multicenter study to determine the clinical outcomes of 70 patients undergoing POEM at five centers in Europe and North America. This study limited its inclusion criteria to patients with (Chicago) type I achalasia, thus categorically excluding patients with (Chicago) type III achalasia who, theoretically, receive the most benefit from the POEM procedure, where there is no limit to extend the myotomy proximally. Additionally, the study excluded patients with previous intervention. Although significant improvement in Eckardt score was reported, with the score decreasing from 7 (pretreatment) to 1 (posttreatment) (P < .001), the incidence of GERD symptoms measured at 3, 6, and 12 months post-POEM were 33%, 30%, and 37%, respectively. Reflux erosive esophagitis on endoscopy at 3 months post-POEM was seen in 42% of patients. At 12-month follow-up, 29% of patients required proton pump inhibitors (PPIs) (19.6% daily; 9.8% occasionally), with only 82% having a sustained treatment success. The mean follow-up in this study was 10.1 months (range, 3–12 months) and demonstrated the necessity for refined, objective outcomes in the long-term, postoperative period.

Inoue et al., the pioneers of the POEM procedure, reported their original findings of the first 500 cases treated with POEM at their institution from 2008 to 2013.³² This study is the largest series to date; with wide inclusion criteria, it aimed to assess patients of all ages and body mass index (BMI) groups diagnosed with any achalasia subtype. The primary endpoints measured were changes in Eckardt score and LES pressure at 2 months, with overall treatment success being defined as a post-POEM Eckardt score of <2, or a reduction of more than four points from the baseline score. The overall success rate was 91.0% for the POEM procedure, with 260 out of 286 patients with available interview data reporting significant symptom reduction according to the Eckardt score at 1–2 years after POEM. The authors deemed that POEM could be performed safely and effectively based on their experience with 500 consecutive cases. However, there are a few glaring issues that need to be addressed while reading and interpreting conclusions from this investigation, and these issues may limit the generalizations that can be drawn from this study. For one, despite the wide inclusion criteria, the study population was not one that was representative of a Western society with greater variability in BMI; the BMI in this study only ranged from 18.8 to 22.7 kg/m². Moreover, conclusions were primarily drawn from assessments of the available subjective data. Long-term follow-up (3 years or more) for GERD symptoms was available for only 61 patients (12% of included patients), of which 21.3% were symptomatic. Furthermore, long-term objective follow-up was available for only 16 patients (3% of study population), of which 56.3% had endoscopic evidence of reflux esophagitis. Therefore, it is difficult to appropriately justify the long-term efficacy of the procedure based on this study.

In the following year, Werner et al.³³ reported clinical outcomes in 80 patients undergoing POEM for achalasia at three centers. These patients were retrospectively analyzed, and the primary endpoint for this study was the rate of POEM failures related to the follow-up time, measured as an Eckardt score <3. The authors followed each patient for a minimum of 2 years post-POEM. The initial success rate due to symptom remission was 93.7% at 3–6 months. However, the success rate dropped to 77.5% at a mean follow-up of 29 months (range, 24–41 months). The POEM procedure is clearly efficacious in the short-term, resulting in very few failures (as shown by persistent remission in symptoms) at the time of 3–6 months post-POEM. Although subjective clinical outcomes in the form of Eckardt scores were available at a minimum of 24 months after the procedure, objective outcomes in the form of endoscopy and manometry were not available in the long term. Three- to six-month endoscopy revealed reflux lesions in 36.8% of patients (20.6% Los Angeles [LA] grade A; 16.2% LA grade B) and 37.5% on mid-term follow-up (20.8% LA grade A; 12.5% grade B; 2.8% grade C). PPIs were required by 18% of patients daily at two or more years post-POEM, compared with 6% of patients pre-POEM and 5% immediately following the procedure. The authors advocated for the long-term administration of daily, low-dose PPIs to all patients and recommended post-POEM pH-metry for guiding the medication. The substantial rate of reflux esophagitis identified on endoscopy proves to be of increasing concern for the long-term quality of life of the patients post-POEM. Although GERD symptoms seem to be relatively controlled in the long term, the indication for daily PPI use and the lack of more long-term, objective evidence leaves the clinical value of the procedure in a state of uncertainty.

In the same year, Patel et al.³⁴ performed a systematic review that assessed subjective and objective metrics of achalasia treatment efficacy, perioperative morbidity, and postoperative reflux in 1122 POEM patients compiled from 22 studies. In presenting the objective findings, the authors identified two large population studies that demonstrated 33%–37% and 46% of patients with erosive esophagitis and Barrett's esophagus on endoscopy post-POEM, respectively. All of these patients were clinically asymptomatic, thus suggesting that subjective symptom analysis underestimates the actual prevalence of GERD after POEM. Additionally, the authors analyzed five studies that investigated objective evidence of acid reflux post-POEM with impedance–pH monitoring. The overall incidence of abnormal acid exposure in patients after POEM was 43%. However, because the incidence of preoperative acid reflux was not determined, the change in acid exposure could not be identified. Lastly, the authors identified three studies investigating pathological changes after POEM and found an increase in the incidence of esophagitis from 0% pre-POEM to 19% post-POEM.

In the majority of studies that analyze the safety and efficacy of POEM in the treatment of achalasia, the audience must compensate for variability in definitions for outcomes reported between studies, making summative analysis especially challenging. Many authors fail to include information on the severity and type of achalasia; patient selection is an important factor in the success and standardization of the POEM procedure. Additionally, conclusions can be difficult to formulate without pre- versus posttreatment outcomes and long-term, objective findings, which are imperative for justifying its use ahead of the current optimal treatment of choice, the LHM with partial fundoplication. Additionally, very few studies have reported the outcomes of POEM in patients with sigmoid esophagus. Because the procedure is still relatively new, surgeon inexperience and the learning curve for this operation should also be accounted for in evaluating outcomes. Experience of <1 year in performing the POEM has been identified as a risk factor for higher postprocedure morbidity and treatment failure.³⁵ Several recent, updated publications have reported the outcome of patients treated with POEM in 2018 (indexed in PubMed) and are shown in Table 2. To compare these reported outcomes to the LHM, investigations have been conducted with the purpose of comparing exactly how effective the POEM is against the LHM in treating achalasia patients.

Table 2.

Studies Reporting Outcomes of Peroral Endoscopic Myotomy for Achalasia in 2018

Author, year (study design)	Patients reviewed (n)	Primary outcome(s)	Median F/U [Range] (months)	Results	Finding(s)
Liu et al., 2018 (Retrospective)⁴⁸	849	Major adverse event(s), clinical failure, clinical reflux	23 [1–71]	Major adverse event: 4%	POEM has low risk of adverse event; risk of clinical failure increases with prior intervention
				Clinical failure: 11.1%
				Clinical reflux: 23.9%
He et al., 2018 (Retrospective)⁴⁹	115	Eckardt score, LES pressure changes, gastroesophageal reflux	36	Treatment success at 12, 24, 36, 48, and 60 months: 91.3%, 90.3%, 89.0%, 83.7%, 80.1%, respectively	POEM is safe and effective in treating achalasia; favorable long-term efficacy
He et al., 2018 (Retrospective)⁴⁹	115		36	Reflux esophagitis: 18.3%
Kane et al., 2018 (Prospective)⁵⁰	50	Symptom relief (Eckhardt score), adverse events, failure, recurrence	6	Mean post-op Eckardt score: 1.0 ± 1.9 [P < .0001]	POEM is a safe and durable treatment for achalasia in the short term; provides marked improvement of symptoms
				Adverse event: 4%
				Failure: 6%
				Recurrences: 4%
Perbtani et al., 2018 (Prospective)⁵¹	143	Long-term HRQOL	16.4 [12–40]^a	Long-term HRQOL baseline mental and physical component scores improved (P < .021, P < .034)	POEM improved all dimensions of HRQOL as measured by the SF-36 survey at short- and long-term follow-up
Martinek et al., 2018 (Prospective)⁵²	133	Mid-term (12–24 months) treatment success (Eckardt score <3)	12 to 24	Treatment success at 12, 24 months: 93.4%, 84.0%	1/3 of patients developed mild reflux esophagitis
Martinek et al., 2018 (Prospective)⁵²	133		12 to 24	Pathological GERD: 41.5%	1/3 of patients developed mild reflux esophagitis
Tan et al., 2018 (Randomized, prospective)⁵³	31 (anterior), 32 (posterior)	Treatment success (Eckardt score ≤3) for anterior versus posterior POEM	15.5^a	No significant difference between the two groups for Eckardt score, manometry outcomes, or adverse events (P < .05)	Short-term treatment efficacy, manometry outcomes, and adverse events were comparable between groups

Indexed in PubMed.

Value expressed as mean.

HRQOL, health-related quality of life; LES, lower esophageal sphincter; POEM, peroral endoscopic myotomy; GERD, gastroesophageal reflux disease.

LHM and POEM for Achalasia Treatment

In 2013, Hungness et al.³⁶ compared perioperative, short-term symptom, and physiologic outcomes between 73 patients undergoing LHM and POEM (55 LHM versus 18 POEM) for achalasia. Eckardt symptom scores were recorded preoperatively for patients undergoing POEM, but the surveys were not given to patients undergoing LHM. Therefore, differences between preoperative and postoperative symptoms could not be compared between the treatment modalities. The operative times were noted to be shorter (113 versus 125 minutes, P < .05), and the estimated blood loss was less in the POEM as compared with the LHM cases (≤10 mL in all cases versus 50 [10–250] mL, P < .001). The myotomy lengths, complication rates, and length of hospital stay were similar. Sixteen of 18 patients (89%) who underwent POEM had a successful treatment, measured as a score of ≤3 on the Eckardt symptom score. The study had several limitations, including lack of randomization for treatment, patient selection bias, and incomparable short-term (6 weeks postoperatively) objective follow-up between procedure type. Postoperative upper endoscopy was not performed in any patients treated with LHM for achalasia, so a comparison was not available for the 33% of POEM patients with esophagitis at follow-up. Although this study added to the existing evidence that POEM is a feasible and safe procedure, the clinical benefits for this procedure remain inconclusive from the evidence provided.

In 2014, Bhayani et al.³⁷ contributed yet another major study that compared subjective and objective outcomes between LHM and POEM. They reported their findings of 101 consecutive patients (64 LHM versus 37 POEM) receiving treatment for achalasia. Although baseline characteristics, preoperative Eckardt score, and preoperative manometry profiles were noted as comparable between groups, patients undergoing LHM had slightly different presenting symptoms, with those receiving this treatment having higher preoperative reflux rates than POEM. The operative time and length of hospital stay were significantly higher for LHM compared with POEM. However, the patient symptoms and esophageal physiology improved equally with both procedures, and at 6 months, the Eckardt scores were similar. Short-term, objective findings revealed similar rates of abnormal esophageal acid exposure between those patients who underwent LHM and POEM (39% versus 32%, P = .7). The greatest limitation of this study was, however, the unequal rates of preoperative acid reflux between treatment groups, as well as the short follow-up from which the stability of the clinical outcomes after the POEM procedure cannot adequately be generalized for the long term.

In 2015, Kumbhari et al.³⁸ reported the outcomes of a multicentric, retrospective study conducted in 75 patients with (Chicago) type III achalasia across nine institutions. Of these 75 patients, 49 underwent POEM in eight institutions, whereas 26 underwent LHM at a single center. The two cohorts of patients had significant differences upon preoperative assessment; patients in the LHM cohort had a significantly higher preoperative mean baseline Eckardt score (2.85 versus 2.37; P < .01), as well as a higher number of prior interventions (72% versus 38.8%; P < .01) in comparison to the POEM cohort. Moreover, patients who underwent LHM had significantly longer follow-up compared with patients who underwent POEM (21.5 versus 8.6 months; P < .01). These differences in (1) preoperative patient profiles, (2) reporting of findings at different follow-up intervals, and (3) sampling of patients from various centers for POEM compared with a single-center LHM cohort can potentially introduce a bias in favor of the POEM for clinical response outcomes. The authors identified a 98.0% successful clinical response in those patients treated with POEM, defined as an Eckardt stage of ≤1, while finding only 80.8% in those treated with LHM. From their results, the authors were the first to provide substantive evidence that POEM is a superior alternative to LHM in treating patients with (Chicago) type III achalasia. Recent studies corroborate these findings. In 2017, Kim et al.³⁹ investigated outcomes of POEM in 11 patients with (Chicago) type III achalasia and reported good clinical outcomes at a median of 16 months postprocedure. In the same year, Khan et al.⁴⁰ performed a meta-analysis of eight observational studies with 116 (Chicago) type III achalasia patients, and the authors reported a weighted pooled response rate for clinical success of 92% (95% confidence interval [CI], 84–96) in these patients. Most recently, Andolfi and Fisichella⁴¹ provided the most substantial evidence for its superiority to the LHM in (Chicago) type III achalasia patients, as the authors found POEM more likely to be successful than LHM in treating this manometric subtype (odds ratio [OR] 3.50, 1.39 to 8.77; P = .007). These assessments are fair in that a myotomy performed endoscopically can be more liberally extended proximally to include the hypertensive contractions.

The results of these comparative analyses offer an optimistic perspective to the future of achalasia care with the advent and standardization of the POEM. Because the POEM procedure is performed largely by gastroenterologists, greater centralization of treatment in the United States of America should improve the overall care of this esophageal motor disorder.⁴² Table 3 demonstrates the results of several other comparative investigations that show similar clinical outcomes, including postoperative symptom and pain control between patients receiving either of these two operations. It is important to note that the clinical outcomes reported by the majority of these high-volume academic centers may differ from the results identified in smaller institutions. The rates of reflux post-POEM, as well as the recurrence of dysphagia that can subsequently follow an LHM with partial fundoplication are likely higher than that reported from experienced surgeons in esophageal centers.⁴² Recent evidence suggests that there is an increasing incidence of patients presenting with recurrent dysphagia after undergoing an LHM with a partial fundoplication at lower-volume institutions.⁴³ A complication resulting in a herniated fundoplication or recurrence of dysphagia symptoms can theoretically be avoided by undergoing POEM instead of the LHM. However, at the same time, dysphagia can recur in a patient undergoing POEM if the gastric myotomy is not performed adequately. It is understood that certain patients may be better suited to receive either the POEM or LHM according to their presentation, with most (Chicago) type III achalasia patients undergoing POEM and most patients presenting with reflux symptoms from hiatal hernia undergoing LHM. Regardless, medical evidence in the form of randomized controlled trials (RCTs) of LHM and POEM are required to determine the most effective and reliable treatment modality in the long-term. Our understanding is that the results of the first RCTs should be made available in the coming year. Until then, it is difficult to make presumptions as to the best choice for treatment in the case of a patient who is determined to be an acceptable candidate for either procedure. It may take years of investigation before reports of extended outcomes in POEM patients reveal the incidence of postoperative complications in the long term, compared with those which may result from a LHM. Additionally, the long-term failure rate for POEM may garner specific interest, and future studies should seek to evaluate whether or not these failures can be easily remedied, as well as the rationale for performing an esophagostomy in worsening circumstances.

Table 3.

Recent Comparative Studies of Laparoscopic Heller Myotomy and Peroral Endoscopic Myotomy for Achalasia

Author, year (study design)	Patients (n)	Primary outcome(s)	Median F/U [Range] (months)	Results	Finding(s)
Sanaka et al., 2018 (Propensity score matching)¹⁴	31 (POEM), 88 (LHM)	Difference in esophageal acid exposure between procedure type	2-Month posttreatment	POEM versus LHM	POEM leads to significantly higher rates of abnormal esophageal acid exposure, w/o an increase in GERD Sx
				Abnormal total acid exposure: 48.4% versus 13.6% (P < .001)
				Abnormal DeMeester score: 54.8% versus 17.4% (P < .005)
Hanna et al., 2018 (Retrospective)⁵⁴	42 (POEM), 54 (LHM)	Patient-reported outcomes between procedure type	21.9 (POEM), 37.0 (LHM)	POEM versus LHM	No significant difference in follow-up Eckardt score; two procedures have similar patient-reported effectiveness
				Daily dysphagia: 24% versus 28%
				Daily regurgitation and chest pain: 7% versus 11%
Ramirez et al., 2018 (Prospective)⁵⁵	35 (POEM), 35 (LHM)	Myotomy extension, treatment success (Eckardt score ≤3), symptomatic reflux	10 (6–32) [POEM], 20 (6–68) [LHM]	POEM versus LHM	Shorter myotomy on the gastric side in POEM may contribute to an acceptable reflux rate with comparable dysphagia relief
Ramirez et al., 2018 (Prospective)⁵⁵	35 (POEM), 35 (LHM)		10 (6–32) [POEM], 20 (6–68) [LHM]	Efficacy (Eckardt score ≤3): 94.2% versus 91.4% (P = 1.0); similar symptomatic reflux rates
Docimo et al., 2017 (Retrospective)⁵⁶	44 (POEM), 122 (LHM)	Postoperative pain	1–24 Hours post-op	POEM versus LHM	POEM has less postop pain; LHM patients required more narcotic analgesic administration during the first 24 hours
Docimo et al., 2017 (Retrospective)⁵⁶	44 (POEM), 122 (LHM)	Postoperative pain	1–24 Hours post-op	Average pain scores upon arrival to recovery room and 1 hour postop: 2.3 ± 3.0 versus 3.61 ± 3.0 (P = .025), and 2.2 ± 2.6 versus 3.5 ± 3.1 (P = .034), respectively
Peng et al., 2017 (Retrospective)⁵⁷	13 (POEM), 18 (LHM)	Treatment success (Eckardt score ≤3), GERD occurrence, QOL	36	POEM versus LHM	POEM and LHM are both effective treatments that have comparable long-term outcomes
Peng et al., 2017 (Retrospective)⁵⁷	13 (POEM), 18 (LHM)	Treatment success (Eckardt score ≤3), GERD occurrence, QOL	36	Treatment success: 83.3% versus 80.0% (P = 1.0), similar GERD rates, no difference in QOL
Schneider et al., 2016 (Retrospective)⁵⁸	42 (POEM), 84 (LHM)	Early clinical outcomes (Eckardt score, QOL metrics, dysphagia, esophagitis)	36.2 (22.2–41.2) weeks [POEM],	POEM versus LHM	Early clinical outcomes are excellent with POEM and comparable to the standard-of-care LHM
			36.2 (22.2–41.2) weeks [POEM],	Eckardt scores, QOL metrics, and dysphagia significantly improved in both groups; esophagitis: 53.4% versus 31.6% (Yates' P = .91)
			158.1 (36.5–272.9) weeks [LHM]

Indexed in PubMed.

GERD, gastroesophageal reflux disease; QOL, quality of life; Sx, symptoms; LHM, laparoscopic Heller myotomy; POEM, peroral endoscopic myotomy.

Meta-Analyses Comparing LHM and POEM

The results of recent meta-analyses have been assessed in hopes of uncovering evidence for the standard use of one procedure over the other. To date, all meta-analyses consists of pooled data from nonrandomized comparative studies, and because of the lack of long-term findings, no analysis exists of studies with outcomes beyond 3 years. In a meta-analysis of four nonrandomized comparative studies that scored highly in the Methodological Index for Nonrandomized Studies (MINORS) criteria,⁴⁴ Zhang et al.⁴⁵ evaluated the short-term outcomes of POEM compared with LHM for achalasia. A total of 317 patients were compiled (192 LHM versus 125 POEM) from the four studies, and these populations were comparable in terms of sex, preoperative Eckardt score, length of the myotomy, length of hospital stay, and complications, while POEM patients were older. Contrary to the findings of most individual studies, the authors found similar operation times between the LHM and POEM groups (mean difference [MD] = −55.62, 95% CI −145.96 to 34.71; P = .23), although with high between-study heterogeneity. Patients in the POEM group had a lower Eckardt score postoperatively compared with patients in the LHM group (MD = −0.30, 95% CI −0.42 to −0.18; P < .001), with high between-study homogeneity. The meta-analysis these authors present is of moderate to high quality, as measured by the Quality of Reporting of Meta-analyses (QUOROM) statement.⁴⁶ The sample size is larger than others published in years prior, and the inclusion and exclusion criteria for searching literature was stringent, with all of the nonrandomized studies having a score ≥18 out of 24 according to the MINORS criteria. The authors concluded that the POEM procedure has specific advantages over the LHM, but because of the great skill required in performing this novel, endoscopic procedure, the learning curve can be quite long, which may explain the heterogeneity among individual studies. Furthermore, this was one more study that assessed the clinical outcome without making a direct comparison between the preoperative and postoperative Eckardt score, and no functional tests for the objective evaluation of the patients were performed.

In 2017, Schlottmann et al.⁴⁷ performed a systematic review and meta-analysis to compare the improvement of dysphagia and postoperative GERD symptoms in patients undergoing POEM and LHM for the treatment of achalasia. Despite the absence of long-term results and RCTs, the authors were able to compile 53 studies reporting data on LHM (5834 patients) and 21 studies reporting outcomes of POEM (1958 patients). The community of gastroenterologists and esophageal surgeons are well aware of the disparaging gap between available follow-up data on patients undergoing LHM and POEM; the mean follow-up was significantly longer for studies of LHM compared with POEM (41.5 versus 16.2 months; P < .0001). The authors identified that at 12 months, the predicted probability for improvement in dysphagia was 93.5% for POEM and 91.0% for LHM (P = .01), and at 24 months, 92.7% and 90.0% (P = .01), respectively. Patients who underwent POEM were more likely to develop GERD symptoms (OR 1.69, 95% CI 1.33–2.14, P < .0001) and GERD as evidenced by erosive esophagitis (OR 9.31, 95% CI 4.71–18.85, P < .0001) and pH monitoring (OR 4.30, 95% CI 2.96–6.27, P < .0001). These results led the authors to conclude that the POEM is more effective in relieving dysphagia, but is associated with a higher incidence in pathologic reflux; further investigation into the stability of these outcomes are necessary, but individual studies seem to support these findings. The results of other recent meta-analyses are demonstrated in Table 4.

Table 4.

Meta-Analyses Comparing Laparoscopic Heller Myotomy and Peroral Endoscopic Myotomy for Achalasia

Author, year	Studies	Patients (n)	Finding(s)	Quality ^a	Limitations
Schlottmann et al., 2018⁵⁹	21 (POEM); 53 (LHM)	1958 (POEM); 5834 (LHM)	POEM is more effective in relieving dysphagia, but associated with a very high incidence of pathologic reflux	High; pooled meta-analysis finds significant difference in reflux rates	Moderate degree of heterogeneity in outcomes; mostly retrospective studies
Repici et al., 2018¹⁵	17 (POEM); 28 (LHM)	1542 (POEM); 2581 (LHM)	POEM is associated with a two- to three-fold increased risk of postintervention reflux compared with LHM with fundoplication	High; pooled meta-analysis finds significant difference in reflux rates	High degree of heterogeneity in pH and endoscopic findings; definition of reflux symptoms were not standardized
Awaiz et al., 2017⁶⁰	7 (POEM, LHM)	233 (POEM); 250 (LHM)	POEM and LHM have comparable short-term perioperative outcomes; LHM has significantly higher failure rate on short-term follow-up	Moderate to high; pooled meta-analysis finds significant difference in failure rate	High degree of heterogeneity in long-term GERD; differing methodologies and definitions in studies
Zhang et al., 2016⁴⁵	4 (POEM, LHM)	125 (POEM); 192 (LHM)	No difference in myotomy length, op-time, hospital stay; lower postop Eckardt score for POEM group	Moderate to high; individual studies reported differences, pooled meta-analysis finds no significant findings	Moderate degree of heterogeneity among operation time, length of stay, and Eckardt scores.
Marano et al., 2016⁶¹	7 (POEM, LHM)	196 (POEM); 290 (LHM)	No difference in major or minor complications, perforation rates, op-time, pain score, hospital stay, post-op GERD Sx, or symptomatic recurrence	Moderate; individual studies reported differences, pooled meta-analysis finds no significant findings	High degree of heterogeneity, no randomization of patients and significant publication bias
Wei et al., 2015⁶²	4 (POEM, LHM)	85 (POEM); 157 (LHM)	Lower postop GERD in LHM group; lower hospital stay in POEM group; no difference in reduction of Eckardt score, op-time, pain score, or dosage of pain medication	Moderate; lower GERD in LHM suggests need for an antireflux procedure after myotomy	Objective esophageal manometric measures could not be synthesized

Indexed in PubMed.

Quality assessed according to QUOROM statement.⁴³

GERD, gastroesophageal reflux disease; LES, lower esophageal sphincter; Sx, symptoms; LHM, laparoscopic Heller myotomy; POEM, peroral endoscopic myotomy; QUOROM, Quality of Reporting of Meta-analyses.

Conclusions

The LHM combined with an antireflux procedure is still considered to be the gold standard treatment modality for achalasia, but as the POEM procedure rapidly becomes common practice among more than 50 POEM centers in the United States of America, this treatment may be performed in the majority of achalasia cases. It is clear that POEM is logical and advantageous in that the procedure is less invasive when compared with LHM. But, because of the number of flaws overlooked in the seminal investigations presented above, careful consideration should be given to the patients being selected for this therapy. One should consider all of the evidence for this treatment modality, as well as the quality of the investigations. At the time of this writing, there is no level 1 evidence to support the use of POEM as the standard of care for all patients, but as stated above, the results of the long-awaited RCTs will presumably be made available in the next year. The need for longer follow-up studies and randomized trials comparing POEM to LHM is particularly important when assessing the generalizability of this endoscopic treatment. Available data suggest that the POEM procedure is efficacious in the relief of symptoms in patients with achalasia, especially in those patients with (Chicago) type III achalasia. Subjective questionnaires should be supplemented with objective evidence and patient interviews before determining treatment success. Physicians are recommended to follow patients, even those who present clinically asymptomatic, with vigilance in the form of pH monitoring and upper endoscopy.

Footnotes

Acknowledgment

The authors would like to thank Dr. Amogh Dudhwewala, MBBS, DNB for his expert critique in revising the final contents of this article.

Author Contributions

Each individual listed as an author on this article contributed substantially and in accordance with the guidelines of the International Committee of Medical Journal Editors.

Disclosure Statement

No competing financial interests exist.

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