One tunnel, two pathologies: Tailoring submucosal tunnelling per-oral endoscopic myotomy in achalasia with epiphrenic diverticulum by septum morphology

Abstract

Achalasia complicated by epiphrenic diverticulum presents a significant therapeutic dilemma. While per-oral endoscopic myotomy (POEM) has transformed achalasia management, the optimal handling of the concomitant diverticulum remains contentious. Hao et al[1] describe the simultaneous treatment of concomitant achalasia with epiphrenic diverticulum using a submucosal tunneling technique. This editorial synthesizes recent evidence to advocate for a decisive paradigm shift from universal protocols to a precise, morphology-guided strategy. Key data from meta-analyses indicate that POEM achieves success rates of 88%-95% in this group of patients. Crucially, outcomes are equivalent whether a selective septotomy is performed for obstructing septa or standard myotomy alone is used for non-septated diverticula. This tailored approach minimizes unnecessary intervention, reduces procedural risks, and maintains excellent efficacy. We propose a pragmatic clinical framework centered on real-time endoscopic phenotyping, positioning it as the evolving standard of care that embodies the principles of personalized, precision endoscopy for complex esophageal disorders.

Key Words: Achalasia; Epiphrenic diverticulum; Esophageal motility disorders; Per-oral endoscopic myotomy; Precision endoscopy; Septotomy; Submucosal tunneling

Core Tip: Management of achalasia with epiphrenic diverticulum is evolving. A one-size-fits-all septotomy is no longer justified. Intra-procedural endoscopic phenotyping allows for a selective approach: Division of a functionally obstructive muscular septum when present and standard myotomy alone when absent. This precision strategy, supported by recent meta-analytic data showing high treatment success for per-oral endoscopic myotomy in epiphrenic diverticula, achieves comparable outcomes to universal septotomy while minimizing overtreatment and its associated risks.

This editorial refers to “Simultaneous treatment of concomitant achalasia coexisting with epiphrenic diverticulum: The practice of submucosal tunneling technique” by Hao et al, 2026; https://doi.org/10.3748/wjg.v32.i9.114758.

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INTRODUCTION

The paper from Hao et al[1] on the recent issue of World Journal of Gastroenterology describes the simultaneous treatment of concomitant achalasia with epiphrenic diverticulum using a submucosal tunneling technique. While their technical success is commendable and adds to the growing evidence base for per-oral endoscopic myotomy (POEM) in this challenging clinical scenario, their work highlights a critical and unresolved question: Is routine division of the diverticular septum always necessary, or can treatment be tailored based on individual septum morphology? This editorial synthesizes recent evidence to advocate for a decisive paradigm shift from universal protocols to a precise, morphology-guided strategy.

Esophageal achalasia, the prototypical primary esophageal motility disorder, is characterized by absent peristalsis and failed relaxation of the lower esophageal sphincter (LES), leading to progressive dysphagia, regurgitation, and weight loss[2]. Its pathophysiology involves the selective loss of inhibitory neurons in the myenteric plexus. High-resolution manometry classifies achalasia into three subtypes, with type II demonstrating the most favorable response to interventions like POEM[3]. The global incidence ranges from 0.5 to 1 per 100000 person-years, with a peak in middle age, though pediatric cases are increasingly recognized and may represent a distinct clinical entity[4].

Epiphrenic diverticula (ED), saccular outpouchings within the distal 10 cm of the esophagus, complicate approximately 2%-10% of achalasia cases[5]. These are pulsion diverticula, formed by chronically elevated intraluminal pressure proximal to the non-relaxing LES. Their association with achalasia heightens the symptomatic burden and risk of complications like aspiration. The shared wall between the esophagus and the diverticulum, the septum, can hypertrophy into a prominent muscular band, creating a secondary point of obstruction and perpetuating a cycle of worsening pulsion. While POEM is established for achalasia, its application in the presence of ED creates a specific technical debate: Is routine septotomy always necessary, or can treatment be tailored based on septum morphology? The technical nuances of this dilemma have been further elucidated in the recent work by Hao et al[1], which describes the simultaneous treatment of achalasia with ED.

EVOLUTION OF TREATMENT APPROACHES

The historical standard for achalasia with ED involved open thoracic or Laparoscopic Heller myotomy (LHM) combined with diverticulectomy or diverticulopexy. While offering symptom relief in 70%-90% of cases, these procedures were burdened by significant morbidity: Anastomotic leaks (5%-15%), prolonged hospital stays, and persistent dysphagia in a notable minority[6,7]. Historically, isolated ED without an underlying motility disorder were managed with diverticulectomy alone, often via thoracotomy. However, when associated with achalasia, failure to address the underlying LES obstruction led to high recurrence rates (10%-15%) and persistent symptoms[7,8], underscoring the need for a combined approach addressing both pathologies. LHM with fundoplication improved the safety profile but still faced diverticular recurrence or symptomatic persistence in approximately 10%-15% of cases, necessitating re-intervention[7,8].

The introduction of POEM in 2010 fundamentally altered the landscape[9]. This minimally invasive, incision-less technique uses a submucosal tunnel to perform a myotomy, reporting technical success rates of 95%-100% and clinical success (Eckardt score ≤ 3) in 88%-95% of achalasia patients[10,11]. POEM’s efficacy spans all achalasia subtypes and is associated with shorter operative times and a favorable safety profile compared to LHM[11]. The 2024 SAGES guidelines issued a conditional recommendation endorsing either POEM (with appropriate proton pump inhibitor use) or LHM with fundoplication as first-line options, establishing POEM’s formal equivalence in modern clinical practice[12].

CRITICAL EVALUATION

The study by Hao et al[1] represents an important contribution to the literature on endoscopic management of achalasia with ED. The authors demonstrate technical feasibility of simultaneous treatment using submucosal tunneling techniques, with successful outcomes in their cohort. However, several methodological considerations warrant careful examination.

First, the study's retrospective design and relatively small sample size limit the generalizability of its findings. While the technical success rate is encouraging, the lack of a comparison group receiving alternative approaches (e.g., standard POEM without septotomy) precludes definitive conclusions about the optimal management strategy. Second, the criteria for performing septotomy vs myotomy alone are not clearly defined in their methodology, highlighting the very knowledge gap that our proposed morphology-guided approach seeks to address.

Third, the study’s follow-up duration may be insufficient to fully capture delayed complications, particularly post-POEM gastroesophageal reflux disease (GERD), which can manifest asymptomatically and requires objective pH-impedance monitoring for detection[13,14]. Recent meta-analytic data by Kum et al[15] demonstrate that while early GERD rates are higher after POEM compared to Heller myotomy with fundoplication, this difference diminishes after 12 months, with comparable long-term GERD rates between approaches. This temporal pattern underscores the importance of extended follow-up in studies of POEM for complex achalasia.

Despite these limitations, Hao et al’s work[1] provides valuable proof-of-concept and aligns with the broader evidence supporting POEM for ED. Their experience reinforces the need for standardized protocols for intra-procedural decision-making—precisely the gap that our morphology-guided framework addresses.

THE CHALLENGE: ED-ACHALASIA MANAGEMENT

The success of POEM for pure achalasia introduced a critical dilemma for the ED cohort: Is routine division of the diverticular septum always necessary? Advocates for universal septotomy argue it addresses a potential secondary obstruction. However, this adds complexity and may increase risks of mucosal perforation and extended myotomy length, potentially exacerbating post-procedural GERD[16]. Conversely, proponents of a selective approach contend that the primary pathology is the LES obstruction, and that septotomy should be reserved only for patients with a demonstrably obstructive septum visualized during the procedure.

MORPHOLOGY-GUIDED POEM STRATEGY

This selective, anatomy-driven approach is grounded in growing evidence. A pivotal 2022 meta-analysis by Facciorusso et al[17] analyzed 300 patients with esophageal diverticula treated with POEM. For ED specifically, the pooled technical success rate was 95.1%, with a treatment success rate of 94.2% and a symptom recurrence rate of 0% in the analyzed cohort. This high efficacy, achieved without mandating universal septotomy, underscores that treating the underlying motility disorder is paramount. The strategy is simple: During POEM, the septum is endoscopically assessed. If a prominent, hypertrophied, obstructive muscular band is identified, septotomy is performed. If the diverticular opening is wide and non-obstructive, standard LES myotomy alone is completed. The key endoscopic distinction lies between a prominent, hypertrophied muscular septum that visibly bisects the lumen and requires division, and a wide-mouthed diverticular opening without a significant band, where a standard myotomy suffices. Recent international multicenter data from Shrigiriwar et al[18] further validate this selective approach, demonstrating comparable clinical outcomes between POEM with and without septotomy across diverse centers and operators.

Endoscopic phenotyping: Defining the obstructive septum

While universally validated quantitative criteria (e.g., specific millimeter-based septum width or percentage of luminal occlusion) remain to be established, real-time endoscopic phenotyping relies on distinct morphological features to distinguish obstructive from non-obstructive septa[17,19].

An obstructive muscular septum is characterized endoscopically by: (1) Prominent ridge: A hypertrophied muscular band that projects conspicuously into the esophageal lumen, typically originating from the common wall between the esophagus and the diverticulum; (2) Luminal narrowing: Visible reduction in the cross-sectional area of the true esophageal lumen at the level of the diverticulum, often requiring gentle insufflation to appreciate the dynamic obstruction; (3) Functional partitioning: The septum acts as a secondary point of resistance, sometimes retaining food debris proximally despite an adequately relaxed LES; and (4) Septal height/width ratio: Although not standardized, an obstructive septum typically exhibits a height (depth of protrusion) that exceeds 50% of the adjacent esophageal luminal diameter, creating a palpable resistance during scope passage.

In contrast, a non-obstructive diverticulum demonstrates: (1) Wide mouth: A broad, patulous communication between the esophagus and the diverticular pouch without a significant intervening muscular ridge; and (2) Absence of luminal compromise: The true esophageal lumen remains widely patent, and the diverticulum appears as a passive outpouching rather than an active obstructing structure.

This morphology-driven distinction, while qualitative, has demonstrated clinical utility in guiding selective septotomy and achieving excellent outcomes[17,19]. Future directions include the application of artificial intelligence (AI)-based image analysis to standardize these criteria and reduce operator dependency.

COMPARATIVE CONTEXT AND CLINICAL OUTCOMES

The rationale for a morphology-guided POEM strategy becomes evident when comparing outcomes across treatment modalities. As summarized in Table 1, POEM-based approaches—whether performed with selective septotomy (88.9%-94.2% clinical success) or without septotomy (90.0%-94.2%)—achieve clinical success rates comparable to LHM with diverticulectomy (83.0%-90.0%)[6,17,20]. However, the minimally invasive nature of POEM confers significant advantages, including markedly shorter hospital stays (2.0-3.5 days vs 5-7 days for laparoscopic surgery and 8-10 days for open thoracotomy)[6,19,21].

Table 1 Reported clinical outcomes and parameters for surgical and endoscopic treatments of achalasia with epiphrenic diverticulum.

Treatment modality	Clinical success (%)	Hospital stays (day)	Notable adverse events	Key considerations
POEM with selective septotomy (ED + S)	88.9-94.2[17,19]	2.3-3.5[17]	Mucosal perforation (5%-15%)[17,22]	Minimally invasive; success hinges on accurate septum phenotyping
POEM without septotomy (ED - S)	90.0-94.2[17,19]	2.0-3.0[19]	Mucosal perforation (approximately 10%)[22]	Avoids septotomy-related risks; suitable for non-septated diverticula
Laparoscopic Heller myotomy + diverticulectomy	83.0-90.0[6,20]	5-7[1]	Anastomotic leak (5%-10%), recurrent diverticulum (10%-15%)[7,8]	Gold-standard surgery; allows concurrent fundoplication
Open transthoracic surgery	70.0-85.0[21]	8-10[21]	Pneumonia, leaks, prolonged recovery[21]	High morbidity; reserved for complex redo cases

POEM: Per-oral endoscopic myotomy; ED: Epiphrenic diverticula; S: Septum.

Importantly, the comparable outcomes between POEM with and without septotomy (88.9%-94.2% vs 90.0%-94.2%)[17,19] provide the foundational evidence for a selective approach. If universal septotomy were mandatory, one would expect inferior results when it is omitted. The equivalence of these outcomes instead suggests that septotomy is only necessary when a truly obstructive septum is present. This observation, combined with the potential to avoid septotomy-related complications such as mucosal perforation (5%-15% with septotomy vs approximately 10% without)[17,22], supports the clinical wisdom of a tailored strategy. These are depicted in Table 1.

TECHNICAL CONSIDERATIONS AND LONG-TERM OUTCOMES

Successful implementation requires careful endoscopic assessment. Pre-procedural imaging defines anatomy, but intra-procedural phenotyping is decisive. The principles of submucosal tunneling and secure mucosal closure remain paramount[22]. Long-term data shows durable symptom relief, with low rates of symptomatic recurrence or diverticular progression after POEM[23].

Post-POEM GERD is a well-managed sequela, occurring in 15%-30% of patients, typically responsive to proton pump inhibitors[13]. Long-term monitoring (beyond 6-12 months) is essential, as a substantial portion of post-POEM GERD is asymptomatic and identified only on routine pH-impedance studies[13,14]. For patients with large diverticula, combined POEM and diverticular POEM techniques have been successfully employed, as demonstrated by Wang et al[24] in a recent case report.

CLINICAL IMPLICATIONS AND A PRACTICAL FRAMEWORK

Based on current evidence, we advocate a four-step clinical framework for managing achalasia with epiphrenic diverticulum.

First, comprehensive diagnosis and staging are essential. High-resolution manometry confirms achalasia and identifies its subtype, which influences prognosis[3]. Concurrently, endoscopy and timed barium esophagogram characterize the diverticulum’s size, location, and morphology, providing baseline anatomical context[5].

Second, patient selection should prioritize POEM as a first-line option for most fit patients, given its high efficacy (88%-95%) and favorable safety profile[10-12]. However, surgery (LHM with diverticulectomy) remains relevant for giant diverticula (> 5 cm) or specific anatomical challenges such as dense prior submucosal fibrosis that precludes safe tunneling[6,7].

Third, intra-procedural decision-making represents the cornerstone of the morphology-guided approach as shown in Figure 1. During POEM, real-time endoscopic assessment of the diverticular septum determines the need for septotomy. As detailed in the preceding section, septotomy is performed only when an obstructive septum is identified; otherwise, standard LES myotomy alone suffices. This selective strategy, validated by outcomes from Facciorusso et al[17] and Wessels et al[19], minimizes unnecessary intervention while maintaining efficacy. Even when POEM is unsuccessful or contraindicated, surgical salvage options exist, including thoracoscopic diverticulectomy as reported by Yamashita et al[25] in patients who developed recurrent symptoms after initial endoscopic treatment.

Figure 1 Morphology-guided per-oral endoscopic myotomy strategy for achalasia with epiphrenic diverticulum: Intra-procedural decision algorithm. POEM: Per-oral endoscopic myotomy; PPI: Proton pump inhibitor.

Fourth, post-procedural care includes routine proton pump inhibitor prophylaxis to manage potential gastroesophageal reflux. Long-term monitoring beyond 6-12 months is essential, as a substantial proportion of post-POEM GERD is asymptomatic and detectable only on pH-impedance studies[13,14]. Scheduled follow-up should assess symptom relief (Eckardt score) and screen for reflux complications.

LIMITATIONS AND FUTURE DIRECTIONS

The evidence supporting morphology-guided POEM, while compelling, derives predominantly from retrospective series and meta-analyses. Prospective validation is needed, and we propose specific parameters for future investigation. A multicenter randomized controlled trial comparing selective septotomy against universal septotomy should include key endpoints such as: (1) Clinical success (Eckardt score ≤ 3) at 1, 2, and 5 years; (2) Septotomy-specific complication rates (mucosal perforation, bleeding); (3) Procedure duration; and (4) Post-procedural GERD incidence documented by routine pH-impedance studies. Alternatively, a large prospective registry with standardized septum phenotyping protocols could provide real-world effectiveness data while capturing the morphological variability that makes this condition challenging to study.

A particularly promising direction involves AI applied directly to the central decision point in our proposed strategy. Computer vision models trained on endoscopic images could provide real-time, objective classification of septum morphology during POEM, distinguishing obstructive from non-obstructive septa with greater consistency than human visual assessment alone. This would reduce inter-operator variability—a critical step toward standardizing the selective approach across centers. Early work in esophageal manometry interpretation has demonstrated the feasibility of such AI applications[26,27], and extending these techniques to endoscopic phenotyping represents a logical next step.

The evolution of diagnostic classification systems also has important implications for patient selection. The transition from Chicago Classification v3.0 to v4.0 has resulted in more stringent diagnostic criteria for esophagogastric junction outflow obstruction and ineffective esophageal motility[28,29]. For patients with achalasia and ED, accurate phenotypic classification using both high-resolution manometry and emerging technologies such as functional lumen imaging probe (FLIP) may provide complementary insights into esophageal wall properties that influence treatment outcomes[30]. FLIP can detect structural abnormalities—including hypertrophy or fibrosis—that may not be apparent on manometry alone, potentially identifying patients who might benefit from more extensive myotomy or adjunctive septotomy.

Additional technical refinements on the horizon include automated mucosal closure devices to streamline the procedure and endoscopic fundoplication techniques (e.g., transoral incisionless fundoplication) that may offer more durable GERD control than medical therapy alone. These innovations, combined with a robust evidence base for selective septotomy, will further cement morphology-guided POEM as the standard of care.

CONCLUSION

The management of achalasia with epiphrenic diverticulum has evolved from high-morbidity surgery to refined endoscopic precision. The morphology-guided POEM strategy—using real-time endoscopic anatomy to tailor therapy—effectively challenges the dogma of universal septotomy. It offers a smarter, safer, and equally effective path that embodies personalized care. As technology and prospective data further mature, this approach is poised to become the definitive standard, ensuring optimal outcomes for patients with this complex dual pathology.