Letter to the Editor: To cut or not to cut-objective metrics in achalasia with septum-less diverticulum

Abstract

We read with great interest the study by Hao et al, published in the recent issue of the World Journal of Gastroenterology, regarding the simultaneous treatment of achalasia and epiphrenic diverticula (ED) via submucosal tunneling. While demonstrating technical proficiency in 31 patients, significant nosological ambiguities and methodological limitations warrant critical scrutiny. Our primary concern lies in the classification of the “ED without septum” (ED - S) cohort. Notably, 60% of patients in the ED - S group had undergone prior interventions, including Heller myotomy or peroral endoscopic myotomy. Conflating iatrogenic “blown-out myotomy” with primary “septum-less” diverticula is problematic, as their pathophysiology and management differ fundamentally. Secondly, the assessment relies heavily on subjective scoring (Eckardt score, gastroesophageal reflux questionnaire). Without paired pre- and post-operative high-resolution manometry or systematic endoscopic follow-up to assess silent reflux, it is difficult to validate whether septotomy provides additional physiologic benefit over myotomy alone, or if the reported safety profile is entirely accurate. Future studies must integrate objective metrics to rigorously validate these endoscopic strategies.

Key Words: Achalasia; Esophageal diverticulum; Per-oral endoscopic myotomy; Blown-out myotomy; Digestive endoscopic tunnel technique

Core Tip: We critically appraise the phenotypic classification proposed by Hao et al, contending that the entity termed “diverticulum without septum” most plausibly represents an iatrogenic blown-out myotomy, given the high prevalence of prior endoscopic interventions in this cohort. Furthermore, we question the asserted necessity of septotomy, as recent multicenter evidence suggests standard myotomy alone is equally effective for epiphrenic diverticula, while mitigating the additional procedural risks. Distinguishing between primary pathology and secondary adverse events, paired with objective functional follow-up, is crucial for selecting the appropriate endoscopic strategy.

TO THE EDITOR

We read with great interest the retrospective study by Hao et al[1], published in the recent issue of the World Journal of Gastroenterology, regarding the simultaneous treatment of achalasia (AC) and epiphrenic diverticula (ED) using submucosal tunneling techniques. While the authors demonstrate commendable technical feasibility with a 100% success rate, we write to express significant concerns regarding the proposed phenotypic classification system, the pathophysiological interpretation of the “septum”, and the lack of objective functional surveillance.

Our primary critique concerns the authors’ classification of diverticula into “ED with septum” (ED + S) and “ED without septum” (ED - S). The authors treat these as anatomical variants of the same disease spectrum. However, a scrutiny of Table from the cited reference[1] reveals a critical confounding variable: 60% of patients in the ED - S group had a history of prior intervention [Heller myotomy or peroral endoscopic myotomy (POEM)], compared to only 4.7% in the ED + S group (P = 0.002). This striking disparity strongly suggests that the ED - S phenotype described is not a primary diverticulum but is highly suggestive of “blown-out myotomy” (BOM). BOM is a distinct, iatrogenic adverse event characterized by a wide-mouthed pseudodiverticulum at the site of a prior myotomy, often resulting from incomplete distal relaxation or residual spasticity[2,3]. The “absence of a septum” in the ED - S group is likely because the muscle layer was previously surgically incised, leaving only a mucosal herniation. To avoid misclassification in future clinical practice, structural differentiation is vital; clinicians should seek imaging or endoscopic evidence of prior myotomy defects, assess the morphological features of the diverticular opening, and utilize high-resolution manometry to identify residual outflow obstruction or distal spasm.

Secondly, the authors assert that diverticular septotomy is necessary for the ED + S group. This conclusion is methodologically unsupported as the study lacks a control group of ED + S patients treated with myotomy alone. The primary driver of symptoms in AC-associated ED is the non-relaxing lower esophageal sphincter (LES), which creates a high-pressure zone that fills the diverticulum[4]. Recent multicenter data including 85 patients demonstrated no significant difference in clinical success or adverse events between POEM with septotomy and POEM without septotomy, reinforcing that effective LES division is the primary therapeutic mechanism[5]. Therefore, the high success rate reported by Hao et al[1] may be solely attributable to the effective LES myotomy. Furthermore, performing an additional septotomy is not benign; it carries potential risks, including increased chances of mucosal perforation, bleeding, tunnel-related complications, and potentially exacerbating the postoperative reflux burden.

Finally, the safety profile regarding gastroesophageal reflux appears optimistically skewed due to subjective assessment. We acknowledge that in routine, real-world clinical practice particularly in retrospective cohorts patients do not universally undergo postoperative potential of hydrogen (pH) monitoring or endoscopy. However, the reliance on symptom-based questionnaires in this specific context reveals a significant logical gap. While the authors report a low symptomatic reflux rate (16.7% in ED + S), the endoscopic data reveals that 66.7% of the ED + S subgroup had esophagitis (Los Angeles grade A/B). This disconnect clearly illustrates that symptom-based questionnaires underestimate “silent reflux” post-POEM, a well-documented phenomenon where esophageal acidification causes mucosal injury without symptom perception due to sensory nerve ablation[6]. Given this high rate of silent mucosal injury, systematic pH monitoring or scheduled endoscopic follow-up is necessary to accurately assess the true long-term safety of this “double-myotomy” approach.

In conclusion, while Hao et al[1] illustrate the versatility of third-space endoscopy, we urge caution in adopting the proposed “septum-based” classification. Future studies must rigorously differentiate between primary diverticula and iatrogenic BOM, as their management strategies and the necessity of septotomy differ fundamentally. Integrating objective functional endpoints will be essential to guide evidence-based therapeutic decisions.