Endoscopic Pseudo-dilation of Esophagogastric Junction During Peroral Endoscopic Myotomy: (With Video).
Pseudo-dilation of the EGJ is frequently observed after submucosal tunneling during POEM, but it may not indicate successful myotomy.
Where it sits
this study against the rest of the glutathione (gsh) corpusSummary and findings
This study evaluated changes in esophagogastric junction (EGJ) appearance during peroral endoscopic myotomy (POEM) in 65 patients. The phenomenon termed pseudo-dilation was observed, with significant increases in EGJ dilation grades after submucosal tunneling. Most patients showed no change in EJD grade after myotomy.
Abstract
Background and aim During peroral endoscopic myotomy (POEM) for achalasia, endoscopic esophagogastric junction (EGJ) opening is generally considered a sign of successful myotomy. However, in clinical practice, the EGJ may appear to open immediately after submucosal tunneling, even before myotomy is performed. We defined this phenomenon as pseudo-dilation and evaluated changes in EGJ appearance during POEM. Methods This retrospective study included 65 consecutive patients who underwent POEM between February and June 2025. Endoscopic images obtained at three stages-before POEM, after submucosal tunneling, and after myotomy-were evaluated using a three-tier Endoscopic Junctional Dilation (EJD) grade. Differences in EJD grade across procedural stages were analyzed using the Friedman test, with post hoc Wilcoxon signed-rank tests and Bonferroni correction. The Bickenböller statistic was used as a complementary analysis. Two certified endoscopists independently evaluated all images, and interobserver agreement was assessed using Cohen's κ and weighted κ. Results The EJD grade increased significantly after submucosal tunneling compared with before POEM (p < 0.001). A significant difference was observed between the post-tunneling and post-myotomy stages (p = 0.002); however, most patients showed no change in EJD grade, and the overall distribution of grades remained unchanged (p = 0.124). Overall, pseudo-dilation occurred in 95.4% of patients. Interobserver agreement in EJD grade assessment was substantial to perfect across all procedural stages (κ = 0.889; weighted κ = 0.940). Conclusion Pseudo-dilation of the EGJ was commonly observed immediately after submucosal tunneling during POEM. Trial registration N/A.
Background
This paper addresses the clinical phenomenon of pseudo-dilation during POEM for achalasia, which may mislead practitioners regarding the success of the procedure. Prior knowledge indicated that EGJ opening is a sign of successful myotomy, but the timing of this opening has not been clearly defined. Understanding pseudo-dilation is crucial for interpreting procedural outcomes and improving patient management.
Methods
This retrospective study included 65 consecutive patients who underwent POEM from February to June 2025. Endoscopic images were evaluated at three stages: before POEM, after submucosal tunneling, and after myotomy. The primary outcome measure was the Endoscopic Junctional Dilation (EJD) grade, analyzed using the Friedman test and post hoc Wilcoxon signed-rank tests.
Results
The EJD grade increased significantly after submucosal tunneling compared with before POEM (p<0.001). A significant difference was also observed between the post-tunneling and post-myotomy stages (p=0.002), although most patients showed no change in EJD grade after myotomy, and the overall distribution of grades remained unchanged (p=0.124).
Interpretation
The findings suggest that pseudo-dilation is a common occurrence during POEM, which may not reflect the actual success of the procedure. While the statistical significance of the findings is clear, the clinical relevance is uncertain, as most patients did not show a change in EJD grade after myotomy. Limitations include the retrospective nature of the study and the lack of long-term follow-up data.
Key findings
- EJD grade increased significantly after submucosal tunneling compared with before POEM, p<0.001.
- Significant difference between post-tunneling and post-myotomy stages, p=0.002.
- Overall distribution of EJD grades remained unchanged, p=0.124.
- Pseudo-dilation occurred in 95.4% of patients.
- Interobserver agreement in EJD grade assessment was substantial to perfect, κ=0.889; weighted κ=0.940.
Limitations
- retrospective study design
- small sample size of n=65
- no long-term outcome data reported
- single-center study
- no control group