Paradigm shift in esophageal diverticulum treatment: is the peroral endoscopic myotomy (POEM) technique the best method?

In the treatment of esophageal diverticula, surgical resection has traditionally been considered the only curative option. However, we are currently experiencing a paradigm shift from surgical excision to minimally invasive endoscopic treatment methods. An esophageal diverticulum itself is not malignant and the esophageal anatomy presents several challenges to open surgery, particularly when the diverticulum is near the oral orifice. Hence, the direct transoral diverticulectomy method (rigid or flexible endoscopic technique) was developed [1]; the primary purpose of these interventions being to alleviate the patients’ symptoms, so we do not have to focus singularly on achieving complete excision of the diverticulum. Furthermore, based on the current issue of Endoscopy, the submucosal tunneling technique using peroral endoscopic myotomy (POEM), originally developed for achalasia [2], seems to have emerged as a mainstream treatment for esophageal diverticula beyond the previously developed direct endoscopic diverticulectomy.

In this issue of Endoscopy, Maydeo et al. report a promising result using the POEM technique for both Zenker’s diverticulum (Z-POEM) and epiphrenic diverticulum (E-POEM) in their case series of 25 patients [3]. Similarly, in another study in this issue, Li et al. also attempted to address concerns about the safety and efficacy of submucosal tunneling endoscopic septum division (STESD) in eight patients [4]. According to the two aforementioned articles, the advantage of the POEM technique for esophageal diverticula (referred to as D-POEM or STESD in the articles) is that the risk of esophageal perforation, occasionally observed at the bottom of the diverticulum in direct diverticulectomy, can be avoided because the mucosa is left intact without being dissected. Therefore, the POEM technique can be successfully used for both Zenker’s diverticula and epiphrenic diverticula, in which perforation is associated with a more severe risk of mediastinitis. Moreover, the bottom of the diverticulum is clearly identifiable via direct vision; therefore, it can be dissected completely until the esophageal longitudinal muscle fibers are properly exposed, which is expected to prevent symptom persistence or recurrence. Additionally, the endoscopic devices used for endoscopic submucosal dissection (ESD) or POEM are applicable without modifications, whereas a special diverticuloscope is recommended for direct diverticulectomy [5].

“...the submucosal tunneling technique using POEM seems to have emerged as a mainstream treatment for esophageal diverticula beyond the previously developed direct endoscopic diverticulectomy.”

In the case series by Maydeo et al. [3], there were no serious procedural adverse events, technical success was 100 %, and the patients’ symptoms were significantly improved at the 1-year follow-up (clinical success of 86 %). Although the potential advantage of the POEM technique was confirmed as above, the author also indicated that, after Z-POEM, closure of the thin pharyngeal mucosa in the narrow working space is still challenging. Through-the-scope clips with short stems are suggested for this purpose and for minimizing the post-treatment foreign body sensation [6]. Li et al. [4] considered STESD and simultaneous POEM a reasonable treatment option for achalasia as most cases of epiphrenic diverticula occur concomitantly with achalasia or other esophageal motility disorders [7]. They experienced no serious adverse events, a technical success of 88 % (one patient showed a residual diverticulum), and clinical success of 100 % at the 1-year follow-up.

Although identifying the location of the septum submucosally is difficult in cases of esophageal diverticula, Maydeo et al. [3] mentioned that injection of non-diluted indigo carmine into the septal base before the procedure can help the surgeon find the bluish septum in the tunnel. Furthermore, both groups used a needle-type ESD knife for septum division, and a rotatable scissors-type knife may assist in easier septotomy in the narrow working space, particularly in Zenker’s diverticulum [6]. In patients with an epiphrenic diverticulum with achalasia or other esophageal motility disorders, POEM through the gastroesophageal junction may pose a higher risk of gastroesophageal reflux disease after the procedure [8] than laparoscopic myotomy with fundoplication. Therefore, careful decision-making and comparison of the treatments are vital.

The clinical implications of these studies are significant, and the novel submucosal tunneling technique is a breakthrough in the treatment of esophageal diverticula, although there are several technical problems that need to be resolved before it can become a standard technique practiced by all surgeons. The authors of the studies acknowledged that their study sample sizes were rather small and comparison with other techniques was lacking, mainly because of the rarity of esophageal diverticula. This field is still in its infancy, therefore head-to-head comparative studies, particularly randomized controlled trials, with long-term follow-up that assess the efficacy and safety of endoscopic treatment and surgery or compare different endoscopic techniques are necessary to arrive at a definitive conclusion.

• References

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