Is gastroesophageal reflux disease after peroral endoscopic myotomy a clinical problem?

Peroral endoscopic myotomy (POEM) is an innovative treatment for achalasia that was devised by Inoue et al. in 2010 [1]. POEM is now a standard treatment worldwide.

One of the features of POEM is its permanence, which is guaranteed by a complete incision in the lower esophageal sphincter. However, because the lower esophageal sphincter plays a role in preventing reflux from the stomach into the esophagus, it is easy to imagine that a complete incision (destruction) of the sphincter may lead to postoperative reflux.

In the Heller – Dor operation, postoperative gastroesophageal reflux disease (GERD) is prevented by the additional fundoplication. However, because standard POEM involves no additional fundoplication, the discussion of GERD after POEM has continued since POEM was first reported.

“...why does POEM result in less refractory GERD, even though we perform the same muscular incision as for a Heller myotomy and fundoplication is not added? We believe that the key to answering this question is ‘preservation of the phrenoesophageal ligament’ and ‘preservation of the oblique muscle’ in the POEM procedure.”

The article by Nabi et al. in this issue reports the latest results from India regarding GERD after POEM [2]. The authors performed a detailed study of GERD in 209 patients with achalasia who underwent POEM at a single center. They evaluated not only the risk factors for GERD after POEM, but also the response rate to proton pump inhibitors (PPIs) for GERD, which has not been studied previously. The study had a single-center design, but the large number of consecutive patients and the high follow-up rate makes this study highly clinically relevant and worth reading.

Another recent report on GERD after POEM was a multicenter prospective study performed in Japan and published in 2019 [3]. In this study, POEM was performed in 233 patients; 1 year later, erosive esophagitis, symptomatic GERD, and oral PPI use were recognized in 54.2 % (5.6 % with severe esophagitis), 14.7 %, and 21.1 % of the patients, respectively. According to a meta-analysis by Akintoye et al. published in this journal in 2016, GERD after POEM occurred in 13 % of the patients with erosive esophagitis and in 8.5 % of patients with symptomatic GERD [4]. The authors reported that GERD was controlled with PPIs in all patients.

In contrast, some researchers believe that GERD after POEM is a clinical problem. Certainly, the rate of GERD after POEM tends to be higher than that following surgical myotomy with fundoplication [5]. Additionally, the secondary development of Barrett's esophageal adenocarcinoma after POEM cannot be completely ruled out in the long-term (this problem can occur with any treatment method for achalasia, and can only be identified by regular endoscopic follow-up). However, even more than 10 years after the development of POEM, few reports have discussed refractory GERD and Barrett's esophageal adenocarcinoma has never been reported.

So, why does POEM result in less refractory GERD, even though we perform the same muscular incision as for a Heller myotomy and fundoplication is not added? We believe that the key to answering this question is “preservation of the phrenoesophageal ligament” and “preservation of the oblique muscle” in the POEM procedure.

Simic et al. performed a comparative study of postoperative GERD in patients undergoing and not undergoing preservation of the phrenoesophageal ligament in surgical myotomy [6]. Results showed that GERD occurred in 23 % of the patients who underwent Heller myotomy in which the phrenoesophageal ligament was circumferentially detached, even if fundoplication was added. In contrast, the rate of GERD following Heller myotomy with detachment of the phrenoesophageal ligament limited to the anterior wall was approximately 9 %, regardless of additional fundoplication.

The inner circular muscle, the oblique muscles, diaphragmatic crus, and the phrenoesophageal ligament are responsible for the mechanism that prevents reflux from the stomach into the esophagus. The phrenoesophageal ligament is thought to play a role in maintaining an appropriate anatomical positional relationship between the aforementioned structures. Therefore, performing myotomy with complete detachment of the phrenoesophageal ligament likely causes friction between the stabilizing structures, which results in postoperative GERD. Conversely, surgery that preserves the phrenoesophageal ligament is less likely to cause postoperative GERD. This theory is the same in POEM. POEM involves dissecting only the inner circular muscle from the esophageal lumen, and the range is limited to the longitudinal muscle at its widest measurement. Therefore, the phrenoesophageal ligament is almost completely preserved and, similarly to Heller myotomy with preservation of the phrenoesophageal ligament, as described by Simic et al., the theory that the incidence of postoperative GERD is low after POEM is reasonable.

There is also a report that POEM which preserves the oblique muscle can reduce GERD after POEM [7]. In Japan, to reduce the problem of GERD after POEM, preservation of the oblique muscle has been attempted but, because of the high technical difficulty, more time will be required to generate data for this procedure.

Regardless of the level of quality with which POEM is performed, even a small number of refractory GERD cases cannot be ignored, and surgeons performing POEM must prepare clinical responses to these problems. For refractory GERD after POEM, additional surgical fundoplication after POEM is one choice, and Inoue et al. have reported the effectiveness of POEM plus endoscopic fundoplication [8]. In their report, endoscopic myotomy and fundoplication were performed at the same time, but technically endoscopic fundoplication can be performed alone. Considering that refractory GERD after POEM is extremely rare, peroral endoscopic fundoplication (POEF) is recommended only when refractory GERD has occurred after single POEM, rather than POEF being routinely added. Because POEF must be performed on the anterior wall for anatomical reasons, POEM using the posterior approach is preferred for the first POEM.

Given these considerations, we can conclude the following:

• the percentage of patients experiencing GERD after POEM is slightly higher than the percentage with GERD after the Heller–Dor procedure

• most GERD after POEM is mild and can be treated with PPIs

• if PPI-resistant GERD occurs or if long-term PPI therapy must be discontinued, the addition of endoscopic or surgical fundoplication can be considered.

Now that information on GERD after POEM and the discussions surrounding this are being clarified, it is safe to say that GERD after POEM is not a clinical problem.

Publication History

Article published online:
28 July 2020

• References

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