Peroral endoscopic myotomy: minimally invasive but truly surgical

In this issue of Endoscopy, Zhou’s group from Fudan University, Shanghai, present an update on their experience with peroral endoscopic myotomy (POEM) for achalasia, which now represents the largest, single-institution experience in the world [1]. Their report concentrates on the perioperative complications of POEM and gives us an unparalleled picture of the status of the procedure.

In 2008 when Inoue presented his first small series of clinical POEM [2], the world was amazed and impressed, though a good number (mostly surgeons) were horrified. The concept of deliberately perforating the esophagus for therapy, and then closing it with notoriously insubstantial endoscopic clips was frightening to many at an almost genetic level. Decades of instruction and experience with this organ, so notoriously hard to close and heal, and the devastating consequences of esophageal leaks had reached an almost mythical status. Indeed, as anecdotal small case series started appearing, claiming no failures and no or minimal complications, some were convinced but many others were skeptical of results that were “too good to be true.”

Then in 2012, Zhou’s group published the first in a series of papers specifically confronting the issue of complications from POEM [3]. Their first study represented, even then, one of the larger series yet reported, and was a refreshingly honest and candid report, which showed that POEM was truly a surgical procedure and not a magic cure for achalasia. In this article reporting on their first 119 patients, Zhou reported a shocking complication rate that exceeded 50 %, mostly resulting from the use of air insufflation at the time. In the current report on 1680 patients, the major complication rate is 3.3 %, which is pretty much the industry standard in most larger series. Interestingly, when the early experience with air insufflation is excluded, the complication rate is a modest 1.9 % and continues to slowly drop with ever increasing experience.

This large series, reported by a group with proven honesty in their reporting, is indeed confirmation that POEM is a safe intervention for 98 % of those who undergo it (at least in the hands of experienced practitioners). The fact that some of these complications are quite serious, serves to remind us that the procedure is truly a surgical one – even if only dangerous for 2 % – and that patients need to be informed of this when treatment options are discussed.

Interestingly, the authors did not classify postoperative gastroesophageal reflux (GER) as a complication. With the incidence of GER as high as 47 % in some series [4], GER remains the biggest argument against POEM to date. I am not convinced that the GER criticism has high validity: multiple comparative studies, even some from the same practitioner, have shown that the postoperative GER rate is about the same between POEM and laparoscopic Heller plus fundoplication (about 33 %) [5]. There is no doubt that uncontrolled reflux after esophageal myotomy is undesirable – it can lead to strictures and even Barrett’s esophagus. On the other hand, the symptoms are almost always controlled by medical palliation, and most patients would trade GER for dysphagia any time.

So what is the future for POEM? My impression, as someone who offers all modalities of achalasia palliation, is that data support the technique as first-line therapy for achalasia and achalasia-like motility disorders. The challenge will be to find ways to modify the procedure in order to minimize the rate of reflux, or perhaps to identify a subset of patients who should undergo an endoluminal antireflux procedure at the time of POEM. Regardless, with excellent results such as those reported by Zhou’s group, POEM is here to stay, and the future for expanding indications and refinements of this unique access is excellent.

• References

• 1 Zhang XC, Li QL, Xu MD et al. Major perioperative adverse events of peroral endoscopic myotomy: a systematic 5-year analysis. Endoscopy 2016; 48: 967-978
• 2 Inoue H, Minami H, Kobayashi Y et al. Peroral endoscopic myotomy (POEM) for esophageal achalasia. Endoscopy 2010; 42: 265-271
• 3 Ren Z, Zhong Y, Zhou P et al. Perioperative management and treatment for complications during and after peroral endoscopic myotomy (POEM) for esophageal achalasia (EA) (data from 119 cases). Surg Endosc 2012; 26: 3267-3272
• 4 Swanstrom LL, Kurian A, Dunst CM et al. Long-term outcomes of an endoscopic myotomy for achalasia: the POEM procedure. Ann of Surg 2012; 256: 659-667
• 5 Zhang Y, Wang H, Chen X et al. Per-oral endoscopic myotomy versus laparoscopic Heller myotomy for achalasia: a meta-analysis of nonrandomized comparative studies. Medicine (Baltimore) 2016; 95: e2736