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Gastrointest Endosc. 2019 Aug 10. pii: S0016-5107(19)32116-9. doi: 10.1016/j.gie.2019.07.034. [Epub ahead of print]

Peroral endoscopic myotomy: anterior versus posterior approach: a randomized single-blinded clinical trial.

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Division of Gastroenterology and Hepatology, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA.
Endoscopy and Gastroenterology Unit, Edouard Herriot Hospital, Lyon, France.
Endoscopy Department, Gastroenterology Unit, Metropolitan Hospital Athens, Athens, and Medical School, Aristotle University of Thessaloniki, Thessaloniki, Greece.
Division of Upper GI & Metabolic Surgery, Department of Surgery, The Chinese University of Hong Kong, Shatin, Hong Kong.
Department of Gastroenterological Surgery, Fukuoka University Faculty of Medicine, Fukuoka, Japan.
Department of Gastroenterology and Hepatology, Nagazaki University Hospital, Nagazaki, Japan.
Division of General Internal Medicine, Johns Hopkins Medical Institutions, Baltimore, MD, United States.
Bayview Pediatrics, Johns Hopkins University, School of Medicine, Baltimore, Maryland, USA.



Peroral endoscopic myotomy (POEM) has become the mainstay for the treatment of achalasia at many institutions around the world since its inception in 2008. POEM can be performed using either the anterior or posterior approach. The primary aim of this study was to compare the efficacy of the anterior and posterior approaches at 1 year after POEM.


This is a single-blinded, randomized, noninferiority international clinical trial. Eligible participants were adult patients with a confirmed diagnosis of achalasia via high-resolution esophageal manometry. Patients were randomly allocated with a 1:1 ratio to receive POEM with anterior or posterior approach. The primary aim was to compare the rate of clinical success (Eckardt score <3) of anterior and posterior approaches at 1 year.


One hundred fifty patients were randomized to receive either anterior (n = 73) or posterior (n = 77) POEM. One hundred forty-eight patients received the POEM treatment, and 138 patients completed the 1-year follow-up and were included in the primary efficacy analysis. Technical success was achieved in 71 patients (97.3%) in the anterior group versus 77 patients (100%) in the posterior group (P = .23). The median (interquartile range) length of hospital stay after the procedure was 2 (1-3) days for both groups. Adverse events occurred in 15 patients (10%), 8 patients (11%) in the anterior group and 7 patients (9%) in the posterior group (P = .703). Clinical success was achieved in 90% of patients in the anterior group and 89% of patients in the posterior group. Abnormal esophageal acid exposure was detected in 29 of 59 patients (49%) and 25 of 60 patients (42%) in the anterior and posterior groups, respectively (P = .67). GERD questionnaire scores were also not significantly different between the study groups. In both groups, quality of life improved after POEM for all 36-Item Short-Form Health Survey measures and was similar between both groups.


Posterior myotomy during POEM was not inferior to anterior myotomy in terms of efficacy and safety in the treatment of patients with achalasia. (Clinical trial registration number: NCT02454335.).


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