observational study, measurement of efficacy in the cohort.

Achalasia is a motor disorder of the esophagus with a prevalence of 1/10000. Multiple treatments have been proposed, including endoscopic dilation, botulinum toxin injection and surgery using the Heller myotomy technique. These techniques are moderately effective and/or carry the risk of per- and post-procedural complications. POEM has been available since 2008, with 80-90% efficacy and 90% safety, and no serious complications have been reported. In the event of failure of a first POEM, a second POEM, known as "redoPOEM", can be proposed. Several studies show efficacy of between 76% and 96% and a safety of between 80% and 86%, with only one serious adverse event reported, and no deaths. However, the studies carried out involved small numbers of patients, generally around 50, the vast majority in Asian countries. The aim of this study was therefore to evaluate the efficacy and safety of redoPOEM reported in patients from several expert centers in Europe.

Inclusion Criteria:

• adult patient
• diagnosis of achalasia based on clinical criteria according to Eckardt score, manometry, and radiology when available.
• failure after POEM (Eckardt score > or equal to 4 in consultation) treated with a new POEM.
• no active digestive neoplasia.

Exclusion Criteria:

• Technical failure of redoPOEM
• Person not affiliated to a Social Security scheme
• Language barrier preventing fair collection of non-opposition.

patient with achalasia and failure after POEM treated with a new POEM