Peroral endoscopic myotomy (POEM) has recently been introduced as promising alternative to laparoscopic Heller myotomy for patients with idiopathic achalasia. Several technical modifications have been proposed but have not yet been tested in randomized trials.

Objective: To evaluate efficacy and safety of water-jet assisted POEM (WJ) versus the conventional technique (C).

Interventions: Patients with achalasia diagnosed by symptoms, endoscopy and barium swallow eligible for POEM were randomized to either the use of Erbe Hybrid knife (WJ group) or the conventional technique using injection and triangle tip knife interchangeably (C group).

Main outcome measurements: Procedure time in both groups; secondary outcomes were clinical efficacy and safety (bleeding complications, pneumothorax or pleural effusion requiring intervention)

Inclusion Criteria:

• With an Eckardt symptom score ≥ 4
• The diagnosis of achalasia was made on the basis of the absence of peristalsis and on impaired relaxation of the LES on established methods (barium swallow, manometry, esophagogastroduodenoscopy)
• Informed patient consent was obtained

Exclusion Criteria:

• Severe cardiopulmonary disease or other serious disease leading to unacceptable surgical risk
• Pseudoachalasia
• Megaesophagus (diameter of > 7 cm)