Outcomes of peroral endoscopic myotomy in challenging achalasia patients: a long-term follow-up study.

POEM is safe and effective for challenging achalasia patients. SMF classification grade 2/3 was shown to be an independent risk factor for incomplete tunneling, adverse events, and procedure time ≥ 90 min. For these patients, POEM should be performed by experienced endoscopists, some cases are better served with traditional surgery, such as minimally invasive Heller with Dor fundoplication.