For the treatment of Achalasia, LHM has been the only surgical therapy. Recently, an endoscopic approach for this therapy has been developed (peroral endoscopic Myotomy POEM). Studies show promising short and mid term results for POEM. At present, POEM is considered a promising new technique with the potential to become a standard achalasia treatment. For this to happen, long-term comparative data with LHM is required. Therefore,the intention for this study is to investigate the short and long-term efficacy of POEM for the treatment of achalasia as it was performed in international centers and compare outcomes with database assessment of LHM.