The pathophysiology of achalasia is largely unknown, and involves the 
destruction of ganglion cell in the esophageal myenteric plexus. High-resolution 
esophageal manometry is the key investigation. Endoscopic pneumodilatation and 
laparoscopic Heller myotomy have comparable short-term success rates, around 
90%. The main complication after pneumodilatation is esophageal perforation, 
occurring in about 1% of cases. Peroral endoscopic myotomy is a promising 
treatment modality, however with frequent post-procedural gastroesophageal 
reflux.