New endoscopic classification of achalasia for selection of candidates for peroral endoscopic myotomy

AIM:To propose a new endoscopic classification of achalasia for selecting patients appropriate for undergoing peroral endoscopic myotomy(POEM).METHODS:We screened out the data of patients with achalasia examined from October 2000 to September 2011 at our Digestive Endoscopic Center with endoscopic pictures clear enough to reveal the morphology of middle and lower esophagus.After analyzing the correlation between the endoscopic morphology of the esophageal lumen and POEM,we proposed a new endoscopic classification(Ling classification) of achalasia according to three kinds of endoscopically viewed structures:multi-ring structure,crescent-like structure and diverticulum structure.There were three types based on the criteria of Ling classification:type Ⅰ,smooth without multi-ring,crescent-like structure or diverticulum structure;type Ⅱ,with multi-ring or crescent-like structure but without diverticulum structure;and type Ⅲ,with diverticulum structure.Type Ⅱ was classified into three subtypes:Ling Ⅱa,Ling Ⅱb and Ling Ⅱc;and type Ⅲ also had three subtypes:Ling Ⅲl,Ling Ⅲr and Ling Ⅲlr.Two endoscopists made a final decision upon mutual agreement through discussion if their separately recorded characteristics were different.RESULTS:Among the 976 screened patients with achalasia,636 patients with qualified endoscopic pictures were selected for the analysis,including 405 males and 231 females.The average age was 42.7 years,ranging from 6 to 93 years.Type Ⅰ was the most commonly observed type of achalasia,accounting for 64.5%(410/636),and type Ⅲ was the least commonly observed type of achalasia,accounting for 2.8%(18/636).And type Ⅱ accounted for 32.7%(208/636) and subtype of Ling Ⅱa,Ling Ⅱb and Ling Ⅱc accounted for 14.6%(93/636),9.9%(63/636) and 8.2%(52/636),respectively.And subtype of Ling Ⅲl,Ling Ⅲr and Ling Ⅲlr accounted for 0.8%(5/636),0.3%(2/636) and 1.7%(11/636),respectively.CONCLUSION:A new endoscopic classification of achalasia is proposed that might help in determining the