Anal sphincter achalasia and ultrashort hirschsprung's disease

Abstract

Internal anal sphincter achalasia is defined as the inability of the internal anal sphincter to relax. The term achalasia is derived from the Greek word χαλααξ (loose, relaxed), in its negative form αχαλασξ (rigid, firm). The concept of anal sphincter achalasia originated with Fenwick [1], who believed a spasm of the internal anal sphincter muscle to be responsible for the development of the so-called idiopathic megarectum. Hurst [2] also recognized that the pathological substrate for the megarectum is situated in the internal anal sphincter, but at the same time demonstrated that the cause of the achalasia is not a spasm, but rather-similar to the situation in the lower esophageal segment-an inability of the sphincter to open. Several histology studies [3-6], electromanometric investigations [7, 8], roentgenological examinations [9], and immunocytochemical analyses [10-12] have shown that various causes can underlie the obstructive behavior of the internal anal sphincter. © 2008 Springer-Verlag.