The efficacy of balloon dilation in achalasia is the result of stretching of the lower esophageal sphincter, not muscular disruption

Abstract

Pneumatic dilation (PD) of the lower esophageal sphincter (LES) in achalasia is a major palliative treatment. It is generally believed, although never substantiated, that therapeutic efficacy of ballooning in achalasia is the result of the disruption and tearing of the muscular layers of the LES. To clarify this issue, we investigated the frequency of muscular disruption at the LES, 24 hours after PD, by employing the endoscopic ultrasound (EUS), in a group of 43 consented patients with achalasia. Between July 2009 and March2012, 51 consecutive adult patients with tentative diagnosis of achalasia, some with recurrence of symptoms after an earlier treatment with balloon dilation, were evaluated and underwent PD, using Rigiflex balloon without major adverse effect. Out of the 51 evaluated, 43 eligible and consenting patients who underwent EUS, 24 hours after PD, using Olympus GF-UE 160 echoendoscope and an Aloka Prosound probe at 7.5 MHZ, are the subjects of this study. The EUS in 43 eligible patients revealed an intact LES in 36 (83.7%), small area of muscular disruption in 5 (11.6%) and small hematoma in 2 patients (4.6%). Our data convincingly demonstrate that the clinical effectiveness of balloon dilation in achalasia is not the result of muscular disruption, but of circumferential stretching of the LES. Our findings on the mechanism of action of PD in achalasia could result in modifying the current method of dilation for a safer procedure, by slowing the rate of inflation and allowing the sphincter to slowly stretch itself to the distending balloon.