<prompt> Esophageal manometry is useful all this conditions EXCEPT:AchalasiaDiffuse esophageal spasmTo assess the peristaltic integrity prior to the surgery for GERDMalignancy  <response>: Esophageal manometry, or motility testing, entails positioning a pressure sensing catheter within the esophagus. Manometry is used to diagnose 1. Motility disorders achalasia, diffuse esophageal spasm 2.To assess peristaltic integrity prior to the surgery for reflux disease. Esophageal malignancy is not diagnosed with esophageal manometry. Upper GI endoscopy is the effective method for malignancy and biopsy can be taken. Ref: Harrison, Edition-18,Page-2430 