title: Reverse ball valve syndrome: retrograde intussusception of a duodenal polyp.
authors.affiliation: Department of General Surgery, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia.
authors.forename: M D
authors.initials: MD
authors.lastname: Hutton
authors.forename: J M
authors.initials: JM
authors.lastname: Hamdorf
authors.forename: P
authors.initials: P
authors.lastname: Imani
mesh_terms: D018253:Adenoma, Villous / Q000150:complications; D018256:Adenomatous Polyps / Q000150:complications; D000368:Aged; D004378:Duodenal Diseases / Q000209:etiology*; D004379:Duodenal Neoplasms / Q000150:complications*; D005260:Female; D006801:Humans; D007417:Intestinal Polyps / Q000150:complications*; D007443:Intussusception / Q000209:etiology*; D011391:Prolapse; D011708:Pylorus / Q000473:pathology