Herein we describe 2 patients in whom a bifid renal pelvis was associated with peristaltic dysfunction and pyelopelvic reflux, causing pyelocaliectasis and flank pain. The patients were improved with pyelopyelostomy. Previous explanations for the yo-yo phenomenon have indicated that there is functional obstruction because of a higher resting pressure in the common stem. The asynchronous peristaltic waves a coincident with a relatively low pressure in the oal fold that acted as a baffle to direct the flow of urine from the lower segment of the bifid pelvis down the ureter. This baffle favored reflux into the upper segment.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.