Third Place: Stones Lodge at Three Sites of Anatomic Narrowing in the Ureter: Clinical Fact or Fiction?

Background and Purpose: Throughout the literature, the ureter is described as having three anatomic sites of narrowing at which kidney stones typically become lodged: The ureteropelvic junction (UPJ), the ureteral crossing of the iliac vessels, and the ureterovesical junction (UVJ). There is little evidence to support this notion, however. The purpose of our study is to evaluate whether three peaks in stone distribution corresponding to these anatomic landmarks exist. Methods: We retrospectively reviewed the kidneys-ureters-bladder (KUB) films of 622 patients with solitary ureteral calculi referred for shockwave lithotripsy (SWL). Pretreatment KUB films were used to categorize the location of their ureteral stone relative to 1 of 19 levels referenced to the axial skeleton. CT scans of 74 patients were used to determine the location of the UPJ, ureteral crossing of the iliac vessels, and UVJ relative to the 19 levels on KUB radiography. Histograms were then constructed to plot the distribution of ...